Pedal Powered Boats [Archive] - Boat Design Forums

Guest625101138

07-14-2008, 09:19 PM

Thought it would be a good idea to start a thread on pedal powered boats. Aim is to cover design, development and operation of pedal powered boats.

A little more specific than human powered boats. The hulls often have a lot of similarity with canoes, kayaks, sculls and other rowing boats that rely on arm power or both legs and arms. This thread is essentially aimed at leg powered boats but any contribution welcome.

So as fuel prices go north and we examine the options to reduce oil demand the pedal powered craft offers an interesting alternative to have fun in boats on the water rather than just sitting at a mooring.

A place for lurkers from more specific HPB forums to contribute and provide insight on boating matters at the low power, high efficiency end of the scale.

For starters I have attached a video of me doing a slow pass in Mike Lampi's Cadence on Lake Union near Seattle. I have also attached the performance data from a couple of hours in the boat. At agressive cruising of 150bpm the boat holds around 10kph. Top speed achieved in a sprint is 16.8kph. There was a bit of slop when this was achieved so the aging engine might nudge 17kph in smooth water.

Guest625101138

07-14-2008, 09:53 PM

Here is something that anyone here can have a go at:
http://www.adventuresofgreg.com/PredictContest.html

ASM

07-16-2008, 03:24 AM

Rick

Nice thought, how about utilizing a very small electric motor in the shaft as additional power up or a as a generator when doing slow spped, to power up a battery in order to have that extra umph when you have wind or waves when going home ? (maybe aided by a little solar panel ?) That is also the main purpose of these electric assust bikes we have overhere, to get 70+'s over a bridge.....

Guest625101138

07-16-2008, 03:58 AM

These boats are as many and varied as the mind can contemplate. The things that I have found that suit my purpose are:

1. The most important feature for me is relaxed exercise. I can sit at home on an exercise machine but it is nowhere near as rewarding as being on the water. I could get out on the roads in a recumbent bike but then I have to be constantly alert for traffic. Australia does not have the cycle tracks or wide road verges that some places have.

2. Safety is a feature. I would not use a boat that can sink if swamped or holed. I do not want to be easily rolled in beam seas. I need to be able to easily uncleat pedals if am rolled and be able to right the boat from the water.

3. A boat that performs well is highly desirable. I work hard on efficiency to get the most out of the 1951 vintage engine. It is a bit of a thrill for an old codger to leave fit young men on surfskis and kayaks in my wake. Also fun to have the sailing fleet chase me around a course. It is nice to nudge 18kph in a sprint. Most onlookers cannot believe what they see when you can outpace a small planing dinghy.

4. Weight is the most important feature for ease of handling and also benefits performance. My design objective is to keep boat weight below 20kg. I do not have many frills. Even selective about the amount of water and nibbles I carry.

5. Length up to 24ft is tolerable for car topping and storage. I think 5m would be considerably more practical but going down to this length impairs performance. I am also working on an inflatable version that can be carried as luggage when I travel on business.

So the variations on the theme of pedal boats is endless. After trying it for a few years I am surprised how few people have actually explored the possibilities.

ASM

07-16-2008, 06:37 AM

Rick
I am intrigued by the human pedal powered desigs you made as seen on your website. And you are right, why do people not use this more often as an excersize gadget ? Since I am also interested in bikes and cycling in general (basically I a interested in all that moves from an design/engineering point of view) I came acroos a shft driven bycicle.. would this be a good tool to incorporate into a pedal powered boat ? no chain, no grease, less maintenance and they claim lifetime warranty....

see: http://dekrabike.com/ddrive.htm

Guest625101138

07-16-2008, 07:12 AM

The appendage drag on a pedal boat can be significant. The most efficient arrangement I have developed uses a 1/4" spring steel shaft hanging off a right angle gearbox driving the prop. The shaft does not need any other support providing it is pushing but I normally use a tiny strut to allow me to go in reverse. The attached photo shows the shaft unsupported and this works very well.

I calculate losses down to as little as 0.25W and work to eliminate them.

OK - so the problem with the cycle drive shaft is that you need a large spinner on the prop to shroud the gear. This comes at a significant cost in extra drag. There are other more efficient ways to eliminate the chain.

Mitrpak are sponsoring Greg K. in his various boats and I have been working with them on a purpose built drive leg that incorporates two of their boxes.
This shows the product range and an idea of costs:
http://www.mitrpak.com/

I have also attached a photo showing a drive leg I made that uses a small gearbox underwater and one at the top with a chain reduction. This could be engineered into a simpler arrangement but again highlights the need to keep the underwater bits small.

It is no accident that the fastest pedal powered boat used an air propeller.

Guest625101138

07-16-2008, 07:24 AM

Here are a couple more options for chainless drives. These are used in conjunction with curved shafts driving on the centreline of the hull.

ASM

07-16-2008, 07:36 AM

I see your points... I was just thinking of the shaft + gear system as a deletion of the chain drive (though people claim that the chain is far more efficient (98%)), then, because one can change the angle of the shaft going to the 'wheel' , you can have a down shaft into the drive leg you made and thus having the prop underneath your seat area.... I am thinking in a more 'overall' usage, not top speeds but good speeds for an fittness tool, less maintenance, no grease, userfriendly. Would a 'gearbox' like a bycicle Shimano 8 speed unit be any beneficial by the way on a pedal boat ? And.... one could the incorporate an small electric motor in that hub (250 Watt).... so you have hybrid human power !

ASM

07-16-2008, 07:40 AM

See attached sketch what I mean...

Guest625101138

07-16-2008, 07:50 AM

I looked at the cycle gear drive a while ago and cannot recall what turned me off it. Maybe the ratio at the cranks was not high enough!

One of the things I like is to readily inspect the prop. This means having it beside the hull so it is easily visible or in a lift-out well. These are the two ideas I pursue now.

Generally gearing is not required but if you are pushing strong winds or have had a long hard day there is some advantage in altering gearing. If you spin fast, say around 90rpm with standard cranks, then you work less efficiently aerobically but the leg muscles last longer. You find most long distance cyclist spin around the 90rpm. I personally like 75 to 80rpm but start to taper after about 4 hours due to muscles giving out.

Guest625101138

07-16-2008, 07:53 AM

See attached sketch what I mean...

Every gear and bearing comes at a cost in terms of both dollars and losses. I try to keep the component count low.

kayakn

07-16-2008, 08:50 AM

do a google search for the "decavitator", i am looking forward to building one before the next 4th of july. it goes 19 knots and is powered by a bicycle and an airplane propeller on a catamaran hull.

kerosene

07-16-2008, 11:10 PM

Guest625101138

07-16-2008, 11:48 PM

I like the trailing (somewhat freely) hanging long shaft as in your boat. However - isn't even slight shaft angle a big problem for efficiency loss and vibration with hi aspect props?

It would seem that horizontal shaft would be quite important

The prop is self stabilising it just aligns itself perpendicular to the flow so it is always at peak efficiency and no induced vibration due to misalignment. The shaft curves and is spring steel so there are no losses in the shaft.

The attached video shows an unsupported prop as the boat turns. Watch for the silver flashes of the blades toward the back of the boat. You can see how it moves in and out from the hull to align with the flow. It does this in the vertical direction as well. As soon as the prop starts to turn it lifts to align itself.

I have not found anyone who believes this unless they actually see it. Hard to believe a 1/4" unsupported shaft can swing a 14" prop pushing a 24ft boat at 10 knots.

Leo Lazauskas

07-17-2008, 04:06 PM

Thanks for starting a very interesting thread.

Of course, the design of the hull will depend a lot on the type of race. In a simple endurance race where steady speed is the key, one type of hull will be optimal. In a Tour de France type of event, with long steady periods punctuated by sprints, a different hull might be preferable.

The attached graphs show the predicted squat and resistance of two rowing shells (lightweight men single sculls): total displacement approx 87kgs; length approx 8.0m, draft approx 0.09m.

The resistance coefficients are non-dimensionalised using the 2/3 power of displacement volume: e.g.

C_W = R_W/[1/2 rho U^2 D^(2/3)].

where R_W is the wave resistance (in Newtons), D is the displacement volume (m^3), U is the hull speed (in m/sec), and rho is the density of water (1000 kg/m^3).

The graph of squat shows the movement of the bow and the stern for the two hulls. In the graph, dzb is the change in position of the bow: dzs is the same for the stern. Positive values mean the bow (or stern) rises out of the water.

It can be seen that Hull 2 trims much more than Hull 1 for speeds greater than about 3 m/sec, i.e. the bow rises further out of the water, and the stern digs in deeper.

The effect of squat on the displacement of the two candidate hulls is shown in the bottom plot of Figure 1. (The graph shows the ratio of the dynamic displacement to the static value.)

Here it can be seen that the dynamic displacement of Hull 2 is about 9% greater than the static value at speeds of about 4 m/sec. Therefore, if designing for speeds of around 4 m/sec, it might be worthwhile using a displacement that is a little larger than the static value. Once over the hump speed, the (dynamic) displacement starts decreasing again.

The effect of squat on resistance components is shown in Figure 2. The thin curves are for the hulls in their static attitude. The thick lines are for the hulls in their squatted attitudes.

At speeds of about 4m/sec the differences between predictions of total resistance, with and without squat, are about 3.5%.

Do you have the offsets and principal dimensions of a representative hull that we can use for benchmarking purposes? Or are there just too many different types? (I'm not that interested in the sidehulls of multihulls at the moment. Ideally, they should only come into play when the vessel heels.)

All the best,
Leo.

Guest625101138

07-17-2008, 05:40 PM

Leo Lazauskas

07-18-2008, 05:00 AM

Leo
I have attached the Michlet file I used for my latest hull.

Actual performance is within 2% of my prediction at design speed of 3.3m/s and measuring power at the crank. This is very accurately measured using an SRM power monitor and includes all aspects of the hull, propulsion and rudder.

Will be interested in what you come up with as I am still trying to track down that last 2%. I am still under predicting power. My prop model uses analytical data for lift and drag coefficients and an empirical model for induced drag so it is not ideal - still waiting on some clever person to develop a pure analytical method for prop optimising.

Rick W.

Rick,
My predictions for the V11J hull are attached.

Calculation of dynamic effects requires offsets above the waterline,
so I just added a few extra waterlines to your data.

As you can see, the dynamic resistance, i.e. with squat included, is
a little higher than the drag assuming a static attitude for all speeds.
Around 3.3 m/sec is close to where the hull starts to squat significantly,
so maybe that's where some of the missing 2% is going.

Cheers,
Leo.

Guest625101138

07-18-2008, 05:45 AM

Rick,
My predictions for the V11J hull are attached.

Calculation of dynamic effects requires offsets above the waterline,
so I just added a few extra waterlines to your data.

As you can see, the dynamic resistance, i.e. with squat included, is
a little higher than the drag assuming a static attitude for all speeds.
Around 3.3 m/sec is close to where the hull starts to squat significantly,
so maybe that's where some of the missing 2% is going.

Cheers,
Leo.
Leo
I would appreciate the dynamic ship_output_by_speed.mlt file if you can provide it. I will use it to repredict performance. It looks like you may have found my lost 2%.

Rick W.

Leo Lazauskas

07-18-2008, 08:47 AM

Leo
I would appreciate the dynamic ship_output_by_speed.mlt file if you can provide it. I will use it to repredict performance. It looks like you may have found my lost 2%.

Rick W.

I used "Flotilla" to predict dynamic effects, so the output file is a bit different to Michlet's. I renamed the files as .mlt because this board doesn't accept .csv files.

Have fun!
Leo.

Guest625101138

07-19-2008, 05:29 AM

Leo Lazauskas

07-19-2008, 01:39 PM

Leo
There is something here that I do not understand. The value of drag at 3.3m/s from the files you provided is:
Static 31.45N
Dynamic 32.13N
They make relative sense.

Now when I run my version of Michlet using the V11.mlt file I sent you I get drag of 33.1N at 3.3m/s.

Not sure what is going on here as I would expect my figure to be the same as your static result.

Rick

The differences between the two sets of results are mostly due to the inclusion of boundary layer displacement effects in Michlet. In the results I posted, I used Flotilla and I did not include boundary layer effects.

I'm very pleased that you are getting good results from Michlet, but be a little careful when interpreting predictions. Michlet and Flotilla are only mathematical models and they do not include many real world effects. (If we included a second order effect like squat, shouldn't we also include other second order effects?)

Your Michlet results and my Flotilla predictions used the ITTC line to estimate skin-friction. That line is theoretically very suspect. I prefer Grigson's line, but that would probably give results that under-predict your experiments. Some people might then use a "form factor" on the skin-friction to improve correlations; others might also use a form factor on the wave resistance. I.e., there are a lot of ways to massage data to get better looking agreements with experiments, but that doesn't mean we have found the best model of "reality".

As it happens though, the inclusion of squat moves the results in the right direction for your problem. If you wanted to improve correlations of your Michlet drag predictions, you should multiply them by the ratio of the total resistance with squat to that without squat from my results. That should give you close to the 2% you are missing.

I noticed that your V11J offsets are given to 3 decimal places. For small hulls, it is sometimes better to use 4 decimal places in the offset table.

If I get some time I'll see if I can do a bit better than the V11J. (But first I have to defeat the evil Mongolians and Persians in another project of great importance.)

All the best,
Leo.

Guest625101138

07-19-2008, 06:18 PM

Leo
The testing that is being done on the hull is quite accurate. Speed is repeatable to 0.1kph in calm conditions. We account for everything and have done power testing and comparison on every aspect as the boat will be used for a water record attempt for 24 hour distance.

Every thing has been refined to the limit and then adjusted for practicalities. The last bit of work now will be to add some fairing as he cannot find a windless lake and the wind factor becomes significant as soon as there is any head wind.

Rick W

Squidly-Diddly

07-19-2008, 06:34 PM

Is that what those two across seater 'pedal boats' have?

I'm toying with attaching a long 'whip' to my kayak rudder, so when I work the rudder back and forth the whip should give me some propulsion, and steering at the same time.

That might be handy for kayak fishing-where you want to be able to maneuver a little bit once you got 'fish on!' but still keep both hands free.

Guest625101138

07-19-2008, 07:08 PM

how about a one piece pedal/paddle wheel across a canoe?

Here is one for sale:
http://snorlax.lampi.us/mike/dakanu.html
You need quite large blades to get efficiency and then wind resistance becomes a factor. Also they suffer the same problem as all paddle wheelers in that they do not operate well in rough water.

Rick W.

beppe

07-23-2008, 10:56 AM

Hi ASM
Rick's posts are quite interesting and detailed, as ever.
I'd like to address what he says: "the problem with the cycle drive shaft is that you need a large spinner on the prop to shroud the gear. This comes at a significant cost in extra drag. There are other more efficient ways to eliminate the chain."

I agree. But you don't need a regular cycle chain for a pedal boat drive unit.
I hope it could be interesting to have a look at this drive unit, developed within the Open Waterbike Project (http://www.openwaterbike.com/)
The thickness of the leg is 32 mm and the (external) diameter of the propeller shaft case is 40 mm.
It is a twisted-chain unit, it's very efficient (details at the Open Waterbike website). Lamar, the small firm that developed it, has been testing it for a couple of years and it never broke nor jammed in operation.

Best regards and thanks to Rick for starting the pedal boats thread!

Beppe Carignani
founder, The Open Waterbike Project

Guest625101138

07-23-2008, 07:17 PM

I57

07-24-2008, 02:26 AM

Its seems to me the reason pedal boats have not really taken off is the lack of a reliable cost effective drive unit. I have had problems with chains coming off and prefer gears but gears can be expensive. Maybe with a belt drive cost could be kept down as well as weight, water getting in would not matter as much if all components were plastic and fibreglass. A drive leg that pivots up could be fitted to almost any canoe or kayak, for a receational boat speed is not so important. A lot of the touring canoes are beamy and very stable and I think would be much easier to move with a drive leg than with a paddle.
Having said that I have gone back to the drive in the boat, drive legs worked but boat was slower and the drive leg I made was large and heavy. I have gone about as far as I can with the current boat and this is its fifth configuration.

Guest625101138

07-24-2008, 03:10 AM

Ian
Have you got any pictures of the latest configuration. I think what you have now is close to ideal. How does it perform?

The gearbox is heavy but will take giant force - see attached. This is the application that the box was built for.

I recommended that Greg K use a universal joint as I had had success with them at high rpm. With his boat at 4:1 cadence the joint felt clunky. I set him up a curved shaft when I was over there and he has since got hold of some 1/4" spring steel. He likes it a lot now.

I am going to use the 1/4" shaft on my latest boat. It is a mould off my old boat used as a male plug.

So a possible improvement would be the curved shaft. Maybe rev 6.

Rick W.

I57

07-24-2008, 05:01 AM

No I don't have photos of this latest revision as I am still working on it. Next few weeks it should be ready, the prop is 450mm with a 3:1 gear ratio. It has two universal joints with the thrust being taken at the skeg, I tried the curved shaft in version 2 but the gearing let me down. This layout is about as efficient as I can get and the most reliable, have gone for the fixed skeg so I can reverse easily. Keep you posted.

Guest625101138

07-24-2008, 05:11 AM

Ian
You can use a skeg with the curved shaft it simply avoids the universals.

With the two universals they should be set 90 degrees out of phase and ideally both have the same set angle. This means they will give steady angular velocity at the prop. I think this was the problem with Greg's as it only had one universal.

I hope to have my latest version of V11 finished in a week or two. I am going slow at the moment because the epoxy won't cure. I am having to heat my garage.

Rick

beppe

07-25-2008, 05:58 AM

The prop is self stabilising it just aligns itself perpendicular to the flow so it is always at peak efficiency and no induced vibration due to misalignment. The shaft curves and is spring steel so there are no losses in the shaft.

The attached video shows an unsupported prop as the boat turns. Watch for the silver flashes of the blades toward the back of the boat. You can see how it moves in and out from the hull to align with the flow. It does this in the vertical direction as well. As soon as the prop starts to turn it lifts to align itself.

I have not found anyone who believes this unless they actually see it. Hard to believe a 1/4" unsupported shaft can swing a 14" prop pushing a 24ft boat at 10 knots.

Rick W.

Hi Rick
this is a remarkable achievement! I considered the bended shaft option when I started my first waterbike design, some 15 years ago (after I saw it depicted in the fampus article by Abbott, Brooks and Wilson in the 'Bishop catamaran') but I discarded it believing that vibration and shaft instability could at least reduce the efficiency. We never thought about an unsupported shaft and a self stabilizing prop. Is that a novel idea of yours? This is brilliant!
The only questions I would like to ask are the following:
1. why the prop is not in front? It should increase the efficiency (I don't know how much, but in principle I think it should) because the props works in undisturbed water and also stabilize even better the shaft that is subjet to traction instead of compression. The problem of the vulnerability of the prop is not relevant for competitions or record boats and after a few years of watrbiking it seems not as relevant as is seemed before also cruising boats, too.
2. In cruising boats I would like to have the possibility of inspecting the propeller; btw this is an important feature of the 'kick-up' connection I would like to propose for the Open Waterbike ( a short video of how it works at http://www.openwaterbike.com/architecture/the-architectural-design-group/the-open-waterbike-drive-unit )
This have proved necessary in severla cases, for example for freeing the prop from weeds, checking damage, beach launch etc.)
Could this feature be implemented within the 'free shaft' solution?
Best regards and congratulations for your brilliant invention and implementation.
Giuseppe 'Beppe' Carignani
founder, The Open Waterbike Project

Guest625101138

07-25-2008, 10:42 AM

Beppe
1. The prop needs to push to stabilise. If it pulls it tries to dive and go into pushing motion. Vic Garza was the first to point out the self-stabilising feature of a water prop to me - he was happy to have the information in the public domain. I believe the forces involved are well understood by the aircraft industry. It is not difficult to work out once you know that it actually works.

2. The curved spring steel shaft just allows me to pull it up to inspect the prop. My previous system was a pull cord from the back of the seat attached to a lever that lifts the prop clear of the water. You will see the cord on the lever in the attached video bouncing around. I can easily throw weed off by lifting the prop clear of the water while spinning. My latest arrangement is simply to have the prop beside the seat so I can reach down and clear any fouling. I can just look over the side to check the prop unless the water is terribly murky.

My spring steel shafts are very forgiving they will just bounce over logs and rock. Vic has a video of an electrically driven prop just bouncing from rock-to-rock but still pushing the boat up a shallow creek. He uses fibreglass shafts and more conventional 2-bladed aluminium prop.

Rick W.

beppe

07-28-2008, 01:17 PM

Beppe
My comment to ASM was with regard to this:
http://dekrabike.com/ddrive.htm
I felt the necessary shrouding for this gearbox would be power sapping.

I have issues with twisted chain drives on reliability and efficiency grounds. I regard their appendage drag to be fair if nicely streamlined.

Have you determined the mechanical and hydrodynamic losses of the leg pictured.

Rick W

Hello Rick and colleagues
as an engineer, I agree in principle with your 'issues' about twisted chain arrangements. It is actually an horrible way to use a chain... but after a decade of waterbiking with twisted chain drive legs I must admit that they are remarkably simple, light, efficient and reliable (this is the most surprising thing), while I have withessed double-bevel failures...
Anyway, I would like to propose a completly different approach for solving the question - and not only this one, within The Open Waterbike Project.

What I would like to do is to propse to the community a standard interface for connecting any drive unit to a waterbike, taking advantage of so many years of collective archiectural design. I believe that we can collectively agree to a good architecture, all of them have already been tested by someone, and the advanteges and shortcomings are well known, not by myself but possibly by some other member of the pedal powered boat community.
I set a page of The Open Waterbike Project

http://www.openwaterbike.com/architecture/the-open-waterbike-architecture/the-open-waterbike-dirve-unit-geometric-interface

defining the startup geometrical interface, including the proposed measures and the proposed geometry in a dwg file.

I also enclose the measures at the end of this reply, and the dwg file (attached).

The concept is based on a 'forward' tube, allowing also for a kickup feature, as shown in a short video at

http://www.openwaterbike.com/architecture/the-open-waterbike-architecture/the-open-waterbike-drive-unit

The idea is to accomodate any drive unit, twisted chain, chainless, possibly also your fascinating free shaft.
The Open Waterbike platform can thus work also as a real-world laboratory to assess in a very convincing way the real value of any solution - and of course opening up a market for it.

I look forward to get your opinion and that of the colleagues on these specific issues:
1. is the 'forward tube' a sound concept for an architectural standard for pedal powered boats?
2. do you agree with the measures proposed or do you suggest any variation?

I look forward to your opinion. Best Regards to all

Giuseppe 'Beppe' Carignani
founder, The Open Waterbike Project

Appendix: OW Drive Unit geometric interface - proposal - see also the enclosed dwg file

Fundamental measures

Vertical measures

VCP - crank axle axis to propeller axis: 800 mm [32']

VCT - crank axle axis to forward tube axis: 225 mm [9']

VWT - water level to forward tube axis: 200 mm [8']
VWC – water level to crank axis: 425 mm [17']

VWP - watel level to propeller axis: 375 mm [15']

ETD - Forward tube diameter (external) european: 50 mm

ATD - Forward tube diameter (external) american: 2'

VCS – crank axle axis to seat (lower point): 0 to 100 mm [0 to 4']

Horizontal measures

HCS– pedal axis to seat: ADJ (adjustable from … to …)

Distances
DPT – from crank axle axis to forward tube axis: 275 mm [11']

Derived measures

PFA - from pedal (axis) to forward tube axis: 100 mm [4']

MPD - maximum propeller diameter: 600 mm [14']

(with a 75 mm [3'] clearance form water level to prop tip)

Guest625101138

07-28-2008, 07:35 PM

Guest625101138

07-28-2008, 09:42 PM

Some interesting craft here:
http://www.youtube.com/watch?v=-QjRM-cQpHw

Rick W

beppe

07-29-2008, 03:23 AM

Beppe
I have difficulty with such constraints. The most commercially successful pedal powered boat is the Hobie Mirage. I cannot see how your envelope fits this unit. You have already contemplating constraints that suit your drive leg.

Here is a nice boat that Chris Ostlind designed using Hobie pedal thrusters:
http://www.youtube.com/watch?v=42YYFVYU720
Why not standardise on the Hobie geometry as this is already the most popular? It is clear a nice hull will perform well with these drives. They are simple and robust.

Here is the worlds fastest pedal canoe:
http://www.youtube.com/watch?v=R83c_gKTGY4
How does this fit with your constraint. Why not just standardise on one of the Hydrocycle drives as it is better engineered than the twisted chain:
http://www.hydrocycles.com/learn.php

Rick W

Hi Rick
the Open Waterbike Project is about innovation, and the idea is that modularization could enable collective distributed innovation managed by a community of peers.
I know the crafts you mention, and I agree that they are fine well engineered products; the eclipse drive unit is also very innovative.
But I beleve they make a bad platform for innovation, also because they are monohulls canoes and multihulls seem in principle more suitable (even if we didn't yet decide).
Just to give a couple of examples, some members of the Open Waterbike Project want to work on waterbike innovations as:
- hybrid human-wind powered waterbikes, equipped with a automatic wingsail;
- human powered boats for disabled people.
They don' want to start from scratch, they need a platform.
I believe that the canoe architecture is not a good platform for such developments.
The idea of using a well engineered drive unit is very good, but we still need a standard interface, that is exactly what we (the Open Waterbike community) are trying to do.
I propose the idea of the forward tube because is came out after a lot of architectural testing, and it seems to me the most suited for starting a technical discussion about architectures, but it is just a proposal, and I will be happy to exchange it for a better one or to improve it with the contribution of all the people interested.
Thank you again for your immediate answers to any message; I know you are lukewarm about The Open Waterbike project but i keep you in high esteem as a pedal boat inventor and builder, so I seek yur advice, please be patient... by the way, I believe the pedal boat community needs new debatable issues and I believe the Open Waterbike attempt is a good one!
best regards to you and all the colleagues
Beppe

Guest625101138

07-29-2008, 04:02 AM

Guest625101138

07-29-2008, 04:29 AM

Here are some nice Hobies:
http://www.youtube.com/watch?v=Tcuh4cU90QI&feature=related

Rick W.

Tiny Turnip

07-29-2008, 07:43 PM

I wholeheartedly support Rick here - whereas I am hugely enthusiastic about human power, boats, and learning, I struggle with constraining invention! It may very well be that it is worth developing parameters for deep, linear strands of research, especially for honing 'best performance' data, however, learning environments (such as this forum) which encourage discussion, transfer of technologies across disciplines, and exploration are most likely to lead to real innovation, and development needs *both* types of learning. I would question that pursuing the fastest possible pedal boat is a particularly useful goal in itself, (if you just want to go fast on the water, there are other much better ways to do it without damaging the environment) though it may well lead to innovations or technology transfer in, say, propellor design, high efficiency transmission, or other areas particular to the field, which are of great importance. My point is that there are other potential developments of great importance that setting speed as the *only* parameter rules out.

I am perhaps an hour (or three, including varnish!) short of completing my pedal powered project, which has benefitted hugely from Rick's generous contributions of time and expertise through the relatively unstructured learning environment of this forum.

This will not be the fastest pedal powered boat, but should be reasonably quick. By combining a number of existing components, I hope to have assembled a boat based on Dart18 hulls, crossmembers and rudders, with recon seacycle sealed pedal units and props, trice recumbent seats, and a bit of ply and timber butchery. It should carry 4 adults, allow swimming, fishing, lobster potting, and the erection of a two person pup tent on the deck for camping, in a total assembly time of 12 hours so far, for about £1500 uk pounds stirling, including road trailer (and still useable alternative Dart rig!). I am quite excited about what I hope will be a pretty practical and useable boat, for not too much money, and a few low skill (mine) hours of woodwork and assembly. But it won't fullfil any of the open waterbike criteria.

Guest625101138

07-29-2008, 08:07 PM

TT
I am looking forward to the report and photos from the first shakedown cruise.

Every pedal boat I have made I have improved substantially after the first trial. I am hoping my next one is close to the money first time out as it is just a lighter version of the last one with a bit more innovation. With some effort and warm weather for painting this week I might have it in the water on Sunday.

Rick W.

Guest625101138

07-29-2008, 08:24 PM

TT
I just refreshed my memory on your project.

One of the things I suggested was engine calibration. Have you had a go at this?

The more you get into pedal boating the more interested you get in the engine performance. I have found the first 10 minutes does not mean much. You need to be at it for about 1 hour before you find out if it is set up right and what the cruising speed will be.

Rick W.

Fanie

07-29-2008, 11:39 PM

The more you get into pedal boating the more interested you get in the engine performance.
He he... Rick, I have found that to be very true. Finally at my advance age :rolleyes: I'm not much interested in paddling, just about any non-physical propulsion tickles my fancy :D

You have too much energy. I save mine for important things... like fishing.

Sorry, just couldn't resist. I find the drive unit quite interesting. Would like to see what you have found to be the most efficient.

On a shaft with a wind vein it may well be wind driven.

tinhorn

07-30-2008, 12:18 AM

I'm looking forward to seeing both of these new boats! I'm fascinated with pedal power, too, but haven't been able to even begin work on my own projects. Thanks for sharing yours.

beppe

07-30-2008, 04:49 AM

Hello TT
i agree with most of your post, especially about the usefulness of this fourm as a 'learning environment', but it seems you are not so well informed about The Open Waterbike project. Please let me set a few records straight:

You wrote: 'But it won't fullfil any of the open waterbike criteria.[/QUOTE]'

Oh I bet it fulfills most of the Open Waterbike requirements (http://www.openwaterbike.com/architecture)
You aren't trying to build an unsafe, dangerous, unfriendly an inefficient boat, are you?

You wrote: 'I struggle with constraining invention!'
Me, too.
We (the Open Waterbike community) are NOT trying to constrain invention. We are NOT trying to provide people with constraints, we are trying to provide them with useful reusable components with which to build and innovate pedal powered boats in an easier way, sparing the time spent in adapting unfit components. This requires interfaces, not constraints. The availability of a platform of reusable modular componenst could be the gateway to innovation, as it was in so many cases.

The Open Waterbike has nothing to do with constraints. If you have a look at the dwg file I posted earlier you will see what I mean.

The Open Waterbike project is a bold attempt, maybe an impossible one, but it is aimed at supporting and improving human powered boating, as we all want. Strong informed criticism is always welcome and helps improving the project (this is why I appreciate so much Rick's contributions) while an misinformed dismissive attitude could contribute to undermine the project in these early phases. Please do not do that.

I wish you success to your project and look forward to learning more from this forum.

Best regards and good luck!
Beppe

beppe

07-30-2008, 05:21 AM

Beppe
My first sticking point is the word waterbike. I suggest you think about it. It is predominantly European terminology that just does not make sense. What you have is in no way a bike that goes on water - a bike by definition has two wheels. It is first and foremost a boat.

If you call it a human powered boat then it brings in all other forms of propulsion. Essentially the architecture you are aiming to derive is based on leg muscle propulsion. So pedal powered boat seems the most apt description.

A mono hull is far superior to a catamaran from a drag perspective. The catamaran requires 39% more power for the same speed. This is a significant penalty for the catamaran. My view is that a stabilised monohull has other advantages as well. Performance advantage being significant. But it is easier to transport and, in fact, two boats can be placed on a single car.

I use my catamaran for tinkering and experimental work but it does not provide the same level of satisfaction I get from powering along in my two preferred stabilised monos. The latter is no pain to transport and launch. No set up required; in the water and away I go.

Rick W.

Dear Rick
thank you for raising the monohull-multihull dilemma, this is the
first architectural question the Open Waterbike community should
address (I already proposed it,
http://www.openwaterbike.com/architecture/the-open-waterbike-architecture/architectural-discussion).
There are so many facets in your mail that I'll try to address only
the most important of them in this - I suspect I'm writing too long
posts, annoying the colleagues...
I don't like the catamaran architecture, BTW it has a bad image being connected in common views with low-performance beach watercrafts, so I like very much the idea of a monohull Open Waterbike, but I see a number of issues I believe are difficult to solve.

I agree, a monohull has lesser drag and is potentially much efficient.
This is a toll we should pay if we embrace the multihull architecture.
Could you please give the source of the figure (39%) you mentioned? It seems
high and doesn't add up well with other less direct measures I have (i'll give the details in a next post) but I know your data are usually accurate.

Also, in principle it is easier to transport a monohull, but I believe
this can be solved, for example with a clever and fast assembly
system; moving two lighter hulls could even be better for some people
than loading on a car one heavier hull and you can possibly transport
four narrower hulls on a car. You didn't mention it, but multihulls
are also usually more complicated and therefore more expensive one more important point in favour of your view.

So, I agree that until now a monohull has a distinctive advantage.

Now coming to a few problems to solve and issues to address if we want to adopt a monohull architecture,

The major problems to solve:

1. Addressing the Open Waterbike requirements
(http://www.openwaterbike.com/architecture/the-open-waterbike-requirements),
in particular safety and user friendliness even for unexperienced
riders.
I believe the enclosed image can explain the concept. You can see a well dressed lady pedalling at five knots (BTW the speed limit in Venice, Italy) through the narrow channels, no training, no fear, no wet shoes.
The Open Waterbike is intended to address the needs of common people, not only watersports enthusiasts.
Question: could these requirements be addressed with a canoe architecture?
What if a pedal powered canoe capisizes, it could happen even in calm water to an unexperienced rider?

Two more subtler points are:
2. suitability as a platform for developing modular innovation
3. one-to-one module-function modularization

I'll address them in future posts, if someone is interested.
I'll also try to answer later to two interesting points of you post ('waterbike' name and hybrid propulsion), I believe I have reached the maximum acceptable length of a post...

Thank you again for your critical but useful contribution to the Open Waterbike project, Rick

Best regards
Beppe

plankton

07-30-2008, 11:38 AM

Has any one made a paddle-wheel vessel ? I was always led to believe that they were efficient at transferring energy into movement and perhaps it could be possible to design a hull utilizing the wheel quarters as hull extensions. I would assume the drive mechanism would have to be geared for paddle-wheels.

Rick, is your propellor on that free shaft of variable pitch ?

Guest625101138

07-30-2008, 05:27 PM

Paddlewheels -
http://www.youtube.com/watch?v=-QjRM-cQpHw

Prop - fixed pitch.

Rick

Tiny Turnip

07-30-2008, 05:58 PM

Beppe - I'm sorry for the slightly abrasive tone of my last post - it was at the end of a long and very frustrating day - I really shouldn't have posted in that frame of mind - I do apologise.

Guest625101138

07-30-2008, 06:16 PM

........
Could you please give the source of the figure (39%) you mentioned? ......
Best regards
Beppe

This is straight from Godzilla optimisations for unconstrained hulls having identical displacement and design speed.

Rick W

Tiny Turnip

07-30-2008, 07:11 PM

Rick, I haven't got to the engine calibration yet - though my other engines and I have discussed it. I would be very interested to see what outputs we can sustain, and how this would affect prop design. Possibly more of an issue is my capacity to fabricate custom propellors. I do have a tame stainless steel specialist though, so I could experiment with asking them to weld up the twisted blade 'blanks' and then grinding the foil profile as you have suggested elsewhere.
I suspect that the most common engine combination will have a big power difference, as one of them is a keen club cyclist, who does audaxes regularly, and the other is me, who isn't and doesn't. Does that raise the interesting possibility of 2 different prop designs tailored for the different capabilities of the engines?

We are aiming for initial testing that the thing works and doesn't fall apart in a local reservoir, and then shakedown and serious testing on Windermere, which gives us a 10.5 mile run each way. This will probably be in September.
I am shortly going on holiday to camp on a Scottish island (Gigha) and it is sorely tempting to take the pedal boat with me, but I think in sense, an untried vessel without a dedicated second pilot, in Scottish coastal waters may not be a recipe for a happy start. Also very difficult to get bits!

In the mean time, here are some workshop photos. The black anodised yoke holding the seacycle units is a standard sea cycle unit, from Meyers boat, as there is some degree of accuracy needed in the fit. The angle brackets in stainless steel which join the yokes to the spars I had made up locally. The spars are packed out to fit with oak. PUR adhesive everywhere.

Guest625101138

07-30-2008, 07:33 PM

TT
I will be very surprised if you are not pleased with its performance. I think there will be a lot of onlookers impressed with the way it goes. You will get questions about how much it cost and where can I get one.

There are some refinements like smaller rudders but these sort of boats are about chasing down detail. Also getting fitter in the process.

Typically a trained rider likes to spin faster so you might find some imbalance because the props will be low slip. If you intend to operate with a single rider at times you might really like a second prop.

With two up you might find the speed of spinning is uncomfortably fast for you if the other rider is good.

One thing I recommend if you intend to go long distances are cleats on the pedals. It is surprising how much more comfortable it is if your feet are locked in. I use standard bicycle shoes. Others just use open sandals with a cleat.

Without weight on the stern you might find it operates a bit bow down but trim should be good with weight on the platform.

Rick W

Tiny Turnip

07-30-2008, 07:43 PM

and a few more. The longitudinal spars are held to the Dart cross members with u bolts. The 3 deck panels bolt down to the spars via captive nuts in the little blocks screwed and PURed to the side of the spars. The whole thing is designed to demount and travel on the original trailer. The red rope is my steering arrangement, to avoid the Dart's original great long tiller sweeping any passengers off the deck. The seat subframes are the final bit to finish. They will have a very simple fore-aft adjustment by clamping the seat base (not in the photos) to the deck through a small cut out, with two small G cramps. The seats themselves are a bit of an extravagance - from Trice engineering for their recumbants, but I thought a good comfortable position was pretty important for long cruises. I will fit new pedals with spds on one side, but the manufacturer of the unit has threadlocked the existing pedals in, so it is a bit of a tough job! I will also put adjustable webbing loops round the front crossmember, as hand restraints to pull on when pedalling hard.

Tiny Turnip

07-30-2008, 07:53 PM

Thanks for your thoughts, Rick. just crossed in the posting - I'm on an ancient PC and dial-up so it takes a while to post pictures. I have been worried about the two up weight distribution being a bit too far forward, but I couldn't see a way round it without fairly major complexity, and I needed a quick and dirty build! I did think too, that a lot of the fun will be messing about with 4 up, or the camping gear, and we could stash that well back.
I really appreciate your encouragement - its a great boost!

Guest625101138

07-30-2008, 07:57 PM

Seat is next to the most important part of the boat; engine being #1!

If you head in the other direction on next holidays you might be able to arrange to meet Clemens mid Channel. He seems to get a lot of satisfaction from his Seacycle in France. You should have a better top end speed.

Rick W.

Tiny Turnip

07-30-2008, 08:09 PM

Now, that sounds like a plan! Though Paul (the fit engine) is working on me to cross the Minch - to the outer Hebrides...

beppe

07-31-2008, 02:23 AM

Beppe - I'm sorry for the slightly abrasive tone of my last post - it was at the end of a long and very frustrating day - I really shouldn't have posted in that frame of mind - I do apologise.

TT, thank you, apologies wholeheartedly accepted.
Maybe I am a bit too sensitive about that project, but it is something in which I believe, you understand...
I saw the photos of your watercraft you posted, TT, and let me say it seems a fine work. Did you build the drive units? I saw that the connection with the boat allows a kick-up action: how does it work? Could you post a photographic detail?
Greetings from Italy!
Beppe

I57

07-31-2008, 02:53 AM

beppe

07-31-2008, 10:05 AM

Beppe

Here is an idea for your open waterbike project. The boat I am proposing is a blend of monohull and catamaran, you get the speed and stability of a catamaran with the single dry deck space of a canoe. The boat would be 4m - 5m long and approx. 1m beam. Construction would be moulded plastic with fixing point for drive leg, the boat would be complete with rudders and moulded seat. The only setup would be putting the drive in place, of course details and final dimensions would need to be worked out but it could be done. This would be a recreational boat that can be easily transported and almost anyone could use it.
The .dwg file you posted I am unable to open, what is the best program to view it on?

Ian Cassell

Thank you Ian
I have put this proposal of yours in the Open Waterbike website, open to comments form visitors, and hope someone will comment in this forum too.
Sorry for the problems with the .dwg file, you need Autocad or another cad program to open and modify it.

I'd like to share drawings in an easier way. Colleagues, any suggestion?

Beppe

johnnyld_3

07-31-2008, 02:16 PM

I am brand new to HPB and have read a lot the past 2 days. I (and a handful of co-workers) am building a 2 hull catamarnan/pontoon type for a local race...more of a recreational event. We will have 6 men powering the boat. It is in the first stage of planning (the race is mid-Sept), but will be about 16' long and each pontoon about 2 to 2.5' wide made from solid foam. We are representing a cement company, so we are going to cover the foam with concrete. The two hulls joined by aluminum framing and covered with plywood. There will be 3 men on each of 2 props. I am estimating the total weight of the boat and "engines" to be around 2000 lbs...give or take a 200 lbs. It will be a beast, but a fun beast.
My question is this...What props do I use? We will be able to fabricate a two blade prop such as the 16" MA409 profile or E193, but will they work for us? I tried to use JavaProp with no success. I plead ignorance. There is a lot terminoligy I do not know yet. Any help is greatly appreciated. - Johnny

Tiny Turnip

07-31-2008, 05:28 PM

Hi Beppe

the drive units are seacycle units from Meyers boat

http://www.meyersboat.com/seacycle/

They have pretty comprehensive online drawings in the parts and manual section.

I bought factory second (cosmetic) units. They are nice and robust, and run in an oil bath.

The kickup is very simple, and is latched by a little spring loaded brass button, which keeps the unit down, or up. the spring pressure keeping the button out is adjustable.

Tiny Turnip

07-31-2008, 05:33 PM

Tiny Turnip

07-31-2008, 05:53 PM

This is the Winsome, a production pedal launch, from Swallow boats (http://www.swallowboats.co.uk/content/view/94/104/)

Length: 5.3m (17ft 6ins), Beam: 1.1m (3 ft 7ins), Weight (fully laden): 72kg (160 lbs), Weight (stripped for transport): 55 kg (120 lbs), Maximum speed: 7mph, Cruising speed: 4mph.

beppe

07-31-2008, 10:35 PM

Beppe, it always used to be possible to export .dwg drawings from Autocad as a .jpg, which would then be universally viewable. I can't remember whether this is through the 'export' dialogue, (on the file menu) or as a screen dump, and its 12 years since I used Autocad in anger, so I'm pretty rusty! I'm sure it is much more user friendly now.
BTW, in your dimension notation, 12' would denote 12 feet as an imperial measurement: 12 inches would be 12".

Adrian

Thank you Adrian! Gross mistake, I'm ashamed. I just corrected it...
Thank you also for the conversion tips. I actually tried a converter downloaded from the web with bad results, my oldish version of autocad doesn't export to jpg, but the screen dump (from the Operating System) gives an acceptable jpg. I didn't think of it. Ashamed again ;-) I post the Open Waterbike proposal for the connection of a drive unit to a forward tube for Ian and other interested colleagues.
This solves half of my sharing problem, the other half being the possibility of modifying the drawing and giving it back to the community. Maybe we need a open source or a free cad software. Is there any commonly used among the members of this forum?
Beppe

I57

08-01-2008, 09:12 PM

beppe

08-02-2008, 01:21 AM

Thought it would be a good idea to start a thread on pedal powered boats. Aim is to cover design, development and operation of pedal powered boats...

Rick W.

The monohull/multihull dilemma, as pointed out by Rick in another post, is possibly the most important architectural choice in designin a Pedal Powered Boat.
It is even more important for an Open Pedal Powered Boat, since it is is an architectural choice that involves modularity and reusability of components.

Could you please give your opinion on this issue, colleagues?

I set up the problem at

http://www.openwaterbike.com/architecture/the-open-waterbike-architecture/architectural-discussion

including Rick's opinion to start up the discussion.

Thank you
Beppe

beppe

08-02-2008, 01:50 AM

Beppe

I have Autocad LT but it is a 1997 version which is why it couldn't read yours.
I do a screen dump and send pic as a .jpg file as this way everyone can see the drawing. There are so many CAD programs and people tend to use the ones they are used to that it opens up another can of worms ( a bit like the open waterbike project ). Until you need working drawings .jpg files are ok.

Ian Cassell

Hi Ian
I enclose a 1997 Autocad LT version of the file, I hope you can open it.

I would like to evaluate different kinds of drive unit mountings in order to assess how they can fit an Open Pedal Powered Boat. I'm trying to set up this at:

http://www.openwaterbike.com/architecture/the-open-waterbike-architecture/the-open-waterbike-drive-unit

Beppe

Tiny Turnip

08-02-2008, 05:52 AM

Maybe we need a open source or a free cad software.

Beppe, there is Sketchup, which is available free from Google

http://sketchup.google.com/product/features.html

It is a very easy to learn and use modeller, with lots of tricks up its sleeve, and can merrily skin 3d surfaces between profiles (it includes a terrain modeller which can generate from contours so should be able to handle hull shapes from lines.) It is fine for straightforward dimensioned 2d cad. It is not designed for naval architecture, and so won't generate any performance predictions - it is primarily aimed at architectural design. The free version will import .dxf, .dwg etc, but only export .jpg and a couple of others. There is no reason why users shouldn't modify and exchange drawings in the native sketchup format, however.

Tiny Turnip

08-02-2008, 06:35 AM

I57

08-03-2008, 04:31 AM

Beppe
Thanks for the drawing, I was able to open it in my version of Autocad.
With the dimensions you show for example 175 (7), what does the number in the brackets mean?

Ian Cassell

beppe

08-03-2008, 06:21 AM

Beppe
Thanks for the drawing, I was able to open it in my version of Autocad.
With the dimensions you show for example 175 (7), what does the number in the brackets mean?

Ian Cassell

Hi Ian
imeasures in this drawing are metric (millimeters, mm); the number in the brackets is the same measure in inches, crudely converted as 1 inch=25 mm.
Beppe

I57

08-03-2008, 09:56 AM

Guest625101138

08-03-2008, 05:21 PM

Ian
There are studies around on this but I do not think it matters a lot. The lower you can get then there are advantages from stability and windage. If you have your heart placed lower than the top of the crank you will find you get numb feet. My understanding on this is that the blood drains out because your feet are not intended to be higher than the pump.

Your body tend to adjust to the position the more you use that position. You train muscles to suit.

The most efficient cadence is around 65rpm. Endurance cyclist work higher than this to avoid muscle tiredness. So there is a trade-off between biomechanical efficiency and muscle soreness.

There is data that shows recumbent position has almost identical efficiency to upright position providing you are using cleats.

Rick W

Guest625101138

08-03-2008, 07:45 PM

Here is a nice pedal propulsion system.

Rick W.

tinhorn

08-03-2008, 11:51 PM

Here is a nice pedal propulsion system.

Looks clean, but I can't figure out the cable routing.

Guest625101138

08-04-2008, 12:13 AM

Looks clean, but I can't figure out the cable routing.

I have attached a view of the test frame I built. It is reeved with green nylon cord so you can follow the path. This shows the 3" drums Warren had made up for me.

There is also a video showing a test load being spun up. This was a little fan rotor geared up to give me some load. The chain and gearbox were done very quickly to get the load to something like I would have in a boat.

Understanding the reeving is possibly the closest thing you could get to rocket science. This is one of those things that are hard to believe until you see it. The guts of it is two $12 roller clutches.

Rick

beppe

08-04-2008, 06:45 AM

Does anyone know the best position for the seat in relation to the pedals. Is there an optimum angle for the seat backrest, I have mine so that I can adjust it but am wondering if I am leaning too far back. With the seat height in relation to the axis of the pedal crank how low or high should this be. The open waterbike shows the bottom of the seat at the same level as the crank axis but a lot of boats have the seat much lower.

Ian Cassell

Hi Ian
In our cat that won the World Championship (long distance regatta, singles) back in 1999 we set the seat height 50 mm (2") over the crank axis level, according with Jake Free's advice for sustained (several hours) efforts.
Since then we were satisfied with this arrangement, so I proposed 0 to 100 mm as an optimal standard. I know many pedal powered boats have the seat level lower than the crank axis (as most of the recumbent bicycles, including mine) but i believe it is a trade-off between biker comfort and other issues (like the position of the center of gravity of the craft); if the genertal architecture allows for that, I'd follow Jake Free's advice: seat at the same level of the crank axis or higher. But I look forward to other experiences...
I remember that correct angles for the seat are discussed in 'Huma Powered Vehicles", the book by Allen at al, but I haven't it here (I'm in holiday ;-) so I can't verify. I believe it should be adjustable in a wide range.
Beppe

alexlebrit

08-04-2008, 12:46 PM

Rick thanks for that, after a few scetches it all made sense.

I'd wondered about fixing the "drive cables" to the hull aft of the swing arm and not the swing arm as in your design, and then looping them forward over pulleys fitted to the swing arms and then back to the drive.

This would mean for every swing-stroke you'd pull twice as much "drive cable". Yes, the effort needed would be greater, but I wondered if the potential increase in prop speed, possible decrease in prop size and/or possible reduction in swing arm length would more than make up for this.

Also can I find roller clutches anywhere in deepest darkest Brittany? Nope (mind you I don't know what one is in French) so I'm considering using single speed bike freewheels in their place and running bike chain over them. In my mind I could see that a single piece of chain could be looped round one, then over a jockey-wheel and then looped over the second. Yes
there'd be slight twist in the chain, but not a great deal and I think it'd handle it. Then this would be attached to the "drive cable" using cable eyes to attach to the chain link pin as in the existing system. And of course it means no slip and no reeving - hoorah.

Now, I await the potential problems.

Alex

PS. Also posted this on the hpv boats mailing list, just in case you're thinking, I'm a mad-multi-poster.

Guest625101138

08-04-2008, 05:22 PM

Both Warren and I got the prop rpm we wanted with single ratio of the pulleys. His prop is 300mm
and mine was a bit over 400mm. Going to a smaller higher speed prop would almost certainly educe efficiency.

The chain sprocket will work and there is/was a swing arm bike available using freewheeling sprockets. The feature of the roller clutches is that the backlash is negligible. They do not rely on pawls but just friction on a hard shaft.

Timken manufactured the ones I have:
http://www.timken.com/en-us/products/bearings/productlist/roller/needle/Pages/DrawnCupRoller.aspx

Rick

alexlebrit

08-05-2008, 12:47 PM

Whilst effeciency is always good, I do like the idea of a slightly smaller prop, it's just less dangling under the boat potentially getting damaged. But, it's not the most important thing in the world.

What I was thinking though is that doubling the cable pull for each "swing" would also mean I could halve the crank length, I've never been keen on the feeling of a top pivot crank, I don't know why but my feet don't seem to like it. You've mentioned previously that you have a 400mm crank with the pedals at 300mm, which is a bit long to have bottom mounted unless the seat is mounted high. If I can double the cable pull for each stroke then I could for instance have ordinary bike cranks, in fact it would even be possible to have a complete bicycle crankset witht he pulleys mounted outboard on the pedals, and consequently have a full rotary motion at the crank.

Guest625101138

08-05-2008, 09:07 PM

Alex
I did the mechanical analysis of the geometry I ended up with. One of the benefits with the top mounted pivot is that the feet lift toward at the end of the stroke so there is some natural harmonic motion through gravity going on. If you set the bottom pivot low then you have to rely on solely muscle fibre to provide the restoring force. My personal view on this is that it will cause a cramping of the legs into the gut.

I have talked to one Hobie mirage owner about this and he has noticed it and was actually thinking of biasing the pedals forward with a spring to improve the action. I do not know if he tried it.

I did no-load comparisons with my swing arm system and it was more biomechanically efficient than a simple crank. It is a very nice motion.

All that said, other things are worth trying. The swing arm cycle used very close to conventional cranks with the crank arm operating around horizontal.
http://www.classicrendezvous.com/images/bike%20shops/First_Flight/Alenax_closeup.JPG

Rick

RVELL

08-07-2008, 01:12 AM

FYI, Here are a couple of human powered videos that might be of interest:

http://www.youtube.com/watch?v=sdBSaAZdHio

http://www.youtube.com/watch?v=9iRnSHIrCa0

While on Youtube.com search for IHSIHS for more hydrofoil videos.

Ray Vellinga

beppe

08-07-2008, 05:31 AM

As I am going away on holiday today, I thought I would temporarily leave you with an artist's impression of my boats first trial.
Taken from 'How Tom beat Captain Najork and his hired sportsmen' by Russell Hoban, illustrated by Quentin Blake. As fine a book as you are likely to read.

Adrian thank you for the beautiful image! I knew Quentin Blake's illustrations from Roald Dahl's children books, but I never saw this one of the waterbike - oops of the watersomething...
I wish you great holidays with your pedal powered boat and I look forward to having a feedback about it - I took the liberty of publishing your description of the Seacycle drive unit here:

http://www.openwaterbike.com/architecture/the-open-waterbike-architecture/the-open-waterbike-drive-unit/the-seacycle-drive-unit/

and I am very interested of course in knowing how these units perform!

Beppe

I57

08-07-2008, 06:45 AM

Finally got the boat on the water today, involute gear box worked great new outriggers performed well. Only problem was the universal joint breaking after 15 minutes, the pin connecting the two halves sheared off. The shaft is set at a 20 deg angle and the UV is 12mm dia, the pin is only 2mm dia so not that surprising. Next step is a bigger stronger UV that can take the load, how much load? Pic of boat is without outriggers, this was when I had paddled back and hauled the boat out of the water. I have the boat about as good as I can get it and now just a case of tuning it.

Ian Cassell

Guest625101138

08-07-2008, 09:35 AM

diwebb

08-07-2008, 04:28 PM

Hi,
you may want to try www.mcmster.com. This catalog is amazing for all those hard to get items. Prices are a bit on the high side but it is a great resource for right angle gearboxes, flexible drive shafts, universal joints etc and they do mail order to anywhere in the USA, and maybe worldwide? I have not asked that question of them yet.
David.

alexlebrit

08-08-2008, 04:47 AM

Rick, I know it's not directly related to the pedalling part, but I seem to remember in the past you've mentioned building in aluminium. I was wondering if you had any tips on this.

Guest625101138

08-08-2008, 05:03 AM

Rick, I know it's not directly related to the pedalling part, but I seem to remember in the past you've mentioned building in aluminium. I waqs wondering if you had any tips on this.

Alex
I find aluminium sheet the best to use for a fast clean build. There is very little compromise in making developable shape and no finishing required unless you want a pretty colour. Even then a couple of spray cans will do the job.

There are a few things to learn.

I only cut the sheet for hulls using a thin cutting disc on a hand grinder - noisy and messy dust but no stretched edge.

I screw and glue seams to a backing plate for nice shape. Usually stainless screws and polyurethane glue. The glue is intended as a sealer. The boats are never in the water long enough to worry about electrolysis and I store dry.

I fold a tight flange on outside edges of the sheet before folding to avoid kinking the sheet.

It is handy to have some nice steel angle or heavy aluminium tubular section to make nice tight edge bends. Also requires a method of clamping.

You can make usable boats out of 0.6mm aluminium but will be prone to denting. 0.8mm is more robust and still quite easy to work. I class 1mm as heavy duty. A drop will not normally cause any damage but it take more to bend it. The thinnest I can get marine grade is 1mm but I have never used marine grade as my boats are normally used in fresh water lakes and rivers.

If you have more specific question I can give more specific answer.

Rick

Guest625101138

08-09-2008, 12:30 AM

beppe

08-09-2008, 05:03 AM

I launched V11J today. This is based on the V11 hull shape from Godzilla.

It is a glass on Klegecell hull and I made an aluminium crank frame to save some weight. The boat is 23kg. So a little heavier than planned as usual but very easy to handle.

There were a few teething problems but had a couple of hours of pleasant exercise at the lake. Not fit enough to take on the sailing boats today and the shaft was slipping at the prop if I cranked hard.

My crank mounting is a little too flimsy so I will need to stiffen that up.

The dipping rudders worked very well. These are two rudder blades at a fixed angle of attack that are sprung up out of the water. To turn I just pull a chord that immerses the appropriate blade.

The outriggers fold up for transport similar to V11A.

I have attached some photos including a close up of the rudders.

Rick W.

Hi Rick
your boat looks really fine; I'd have a lot of questions...
Just one for now... why do you need twin rudders? Have you any vibration problems with the chord kick-up system at high speed? We had them. We worked a lot on these problems, before ending up with the solution in the enclosed image & video. We use a push-pull aluminum tube for lifting and pushing down the rudder, and a flexible cable to operate the rudder, so we can have control of it even when it is just halfway, in shallow waters. We also worked on the shape, as yoy can see.
I look forward to more details on the performances of your boat.
Best
Beppe

Guest625101138

08-09-2008, 05:18 AM

beppe

08-09-2008, 07:10 AM

The rudders are so-called "dipping" rudders. They are only immersed when required for turning. They normally sit up out of the water and are just immersed when turning or course correction is required. For a full turn the whole rudder is immersed. If it is only a course correction then just a tiny portion is immersed. The rudders have a preset angle of attack roughly set at the maximum L/D ratio for the particular foil.

It means I do not have the continuous drag of the rudder. Depending on the size of the rudder it could be worth 0.5kph.

Rick W

Wow! now that's a nice concept, so you have the maximum turning efficency just when you need it. I was wondering how this could apply when you need also maneuvearbility. It seems to me that you need to vary the rotation of the rudder when the boat turns to maintain a correct angle of attack, if you need to minimize the turning radius. See in the attached image what I mean: I manage to turn in these narrow channels with the rudder assembly I showed before.
Beppe

MLampi

08-10-2008, 08:50 PM

...
Here is the worlds fastest pedal canoe:
http://www.youtube.com/watch?v=R83c_gKTGY4
How does this fit with your constraint. Why not just standardise on one of the Hydrocycle drives as it is better engineered than the twisted chain:
http://www.hydrocycles.com/learn.php

Rick W

Rick,

How on earth do you know that the Youtube video that the above link points to is the world's fastest pedal canoe?

First on all, it is certainly not a canoe. I'd venture that it is probably a WaveWalker, which is by no means a canoe.

Secondly, that boat isn't even as fast as a paddled canoe, unless you are talking about one of those slow, heavy cargo boats people take on vacations for fishing.

The last I heard, the Hydrocycles folks weren't selling their drives without a boat attached. It's a pity. Those drives are certainly nicely engineered, and seem to be much better built than the SeaCycle drives.

Michael Lampi

MLampi

08-10-2008, 08:53 PM

For starters I have attached a video of me doing a slow pass in Mike Lampi's Cadence on Lake Union near Seattle. I have also attached the performance data from a couple of hours in the boat. At agressive cruising of 150bpm the boat holds around 10kph. Top speed achieved in a sprint is 16.8kph. There was a bit of slop when this was achieved so the aging engine might nudge 17kph in smooth water.

Rick W.

Rick didn't mention this, but that boat is also very much a heavy weight version of the Cadence. A normal Cadence is about 10 pounds lighter and I think would have helped Rick achieve a better top speed.

Michael Lampi

Guest625101138

08-10-2008, 09:06 PM

Rick,

How on earth do you know that the Youtube video that the above link points to is the world's fastest pedal canoe?

First on all, it is certainly not a canoe. I'd venture that it is probably a WaveWalker, which is by no means a canoe.

Secondly, that boat isn't even as fast as a paddled canoe, unless you are talking about one of those slow, heavy cargo boats people take on vacations for fishing.

The last I heard, the Hydrocycles folks weren't selling their drives without a boat attached. It's a pity. Those drives are certainly nicely engineered, and seem to be much better built than the SeaCycle drives.

Michael Lampi

Mike
Because it says so - why else. I am just repeating the totally unfounded claim made with the video. Both you and I know it is nonsense. I was hoping someone would pick up on it.

I know you are impressed with the drives and I also believe they are well engineered. Much superior to twisted chain in my view.

Did you see that Hydrocyles has picked up Pedalos as a test mule. I think they may have recognised the merit that length offers.

They offered Greg K a full boat to do his 24 hour effort last year and predicted he would not get anywhere near the distance he achieved in the kayak hull. I believe they felt their boat was superior but I am supposing now realise length counts.

Not sure if you visit Greg's blog. He has been doing 1000m sprints in 4 minutes. Still not Olympic class for a K1 or skull but not bad for a 48yo.

Rick W.

beppe

08-11-2008, 02:28 AM

Hi Michael
as you know I like very much your boat, but browsing through your website I didn't find the performance data.
Since the google search gives

'Open Water Cycling - The fastest production pedal boats on the planet'

I'm really interested about them!

Immediatlely after I wrote this post I found

'The FASTEST production pedal-driven watercraft on the market today!'

as the opening catch-phrase of the Hydrocycles home page.

Really, I don't doubt youre claim is founded, Michael, but I believe we need to discuss some hard data here in this technical forum...

Best regards
Beppe

Guest625101138

08-11-2008, 03:59 AM

..........

'Open Water Cycling - The fastest production pedal boats on the planet'

I'm really interested about them!

Immediatlely after I wrote this post I found

'The FASTEST production pedal-driven watercraft on the market today!'

as the opening catch-phrase of the Hydrocycles home page.

Really, I don't doubt youre claim is founded, Michael, but I believe we need to discuss some hard data here in this technical forum...

Best regards
Beppe

Beppe
Mike will probably make his own response but I think I can contribute here.

Mike markets the Cadence and I believe he can rightly lay claim to the fastest production pedal powered boat. He provides a huge amount of performance data on his own web site including this blog:
http://snorlax.lampi.org/blog/index.html
that is regularly updated.

The very first post on this thread has performance data on the Cadence using a 1951 vintage engine that was/is somewhat out of tune.

Mike is one of the few people regularly racing a PPB against other forms of human propulsion.

The Hydrocycles claim relates to Pedalos. The basis of this information is wrong on two counts. I do not believe a version of the boat is in production yet and the 24hr PPB distance record is now owned by Greg Kolodziejzyk, set last year in a 2-man kayak hull and planning to exceed later in the month in Critical Power 2.

I believe the Wavebike was faster than the Cadence but it is no longer in production.

With all these things it is buyer beware. Most people wanting a pedal boat are not going to be looking for performance in the first instance. Just that they can get horribly disappointed when they actually get alongside a kayak or rowing scull.

The first year I did the Murray Marathon I was occasionally heckled by onlookers who accused me of cheating because it looks so easy. However I am under no illusion about the amount of effort I need to put in to be competitive with a well-paddled K1 or OC1. People unfamiliar with K1s, OC1s and sculls find a reasonable pedal boat like the Hobie exciting. The advantage is that there is no skill or unusual muscle development involved in its operation compared with the paddled/rowed forms. So if people have a go they get interested.

The Cadence is very similar in performance to my OC1 with small prop and about 1kph slower than V11A for same engine at 130W. I have hard data to demonstrate this and the calculated data gives the same result. In the same way, I can calculate you require about 40% more power to do 10kph than a Cadence requires. Doing 1000m in 4 minutes would require a very powerful rider in any catamaran.

By the way, Mike is the only person I know who has tried both a Cadence and a Hydocycle so he is one person who can talk with authority on the relative performance.

Rick W

alexlebrit

08-11-2008, 04:21 AM

Guest625101138

08-11-2008, 05:36 AM

Beppe
This is a video of the Hydrocycle Wavewalker in action:
http://www.youtube.com/watch?v=XsdBPC4T6wU
Mike Lampi provided the video and was able to take a test ride on the same day the video was taken. As far as I know the boat has never been placed in a competition against paddled craft like K1 or OC1.

This video that I linked to earlier is a Wavewalker:
http://www.youtube.com/watch?v=R83c_gKTGY4
The rider clearly believes the advertising and is the sort of owner who ends up disappointed when they get in a competitive position. But if a misleading claim helps sell something to the ill-informed so what, it's a sale. The money is in the bank.

You see outlandish claims - here is one of the more recent ones; post #13 here:
http://boatdesign.net/forums/showthread.php?t=23665
So what - you can waste a lot of time challenging nonsense and it is not productive.

I would like to see the individual who could punt these along at the claimed top speed:
https://www.msu.edu/~pengchun/
Not impossible but would be an Olympic class cyclist.

Here is another:
http://www.inventist.com/index.php?option=com_content&task=view&id=23
17mph may be possible but I determine one would need to be extremely fit and tied down to apply greater acceleration than 1g to the aparatus.

You will waste a lot of time if you set out to challenge all non-supported claims.

Rick W.

ASM

08-11-2008, 07:24 AM

Rick or anyone else.
It looks like the link to the chinese drive unit is promissing, though not for sprinting purposes. Has anyone used this unit ? Seen this unit ?

Sandor

Guest625101138

08-11-2008, 08:02 AM

I have tried one mounted on a lightweight rowing scull.

It is geared to protect the internals. I could manage 13kph as I recall on a hull that would nudge 18kph with a good drive unit. I was spinning out at maybe 140rpm. This is well past my peak power cadence. I expect that you would need to be able to spin to maybe 200rpm to get the claimed 18kph. Not impossible but need to be well trained.

It is not very streamline either. It carries the same dimension full depth. Roughly 45mm thick and maybe 200mm long. It has 45 degree wedge shape as the fore and aft fairing.

Finally the prop is a bit rough. If it was trimmed and profiled it would do better.

The one good thing is the price and I do not know of any failures but use is usually low.

The longer boat in this clip is the one I have tried:
http://www.youtube.com/watch?v=adS1ywFsFkE

There is another one used here:
http://www.wisil.recumbents.com/home.asp?URL=wisil/main.asp

Rick W.

ASM

08-11-2008, 10:36 AM

beppe

08-11-2008, 11:52 AM

Beppe
Mike will probably make his own response but I think I can contribute here.

Mike markets the Cadence and I believe he can rightly lay claim to the fastest production pedal powered boat. He provides a huge amount of performance data on his own web site including this blog:
http://snorlax.lampi.org/blog/index.html
that is regularly updated.

The very first post on this thread has performance data on the Cadence using a 1951 vintage engine that was/is somewhat out of tune.

Mike is one of the few people regularly racing a PPB against other forms of human propulsion.

The Hydrocycles claim relates to Pedalos. The basis of this information is wrong on two counts. I do not believe a version of the boat is in production yet and the 24hr PPB distance record is now owned by Greg Kolodziejzyk, set last year in a 2-man kayak hull and planning to exceed later in the month in Critical Power 2.

I believe the Wavebike was faster than the Cadence but it is no longer in production.

With all these things it is buyer beware. Most people wanting a pedal boat are not going to be looking for performance in the first instance. Just that they can get horribly disappointed when they actually get alongside a kayak or rowing scull.

The first year I did the Murray Marathon I was occasionally heckled by onlookers who accused me of cheating because it looks so easy. However I am under no illusion about the amount of effort I need to put in to be competitive with a well-paddled K1 or OC1. People unfamiliar with K1s, OC1s and sculls find a reasonable pedal boat like the Hobie exciting. The advantage is that there is no skill or unusual muscle development involved in its operation compared with the paddled/rowed forms. So if people have a go they get interested.

The Cadence is very similar in performance to my OC1 with small prop and about 1kph slower than V11A for same engine at 130W. I have hard data to demonstrate this and the calculated data gives the same result. In the same way, I can calculate you require about 40% more power to do 10kph than a Cadence requires. Doing 1000m in 4 minutes would require a very powerful rider in any catamaran.

By the way, Mike is the only person I know who has tried both a Cadence and a Hydocycle so he is one person who can talk with authority on the relative performance.

Rick W

Thank you Rick
I believe this thread you opened here gives us the unique opportunity to set some records straight; there are numbers around the Internet about the performances of pedal boats that are just ballpark figures or worse.
In my opinion we should rely on

1. experimental measurements,
2. calculated theoretical data and
3. the experience from races and regattas

and reach eventually some simple numbers on which we can agree...
I have some reliable experimental data I believe from prevoius post exchanges are roughly in accordance with yours and with those form Michael, maybe we can work out a synthesis.
I'd be happy to provide them to anyone interested.
Since a comparison is difficult, I believe that from a practical point of view the length of the boat can be a useful concept for a classification, because it is the most important factor that affects the usability of a boat (e.g. the possibility of transporting it on a car etc.).
Maybe a simple (?) table reporting drag and mechanical power needed at significant speeds (e.g. 4,5,6,7 knots) and including boat length could be a nice output of this effort.
Best
Beppe

beppe

08-11-2008, 12:12 PM

I'm wondering if we could agree a few terms when talking about PPBs. Different people have different wants from their boats, and sometimes I know I find it confusing identifying what they're talking about, and what I can apply from other people's boats to any design of my own.

Broadly speaking, I reckon there's the following categories of boat.

Racing - Fairly obvious, it's a boat designed primarily for high speed
Cruising/Touring - Similar to racing, but with a few more creature comforts
Working - A platform for another activity - eg fishing, hunting, photography
Expedition - Plenty storage space, capable of multiday trips
Multi-powered - Combining pedal power with another means of locomotion - sail, electric etc

But that's just my impression and there's obvious overlaps, and please feel free to completely rewrite everything. Personally I'm interested in a versatile boat that I can use for multiday expeditions, and it might even have dual propulsion, and so this will effect the design of any boat I'm building.

Anyway, just some thoughts.

Hi Alex
your classification is interesting; what's strange is that PPBs' performances of several categories of the boats of your classification are much closer than what happens in many other fields; e.g. in rowboats.
For example a pedal powered catamaran I designed as a leisure boat in the nineties won unexpectedly the World Championship in 1999; the boat is admittedly not the fastest boat in the world, but she is not as far as expected, considering that anybody can ride it without any training and is reasonably easy to transport and operate. Please find the details at

http://www.openwaterbike.com/the-idea/the-story

if you are interested
This could be because PPBs are not yet so specialized, no dominant design have emerged yet, and they have huge margins of improvement, as for example were the bicycles back in the 1880s.
This is what makes them so exciting to work on...
Best
Beppe

Guest625101138

08-11-2008, 05:23 PM

Rick
You really think I can do soo much more in rpm ? haha don't think so.... anyway, would the drive unit be simply redesigned with a GRP enclosing instead of the steel one ? this makes it lighter and the streamline could be improved.. the price is what striked me in the first place as I am not that handy that I can create one myself.... I have contacted them, no reply yet.

If you go to the WISIL site listed previously and look at the next boat page you will see Warren faired his leg by fairing over the existing casing. Made it slightly bigger but more streamline. This is much easier than total rebuild.

The best improvement is likely to come from a new prop or just reshaping the prop.

The unit is not the best but it is a good price and fine for a first time boat.

Rick W

MLampi

08-12-2008, 12:41 AM

After making a mess of things I finally have some data recorded with a Garmin Forerunner 305, its heart rate monitor and its cadence sensor while engaging in a couple of races.

The race I was in Saturday was not one of my better ones, though the time of 2:22:xx was fairly close to my time in 2004 of 2:25:xx in a 10+ pound lighter boat without outriggers. Weed consumption this year seemed to be worse, though some of that was probably just my imagination. The currents, waves and winds were pretty mild over all.

Rick, would you like to see the data?

As an aside, I have worn the Forerunner and HRM belt while doing my morning runs for nearly two months, and can offer that data as well if it might help compute engine parameters.

The SportTracks power plugins don't seem to do the trick in calculating my actual power output.

Michael Lampi

P.S. The photos I took can, as always, be seen at the Sound Rowers (http://www.soundrowers.org) web site's photography page along with basic GPS speed/position performance graphs.

P.P.S: The Pedalos was built almost in time for the 2000 Hydrofest, where it was merely demonstrated as a concept boat. I don't think it was ever planned to be a production vessel; rather, it was supposed to be used in setting the 24 hour HPB record.

Guest625101138

08-12-2008, 01:04 AM

Guest625101138

08-12-2008, 06:39 AM

....
P.P.S: The Pedalos was built almost in time for the 2000 Hydrofest, where it was merely demonstrated as a concept boat. I don't think it was ever planned to be a production vessel; rather, it was supposed to be used in setting the 24 hour HPB record.

Mike
This is from the Hydrocycle web site:
http://www.hydrocycles.com/pedalos.php
The Pedalos is spoken of as going into production. It is also claimed to be the fastest production PPB as Beppe pointed out.

MLampi

08-12-2008, 10:29 AM

Mike
This is from the Hydrocycle web site:
http://www.hydrocycles.com/pedalos.php
The Pedalos is spoken of as going into production. It is also claimed to be the fastest production PPB as Beppe pointed out.

Perhaps I'm being picky, but if there is only a single one of these boats in existence, and the maker has not made more than one, then I claim that the thing is not truly a "production" boat.

Michael Lampi

MLampi

08-12-2008, 11:19 AM

Mike
I would like the hst file from one of your races if you have it. I have been loading into Excel for analysis. I can do that with your data.

I will leave the running data for now. I think the GPS is set up for a bike so does not do all that well for running.

I went through one of your recent blogs showing a blue decked, black hull that you said used a Hobie flapper drive. I would be interested in any information you have on the boat. I saw that it finished well behind you and I was wondering if the boat met the builder's expectations. Hobie have done a tremendous job on over-selling the efficiency of their drive and I expect buyers would be disappointed when put alongside more efficient systems.

I've looked through the SportTracks and the Garmin Training Center (GTC) programs and neither appear to offer hst file output. The GTC has tcx files only. Are those what you want?

As far as I can tell the GPS has three main modes: running, cycling and other. The running mode seems reasonably accurate, but I guess your mileage may vary (pun intended).

I never saw that blue/black Mirage driven boat since that race in February. There have been a number of races in areas to the north of that venue since then, as well as quite far to the south and southwest, but that boat never appeared again.

In about two weeks there will be a fairly major race not far from downtown Seattle that crosses Puget Sound that has historically been a popular one for unique boats to appear in. Perhaps it will show up again.

Michael Lampi

beppe

08-12-2008, 04:22 PM

Mike
... Hobie have done a tremendous job on over-selling the efficiency of their drive and I expect buyers would be disappointed when put alongside more efficient systems.

here
you can find a nice explaination about why the performance of the Mirage drive is superior to that of a propeller drive system,

http://www.hobiecat.com/kayaking/miragedrive.html

but no hard data... ;-) hehe

I believe that the success of the Mirage is not a threat, but a great opportunity for PPBs... it creates a potential market for higher efficiency PPBs as you point out.
A different way of thinking is needed to exploit this opportunity, possibly embracing a more collaborative view; the Open Waterbike Project is of course just an attempt to do that...
The future belongs to those who can imagine it...

Beppe

Guest625101138

08-12-2008, 05:40 PM

Hi Rick
here
you can find a nice explaination about why the performance of the Mirage drive is superior to that of a propeller drive system,

http://www.hobiecat.com/kayaking/miragedrive.html

but no hard data... ;-) hehe

I believe that the success of the Mirage is not a threat, but a great opportunity for PPBs... it creates a potential market for higher efficiency PPBs as you point out.
A different way of thinking is needed to exploit this opportunity, possibly embracing a more collaborative view; the Open Waterbike Project is of course just an attempt to do that...
The future belongs to those who can imagine it...

Beppe
Beppe
I have hard data. At energetic continuous effort the flappers achieve around 35% efficiency. For a full effort sprint the efficiency lifts to just over 50%.

The site you point to is just marketing hype - it is drivel from any engineering perspective.

Some interesting comparisons here for full effort 100m sprints:
http://www.humanpoweredboats.com/HydroFest/2001/HydroFest2001Results.htm
Considering power is roughly a cube function of speed you can imagine the sort of engine needed to get a Hobie from 10kph to the 18kph achieved with the WaveBike.

Like I say Hobie have done a great marketing job and reasonable engineering on the flapper system but all statements about efficiency are nonsense.

Guest625101138

08-12-2008, 05:45 PM

beppe

08-12-2008, 11:07 PM

Beppe
I have hard data. At energetic continuous effort the flappers achieve around 35% efficiency. For a full effort sprint the efficiency lifts to just over 50%.

The site you point to is just marketing hype - it is drivel from any engineering perspective.

Some interesting comparisons here for full effort 100m sprints:
http://www.humanpoweredboats.com/HydroFest/2001/HydroFest2001Results.htm
Considering power is roughly a cube function of speed you can imagine the sort of engine needed to get a Hobie from 10kph to the 18kph achieved with the WaveBike.

Like I say Hobie have done a great marketing job and reasonable engineering on the flapper system but all statements about efficiency are nonsense.

Rick, I have no hard data about the Mirage, but I believe you are right.
Though, I believe we should focus on long distance performance, not on sprint peaks. Say 10 to 14 KpH, this is enough...
I exchanged a few emails with George Tatum at the beginning of the Wavebike endeavour, the boat was innovative (even if the concept had been tried years before at Oxford University, if I remember well) and George was very focused and enthusiastic. I was working on a more traditional concept at the time, we talked about the possibility of importing Wavebikes to Europe.
We all know the following story of that beautiful innovative PPB.
The Mirage, on the other hand, is successful, but we suspect we can do better. Should we try the same George (and many others, remember the Sea Saber?) tried?
I'd say a different approach is needed here. If it will be The Open Waterbike' I can't say for sure, I certainly hope so. What I'm sure of, is that the old way spells disaster...
Beppe

beppe

08-12-2008, 11:22 PM

Guest625101138

08-12-2008, 11:36 PM

........
Though, I believe we should focus on long distance performance, not on sprint peaks. Say 6 to 9 KpH, this is enough...
.....
Beppe

Beppe
The Hobie Adventure drive achieved 5.3mph with input of 180W to give calculated drive efficiency of 38%.

Same power on the V11 boat gives 8mph with overall drive efficiency of 84%.

So the sprint speed relativity translates well to performance at a more relaxed pace.

MLampi

08-13-2008, 01:13 AM

Mike
The hst file is a history file you export. So it is on the file menu. If you have kept all your data it will be very large. However I think you can just export one session.

There is mention of a history file on the export menu. However, it only seems to output files with a .tcx extension.

beppe

08-13-2008, 02:21 AM

Beppe
The Hobie Adventure drive achieved 5.3mph with input of 180W to give calculated drive efficiency of 38%.

Same power on the V11 boat gives 8mph with overall drive efficiency of 84%.

So the sprint speed relativity translates well to performance at a more relaxed pace.

This is very intesting!
Are there data accepted officially by Hobie? If not, are they reliable?

The Open Pedal Powered Boat requirements (http://www.openwaterbike.com/architecture )

are:

"Intended users range from amateurs to athletes (design total mechanical power output about 150 to 400 W and up to 1,000 W in sprints).

Particular users should be able to make good progress with as little as 50W"

and I believe that we need data in this range of mechanical output power.
Even more important for commercial purpouses the performance of double seaters.

This gives also an answer to a previously debated question: any boat significantly more efficient then the Hobie could have a great market opportunity because the market is opened up by the Hobie itself and there is always people wanting more performance and willing to pay for them.
But the offer should be global, and this is beyond the possibility of very small firms. This is a key point of my project...

Beppe

Guest625101138

08-13-2008, 03:21 AM

This is very intesting!
Are there data accepted officially by Hobie? If not, are they reliable?

........
Beppe

I doubt that Hobie have any interest. As long as they sell boats that is all that concerns them. And the data is considerably more accurate than any performance information published by Hobie.

Guest625101138

08-13-2008, 03:46 AM

I've looked through the SportTracks and the Garmin Training Center (GTC) programs and neither appear to offer hst file output. The GTC has tcx files only. Are those what you want?

As far as I can tell the GPS has three main modes: running, cycling and other. The running mode seems reasonably accurate, but I guess your mileage may vary (pun intended).

I never saw that blue/black Mirage driven boat since that race in February. There have been a number of races in areas to the north of that venue since then, as well as quite far to the south and southwest, but that boat never appeared again.

In about two weeks there will be a fairly major race not far from downtown Seattle that crosses Puget Sound that has historically been a popular one for unique boats to appear in. Perhaps it will show up again.

Michael Lampi

Mike
I have attached a screen image of producing the hst file from my Garmin software.

alexlebrit

08-13-2008, 03:57 AM

Guest625101138

08-13-2008, 04:29 AM

Dare I say it but isn't one of the reasons the Hobie set-up is so successful the fact that they were in the business for quite a while before they ventured into PPBs, they have an extensive dealer network and have plenty of cash to spend on marketing. Add in the fact the drive's small, easy to use and easy to remove and that once removed the boat is still usable and you end up with a versatile, if not hugely efficient, machine.

Purely from a saleability standpoint it looks to me like Hobie have it just right.

PS, Is it just me or does the Mirage drive in motion remind you of a sea-turtle?

Alex
I am not certain they have utilised an existing distribution network. I think they are into another market segment with these boats now. They may leverage on their old sailing name and network but you see their boats in outdoor/camping stores not just boating.

As far as product goes it sets the benchmark. I simply take issue with their marketing on the basis of efficiency when this is in fact poor to ordinary.

If I made a 2m X 0.8m prop with 1:2 gearing I could pull a rowing 8 backwards in a tug-of-war. Tug-of-wars have little bearing on real world performance unless you are making a tug. Any towing demonstration against paddlers is nonsense from a boat performance perspective. Just a good sales pitch for the gullible.

On the negative side Mirage users get disillusioned when they get beside an ordinary kayak or canoe because they have been mislead to believe they have a performance craft, which it is not.

Rick

I57

08-14-2008, 01:46 AM

Ian
With 3.3:1 reduction you will find it expensive to get a universal joint that will stand up.

I cannot recall the circumstances that you tried the curved shaft but I think it is a better option with the big box. You need a couple of small bearings in the strut to carry the shaft without damage but you could test first without bearings.

10mm machinable aluminium rod with carry the torque and should not be too rubbery.

The inline torque rating of the universal you have is more than enough but once it has a bit of angle the rating drops off. I do not know by how much. Obviously not satisfactory. Greg had the same problem with this universal. I used one with 7.5:1 gearing and it was fine. Angle was about 12 degrees.

I hope to launch V11J on the weekend. Has been a real pain trying to get epoxy to cure in the cold weather.

Rick

Rick

I did try the flexible shaft on an earlier setup and it did work well, very smooth. What didn’t work was the hand drill gear I was using which didn’t last long. This was before I had the involute gear box and after this I was trying drive legs. I am waiting on the delivery of a bigger universal joint and am keeping the current setup. I looked at using a flexible shaft but this would involve major work on the boat, the skeg relocated further aft and a new shaft housing in the hull. I’ve modified this boat so many times now I will only try a new layout if the current one gives me too many problems. Also when I had the flexible shaft the seat had to be raised which is why it had the bigger outriggers (see pic) which made turning harder. Let you know when the boats ready maybe this time I’ll get it right.

Ian Cassell

Guest625101138

08-14-2008, 02:07 AM

Rick

I did try the flexible shaft on an earlier setup and it did work well, very smooth. What didn’t work was the hand drill gear I was using which didn’t last long. This was before I had the involute gear box and after this I was trying drive legs. I am waiting on the delivery of a bigger universal joint and am keeping the current setup. I looked at using a flexible shaft but this would involve major work on the boat, the skeg relocated further aft and a new shaft housing in the hull. I’ve modified this boat so many times now I will only try a new layout if the current one gives me too many problems. Also when I had the flexible shaft the seat had to be raised which is why it had the bigger outriggers (see pic) which made turning harder. Let you know when the boats ready maybe this time I’ll get it right.

Ian Cassell
Ian
You are only on V1.6. I up to something like my 15th boat and I do not bother counting the variations on each boat. I still cannot get the boat right on the first outing. Always teething problems.

Greg did try a universal joint that would stand up but it was about 30mm in diameter with coupling balls. It was strong enough but not as smooth as the curved shaft. He now wants to use a curved shaft on his ocean boat because he likes the action so much. He just told me he did 109km today in 10 hours so is getting close to having a crack at the 24 hour distance record.

I am planning on being at the lake Saturday morning with the new boat. It should be sorted by then. If it is good weather I will hang around for a few hours.

Rick

beppe

08-17-2008, 05:52 AM

Dear colleagues
I took the holiday opportunity for reading again 'Human Powered Vehicles', by A.V. Abbott and D.G. Wilson (eds), Human Kinetics, 1995
I found this book (in fact, a collection of papers form different authors) a wonderful comprehensive introduction to HPVs and HPBs, so I recommend it to all the members of this forum serously interested in PPBs builidng.
It has a scientific approach, but no academic heaviness, it reads more like the Scientifica American...
Ther is an extensive body of knowledge about PPBs, and we need to share the basics if we want to go somewere...
One of the shortcomings of the book is that it lacks a single article on high performance kayaks and skisurfs (while there is one on rowing shells and another on hydrofoil, plus a genaral one on hpbs).
Has anybody a suggestion about a good serious source about surfski performance and building?
Beppe

MLampi

08-18-2008, 10:34 AM

Guest625101138

08-18-2008, 05:14 PM

Hi Rick,

I tried to send these directly to you last week, but perhaps it was to an old e-mail address.

Anyway, here is what the Forerunner recorded for the trip around Shaw Island. Note that there was a very helpful flood current on the west side of the island, and some not-so-helpful currents around most of the rest of the island.

I even did a little wake surfing on the north side of the island. :)

Michael Lampi

Mike
I got the one direct but I was having trouble unzipping it. This one at least has a recognisable compression.

I did some reading on the Forerunner and I think they have updated the software. I believe it will be compatible with the hst format I have but will let you know.

Rick

Guest625101138

08-18-2008, 06:06 PM

Mike
Here is Shaw1 data.

Top speed was 15.65kph.

I will send the Excel file direct to you with some explanation.

Rick

beppe

08-22-2008, 12:25 PM

Guest625101138

08-22-2008, 06:27 PM

Hi everybody
I believe this forum gives us the unique opportunity to assess the relevant performances of some outstanding pedal powered boats, according to the goals set by Rick (... to contribute and provide insight on boating matters at the low power, high efficiency end of the scale.

Maybe we can start from the data Rick himself gave recently

I have a question for Rick and a proposal:
question: is Drive Efficiency the same as 'propelling efficiency', that in literature is defined by the following formula?

Drive Efficiency = Drag * Speed / Wtot

Where
Drag is the Hydrodynamic resistance (passive drag), e.g. the external force necessary to drag the boat at constant speed

and

Wtot is the total mechanical input power

If the formula is correct this would give a drag of 49 N at 3.58 m/s for the V11 and of 29 N at 2.37 m/s for the Adventure. The latter seems rather low, maybe a bit too good, to me. Are these figures in agreement with yours, Rick?

Proposal:

I believe we need some more data to assess the performances of a Pedal Powered Boat, namely drag (at different speeds), length, weight (mass), possibly wetted surface.
I'd like to confront my data with those of other high performance boats, in particular the Cadence, since we agreed that she could be the fastest long distance production boat, the Hobie Adventure, since it's so succesfull, Rick's boats.
I believe these data can really give value to this forum and this thread and help us all improve our PPBs.
I'll give all my own data to all the colleagues interested, just ask me, and also in this forum in following posts.

Beppe
Beppe
Your maths is almost correct. You are inferring all mechanical losses as hull drag which is not quite correct. Particularly with V11. I have 97% mechanical efficiency on V11 so there are some small losses not manifested as drag. Actual main hull drag is 39N at 3.6m/s. There are other components of drag for windage, rudder, prop shaft and outriggers that bring total drag to just over 43N.

At 3.6m/s the Adventure hull has a drag of 82N.

At 2.4m/s the main hull drag on V11 is only 17N. So by this comparison the Hobie hull is not very good even at this relatively low speed.

I expect you are comparing these monohull numbers with your catamaran. It has a 40% power penalty with the concept to start with and then your hulls may not be drag minimised for any particular operating condition. Then you have a large wetted syrface for the drive leg and quite a large rudder. There is also substantially more windage with the high seating position and pilot sitting between the two hulls. These are all substantial components of drag and become more significant relative to the hulls if the hulls are well designed for minimum drag. I expect total weight is greater as well because you need the heavy structure to support the pilot over the water.

Look at the underwater of the Hobie. There is no appendage drag with the drive. All exposed surface is propelling. There is only the rudder adding drag. The pilot sits down in the hull so windage is lower.

I am always interested in useful data but I already have a lot of information on boat performance and can make performance predictions within a few percent.

Rick W

beppe

08-23-2008, 01:22 AM

Beppe
Your maths is almost correct. You are inferring all mechanical losses as hull drag which is not quite correct. Particularly with V11. I have 97% mechanical efficiency on V11 so there are some small losses not manifested as drag. Actual main hull drag is 39N at 3.6m/s. There are other components of drag for windage, rudder, prop shaft and outriggers that bring total drag to just over 43N.

At 3.6m/s the Adventure hull has a drag of 82N.

At 2.4m/s the main hull drag on V11 is only 17N. So by this comparison the Hobie hull is not very good even at this relatively low speed.

I expect you are comparing these monohull numbers with your catamaran. It has a 40% power penalty with the concept to start with and then your hulls may not be drag minimised for any particular operating condition. Then you have a large wetted syrface for the drive leg and quite a large rudder. There is also substantially more windage with the high seating position and pilot sitting between the two hulls. These are all substantial components of drag and become more significant relative to the hulls if the hulls are well designed for minimum drag. I expect total weight is greater as well because you need the heavy structure to support the pilot over the water.

Look at the underwater of the Hobie. There is no appendage drag with the drive. All exposed surface is propelling. There is only the rudder adding drag. The pilot sits down in the hull so windage is lower.

I am always interested in useful data but I already have a lot of information on boat performance and can make performance predictions within a few percent.

Rick W

Rick
forgive me, but my math IS correct, while the terms we used are misaligned.
I believe we should use 'propelling efficiency' (Wd/Wtot) including mechanical losses in the efficiency, and using total drag, not only hull drag, so we can compare different watercraft and also swimming and scuba swimmnig, available in literature. Do you agree?

I believe we need a few other data for the comparison, and in particular total weight (or mass), that is important from a theoretical point of view, and length, that is the most important practical parameter. Could you provide them?

I am not very interested in claiming the excellence of my catamaran, it is just one of the starting points of The Open Waterbike Project (be patient, no better name emerged so far...), but according to your data she is faster and more efficient then the Hobie Adventure, over 2.7 m/s at 180 W (Wtot). But it is nice to know that there is a huge margin of improvement, as the amazing data of your V 11demonstrate.

I look forward to your answer and to sharing data with other colleagues, and in particular with Michael Lampi about the Cadence.

Best
Beppe

Guest625101138

08-23-2008, 05:13 AM

Rick
forgive me, but my math IS correct, while the terms we used are misaligned.
I believe we should use 'propelling efficiency' (Wd/Wtot) including mechanical losses in the efficiency, and using total drag, not only hull drag, so we can compare different watercraft and also swimming and scuba swimmnig, available in literature. Do you agree?

......
Beppe

No need for my forgiveness you are not doing the sums correctly if you do not isolate the various sources of losses. This allows you to determine the relative merits of each component. Ultimately it is the speed you get for the amount of power input that counts but inferring all losses are hull drag is just silly.

It would be possible to have a very efficient hull with a very inefficient propulsion system. It is then a waste of effort trying to improve the hull because the mechanical losses and the propulsion unit need to be addressed first. It is only through isolating the components of loss that you can address them.

You may find the table that is part way down this web page of interest:
http://www.adventuresofgreg.com/HPB/2008_06_16_archive.html
It shows the effort put into isolating, and working to reduce, the various loss components. The power measurements are done using an SRM power crank so within 2%. Greg calibrates before each test run. If you go back through Greg blogs you will see all the aspects that have been evaluated. Most of these things are what I have worked through in the past and have my own data on.

Greg's hull is a copy of V11A. I think he has managed to keep total weight under 20kg although I have not seen the latest weights. He is having the outriggers rebuilt to shave a pound or two.

V11J weighs 23kg. It is 7.2m long and 240mm WL beam.

If you can find the IHPVA archives you will find a good deal of my information posted there over the last few years.

I posted some concrete data on Mike Lampi's Cadence (albiet an overweight one) at the very first post on this thread. Also post #127 above has actual engine and boat data for Mike Lampi's Cadence.

If you post an igs or 3D dxf file of your hull, the hull separation, total displacement and some basic measurements for the drive leg and prop on you boat I will calculate the various components of loss and post them here. You can then compare with the measured data you have. If you like I can give you designs for the optimum hulls for your design displacement and chosen power level. This is always instructive as it shows what potential you have to improve. That said a cat will always require considerably more power than a stabilised monohull.

Rick W.

Guest625101138

08-23-2008, 06:21 AM

I got some video of the dipping rudders in operation. WARNING - this is not very spectacular unless you have an interest in such things. I complete a 180 degree turn at about half rudder. Turning radius is around 25m. You can see the rudder dip as it starts to splash. At the end of the turn you can see splashing from the port rudder to provide a bit of course correction. Tightest turning radius is around 10m with the current rudder settings. Very hard to look to see what they are doing so I do not know if they are stalling out when fully immersed but turning seems progressive.

I made a small windlass per attached photo that has sufficient friction to keep the dipped rudder down in position so turning and any course holding can be done almost hands free. With the side mounted prop the boat has a tendency to turn slowly to starboard so I can set the port rudder so it just clips the water to give steady correction.

The boat is now reasonably sorted and I can get back into some engine tuning. I am pleased with the boat so far. Shaving 5kg off the weight makes a big difference for ease of handling. The only disadvantage is the tendency for uplift when on the car top travelling over 80kph. Probably a combination of lower weight and the hull/deck flange.

Rick W.

beppe

08-24-2008, 02:18 AM

Rick
I am enthusiastic about your dipping rudders concept; I understand that the idea has been around for years but it i believe is new in the realm of pedal powered boats and just perfect for them.
With just one rotational axis you can eliminate the rudder drag and also have a remote controlled kick-up for shallow waters. Just great.
I am concerned about the maneuverability, but I believe it is possible to work on it, maybe increasing the angle after all the dipping rudder is down and the boat has started turning.
Just a couple of little ideas:
1. maybe the dipping rudders can be installed forward, at the bow of the boat, maybe 20 cm right and left, in order not to disturb the incoming flow to the hull. I believe they can be more efficient working in undisturbed water and is is easier to see and control them.
2. maybe an asymmetrical profile could be better for the rudder, since it works only one way
I would like to present the concept in the Open Waterbike webpage, acknowledging your paternity of course, for development by the community.
With congratulations for the great invention (or re-invention maybe, but this is often the case for grat inventions)
Beppe

Guest625101138

08-24-2008, 03:41 AM

Beppe
Forward mounted rudders are not the best. They will roll the boat the wrong way - out of the turn rather than leaning in.

My dipping rudders only achieve full efficiency when fully immersed. They are just water deflectors up to that point like any stern hung rudder.

The idea was first discussed with me some years ago. Maybe Larry Smith suggested it to me. I cannot remember now but the information is clearly in the public domain so no problem using it anywhere.

Rick W.

beppe

08-24-2008, 07:06 AM

No need for my forgiveness you are not doing the sums correctly if you do not isolate the various sources of losses. This allows you to determine the relative merits of each component. Ultimately it is the speed you get for the amount of power input that counts but inferring all losses are hull drag is just silly.

It would be possible to have a very efficient hull with a very inefficient propulsion system. It is then a waste of effort trying to improve the hull because the mechanical losses and the propulsion unit need to be addressed first. It is only through isolating the components of loss that you can address them.
...
Rick W.

Rick
computing the propelling efficiency including total drag and total input power is not uncorret nor silly. It's just a different definition. I agree with you that it is necessary to isolate the components of loss for designing purposes, but a more aggregate concept of efficiency can be better if your aim is comparing. This is what propelling efficiency is about, there are data available in literature for conventional boats that we want to use.
Beppe

Guest625101138

08-24-2008, 08:15 AM

Rick
computing the propelling efficiency including total drag and total input power is not uncorret nor silly. It's just a different definition. I agree with you that it is necessary to isolate the components of loss for designing purposes, but a more aggregate concept of efficiency can be better if your aim is comparing. This is what propelling efficiency is about, there are data available in literature for conventional boats that we want to use.
Beppe

Mechanical losses ahead of the prop shaft have nothing to do with hull drag. If you have a gearbox efficiency of 50% it would be obviously silly to infer all losses are related to drag on the null. If your propeller was working at 60% efficiency it would be silly to say all losses associated with the propeller could be inferred as hull drag - just silly maths for no meaningful outcome. You must isolate the inefficiency at the source not infer all losses to hull drag.

If your objective is to move across the water with least effort then all that matters is the speed achieved for any given input. So if I can do 8mph for 180W and another boat can do 5.3mph for 180W my boat is superior for the intended purpose.

Efficiency does not come into the performance equation - power in, speed out is all that matters. Efficiency only has meaning if you want to make detailed comparison of each component. This is the point where you need to isolate losses in each component of the system. Inferring mechanical losses in the drive train and slip/drag in the prop to be hull drag simply has no meaning.

The reason why I did the efficiency analysis on the Hobie flappers was to challenge the marketing blurb about them being highly efficient. Their tug-of-war demonstration only has meaning if you want a boat to be good at tug-of-war. It has no bearing on the normal intended use of moving easily across the surface of the water. You would not choose a tug if your objective is fast passages. Hobie have identified a good feature of the flappers and use it shamelessly to market the drive to a gullible public. Any actual use of the word "efficiency" is false marketing. The flappers exhibit poor efficiency.

Rick W.

MLampi

08-24-2008, 06:02 PM

Rick
I am enthusiastic about your dipping rudders concept; I understand that the idea has been around for years but it i believe is new in the realm of pedal powered boats and just perfect for them.
With just one rotational axis you can eliminate the rudder drag and also have a remote controlled kick-up for shallow waters. Just great.
I am concerned about the maneuverability, but I believe it is possible to work on it, maybe increasing the angle after all the dipping rudder is down and the boat has started turning.
Just a couple of little ideas:
1. maybe the dipping rudders can be installed forward, at the bow of the boat, maybe 20 cm right and left, in order not to disturb the incoming flow to the hull. I believe they can be more efficient working in undisturbed water and is is easier to see and control them.
...

I, too, like the idea of not having drag when you don't need it.

In a cat or tri in open water where you don't need a lot of maneuverability I think they are a great idea. On the other hand, if you want high maneuverability, or perhaps want to employ the rudder as a dynamic stabilizer in rough water for a monohull, then having a fixed rudder directly behind the propeller works very well.

Even at low speeds the prop wash against the rudder can be used to turn the boat much more rapidly. It can also be used to recover some of the rotational energy imparted to the water by the propeller and achieve somewhat higher net thrust.

Michael Lampi

MLampi

08-24-2008, 06:17 PM

Yesterday I completed the Sound Rowers Great Cross Sound Race (http://www.soundrowers.org). My time of 1:15:xx wasn't stellar for the 7.5 mile distance, but then again I did take some 550 photos or so of the other racers. I had lots of energy left over that could have been (should have been?) left on the course.

In addition, I was wearing the Garmin Forerunner 305, and had the cadence and heart rate sensors working throughout. The GPS function seemed to be working reasonably well, too, with no 50 mph stretches. :)

Using the SportTracks software to analyze the data I took a screen shot and posted it on the SR web site (http://soundrowers.org/photography/2008/GXSC2008/slides/orig_LampiStats.html).

The water was rather weird. While it was generally flat and close to high tide, so there should have been minimal current in any given direction, both of the GPS's I had with me and my own sense of speed indicated that some adjacent sections of the course seemed to be slower and some were faster with no obvious reason. The difference in speed was about 1 mph (5.9-6.0 vs. 6.9-7.0). My heart rate and pedaling cadence were the same throughout.

My guess is that in the slow sections some weeds were attached to the rudder or other part of the boat and they let go with no assistance by me, or perhaps an eddy was encountered mid channel.

Michael Lampi

Guest625101138

08-24-2008, 06:39 PM

Mike
You are in some good company with your race times. I get the impression you are more consistent this year.

On rudders - I would not recommend dipping rudders on the Cadence for the reasons you state. One point worth considering is a rudder that can be lifted clear to shed weed. This has been a spin-off with my rudders. I now have nothing underwater at the stern that catches weed. Having the prop right beside me makes it easy to clean. With the local lake in the present low water state it would be annoying if I could not easily clean the prop.

On GPS - were you able to get the speadsheet working? I found the Garmin charts to be limited although they are very easy and fast to use.

Did you see the blue-black boat with the flappers?

I had my first decent exercise for some months this weekend. I managed 20km on Saturday and another 15km yesterday. Start of a long road to get back some fitness. Our weather is now starting to warm up.

Rick

beppe

08-25-2008, 05:45 AM

...That said a cat will always require considerably more power than a stabilised monohull.
Rick W.

Rick and colleagues
I am not at all committed to the catamaran architecture, I like much better the stabilized monohull concept and I agree with you about the superior intrinsic efficiency of monohulls against catamarans, wetted surface and front section issues are unescapable.
Meanwhile, I believe there are a few problems to be addressed in order to satisfy the requirements for the Open Architecture Pedal Boat

http://www.openwaterbike.com/architecture/the-open-waterbike-requirements

within the monohull architecture.
Also, modularity can be more problematic within the monohull architecture then with the cat, and this is a central point for the Open Waterbike project.

Anyway I am very interested in proposing monohull architectures within the Open Waterbike project, the stabilized monohull concept is the best for performance and the possible evolution of stabilizers within the collective project is fascinating.
I would like to submit to you and the the other colleagues the startup concept of a twin monohull architecture as in the attached schema (dwg and jpg, excuse me for the poor quality, I'll provide something better ASAP), with two people on each side of the single hull, each with his or her own drive unit.
This architecture has the advantage of being modular, allowing the usage of OW standard drive units with forward kick-up mounting.
I understand that they are intrinsically less efficient than a single drive unit, but modularity comes at a price, as the enhanced safety of twin independent engines.
Meanwhile a twin boat should have an advantage against a single one, since power doubles, while drag does not.
I believe we can adopt a design power of 200 W for each rider, total 400 W.
I'd like your opinion of this architecture; I don't know if it was already used in the past, I don't recall similar PPBs.
Best
Beppe

Guest625101138

08-25-2008, 06:37 AM

Rick and colleagues
I am not at all committed to the catamaran architecture, I like much better the stabilized monohull concept and I agree with you about the superior intrinsic efficiency of monohulls against catamarans, wetted surface and front section issues are unescapable.
Meanwhile, I believe there are a few problems to be addressed in order to satisfy the requirements for the Open Architecture Pedal Boat

http://www.openwaterbike.com/architecture/the-open-waterbike-requirements

within the monohull architecture.
Also, modularity can be more problematic within the monohull architecture then with the cat, and this is a central point for the Open Waterbike project.

Anyway I am very interested in proposing monohull architectures within the Open Waterbike project, the stabilized monohull concept is the best for performance and the possible evolution of stabilizers within the collective project is fascinating.
I would like to submit to you and the the other colleagues the startup concept of a twin monohull architecture as in the attached schema (dwg and jpg, excuse me for the poor quality, I'll provide something better ASAP), with two people on each side of the single hull, each with his or her own drive unit.
This architecture has the advantage of being modular, allowing the usage of OW standard drive units with forward kick-up mounting.
I understand that they are intrinsically less efficient than a single drive unit, but modularity comes at a price, as the enhanced safety of twin independent engines.
Meanwhile a twin boat should have an advantage against a single one, since power doubles, while drag does not.
I believe we can adopt a design power of 200 W for each rider, total 400 W.
I'd like your opinion of this architecture; I don't know if it was already used in the past, I don't recall similar PPBs.
Best
Beppe

Beppe
As you increase the crew size in a monohull you can sit the riders within the hull. In this way you avoid the outriggers for stabilising. I have attached concepts for an enclosed 2-man craft and an open 4-man boat. I have also attached a sketch of the in-line pedal stations for such craft.

The 4-man boat has a design speed of 16kph and the 2-man 14kph. These speeds are based on sustained power level of moderately fit crew.

You would not want to hang the riders out on the side of the hull as you add considerable windage. These boats have the ability to move fast so windage becomes a sizable component of drag and needs to be addressed by the design. Windage can actually be less than a single person boat because the riders sit within the hull behind front deck cowling or fully enclosed.

Again this points out the need to isolate and understand the losses within the whole system. If you do not do this you are bound to have a flawed design.

So it would not make sense to design to suit independent drive legs when each rider can simply gang to a single through-shaft using efficient right angle drives. It also allows a single large efficient prop. With a tiny tension strut as opposed to large draggy appendages supporting each prop.

Overall your monohull proposal is a very poor concept. I could not see any good reason to do it like this unless one is wedded to a particular type of drive leg.

Rick

MLampi

08-25-2008, 09:36 AM

Rick,

Your enclosed boat designed for two or four people looks like it would be highly efficient and is certainly optimized for speed at low power input. I'm sure it would do pretty well, at least until the pilots collapsed from heat exhaustion. :)

I'm only partially kidding. One of the things I'm found while pedaling in races is that having a nice cooling breeze and the easy availability of water cooling is important on all but the coldest days out on the water.

If you have no way of getting those breezes to cool off the pilots, and if the water is unreachable for their hands, then they will heat up very rapidly and performance will diminish rapidly.

How does Greg K. do it in his enclosed boat? Doesn't he find himself getting rather toasty, the air stale, etc.?

MLampi

08-25-2008, 10:20 AM

Mike
You are in some good company with your race times. I get the impression you are more consistent this year.

That's one way you could put it. For almost the entire race, with the exception of the start and the last part of the finish, I was racing the speed and heart rate reported by the Forerunner, or going slow to take reasonably steady pictures. The times are not out of line from previous years where I actually raced with the field, but ran into more weed problems.

On rudders - I would not recommend dipping rudders on the Cadence for the reasons you state. One point worth considering is a rudder that can be lifted clear to shed weed. This has been a spin-off with my rudders. I now have nothing underwater at the stern that catches weed. Having the prop right beside me makes it easy to clean. With the local lake in the present low water state it would be annoying if I could not easily clean the prop.

Don't get me wrong - I think your setup is excellent just for those reasons. If I didn't feel the need for a good, strong reverse and dynamic stability forward I'd strongly consider using your type of arrangement.

On GPS - were you able to get the speadsheet working? I found the Garmin charts to be limited although they are very easy and fast to use.

I did get the spreadsheet open, but I need to spend some more time analyzing the results with respect to power vs. heart rate, etc.

Yes, the Garmin Training Center stuff is pretty limited and a little buggy. The freeware/shareware SportTracks software (http://www.zonefivesoftware.com/SportTracks/) is much better, but even that I haven't spent enough time with to understand all of its capabilities nor those of all the user-written plugins that are available.

Did you see the blue-black boat with the flappers?

No, that boat didn't show up for this race, either. In fact, there was no other pedal boat of any type at this event. Sigh...

One thing I neglected to mention about Saturday's race, that I touched on a little in my blog and other places, is that I'm beginning to think there is the possibility that the Cadence can actually get on a plane at about 8 mph under certain conditions.

I first noticed this phenomenon last fall when I had a 10+ pound lighter boat and decided to not carry anything else but water, and the canoe paddle I normally kept strapped to the right rear side of the boat for easy access was, instead, strapped to the front cockpit cover. This still allowed for easy access, but the weight was now forward and centered.

At that flatwater race I decided to have a faster start and the boat just moved. My pedaling cadence was quite high and my heart rate was in the 160's. I didn't have a cadence sensor at the time, but I'd guesstimate I was pedaling around 90 to 95 rpm. The GPS had turned itself off, but my sense of speed was that I was going at least 8 mph and my legs were feeling absolutely fine. The OC-6 and everyone else were quite far behind for at least the first half mile when I sort of panicked and thought to myself "1. I don't know where I'm going in these channels and a turn is coming up, and 2. I don't know how I am going this fast and I'll probably burn out even though I'm feeling fine right now.".

It was weird.

Anyway, at the flatwater GXSC in the heavy boat I've been racing all year I had the paddle in front again, but also had the 3 pound camera around my neck. I didn't have the outriggers on it as I have had for most of the other races, either. Anyway, there were a couple of times when it seemed like this boat was almost but not quite in that same mode.

I think that if I had a truly lightweight carbon Cadence I just might be able to get it to plane for most of a race, so long as it was trimmed a little more bow heavy. If so, then the gearing will need to be adjusted from 6.5:1 to 7:1 or higher. :)

Michael Lampi

tinhorn

08-25-2008, 12:12 PM

Yesterday I completed the Sound Rowers Great Cross Sound Race (http://www.soundrowers.org). My time of 1:15:xx wasn't stellar for the 7.5 mile distance, but then again I did take some 550 photos or so of the other racers.

THIS is why your name sounds so familiar to me. I've spent a lot of time viewing your pictures of previous races. (I just moved away from Walla Walla, and was particularly intrigued by NW events.)

In fact, there was no other pedal boat of any type at this event. Sigh...

That's odd, but this is a great segue for a question I haven't been able to get answered: We know leg muscles are more powerful than arm muscles, but to what general degree? Twice as powerful? More?

I'm curious because I've seen old hpb designs that use the upper body for propulsion when it seems that pedals would have been more effective.

beppe

08-25-2008, 03:37 PM

Beppe
As you increase the crew size in a monohull you can sit the riders within the hull. In this way you avoid the outriggers for stabilising. I have attached concepts for an enclosed 2-man craft and an open 4-man boat. I have also attached a sketch of the in-line pedal stations for such craft.

The 4-man boat has a design speed of 16kph and the 2-man 14kph. These speeds are based on sustained power level of moderately fit crew.

You would not want to hang the riders out on the side of the hull as you add considerable windage. These boats have the ability to move fast so windage becomes a sizable component of drag and needs to be addressed by the design. Windage can actually be less than a single person boat because the riders sit within the hull behind front deck cowling or fully enclosed.

Again this points out the need to isolate and understand the losses within the whole system. If you do not do this you are bound to have a flawed design.

So it would not make sense to design to suit independent drive legs when each rider can simply gang to a single through-shaft using efficient right angle drives. It also allows a single large efficient prop. With a tiny tension strut as opposed to large draggy appendages supporting each prop.

Overall your monohull proposal is a very poor concept. I could not see any good reason to do it like this unless one is wedded to a particular type of drive leg.

Rick

Rick
Thank you for your opinion, but this time, I believe, it is off the point.
The examples you give, althought so cool, doesn’t seem to take into account the OW specifications http://www.openwaterbike.com/architecture. As we all know, engineering is about trade-offs between (sometimes contradictory) different goals. This is the case here.
The Open Waterbike, as described by its specifications, is essentially a high-performance recreational boat. It is intended for use in good weather, calm or not so choppy waters, by reasonably fit but not-highly-trained common people who like to stay out in the open. Safety (and the perception of safety) and user-friendliness are as important as performance.
What you propose are essentially canoes in which you sit in a position not so comfortable nor necessarily so efficient. I am a kayaker and a recumbent cyclist; in any canoe you can get wet and capsize also in good weather, if you are not well trained. Your enclosed canoe could possibly need a good ballast and/or floaters for beginners or waves.
A low recumbent position, comparable to that of your drawing with the seat lower than the crank axis, is less comfortable then that of the OW prototype catamaran, with the seat 10 cm over crank axis level (http://www.openwaterbike.com/architecture/the-open-waterbike-architecture/the-open-waterbike-drive-unit/the-forward-tube-connection/). This could be also more tiring on long distances, even if the effect on performances is not well known.
For recreational (but also for tourism and commuting in good weather) you could prefer to sit higher out of the boat.
Finally, if I remember correctly, the Wavebike twin was a pedal boat in which the riders were not sitting inside the hull, but riding in a traditional cyclist position with high windage, possibly comparable with this of two recumbent riders side-by-side; if I remember well that was possibly the fastest production boat ever.
I agree with you, anyway, about the shortcomings of my monohull design (windage and double drive unit) but the real point is how much you pay for these choices, so I believe that a correct evaluation of the concept should be quantitative rather then just qualitative.
It could be very interesting to compare the canoe design performance and with this monohull concept.
I suspect the loss could be fairly acceptable.
Finally, no, I am not ‘wedded’ to any particular type of drive leg. I am interested in a standard interface for drive units to enable modularity. And yes, I am ‘wedded’ to modularity , the gateway to collective development according with the Open Waterbike concept.

Quandoque dormitat et bonus Homerus ;-)

With high esteem…
Beppe

Guest625101138

08-25-2008, 05:23 PM

......

How does Greg K. do it in his enclosed boat? Doesn't he find himself getting rather toasty, the air stale, etc.?

Ventillation is an important requirement as is sun protection. Greg set up a small fan and a couple of vents in the the test boat. His biggest issue with it is that the cabin top is so low that he cannot lean forward.

The concept that has evolved for the ocean boat has a number of port holes that can be opened to get free flowing air. The port holes can be sealed tight for heavy weather.

Greg found the most difficult aspect of the enclosed cabin was motion sickness but this is to be expected for a first time outing in the ocean.

The ocean boat is about 8m long and 1m beam by a bit over 1m high.

Rick W.

Guest625101138

08-25-2008, 05:39 PM

That's one way you could put it. For almost the entire race, with the exception of the start and the last part of the finish, I was racing the speed and heart rate reported by the Forerunner, or going slow to take reasonably steady pictures. The times are not out of line from previous years where I actually raced with the field, but ran into more weed problems.

Don't get me wrong - I think your setup is excellent just for those reasons. If I didn't feel the need for a good, strong reverse and dynamic stability forward I'd strongly consider using your type of arrangement.

I did get the spreadsheet open, but I need to spend some more time analyzing the results with respect to power vs. heart rate, etc.

Yes, the Garmin Training Center stuff is pretty limited and a little buggy. The freeware/shareware SportTracks software (http://www.zonefivesoftware.com/SportTracks/) is much better, but even that I haven't spent enough time with to understand all of its capabilities nor those of all the user-written plugins that are available.

No, that boat didn't show up for this race, either. In fact, there was no other pedal boat of any type at this event. Sigh...

One thing I neglected to mention about Saturday's race, that I touched on a little in my blog and other places, is that I'm beginning to think there is the possibility that the Cadence can actually get on a plane at about 8 mph under certain conditions.

I first noticed this phenomenon last fall when I had a 10+ pound lighter boat and decided to not carry anything else but water, and the canoe paddle I normally kept strapped to the right rear side of the boat for easy access was, instead, strapped to the front cockpit cover. This still allowed for easy access, but the weight was now forward and centered.

At that flatwater race I decided to have a faster start and the boat just moved. My pedaling cadence was quite high and my heart rate was in the 160's. I didn't have a cadence sensor at the time, but I'd guesstimate I was pedaling around 90 to 95 rpm. The GPS had turned itself off, but my sense of speed was that I was going at least 8 mph and my legs were feeling absolutely fine. The OC-6 and everyone else were quite far behind for at least the first half mile when I sort of panicked and thought to myself "1. I don't know where I'm going in these channels and a turn is coming up, and 2. I don't know how I am going this fast and I'll probably burn out even though I'm feeling fine right now.".

It was weird.

Anyway, at the flatwater GXSC in the heavy boat I've been racing all year I had the paddle in front again, but also had the 3 pound camera around my neck. I didn't have the outriggers on it as I have had for most of the other races, either. Anyway, there were a couple of times when it seemed like this boat was almost but not quite in that same mode.

I think that if I had a truly lightweight carbon Cadence I just might be able to get it to plane for most of a race, so long as it was trimmed a little more bow heavy. If so, then the gearing will need to be adjusted from 6.5:1 to 7:1 or higher. :)

Michael Lampi

Mike
There is a target speed around 18kph (maybe higher) where planing becomes less drag than displacement. Probably require around 300W for a very light boat. The most efficient hull for this is shorter and wider than the Cadence. The wide flat aft run on the cadence lends itself to planing though.

You may also find that with very good finish on your hull and increasing beam aft that in smooth water it can sustain laminar flow over a good portion of the hull. When this happens it is like you are on wheels. The smallest of chop upsets it so you can detect the change if you are looking for it.

Rick

Guest625101138

08-25-2008, 05:49 PM

........
I'm curious because I've seen old hpb designs that use the upper body for propulsion when it seems that pedals would have been more effective.

The size of muscles in legs or arms does not have much bearing on it. It is the ability to process oxygen and convert to energy so lungs are the main determinant of performance unless you are just sprinting.

Rowing sculls make use of both legs and arms but they are doing 6 minute events.

Paddling or pedalling have almost identical biomechanical efficiency measured in labs at around 26%. Sculling is lower at around 22% but then there are more muscles involved and it is normally anaerobic so making use of stored reserves.

Rick W

beppe

08-26-2008, 02:41 AM

If you post an igs or 3D dxf file of your hull, the hull separation, total displacement and some basic measurements for the drive leg and prop on you boat I will calculate the various components of loss and post them here. You can then compare with the measured data you have. If you like I can give you designs for the optimum hulls for your design displacement and chosen power level. This is always instructive as it shows what potential you have to improve. That said a cat will always require considerably more power than a stabilised monohull.
Rick W.

Rick
here are the data you require. My data about this boat include the usuals but also total metabolic power, and they are comparable with those of other boats found in literature, including olymic kayaks. I believe that analyzing these data with your computational tools and extending the results to more efficient PPBs can allow an assessment of the potential of our pedal powered boats against traditional high performance boats.

each hull:
length (WL) = 4800 mm
design displacement= 50.3 l (0,05 m3)
wetted surface 1.13 m2
prismatic coefficient= 0,60
section under WL is semicircular, dmax = 103 mm

hull separation:1.35 m

drive unit:
thickness: 25 mm
wetted surface: 16 dm2

rudder:
thickness: 8 mm
wetted surface:8 dm2

enclosed : dwg files with cross sections

Best
Beppe

Guest625101138

08-26-2008, 05:21 AM

Rick
here are the data you require. My data about this boat include the usuals but also total metabolic power, and they are comparable with those of other boats found in literature, including olymic kayaks. I believe that analyzing these data with your computational tools and extending the results to more efficient PPBs can allow an assessment of the potential of our pedal powered boats against traditional high performance boats.

each hull:
length (WL) = 4800 mm
design displacement= 50.3 l (0,05 m3)
wetted surface 1.13 m2
prismatic coefficient= 0,60
section under WL is semicircular, dmax = 103 mm

hull separation:1.35 m

drive unit:
thickness: 25 mm
wetted surface: 16 dm2

rudder:
thickness: 8 mm
wetted surface:8 dm2

enclosed : dwg files with cross sections

Best
Beppe

Beppe
I have attached the reconstructed lineplan of your cat.

It will achieve 10.1kph with 150W in calm conditions providing it has an efficient prop. It will require 245W to do 12kph. By comparison V11J requires 150W to do 12kph - cat is requiring 63% more power than the optimised mono.

An optimum catamaran for 10kph would require 15% less power than your cat.

If you give me some dimensions of your prop I can do a more accurate calculation using it. Need to know the design pitch, overall diameter, hub diameter, blade chord at a few points to get an idea of planform and blade section profile if you have it (Is is based on a symmetrical section or is it an asymmetric profile?)

Rick W.

Guest625101138

08-26-2008, 07:29 AM

beppe

08-27-2008, 05:29 AM

Beppe
The power estimate in the previous post was based on one of my props.

I did some back calculation from your published matabolic data using 26% biomechanical efficiency. Based on this your measured power is much higher than I calculate. It would be interesting to have the actual crank power.

I have attached my comparison. It suggests you have measured power of more like 350W to do 12kph. This indicates either poor biomechanical efficiency and/or poor drive efficiency.

Your data on the rowing scull at 4m/s is precisely what I predict for the hull using my standard figures of 22% biomechanical efficiency for rowing and 64% for rowing efficiency. This gives me confidence in my numbers.

You could improve the biomechanical efficiency using cleats as I notice they are not fitted to your boat. This is well documented for recumbent cycling position.

If you have a symmetrical foil section for the prop it will be less than optimal.

Rick W

Rick
your calculated results are very very interesting, I believe we can get somewhere from here, and in particular we can understand in a better way better if building a long distance PPBs faster then a traditional high performance HPB is really possible, against the frustrating evidence of Michael (and others, including myself) in races. And if it's possible, of course, I believe the Open Waterbike will get there first...

Have you got the whole paper we published in the Journal of Sports Sciences?

The complete reference is:

Zamparo, P; Carignani, G.; Plaino, L; Sgalmuzzo, B. and Capelli, C.; "Energy balance of locomotion with pedal-driven watercraft", Journal of Sports Sciences, Volume 26, Issue 1 January 2008 , pages 75 - 81

I am one of the authors, but I believe it's against the rules of this forum to upload the whole paper since now that it's published it's copyrighted material.
I have a zillion questions about your results but I can give you before that a few more data for refining the analysis:

overall efficiency for the cat is 0.27 in this case;
propelling efficiency is 0.57@2 m/s and increses slowly with speed (as usual) to 0.62@3 m/s

The disappointing figures of measured propelling efficiency can have different explainations due to the conditions of the drive unit during the testing procedure, I'll tell the story later; I believe we can treat the drive system as a black box for now using these efficiency figures. This figures can explain why your simulation gives better results than the measured data, and a correction of your calcululation using the experimental efficiency should show an even better alignment.
Also, the displacement of the craft during the tests was of course slightly different form the design displacement, due to different body mass of each subject (we tested seven of them, five males, two females).
Effective displacement was 97 to 114 l. This also could have lead to worse results of course.

The first of my zillion questions:
Have you estimated the drag of the boatat different speeds?
How much of the drag is due to hull drag and how much to appendages and hulls interference?
Is the comparison with a monohull based on same displacement and same length?

Thank you for your analysis Rick, I'm really impressed...
Beppe

Guest625101138

08-27-2008, 06:39 AM

...
I am one of the authors, but I believe it's against the rules of this forum to upload the whole paper since now that it's published it's copyrighted material.
...
Beppe

Beppe

This statement suggests to me that it is the "Open" waterbike providing you are not required to provide any intellectual property.

I appreciate the information supplied on the hull and the time taken by you to understand that you need to know the sources of losses before you can methodically address them - the fact that you are impressed by it also indicates you did not comprehend what I was pointing out earlier.

For the other questions I feel it is going to be a one way street with me providing you intellectual property freely and you claiming copyright as soon as there may be something I have interest in. Certainly not what I regard as an OPEN community.

You collect all the information from others on the pretext of being OPEN and then clam up when it comes to contributing your own data. It certainly puts your motives into question!

Rick W.

beppe

08-27-2008, 07:07 AM

Beppe

This statement suggests to me that it is the "Open" waterbike providing you are not required to provide any intellectual property.

I appreciate the information supplied on the hull and the time taken by you to understand that you need to know the sources of losses before you can methodically address them - the fact that you are impressed by it also indicates you did not comprehend what I was pointing out earlier.

For the other questions I feel it is going to be a one way street with me providing you intellectual property freely and you claiming copyright as soon as there may be something I have interest in. Certainly not what I regard as an OPEN community.

You collect all the information from others on the pretext of being OPEN and then clam up when it comes to contributing your own data. It certainly puts your motives into question!

Rick W.

Rick
you don't understand.
The problem is not my intellectual property, but the rules of this forum (have you read them?) and the copyright of the publisher of the Journal.
The paper is published, it's no secret at all.

Please have a look at this page
http://www.openwaterbike.com/our-boat/fastest-boat-in-the-world
and download the file, it has always been there.
All the other more detailed data we have recorded during the tests are also available to you and all the other colleagues, just ask.

I humbly believe I understand what you pointed out earlier, what I said is just that a more aggregate concept of efficiency (the propelling efficiency, that is the data I gave you before) could be interesting for comparing purposes, because we have the data in literature, while we have not those of more detailed efficiencies that are meaningless for other kinds of watercraft and aquatic locomotion.

Best
Beppe

Guest625101138

08-27-2008, 07:16 AM

Guest625101138

08-27-2008, 08:35 AM

Beppe
Based on the SRM power measurement your propulsion system has very large unaccounted losses. There is an unaccounted gap of around 65W.

My drag calculations and your total drag measured data are almost identical. At 10.1kph the power is apportioned as follows:
Rudder 4.8W
Drive leg drag 13.2W
Windage 4.7W
Wave making 26.9W
Viscous hull drag 74.7W
Prop losses 21.6W (this is for my V11J prop - sub-optimal for your boat)
Mechanical losses 4.5W (this is with a precision right angle drive)

Total calculated power is 150.4W.

This compares with your regression curve of 214.9W.

Hence there is something like 65W gone missing. More if the prop was optimum.

There seems to be high no load losses on the drive unit of about 20W. You should be able to check this using the SRM crank without any load on the prop or even with the prop removed from the shaft. We eventually got Greg's unit below 2W and mine runs around 3W. His with new seals was costing between 6 to 7W at no load.

It is hard to imagine your prop being so poor as to lose an extra 50W but I would need more detail on it to assess. From the photos it looks to be 420mm diameter with 50mm blade chord. I cannot guage the blade thickness. There is a Canadian firm who milled Greg's prop from my CAD file and is prepared to make other one-offs for CAD550. I hand fabricate my props but the ones Greg has had milled are more precise and give almost 1% higher efficiency. I have attached a photo of one of the props Greg had made.

I expect if the chain was dragging enough to rob 50W or more it would be showing metal shavings in the oil by now.

So you need to be looking for 65W that you are just throwing away. That is not to say you should be happy with the rest as there are many opportunities to go faster for much less effort.

In calm conditions V11J will cruise at 10kph with 92W. Basically just rolling the legs around.

Rick W.

beppe

08-27-2008, 04:09 PM

Beppe
I did not realise the paper was on the web site. I would have looked at it earlier. I had only seen the graph - not the link to the paper.

I will read through it to digest what you have actually measured.

Rick

I take this as an acknowledgment that my intentions are not after all as vile and evil as you said before... Your words are a bit heavy sometimes, Rick; try not to scare off all the contributors of this thread you started ;-)
Beppe

Guest625101138

08-30-2008, 04:47 AM

Took my first steps to repower the new boat today.

Conditions were not ideal as the wind picked up but Jeff Nielsen came down and had his first test ride. I will now do some alterations to better suit his preferred pedalling geometry. He is taller than I am and his recumbent racing position is more straight legged with lower bottom bracket. I will make the position of the crank adjustable.

The testing gave me the chance to take videos off the boat and I have posted a clip of the session here:
http://www.youtube.com/watch?v=8BiGp94RLX0

The attached chart shows the GPS trace. Even with the wind up around the 20kph mark he was able to hold over 11kph without a lot of effort so he is a good engine.

Rick W

beppe

08-31-2008, 04:16 PM

Nice testing day yesterday for Open Waterbike 'prototype 0'. Not really the Open Waterbike, just the starting point of the project...
Nice weather at lake Cavazzo, our usual testing site. It is a small lake in North
eastern Italy, not far from the Austrian border. There is also a monster in the lake, but it didn't show up. A bit windy at first, then flat water. Actually, we were not testing performances, just user-friendlyness, the perception of safety by common people and the reliability of the new drive unit.
Several people tried the boat, most of them ladies and children. The registered speed (GPS) range was from 5 to over 7 knots , as expected. We discovered that ducks are not afraid of the waterbike, and the ladies just loved that.
Maneuverability was also tested for duck-chasing with good results...
We recorded a few videos, but most of them they are too cumbersome for uploading; we'll put them after editing on utube. Just a picture and a video for now, Open Waterbike with lady nere:
http://www.openwaterbike.com/our-boat/our-boat-safe-fast-easy
Beppe

markdrela

08-31-2008, 10:20 PM

Guest625101138

08-31-2008, 10:56 PM

Here's a potential system to consider for your open waterbike project.

The attached sketch shows an HPB drive system which I and two other guys built back in 1994, right after the Decavitator project. It worked very well. The thin shaft was quite stable, and did not exhibit any whipping tendency even at full sprint power.

The nice features are:
* only a simple and cheap 1:1 bevel gearbox is needed
* no complex mechanism or seals under the water
* no additional axial-loaded bearings besides the gearbox itself
* very simple prop replacement system

The "screwdriver" shaft-end system mimics a bike crank axle taper,
and allows a much smaller flex drive shaft than what a shear-pinned joint would need.

The 1/4" pitch chain and sprockets are easy to get.
The only special item was the large 120 tooth chainring, but that was
a fairly simple CNC job from aluminum plate.

Mark
You may be interested in this photo:
http://boatdesign.net/forums/attachment.php?attachmentid=23439&d=1216205907

That shaft operates without any support other than at the gearbox. A pushing prop is self stabilising so as soon as it starts to turn the prop just rises and aligns with flow.

This video clip shows a completely unsupported prop using an 8mm aluminium shaft:
http://www.boatdesign.net/forums/attachment.php?attachmentid=23455&d=1216266495
I pushed the OC1 to 15kph with just that shaft. The aluminium section is 1.2m long.

I normally use a tension strut to enable going in reverse. With this and the prop beside me I can reach down and pull it up to remove fouling. Also for beaching or obstacles the prop just bounces over.

There is a balance between torsional rigidity and fatigue life. With good spring steel you can get a good compromise. I design for prop speed of 300rpm at design boat speed and 1/4" steel is just a bit thin. For sprinting I go up to 10mm spring steel and live with the extra weight to get a tolerable stress range. There is very little loss due to shaft torsional constant once you get to this thickness.

This system does result in very low appendage drag for the prop.

The other thing I have posted in earlier posts on this thread is my dipping rudders. These are only immersed when you want to turn or one just immersed enough hold a straight course.

I can provide the design data if anyone wants to have a go at a reliable curved shaft system.

Rick W.

markdrela

08-31-2008, 11:42 PM

That shaft operates without any support other than at the gearbox. A pushing prop is self stabilising so as soon as it starts to turn the prop just rises and aligns with flow.
Yes, but only if the shaft is thick enough (and hence draggy enough). With the minimal 3mm shaft there is a buckling mode at low speed and high power, since then the P-factor forces are not enough to restrain it. Also, a dangling prop like that is not attractive if the boat is to be usable in knee-deep water (e.g. beach launching).

Guest625101138

08-31-2008, 11:52 PM

Yes, but only if the shaft is thick enough (and hence draggy enough). With the minimal 3mm shaft there is a buckling mode at low speed and high power, since then the P-factor forces are not enough to restrain it. Also, a dangling prop like that is not attractive if the boat is to be usable in knee-deep water (e.g. beach launching).

Current shafts are either 6 or 8mm spring steel and approximately 3.5ft immersed length. The tension strut is faired 20mm long by 1.2mm thick aluminium. The stainless steel bearings I use in my prop strut fit within a 14mm OD tube.

I will need to do some calculations to see what is more efficient. What I have is very low drag and uses standard bicycle chain with 4:1 reduction so chainring is only 52T.

Rick W

Guest625101138

08-31-2008, 11:58 PM

MLampi

09-01-2008, 01:13 AM

I should add that the system I use has a side mounted shaft to avoid through hull penetrations.

One common problem with the prop drive boats is prop fouling so mounting the prop beside me allows easy access to remove weeds.

Also a prop mounted on the stern under the hull would be wiped out on the first log encountered. I have designed for things to just flex out of the way to avoid fatal damage.

Rick W

It depends on the durability of the prop, too.

I've encountered submerged rocks with an under the hull stern mounted prop. Yes, it makes a big CLUNK sound, and yes the propeller blade is no longer quite the same shape. Still, the propeller worked quite well and I was able to complete the journey some 5 miles later without much loss in speed.

With a manganese bronze prop the blade curls over a bit, and can be easily repaired at a prop shop.

With a ZnAl alloy or a plastic prop, I'm sure that bits and pieces of the prop would have been left behind.

A free prop shaft such as yours would enable the prop to experience far less damage, regardless of the material, but you lose the ability to go in reverse via pedaling action. Whether that is significant depends on where and how you use your boat.

Guest625101138

09-01-2008, 01:25 AM

It depends on the durability of the prop, too.

I've encountered submerged rocks with an under the hull stern mounted prop. Yes, it makes a big CLUNK sound, and yes the propeller blade is no longer quite the same shape. Still, the propeller worked quite well and I was able to complete the journey some 5 miles later without much loss in speed.

With a manganese bronze prop the blade curls over a bit, and can be easily repaired at a prop shop.

With a ZnAl alloy or a plastic prop, I'm sure that bits and pieces of the prop would have been left behind.

A free prop shaft such as yours would enable the prop to experience far less damage, regardless of the material, but you lose the ability to go in reverse via pedaling action. Whether that is significant depends on where and how you use your boat.

Mike
I was a bit more concerned about the fate of a 3mm shaft carrying the weight at the stern of the boat as it was being ridden up a log or rock. I have found it has to be very robust with ability to support the weight or compliant so it just flexes out of the way. The Cadence is on the robust side and not overly large to add to drag.

In the 2005 Murray Marathon the fastest +50yo fellow hit a log with his rudder and the back of the blade punctured the hull. He managed to finish but the boat was half full of water.

There are lots of ways to cause damage and it seems one of the issues with PPBs over paddles or oars is the prone nature of underwater bits. It would be nice to have a 90% efficient jet drive.

Rick

beppe

09-01-2008, 11:35 AM

Here's a potential system to consider for your open waterbike project.

The attached sketch shows an HPB drive system which I and two other guys built back in 1994, right after the Decavitator project. It worked very well. The thin shaft was quite stable, and did not exhibit any whipping tendency even at full sprint power.

The nice features are:
* only a simple and cheap 1:1 bevel gearbox is needed
* no complex mechanism or seals under the water
* no additional axial-loaded bearings besides the gearbox itself
* very simple prop replacement system

The "screwdriver" shaft-end system mimics a bike crank axle taper,
and allows a much smaller flex drive shaft than what a shear-pinned joint would need.

The 1/4" pitch chain and sprockets are easy to get.
The only special item was the large 120 tooth chainring, but that was
a fairly simple CNC job from aluminum plate.

Thank you Mark for your contribution to The Open Waterbike Project
I’ll send your draft to the Open Waterbike members; ours is a small (but growing) community and we have already a few members with manufacturing capabilities scattered around the World.
Meanwhile we will discuss modularisation, but is seems to be straightforward for the catamaran architecture and easy also for the a monohull architecture. Moreover, the principle of one-to-one function-component mapping is respected.
Rick Willoughby 'offset shaft' is a way to address the hull-shaft interference solving one of the modularization problems and also a couple of practical issues, as he explains in one of the following posts.
Anyway they are minor points; I believe your proposal could be a major step forward in this early phase of the Open Waterbike Project.
Thank you again!
Giuseppe ‘Beppe’ Carignani
Funder, The Open Waterbike Project - ‘Our boat is faster than mine’

MLampi

09-01-2008, 11:49 AM

...
There are lots of ways to cause damage and it seems one of the issues with PPBs over paddles or oars is the prone nature of underwater bits. It would be nice to have a 90% efficient jet drive.

Rick

Hi Rick,

I guess the stories of some of the details of the open water races between rowed, paddled and pedaled boats didn't get published as well as they could have been.

There is a very strong rower in our club who normally rows one of his three double shells with either his son or another strong rower, and is very competitive. Several times he has managed to row over reefs, rocks, buoys, and even into the broad side of an anchored yacht in his zeal to win.

He and others have often broken the small skegs on the bottoms of their shells that help the boats track in straight lines, sometimes with extremely disastrous results as the skeg cuts through the carbon hulls like a knife through butter.

It doesn't help that his $10K+ shells just don't seem to be quite up to the task of staying in one piece during these mishaps.

There are also many stories from the surf skiers in this area complaining about catching weeds on their rudders, even on the swept back "weedless" style. They also talk about switching rudders depending on the size of the waves they encounter. Some folks even carry different sized rudders with them, so they can switch them out as conditions change - or if they happen to lose one due to mishap.

Of course, in the less competitive world of sea kayak touring, most of the boats have kick up rudders and absolutely nothing but hull below the waterline.

FYI.

Michael Lampi

beppe

09-02-2008, 02:30 AM

Mark Drela's drive system with its incredibly thin shaft is just another demonstation that 'invention' and 'innovation' (the successful diffusion of invention) are different issues indeed.
Rick Willoughby amazing 'unsupported shaft' and 'dipping rudders' are also beautiful achievements; we hope that the Open Waterbike Project will prompt the diffusion and improvement process
Following the principles of openness we will try to diffuse them keeping them open and preserving the acknowledgment original (Mark's and Rick's) paternity of the invention.
Rick, have you a draft of the same kind of that provided by Mark, including also your name?
The Open Waterbike Project has already turned in an unexpected way, it seems that we will have to throw to the wind some extablished knowledge about drive units, but this is always the case with radical innovation.
Also, it shows the Open Waterbike catchprase 'our boat is faster than mine' in action. It seems that our boat will be 'much faster than mine' and this is just great!
Thanks again Mark and Rick!
Beppe

I57

09-02-2008, 09:35 AM

Markdrelas drive system looks great, it keeps the drive very compact with the minimum amount in the water. A bigger prop with a 4:1 gear ratio is the most efficient but makes for a large prop. What is more efficient, a large more efficient prop with higher drag or a smaller less efficient prop with less underwater drag? The smaller prop has the advantage of a lower draft and able to launch in shallower water.
I am thinking of a monohull similar to a rowing shell but a bit wider with the 10:1 drive unit connected to a flexible shaft and fixed at the prop with a skeg this would have a prop of say 200-250mm. The boat would be a complete unit ready to go and small and light enough to be carried on a cars roof rack.
Rick, my boat is ready to go again but waiting on the weather.

Guest625101138

09-02-2008, 09:39 AM

Guest625101138

09-02-2008, 10:18 AM

Ian
At 150 watts there is probably about 2W difference in the prop to the advantage of the larger prop. The difference in shaft losses would offset this.

I find having the prop beside me and able to flip up out of the way is a bonus. You simply will not operate in the lake at the present time unless you can easily inspect and clean the prop.

A prop under the hull without any protection for the shaft is bound to be fragile.

The 10:1 gearing will be harder to get. It will not be bicycle components. The gearbox could be smaller and cheaper than one for 4:1. A 9mm shaft would be more than adequate. Only issue will be the radial load on the input shaft. It may need an outboard bearing to provide sufficient support.

There are swings and roundabouts. Most people take a second look when the see the 1/4" shaft so a piece of thick wire would have them really wondering.

One thing I have not checked is the torsional rigidity. It might feel very rubbery.

Rick

markdrela

09-02-2008, 11:16 AM

The 10:1 gearing will be harder to get. It will not be bicycle components.
Not as hard as you think. See
http://ubicycle.wordpress.com/2008/07/15/are-you-still-riding-on-old-fashioned-12-pitch-chain-its-time-to-move-up-down-to-nanodrive/
You can get 1/4" pitch chain hardware from lots of outlets.

One thing I have not checked is the torsional rigidity. It might feel very rubbery. A thin shaft is relatively compliant in torsion, but this is not a drawback we found. One effect is that it smooths out the prop's RPM/torque variation if the legs' speed varies over the pedal cycle, which improves prop efficiency. It does feel "different" than pedaling a bike, but it certainly doesn't cause any direct mechanical losses.

A uniform RPM like on a bike would of course be ideal. But this would require a substantial flywheel on the high-speed side at the gearbox, which probably isn't practical.

Guest625101138

09-02-2008, 05:37 PM

Not as hard as you think. See
http://ubicycle.wordpress.com/2008/07/15/are-you-still-riding-on-old-fashioned-12-pitch-chain-its-time-to-move-up-down-to-nanodrive/
You can get 1/4" pitch chain hardware from lots of outlets.

A thin shaft is relatively compliant in torsion, but this is not a drawback we found. One effect is that it smooths out the prop's RPM/torque variation if the legs' speed varies over the pedal cycle, which improves prop efficiency. It does feel "different" than pedaling a bike, but it certainly doesn't cause any direct mechanical losses.

A uniform RPM like on a bike would of course be ideal. But this would require a substantial flywheel on the high-speed side at the gearbox, which probably isn't practical.

Mark
The torsional rigidity has a large bearing on the ability to apply power unless you are a well trained cyclists. It has a large bearing on the overall biomechanical efficiency for most riders. There would be very few who have trained with springy systems long enough to cope well. It feels very awkward when extreme.

I did the numbers for an 8mm aluminium shaft and the RMS power is quite a lot higher than the average power for most people once you start to apply a reasonable power level.

I have set an acceptable limit of 7Nm/rad for my shafts spring constant at 4:1. So at 10:1 the torsional stiffness should be above 2.8Nm/rad on this basis. The 3mm shaft at 8ft long is 0.25 so would be unacceptable to most for any reasonable feel.

If you get above 7 the feel is tolerable for cruising power level of 120 to 150W at 4:1 and design cadence of 80. If you are trained to spin at higher cadence, so design torque is lower, then 7 is quite good. Greg K can do 1000m sprints at 15kph with his 1/4" shaft and this requires 280W average. The spring constant is 11Nm/rad.

For my sprinting I like a stiff shaft. The torsional rigidity above 20Nm/rad. Once you get to levels like this the feel is virtually the same as road cycling. There is no notion of rebound through the dead spot.

Rick W.

Guest625101138

09-06-2008, 03:42 AM

Started the slow process of de-coking the old engine to day. Spent 2.5 hours on the lake holding heart rate around 150bpm. Attached chart shows the result.

Weed is still a nuisance in the little lake but it was an incredibly balmy spring day for us here. Just about the perfect day. Quite often glassy smooth and occasional breeze to 10kph.

I expect I am about 20W down on my average condition but a few more weeks on the boat and a bit of running will get me back into some level of fitness.

Rick

Tiny Turnip

09-09-2008, 05:41 PM

The 24 hr HPB record dashboard on Adventures of Greg is looking very promising, Rick. Baited breath here...

Guest625101138

09-09-2008, 05:44 PM

TT
I am just making a post on the pedal powered thread. He got the record with 10 minutes to spare but they have stopped updating so I do not know the exact finish.

Rick

Guest625101138

09-09-2008, 05:51 PM

Greg K managed to better the world record for distance covered on water in 24 hours. He passed the old record, set on a surf ski by Carter Johnson, with 10 minutes to run. The old record was 242km and Greg was heading for 245km.

Exact distance is yet to be confirmed but he aimed to claim both IHPVA and Guinness records. It could be a silly situation where they are different distances because one allows GPS indication while for the other it must be over a marked course and he has to have some clearance to the buoys. Still to see the end results. No doubt he is in recovery mode.

He maintained a very steady pace with average in the first few hours around 10.8kph dropping to 10.2kph at the finish. He had a little left because pace picked up a bit toward the end.

Rick W.

Tiny Turnip

09-09-2008, 06:05 PM

Rick - huge congratulations on what you have achieved with the rest of the team - absolutely fantastic!

http://msp236.photobucket.com/albums/ff304/Disturbed_11/congratulations.gif

very best

Adrian

Guest625101138

09-09-2008, 06:27 PM

TT
I did the engineering. Greg built the boat and was the perfect engine. He also persevered to get it as good as possible.

I doubt that anyone else could hold their nerve as well as he did over a 24 hour period. The strategy was to hold a constant speed and he very nearly managed that. Initially he would have been well within himself so he could stay nourished.

The weather played its role as well. The beginning had a little more wind than you would like but the evening and early morning were calm. Under those conditions the boat just glides and this would be encouraging.

Now when do you get your boat in the water for first trials?

Rick

Tiny Turnip

09-09-2008, 07:09 PM

Guest625101138

09-09-2008, 07:30 PM

I've just taken 'Fangle' apart for painting. I spent as long messing around with the seat bases as I did with the rest of the build. And still not great. With a couple of late nights, we might get into the local lake at the weekend - with a bit of a family gathering along - nothing like a little pressure!

I can offer some useful information here - maybe I have already stated it.

I have never managed to be satisfied with any boat on the first outing. Some have been terribly disappointing. It is primarily a learning experience that has a lot of anticipation. It marks a different phase of the work. Typically second outing results in better performance but only after correcting niggling issues.

I am looking forward to the photos.

A GPS is a very handy piece of equipment to guage performance and subsequent improvements. I have three portable ones and there is a fixed one in wife's car. They are everywhere now days and cost very little. If you are into exercise and engine calibration then the Garmin Edge are brilliant little units.

Rick

Guest625101138

09-09-2008, 07:52 PM

TT
Greg just posted his GPS distance - 245.164km. So now wait to get it officially recognised.

The number of comments suggests quite a few watching his progress. Advances interest in pedal powered boats and their real potential as a means of getting about on water. Still a long way off being an Olympic event though.

Rick

tinhorn

09-10-2008, 12:50 AM

The number of comments suggests quite a few watching his progress. Advances interest in pedal powered boats and their real potential as a means of getting about on water. Still a long way off being an Olympic event though.

I've already stated that pedal-powered boats could become as popular on the water as fancy bicycles are on land. Many people enjoy the exercise, the quiet, the slower pace. But mention pedal boats and most people think of those kids' toys. It's guys like Greg, and you and Geno, and a couple small firms now moving from Model T to Model A models that will make them practical and acceptable and eventually available. I think that in ten years we'll be seeing them everywhere.

beppe

09-11-2008, 11:56 AM

I've already stated that pedal-powered boats could become as popular on the water as fancy bicycles are on land. Many people enjoy the exercise, the quiet, the slower pace. But mention pedal boats and most people think of those kids' toys. It's guys like Greg, and you and Geno, and a couple small firms now moving from Model T to Model A models that will make them practical and acceptable and eventually available. I think that in ten years we'll be seeing them everywhere.

Congratulations again to Greg and Rick... I would say (and hope) less than ten years, times are ripe. But look at collective distributed innovation, this will be the gateway to innovation this time.
Giuseppe

Tiny Turnip

09-21-2008, 08:12 PM

I got my pedal boat fangle into the water today, and I am very, very pleased. It is a conversion of Dart 18 hulls, with the addition of a deck in place of the trampoline, and two seacycle drive units with 16" seacycle props, and Trice recumbent bike seats. It packs up well on the trailer, and assembles and breaks down readily. As predicted, trim is slightly down forward, about 40mm at the prow, with two adults only, but the upward aspect of the deck disguises this, and it allows for passengers and gear on the deck. The boat tracks beautifully, but is also very manoueverable under rudders. It is also very manoeverable under power alone, just requiring more communication between the two engines! This gives us the possibility of cruising with no rudders in the water, only putting them down when a lot of fiddly manouvering is necessary. The only downside of this would be the fact that the more powerful engine, Paul, would have to ease off to match my weaker pedalling, to allow us to track straight. I have no idea whether the reduced drag of those large rudders out of the water (which could be used to correct the power differential) would compensate for Paul not being able to max out.
The lake trials revealed some snagging: The seat bases and attachments of the seat to the base needs work. The straps round the front spar to provide hand holds to pull against when pedalling hard would help.
There was a slight tendancy for the hulls to creep apart - my deck panels don't tie the hulls together the way the trampoline would have.
The pedals could do with being a couple of inches higher, and nearer the back of the boat, to allow shorter legged engines to perform. This will mean rather more fiddley engineering of the beams.
The trial was hindered by a lack of understanding of the country park staff: A meathead in the rescue RIB came hairing after us at about 25 knots, yelling that we were "classed as a pedalo, and had to stay within the pedalo area" - though there was no evidence of any pedalos, and that meant access to about an eighth of the water area. I also hit an underwater something while pedalling hard, which has bent and stressed the ABS? propeller, and seems to have damaged the drive unit internally - it clonks on the power stroke now under load, and starts to bind if pushed hard. I shall have to see if I can get it apart.
Anyway, the leisurely, pedal all day pace you can see Paul and his wife Fiona not getting out of breath at is 3.8 knots, according to the elderly GPS, and we hit 5.3knots in a burst, until I knackered the prop and drive. So, teething troubles, but overall, I'm delighted with what promises to be a very controllable, manouverable, versatile and reasonably quick boat.

The wmv movie is about 1min 45seconds long, and under 4mb.

Guest625101138

09-21-2008, 09:23 PM

TT
Nice to see Fangle on the water. Where did the name come from?

Actually the trim looks good. Hard to tell it is bow down.

The performance is below what I calculated but it is early days. You would certainly get benefit from removing the rudders. You only need one at most.

I will be interested in what you find with the damaged drive leg.

Need to do some engine calibration and get some data on the power level. Do you have any idea of the cadence for a particular speed? You can get this off a good video clip by counting frames for say 10 revs at a known speed. The Garmin edge 305 is a great unit if you want to get serious with engine/boat data. It helps quantify benefits of any changes - guess it depends on what you want to do.

I look forward to your next report.

Rick

Guest625101138

09-21-2008, 10:09 PM

The gap between predicted and actual was enough for me to check my earlier calculations. I did find an error. The impact is not as dramatic as the scale of the error because of the hull shape. I used pounds instead of kilograms from your original weight estimate.

I have attached the new curve. It still suggest a significant gap. With two reasonably fit men you could expect to hold 100W each in an all-day mode. This should give you about 4.7kts. At a more energetic level then 150W for 30 minutes or so is possible. This should give over 5kts. In an all-out sprint then two men could each get over 500W in a well set up system. This should get Fangle to the 7.5kt mark.

These estimates are based on overall drive/propulsion efficiency of 80% in calm conditions. The allowance for appendage drag is taken up in the overall efficiency. Big rudders and poorly shaped drive leg would make this worse. Thing is, you can isolate the cost of these individually if you have the engine/s calibrated.

Anyhow the boat goes and is not at all shabby in performance or looks. Just have to convince the local authority it is not your typical pedalos.

Rick

Tiny Turnip

09-22-2008, 07:50 AM

Rick, thanks. I am arranging a callibration session at the local gym.
I forgot to mention that before damage to the drive leg, which considerably limited the amount of power it was possible to exert on the cranks, we were previously hindered by insufficient resistance in the kick back buttons, so every time we pedalled hard, the units kicked up. I didn't get this correctly adjusted until after the drive leg damage occurred.
Also, we out ran the longest straight course in the 'Pedalo area' very quickly - perhaps 200 metres at most. The gps was struggling to keep up. And in addition to the adult engines, we were carrying another 140lbs of boisterous young boys. Bar testosterone fuelled rescue RIBs, we were still the fastest thing on the lake - outstripping a canadian canoe with three paddling with ease. So, we are looking forward to better things.

Tiny Turnip

09-22-2008, 07:54 AM

Tiny Turnip

09-22-2008, 07:59 AM

I was very interested to see how linear the speed/power relationship is both below and above 4.5 - 5 knots on your graph, too. I had expected it to be more exponential - presumably the curve will go exponential at much higher speeds?
What makes it change angle at the 4.5 - 5 knot mark?

Tiny Turnip

09-22-2008, 08:58 AM

Oh, and Fangle comes from the delightfully translated sales blurb on the package of a cheap toy combine harvester for my boys, which was described as 'All are fangle' as in new fangled. - it means a new thing, something invented for entertainment. And the rhyme with 'mangle' combined with the rotating thresher of the combine harvester rather suggested a slightly sinister pedally action. Fanglewangmangler perhaps?

Guest625101138

09-22-2008, 09:22 AM

Oh, I forgot to ask - I am thinking of raising the drive legs a little, to improve the pedalling position, and bring them further back to accommodate shorter legs. Is there a minimum recommended depth of water over the top of the prop?

TT
I set my props about 2" below the surface. This is borderline once you get some chop. If I accelerate hard the swirl from the tip vortex will suck air but once moving it is OK.

With your drive leg you need to watch out for wake from the drive leg causing a trench. If the prop is facing forward then this will not be an issue. The bow wave from the hull may cause a trough as well. So the setting is dependent on conditions to some degree. If you can set it so it does not ventilate most of the time then you have found the best position.

The kick in the curve around the 4.7kt mark is where the wave drag starts to develop. The wave drag does not increase much beyond 5.5kts so the viscous drag dominates. If you remember, in my original analysis I pointed out that the boat responds well to extra power for a relatively short hull length.

The Garmin Edge 305 I have can give time resolution down to 1 second so is very good for data collection. It has heart rate and cadence recording included. They are not the cheapest but certainly good value.

You should be able to do some reasonably comprehensive testing by trying things like 1 rudder, no rudders, one drive leg and so on. If you are into the engineering aspects it can be good fun understanding where the power goes.

Rick

Guest625101138

09-23-2008, 07:58 PM

TT
I was wondering what you are doing about your damaged prop?

It is quite easy to make very good props from stainless flat bar if you can weld. A bit tedious shaping with a hand grinder but not very difficult to get a good profile.

If you want to have a go at this then I can provide details on what to make and how to do it.

Rick

Tiny Turnip

09-24-2008, 06:05 PM

Guest625101138

09-24-2008, 06:59 PM

Rick- I would like to have a go at this- I do have a 125amp mig, but my welding is pretty Chickensh*t and I've never tried s/s which I understand is pretty techniquey. but I do have an excellent, cheap s/s Shop down the road from me, with laser cnc, so I could get them to make up hub and blade 'blanks', and then get medieval on them with the grinder. the pictures you have posted of your props look beautiful. how critical is the foil profile? its hard to imagine getting this very accurate by hand with the grinder. I remember you saying that the props would be low slip. would that imply that a lot of their effectiveness is from screwing forward through the water and less from lift off the foil?
would the engine calibration inform the prop design significantly? I'm wondering about props designed to an 'average' engine, or tailored - two different props for the different engines?
In the mean time I have straightened the bent prop (not abs on second thoughts) reasonably successfully.

I find stick welding stainless easier than mild steel if you have the right rods.

I use stainless nuts ganged or stainless rigid coupling or a combination of them for my hubs. Coupling nuts are also a possibility. These options are heavier than normal tubing and are hard to blow away when welding. The blades are usually made from 40mm wide by 3mm thick stainless flat bar or their close equivalent in imperial size. I would design specifically for the material you can get but this size is close to the right proportions.

The shape is not absolutely critical. The range of performance will be around 80 to 87% efficiency depending on how well you can achieve the foil shape. The 80% would be for a tapered and curved leading edge and a pointed trailing edge. It is not that hard to achieve a good foil because you mark up grind lines to work to. Just takes a bit of time and care. I use a sanding disc for rough finishing and then hand sanding to get really smooth. You can always come back to it after testing anyhow.

The idea of the engine calibration is to get the desired cadence and the power level. I then make the prop to match the engines to the boat. In this regard I could adjust the prop design to suit different engines if needed. Remembering that different thrust will need to be corrected by some constant helm to track straight. The drag associated with this will be small. You could use a single rudder much smaller than you currently have.

There are some photos of a prop on this link showing how they can be fabricated:
http://web.mac.com/cschaffh/iWeb/HPB/HPB%20Drive%20v2%20Build.html
This was a three bladed prop but a 2-bladed prop would be best if there is no diameter constraint. I doubt that they would be any bigger than you currently have.

Rick W

Guest625101138

09-30-2008, 06:09 AM

More engine tuning. A perfect day last Saturday. Close to dead calm throughout the morning. Temperature around 20C.

I finally got the cadence sensor mounted on my new frame so the Garmin Edge is now giving me the full data set.

I covered 25km on Saturday in a little under 3 hours. Weed still an issue so a brief stop at either end of the lake to clear the prop. This reduces the average speed but I am getting the muscles used to a bit of exertion again. The bottom bracket is set further out to get legs flatter so some new muscles are being trained. The calves were noticing the change after a couple of hours.

Rick W.

MLampi

10-05-2008, 08:41 PM

Last weekend was spent at Ocean Shores, WA, USA. Saturday morning had a race on Duck Lake, Sunday was a poker paddle.

The race was pretty fun. Unencumbered by a camera or taking photos of other racers, I was ready to fight for first place overall. Unfortunately, a last minute adjustment of the Cadence chain tension proved to be my undoing, as I apparently didn't tighten the eccentric clamp adequately. Very soon after the start of the race the chain started skipping and I had to return to the dock. After running back to the car for the tools, tightening the chain again as well as the clamp, and returning the tools to the car, I started the race over again some 15 minutes after the official start.

It was fun catching the other racers, cheering them on and then leaving them far behind. I ended the race almost exactly an hour after the official start, and in 7th place overall. If I had not had adjusted the chain originally I probably would have finished in first place overall, beating two men in an OC-2 as well as breaking my record from last year. My average speed was about 6.8 to 7, and it seemed that the boat had slightly less drag with the foil rudder as I moved through 7 mph.

The Garmin Forerunner was an excellent tool in terms of keeping me focused on pedaling at a constant rate and moving the boat at a relatively constant speed, without the need to have targets in sight on the course. This year both GPS units were on and recording throughout the race. I have the results posted on my web site (http://snorlax.lampi.org/images/Paddle%20the%20Shores%202008/index.html) but at this moment my ISP is having troubles and it is not connected to the Internet.

My wife took our two kids who are still living at home in the Escapade and raced also. They had a good time pedaling around the course, and my daughter helped pedal on the return leg.

The Poker Paddle was a nice jaunt back through Duck Lake and into the tree lined canals of Ocean Shores. There were a few weeds, reeds and branches, but generally it was a great place to pedal from stop to stop, picking up sealed envelopes containing playing cards.

Between the four of us only my wife managed to get a decent hand, which was good enough to claim a gift certificate to a restaurant in Seattle.

The final event was a cardboard boat race, where teams take sheets of corrugated cardboard, 2 inch packing tape and box cutters and put together some sort of watercraft in an hour. When the hour is up the boats are launched with a single paddler who then tries to head around a buoy a hundred feet or so from the launch point and return.

It was quite fun to watch!

Michael Lampi

Guest625101138

10-05-2008, 09:39 PM

Mike
It was a very consistent performance. Average certainly seems a little higher than previously. Good result despite the slow start. Nothing like having good engine data. Will help you determine the immediate impact of current if weed is not an issue.

Is the new rudder any twitchier than the bigger plate from the perspective of dynamic stability?

I am still trying to get some fitness.

Rick

MLampi

10-05-2008, 11:48 PM

At this race I only paused for a moment as I passed the Escapade carrying my family so I could greet them and pick up a tube of sunscreen. Following that I spent a little time applying it while pedaling down the course, which contributed to a slightly slower time for the first part of the race. I felt pretty strong throughout the event, and the general lack of weeds was quite welcome.

The rudder is very sensitive in the forward direction, providing perhaps even more dynamic stability than the plate rudder. There is definitely much less speed loss in sharp turns than with the plate rudder, though I'm not sure it turns as sharply.

In reverse the foil rudder is still nearly useless, unfortunately.

Michael Lampi

Guest625101138

10-06-2008, 12:47 AM

In reverse the foil rudder is still nearly useless, unfortunately.

Michael Lampi

Mike
You will find the sharp trailing edge on the rudder will cause it to stall at low angles.

Next time you get an opportunity, go slow astern and gradually work the rudder off centre to full lock and then back to centre. You will find the best turning will occur with around 15 degrees. More than this will be worse. If the linkage is in any way sloppy it will be hard to keep the best angle. Jiggling it in and out of stall will increase steering. You soon learn the best point.

Reverse steering can be improved by rounding the trailing edge but this adds a little extra drag going forward.

Rick

I57

10-09-2008, 08:21 AM

Got the boat on the water today at the rowing course in Carrum. First time with the current fitout nothing broke or cracked, did 4 runs along the course at a comfortable pace and it took 17 min to do the 2km course. Going out with the wind and coming back into the wind the times were almost the same.
Gives me a speed of approx. 7km/hr so room for improvement. Still needs some adjustments with seat position. The rudder is 220mm wide by 300mm deep, on the big side but any smaller and it takes forever to turn.
On the subject of rudders I saw in a book that some of the early destroyers
(1900-1920) had an extra rudder at the bow to make them more easier to handle. How much would an extra rudder at the bow help? When I go backwards the boat turns a lot tighter, would two small rudders with area
smaller than one big one be better?

Ian Cassell

Guest625101138

10-09-2008, 04:32 PM

Ian
I do not know why it turns better going astern. That is unusual.

The prop shaft strut is quite large and will resist easy turning because it is close to the stern.

Your boat would turn easier with a bow rudder but it would create a tipping feeling. The centre of effort on most rudders is usually well below the centre of gravity of the boat. When you apply initial helm the rudder force and boat momentum produce a rolling couple. If the rudder is on the stern the couple causes roll into the turn whereas at the bow it causes roll out, so initial tendency is to roll you over. The faster you go the more noticeable it is.

Rick W

Guest625101138

11-02-2008, 05:52 AM

Thought I would revive the thread with some of my weekend activity.

On Saturday I did a couple hours in nice weather. Light breeze from the south had pushed most of the weed up the lake so I was able to get a reasonable average. Only interference was salvaging a fuel powered model boat that had stopped some distance from shore - I claimed salvaged rights but the owner would not think kindly of me given it was worth close to AUD2000.

On Sunday the late model engine, Jeff, had a spin to get some baseline data. Jeff is the current 12 hour cycling distance holder in Australia and wants to try for a record on water. He can hold better than 160bpm continuously over 12 hour period and is working on sustaining that for 24 hours. You will see from attached that he can push along around 11.5 to 12kph at the level.

The other thing to see is how significant a 30kph wind becomes when it is on the nose. It sprung up about 40 minutes in and we called it quits after that. The other feature that is noticeable is the increase in prop slip as the breeze comes up.

So got my endorphin dose and did some alternative engine evaluation.

Rick W.

MLampi

11-02-2008, 11:42 AM

Guest625101138

11-02-2008, 04:13 PM

Rick,

The performance I see with you and Jeff pushing your boat doesn't seem to be a whole lot different than the performance I'm seeing with my Cadence.

I suspect that if my boat were the weight it was supposed to be, i.e., low 70 pound range, it would be about as fast as Jeff's performance on your boat with me as the engine on my boat.

All-in-all, I think Gordy Nash's boat (a failed rowing shell design) at 27 feet length is still about the optimum length and configuration for a distance speed record vessel.

You need a longer, weed-free lake. :)

Mike
I was working hard in my effort but Jeff only had one period when he was putting in any real effort.

From my own data, V11J is around 1kph faster at the same power level than the Cadence I used in Seattle. It would have been good to do longer comparisons but time did not permit. I think you have made improvements to the rudder since I was in it. I believe your recent times have been better than ever and I expect if you continued to shave weight and optimise things you will be competitive with rowing sculls on the distance events even in good weather. The Cadence is also more streamline for airflow. From my chart you can see the impact of wind no more than 15kph. Jeff's last loop was in very strong wind. I do not have the muscle strength to hold my speed in such wind. Jeff finds 150 to 160bpm not anything strenuous. He would be working over 180bpm for strenuous effort and this would see around 14kph in calm weather. That would be the one to two hour speed.

I was a little surprised at Jeff's heart rate but he has only used a heart rate monitor once before. That was in his 12 hour run and he sustained between 160 and 170bpm for the entire period with one very brief stop. This sort of level would kill me. The reason we did the run yesterday was to get a baseline on the boat so we can estimate what will be possible with the boat by comparing data from his various bike events. He is also working on his water and food intake to go 24 hours.

Jeff is quite young and has only started to think about proper training for long distance events. I expect as he gets to optimum age and with improved training his heart rate will drop for the power level.

V11J is optimised for 12kph. Greg's target speed for the record was 11kph. His average ended up at 10.2kph. If he had sustained 11kph he would have done 264km. My next boat is shorter and a bit lighter. It is all carbon fibre and foam sandwich. I aim for 15kg total.

If you had a world class athlete who can sustain something like 200W for 24 hours then the 28ft boat might work out optimum. Same person in a Cadence would do better than Greg did for sure. Greg's average overall was not a lot over 100W.

Like you, weed is a significant factor from time to time for me. Over the next few weeks I will be looking for a weed free lake. The Murray River does not have the long weed that I have in the local lake. It has got worse in the last couple of years because of drought conditions.

So the Cadence engine is in good shape and could probably get better with proper tuning and the Cadence is already a very good boat but could do better if was made lighter. By the way I have made test panels of carbon fibre and fibreglass sandwich and the comparison on rigidity is staggering.

Rick W

Guest625101138

11-02-2008, 05:02 PM

Mike
I also took video of Jeff before the wind came up. It was taken as he passed on the second lap. He is doing 11.5kph in the video and heart rate was a bit over 150bpm. You can probably guage from his voice in the attached video it is not a difficult pace for him. He had collected some weed at that stage as well.

I did not ask him to go as fast as he could. I asked that he hold above 11kph but not exceed 12kph. He may be able to sustain 12 or higher continuously but I only wanted a baseline that was good enough to do 250km or so over 24 hours.

Rick W

I57

11-07-2008, 12:22 AM

Started construction on my new boat, a 5m x 300mm beam outrigger. This boat I will sit on top and position the outriggers forward of the cranks, about 1-1.5m forward of midships. What I'm going to try is using the outriggers as rudders, my thinking being outriggers are in the water already so why put another appendage in the water. The pivot point will be controlled by wires or a lever at the seat and the outigger pole fixed to the pivot bracket. The outriggers will be 2m long x 100mm beam and 200mm deep with about 10-20mm in the water, how hard it will be to turn I don't know but at least being summer if I go for a swim it won't matter. The hull will be fully decked in so no problem with water getting in.

Ian

Guest625101138

11-07-2008, 11:18 PM

Ian
What is the building material this time?

I went out to the Blue Rock Pool today. It was blowing a gale when I left home and the same when I got to the lake.

I mooched along the sheltered shore in the north western corner but even that got a little rough. I could not find the entrance to the river valley. Or more accurately I was not prepared to dodge the dead trees at what I believe was the mouth in the strong winds. Wind was actually strong enough to have me worried about it lifting the boat and rolling me.

So not a good day out. I will look for better weather before I go on another trip looking for a nice lake. Spent three hours driving in total for 5km on the water. Not a good ratio.

Rick

I57

11-09-2008, 04:44 AM

Rick
New boat is made from plywood and of hard chine construction. Camera has stopped working so can't show any pics at this stage, looks like a new camera. I'm putting the shaft through the centreline and making it a curved shaft. Still early days yet but maybe in the new year it might be ready. Boat dimensions are ,length 5m, beam 300mm at deck, 250mm at chine. Outriggers are 2m long, 100mm beam.
With your search for lakes one I know of is Lake William Hovell, went there a few years ago and it is a great spot. It is on the upper King river south of Whitfield, not a large lake but is for non powered boats only and is in a valley so is sheltered. Camping is not allowed at the reserve but if you talked to Parks Victoria you may get permission. With the drought it is a real problem as there are some lakes that have completely dried up.

Ian

philSweet

11-09-2008, 11:30 AM

Rick and others, fascinating thread.
I used to compete on road bikes twenty years ago.
Rick, you mentioned you were chasing down losses on the order of .25 watts. I would guess all the bioefficiency and mechanical efficiency work was done using road bikes. Pedaling produces all kinds of harmonic forces and stray torques affecting all six degrees of freedom (the three axes of rotation and the three axes of translation). Bikes and boats resist these forces very differently and I was wondering if you had compared the power difference between your boat being pedalled and being propelled by a small motor that doesn't cause any bobbing and rocking and yawing as it goes? How far did you get with this? were you able to distribute the proportion of losses among the six degrees of freedom?

If your purpose is to be able to compare different hulls with out resorting to elaborate testing apparatus, the dynamic losses could be related to an easily duplicated and measured static configuration. (that came out like gibberish, didn't it :confused: ) example- The yaw caused by pedalling could be equated to propelling the hull in a turn of a given radius buy a motor that doesn't produce cyclical yaw. Like wise for the other axes. To the extent this is valid, you can use static tests to predict relative performance in a more dynamic environment.

My other thought for some do-it-yourself science would be to consturct an eccentric flywheel in the manner of a harmonic ballancer and play with its phase angle as the boat is pedalled. Should work well to counter vertical movement.

P.S. I always wondered if a sidesaddle bicycle wouldn't be a more efficient machine. Probably not faster due to windage, but maybe a better setup for a two wheeled pedicab.

Guest625101138

11-09-2008, 03:39 PM

Phil
The most accurate power testing we have done was taken using an SRM metering crank. So biomechanical effects are not measured.

I usually do a calibration of my heart rate versus power at a local gym each year so I can get numbers to compare with the boat so this takes biomechanical factors into account. At low power level my gym numbers translate well to the boat at sprint type levels I can get about 20% higher in the gym than the boat. This is because of the flywheel on the gym machine.

The lack of flywheel effect is a factor in biomechanical efficiency. In fact with the thin shafts I have been using it is quite noticeable because they feel distinctly rubbery. If I was sprinting I would use a thicker shaft. However adding a thicker shaft adds drag through the water so it is a compromise.

With the flywheel you add weight and this adds drag plus any associated gearing also adds to losses. So flywheel does not provide benefit - at least for systems I can engineer and for the cruising power level.

Most of my effort has been directed at long range cruising. My own power level target is between 120 and 130 watts. So things I observe relate to that sort of level.

A stiff frame is a benefit. You need to be able to lock in the forces between backside and cranks. I am working on a new carbon fibre frame and seat that will have a total weight of 3kg and be very stiff. It will also have the gearbox mount. I will post some pictures when finished.

If you want to go as well as you can on the boat you need to train on it. I am not sure if you have watched the videos I have posted or linked to but you should be able to see that the boat moves without much pitch, yaw, roll or speed variation. It is far more efficient in this regard than a rowing scull or kayak. The more you train on the boat the better you are able to spin and keep the body aligned.

Biomechanical factors are important and things to work on.

Rick W

Guest625101138

11-09-2008, 07:26 PM

....... I'm putting the shaft through the centreline and making it a curved shaft. Still early days yet but maybe in the new year it might be ready. .........
With your search for lakes one I know of is Lake William Hovell, went there a few years ago and it is a great spot. It is on the upper King river south of Whitfield, not a large lake but is for non powered boats only and is in a valley so is sheltered. Camping is not allowed at the reserve but if you talked to Parks Victoria you may get permission. With the drought it is a real problem as there are some lakes that have completely dried up.

Ian

Ian
I have a recent arrival of spring steel for shafts. This is really good stuff with UTS around 1600MPa although it does corrode. I paint it to reduce corrosion.

You can use machinable aluminium but it would need to be thicker to avoid the rubbery feeling. It also corrodes but not as fast as the spring steel. I tried to get some high strength stainless steel but there is nothing readily available near me.

I can give you design calculations on the shaft if you want it and provide the spring steel at my cost if you are interested. If you try to curve the shaft too severely it will fail in fatigue. Also the stern tube through the hull should follow the intended curve so you need to have this sorted before you place the tube. I have used the 19mm poly pipe used for watering plumbing watering systems.

philSweet

11-09-2008, 08:13 PM

Rick, have you tried using oval sprockets (do you even use sprockets)? They were being tried twenty years ago, with out much luck, on street bikes. On a boat, they could be used to match the prop slip to the differences in torque as you crank. That might get you some of that 20 % back.
Good luck on your future endevors.

Guest625101138

11-09-2008, 09:10 PM

If you go down this blog you will see a photo of the oval chainring Greg K got for his boat:
http://www.adventuresofgreg.com/HPB/2008/08/gps-distance-measuring.html
He was experiencing knee problems and this helped.

If the shaft is stiff enough it does not make much difference. If the shaft is borderline then it will make a difference as was Greg's situation. He should have been using an 8mm shaft not a 1/4" shaft. If the shaft is too flexible then it will not help much. I have had shafts that are so rubbery that you virtually stop rotating at the crank deadspots until the shaft unwinds. It is very awkward. The difference is significant. With one of my boats using an 8mm aluminium shaft at 3.75 step up I could get it to 12kph at full tilt. By going to spring steel I could get to 17.8kph.

A few recumbent riders use small cranks so they spin faster but with the same force. These would reduce the range of movement with knees as well. There has been a lot of testing on these aspects but I think it mostly gets down to what feels nice. I tend to set my clips toward the instep to reduce calf strain. Others like to have them more on the toes and they really stretch out. Greg traded biomechanical efficiency for reduced muscle strain. However he did pull back on cadence a little by increasing the gearing from the original design of 90rpm.

Rick W.

I57

11-10-2008, 04:30 AM

Rick
I have some 10mm aluminium tube which I am using for the shaft, do you know what the minimum radius would be?

Ian

Guest625101138

11-10-2008, 04:53 AM

Ian
The tube will need to have at least 8m radius to survive. If you can fit this in then there will be other options available if you find it too rubbery. I expect it will be borderline.

At that radius you could use ordinary stainless. It will have ample torsional stiffness. With the spring steel I get below 3m radius but this is so I can locate the prop beside me. Running it aft makes it much easier to get the large radius.

I figure the shaft of the gearbox will need to be angled around 20 degrees with the required vertical offset over the shaft length. You need to lay it out showing the height of the prop and the gearbox.

Rick

I57

11-13-2008, 01:37 AM

Just an update on progress with the new boat, hull is progressing and have made the skeg and the seat, camera still not working. Got hold of some 6mm galv. steel rod and will try using that as a flexible shaft, length is 2100mm and connected to 3.3 step gearbox. Prop is 450mm dia and the thrust will be taken at the skeg, approx. radius of shaft is 4m. Found that with the thicker aluminium shaft prop would be way past the boat to get an 8m radius.

Ian

Guest625101138

11-13-2008, 01:52 AM

Ian
The galvanised shaft should not fail but could feel rubbery. I have the spring steel if you find it does not feel nice. It can go up in diameter and still survive.
Rick

Tiny Turnip

11-28-2008, 11:35 AM

I thought a couple of shots down the inside of my seacycle drives might be of interest. I've had the tops off to inspect, as after my first outing, I hit an underwater obstruction with the prop, and the unit started binding. I can't see anything out of place, and the drive rotates perfectly when not under load. I think I may just have the chain tension too tight - I hadn't realised that it was a twisted chain unit till I got it apart - I'd assumed it was a bevel. I can understand that if the chain is too tight when twisted it may bind. Interestingly, the chain is not bike chain, but is quite a lot smaller, with a link wavelength of only about 8mm.

Anyway, I've slackened the chain off, and I'm trying to find the time for a second outing.

Guest625101138

11-29-2008, 04:48 AM

TT
The short pitched chain will twist easier than long pitch. Normal bike chain is not the preferred choice for twisted chain drive.

The short links work OK and some say they will last a long time. The are arounf 97% efficient or even worse so there is a lot of extra rubbing going on compared with a straight chain run at 99% efficiency. I get around 96% efficiency with my chain/right angle gearbox combination and they last a long while without any deterioration.

You can get around 97% efficiency with a big gearbox without chain but the boxes are quite heavy- up around 4kg. Both Ian and I have boxes from India that have 1:3.3 step up that you just fit cranks too. The housing is purpose built but the gears are the same used in large angle grinders. Ian really likes his. I have not had the need to use mine yet but the price was too good to pass up.

I only ever tried one twisted chain and after looking at the torture that the chain goes through I chose other methods. Mine had a heavy duty chain and it did not like to be twisted, at least while new. My main issue with them is that they cannot be engineered to chain data because they are using the chain in an unintended way.

Rick W

Tiny Turnip

11-29-2008, 08:17 AM

thanks, Rick- that's an interesting insight. Re reading the seacyde webSite, they recommend tensioning the drive when there is more than 2" of movement in the pedals, and I've still only got 18-20mm slack at the pedals, so I might slacken the chain off further- it does feel pretty tight at the moment.
looking at the efficiencies of a straight chain drive- do You think there is any mileage in a 2 person double outriggEr monohull, a larger version of your series, with 2 sideways facing engines seated in the main hull, facing out on opposite sides, straight chain drive, and the props combined with the outriggers? There was a boat using the sideways seating position on the IHPV website. I imagine that the neck twist issue would put the mockers on it, without mirrors (or cameras and displays!) but the curvature possible in your flexible shaft might alleviate the issue?

Tiny Turnip

11-29-2008, 10:11 AM

a cruddy sketch of the idea (photographed and submitted by phone! )

Guest625101138

11-29-2008, 04:16 PM

The efficiency is not a really big deal. Difference is 2%. The real benefit of the straight chain is reliability - low wear rate, low stretch, no risk of jumping off.

I have attached a picture of Close to Perfection from Duisburg. It was a good performer in sprints which is impressive since it is a catamaran. It has a direct chain drive to a prop in each hull.

With two people in a monohull you would have a design speed around 14kph if you wanted to optimise. This would require a long hull say 9m.

There are advantages in having people sitting behind each other to reduce windage. At 14kph it will be significant. Also two people cranking a common drive with each pair of cranks offset by 90 degrees improves efficiency. My choice would be two little boxes to a single shaft. One of the boxes would be a "T" box:
http://www.mitrpak.com/product_datasheet.php?product_id=66
The shaft could be set up under the seat for inline drive or beside the hull to avoid hull penetrations.

Rick W

Guest625101138

11-29-2008, 11:39 PM

More time on the lake yesterday. The weather was overcast with some very light rain. Wind was variable. Some gusts to 40kph but mostly 15 to 20kph from the southwest. Most of the weed has been pushed to the northern end so this was not a serious problem - just a clean each loop.

I did 29.3km in just over 3 hours. I started well but the effort of pushing into the wind caused muscle fatigue after a couple of hours. Still not able to average 10kph.

Rick

Guest625101138

12-07-2008, 03:57 AM

Still getting some useful distance into my legs. I did 35km on Saturday in a little under 4 hours including brief stops for cleaning weed from prop and a longer stop to adjust outrigger trim.

I held a reasonably steady pace but still pulled up feeling quite done. Still a long way to go to get to the 70km or so needed for a day on the Murray River. The current assistance on the river adds about 20km to make up the 90+km on the first two days. The last three days are shorter but no easier. Race is only 3 weeks away so have some hard miles in front of me.

Rick

MLampi

12-07-2008, 10:54 PM

Today the Deception Pass Dash was held. The roughly 7 mile long course starts at Bowen Bay, in Washington, goes around an island to the west of Deception Pass, heads through the pass to go around another island, and returns through Canoe Pass to head back around the first island and then to the start.

There was a pretty strong SW wind (flags spread almost completely horizontal), which turned this into a rather interesting event.

Approximately 132 boats were there at the start, including one Cadence pedal boat.

Having never been on the water here before, other than in a big whale watching vessel, I figured that it would be a good idea to have the outriggers on the boat. While we were supposed to be going through the pass around slack, the area was still known to have lots of waves and eddies.

The start was rather chaotic with all the boats trying to keep station at the starting line in the not quite headwind. The 1 to 2 foot chop in the bay also splashed me and my camera lens. Most of the pictures taken were of poor quality.

As we headed out to the island the waves quickly grew higher, and most of the paddled boats started falling behind. Piercing wave after wave I needed to open the speed bailer, or suffer with a flooded cockpit.

Interestingly enough, the prop on the Cadence didn't aerate very much, and I was able to keep within fairly close range of some of the really strong paddlers. My heart rate was in the upper 150's, and the speed was over 6 mph.

Going around the island I encountered a tandem surf ski that had capsized, but by the time I reached them they got back under way.

Shortly after that I ran into a large kelp bed. After clunking into one with the prop I paddled through the rest of the bed into clear water. The prop was able to spin, and off I went towards Deception Pass with the wind at my back.

Heading east I was able to surf on quite a few of the waves. The outriggers worked very well in their raised position, though every so often they would dig into the water and rotate on their axis into the lower position. I just flipped them back up and kept on pedaling.

Heading downwind I was able to catch a couple of outrigger canoes and another surf ski, but as the water grew calmer in the pass they stuck close to the shore. I stayed a little further out into the channel, but realized that the ebb tide must have begun. My pace was only 4.2 mph as I pedaled under the bridge at the pass, perhaps 200 feet above me.

Not much further we reached the other island. There was a bigger kelp bed on the southern and eastern side, so I steered clear - until I noticed a kayaker taking a line very close to shore in an area that seemed kelp-free.

A paddler I had been following headed towards the shore through an area that seemed clear, and I followed. It was great - no problems were encountered and the route was several hundred feet shorter than the "great circle" route.

Heading back towards Canoe Pass (the pass to the north of Deception Pass), the wind started rising. Again the paddlers dropped behind, due to their more significant windage.

Canoe Pass was much like a narrow canyon, but at the west end I saw some really large standing waves as the ebb flow met the Sound. Some of these waves were 5 or 6 feet in height. I decided to try going around the waves rather than through them, which was what I had inadvertently been doing by concentrating on photography rather than navigation. Outriggers really work! :)

Heading into the waves was getting a bit tiresome, and with the temperature in the upper 40's or low 50's I was even starting to get a little cool. Getting plastered by waves (not spray - full-on waves) tended to reduce my body heat a bit, even though I was wearing Gore-tex insulated winter cycling tights, two layers of wicking shirts under a thick PFD covered with a large windbreaker, and thick wicking socks on my sandaled feet. I really hoped that we merely headed back to Bowen Bay after Canoe Pass.

Unfortunately, however, the guys ahead kept heading west towards that first island. I kept pedaling, and even managed to catch up to them on the other side of the kelp patch.

The other guys took a course that kept them far away from the rocks and breaking waves on the west side of the island. They were near a couple of safety boats that had their lights flashing for some reason, probably picking up some defunct paddlers. I took a course a bit closer to shore, but with enough of a margin that the side wind and waves wouldn't force me against the rocks.

Rounding the island I was again able to surf downwind, though not quite as well as before. I was getting a bit tired, or perhaps there were some weeds on the prop. Clearing the prop seemed to help a bit, and then I had to dodge a field of kelp that had grown up in the bay between the start of the race and now. I hate it when that happens.

Just before the finish a pink double surf ski managed to slip ahead, putting me in 20th place overall out of a field of 92 or so boats that completed the race. My time was 70:41, which surprisingly enough was about what I thought I'd do before encountering the waves and wind.

For me this race was a blast! It would have been suicide without the outriggers, which pretty much let me do whatever I wanted with the camera - like wipe off the lens time and time again. Many strong surf ski paddlers and kayakers did not finish the race due to the waves, wind and kelp.

After beaching I had a great lunch of home-made vegetable soup, garden burger with roasted chilis, chips, etc., provided by the organizers. The raffle was fantastic, and everyone who stayed got some sort of prize.

Woo hoo! :)

Michael Lampi

MLampi

12-09-2008, 12:58 AM

Photos are here (http://snorlax.lampi.us/images/Deception%20Pass%202008/index.html).

I understand the winds were gusting to 26 mph, and the waves were in the 5 to 6 foot range, with up to 8 feet in some parts of the Pass.

Michael Lampi

Guest625101138

12-14-2008, 05:17 PM

Mike
I did not have to put up with large waves but I spent a windy day on the lake on Sunday. I did almost 5 hours in trying conditions - managed a bit over 40km. Wind gusts to 90kph reported but I was able to get some shelter from the worst. Initially it was from the south but moved more to the west as the afternoon progressed. The old engine was torque limited going upwind but it was easy going down wind. The knees are a bit stiff now.

Early on Sunday I took the boat into the city for scrutineering for the Murray Marathon. For me it is simply to check that the boat will float so a two hour return trip for very little. I do get a sticker to indicate it passes. Interestingly the application form now recognises pedal power so I am wondering if there are more pedal boats this year. This is the 40th year and the last year that Red Cross will organise it. They have said there is a very large field this year.
http://www.redcross.org.au/vic/murraymarathon.htm

I am not quite where I would like to be with training but that is always my predicament. I will probably do one more decent training day on the boat.

We have had some good rain recently so may mean they have plenty of water to release and there will be local run-off. Any current assistance will be greatly appreciated by my aged legs.

Rick W

MLampi

12-14-2008, 07:28 PM

http://www.goskagit.com/home/article/recreation_kayakers_dash_through_the_pass/

Part 1 of a 2 part series:
http://www.youtube.com/watch?v=pPH8wjkeG9A

Part 2 of 2:
http://www.youtube.com/watch?v=x3Daf3KuJcI&feature=related

Guest625101138

12-24-2008, 04:43 AM

Have been doing some final mods on the boat ready for the Murray Marathon.

Managed to lighten it by a few kilos with new CF outriggers and new CF drive frame. All up weight now around 20kg. Gave the hull a fresh coat of paint as well.

Replaced 1/4" (6.34mm) prop shaft with 8mm. This feels much less rubbery so I expect it will be easier on the legs.

Attached chart shows my last run. Only one hour to check things out but averaged 10kph even with a bit of weed and variable wind up to about 20kph.

I head off on the 26th for the race. Just hope the boat holds together for the 5 days and nothing gets broken or holed jumping logs and sandbars. Recent rain has increased river level a bit so might not be too bad for me.

Rick W

I57

12-30-2008, 06:13 AM

Just an update on the progress of my new boat, the idea I had of using the outriggers as rudders proved too cumbersome and heavy. To get it to work was proving to be very heavy, the gain was outweighed by the extra weight. Also I was mucking around with different drive layouts trying to get higher gearing and smaller prop but in the end I decided the simplest layout was the best. I've used an Involute gear box attached to a 6mm flexible steel shaft going through the centreline attached to a 450mm prop supported on a fixed skeg. Outriggers are large as I intend to take it out on the bay. Boat is 5m long, beam 300mm at deck with 2m long outriggers, it is a modified version of Ricks V11 boats but a shorter length (5m is the biggest boat I can store in my garage).

Guest625101138

12-31-2008, 04:05 PM

Ian
Looks good.

When do you aim to test it?

I am back from the Murray. I had a good time. Some minor drama but otherwise went well. Will make a full report of it.

Rick W

Guest625101138

01-01-2009, 08:25 PM

I have attached my report on the Murray Marathon for 2008. Much of the information is for my records in case I decide to do it again. This detail will provide ready reminders for planning purposes. If anyone wants to join me it will be a good planning reference.

Rick

MLampi

01-02-2009, 12:33 AM

That was an excellent write-up, Rick. Congratulations on finishing with flying colors!

Did you find the extra width of the outriggers to be a problem in maneuvering around the logs, rocks or other obstructions in the river? Did you encounter any situations where having a reverse would have helped?

On another note, did you have to do anything to make your Forerunner last the entire day? Did you have to use an auxiliary power source? I wasn't sure that the battery would last an entire day.

The Murray Marathon got me to thinking about possibly doing something similar around here. Travel down the Columbia River, for example, might be a fun thing to do, though portaging around some of the dams might be necessary.

Mkichael Lampi

Guest625101138

01-02-2009, 01:06 AM

Mike
I appreciate your comments and will attempt to answer the questions.

Outriggers are only slightly wider set than others I have used. The boat is 2m overall. The only real issue with them is working through crowded launching and retrieval spots. People cannot grasp how wide and long it is. The outriggers fold up and sit above the seat for transport and this make it less cumbersome to carry as well. Being only 20kg I managed to carry it by myself most times. There was always someone willing to lend a hand at the water's edge.

The new outriggers are Carbon Fibre foam sandwich and weigh less than 1kg. They displace about 10l and I found this to be marginal if I leant out. The others I have are between 15 and 20l displacement and this gives a much higher safety margin. After my initial dunking I was very cautious with weight distribution.

The logs you can see are not an issue. It is the ones sitting a few inches under the water and you miss the eddies. It takes a lot of concentration. Many boats take hits and end up with patches. In the narrow spots you can have 3kph of current so it is easy to have approach speed of 13 to 14 kph. Many people get caught out initially by how early they need to turn to avoid something fixed.

My boat goes in reverse and it is handy at start and finish. In some narrow spots I cannot complete a 180 degree turn without backing up. There were a couple of times when I saw logs too late to turn so I was able to slow by quickly reversing and then unloading the prop so it had a better chance of bouncing over the log. There were a few occasions with logs spanning my course where I lifted the prop as a precaution.

I was really pleased with the Garmin Edge. It makes life much easier when you know the distance done, elapsed time and heart rate just by taking a quick glance. My cadence transducer was troublesome. I think it has a water problem. The battery indicator was down to the last bar on the long days after 8 hours but I did not carry any back up. I recharged it fully each day.

Some of the older guys now use the heart monitors under doctor's orders not to exceed a certain level. Many boats now use a GPS. Some guys have done it so many times they know exactly where they are at any time so a GPS is just wasted weight.

By the way Rhonda and I wish you and family good health and good fortune in 2009. You made a significant contribution to our 2008 holidays and we remain appreciative.

Rick W

venomousbird

01-02-2009, 01:12 AM

Great looking boats!

BOATDOCKTOR

01-02-2009, 09:01 AM

Guest625101138

01-02-2009, 03:20 PM

Rick,
I'm very intrested in your paddle boat endevour. I live on a lake in central Ohio where many of the residents are OUR age. I know this concept would be a huge hit. Did you start with an existing kayak and redesign it or is this a new built from scratch hull design?
John

John
I have built about 14 pedal boats with numerous variations on each. There are 4 hulls to the current design. One was built by a Canadian friend to set a new world distance record. He achieved 245km in 24 hours with it. http://www.adventuresofgreg.com/HPB/2008_09_15_archive.html

The hull is designed from scratch and is optimised for 12kph with a 75kg rider. That requires 150W at the crank. I believe it to be close to the most efficient boat possible for this power level.

It is intended for use in sheltered waters.

It is longer than most single kayaks but shorter than a rowing scull with slightly lower power requirement at 12kph than either of these.

If you are a recreational cyclist or keen kayaker living near a lake then V11 style boat is close to ideal I expect.

There is a commercially built boat with similar performance known as the Cadence. It is quite different in configuration and slightly slower for the same power but a good ride.

Rick W

I57

01-04-2009, 04:15 AM

Congratulations Rick for the Murray Marathon, a long hot race so well done. Its an event I thought about back in my younger canoeing days and then just as quickly stopped thinking about it.
Hope to have the boat on the water by the end of the week. The flexible steel shaft is not spinning as smooth as I would like, maybe because it is fixed at both ends. I have made a long thin slot in the middle of the boat to allow a bit af movement so have to see how it goes on the water.
Only drawback is the 450mm deep skeg to support the prop, makes setup and launching a bit awkward but with the involute gearbox its the simplest setup.

Guest625101138

01-04-2009, 04:49 AM

Ian
Thank you for the acknowledgement of the MM.

I use a bearing at the shaft tube to centralise the shaft in the tube. When in operation the thust will force the shaft against the front of the tube if the thrust is not taken by the strut. I also use bearings in the shaft strut. These are not all that important because the prop will unload at the strut once operating. I carry the thrust at the gearbox. Maybe a little at the strut but it is not particularly rigid so most goes to the box. It has plenty of capacity to handle the thrust.

The other thing you could do is make the strut detachable. It could be mounted in a tube that runs to the deck and you use a wing nut at deck level to keep it in place. Remove the whole shaft for transport and storage. I have a thumb screw at the gearbox and strut to remove the shaft so I do not need to carry tools.

If you let me know when you plan to have a test I might come over for a visit or you could have the first outing at Lysterfield. Today was too good not to spend a bit of time on the lake so I went out for a couple of hours early in the day and just went around a few times. It was a perfect day.

Rick W

I57

01-04-2009, 05:32 AM

Rick, thats a good idea about a detachable shaft, may have to try it as setting up and launching with a big skeg is awkward. The way I have made it all of the thrust is taken at the skeg with the shaft detaching from the gearbox to make the boat easier to carry.
Hope to try it at the end of this week as going to Cairns next Sunday for a week, so see how I go for time. If going to the lake will let you know.

I57

01-08-2009, 05:22 AM

Tiny Turnip

01-08-2009, 07:28 PM

Rick - congratulations on the MM - sounds like man and boat performed well. That is a serious distance. Getting me motivated for an early start to the season, though we've had a real cold snap here in the UK, harbours freezing up, which is pretty unusual.

Good luck Ian - glad to hear the maiden voyage went well - look forward to some pictures of the boat in action.

Guest625101138

01-08-2009, 08:52 PM

Tried out the new boat today for the first time at Patterson River and despite very windy conditions performed well and nothing broke. The flexible shaft feels very smooth compared with the universal joints, didn't crank it up a lot as conditions were not good. It's very stable so will raise the outriggers a bit and see how it goes, outriggers tended to wobble up and down so might add a second pole. Should be out at the lake on Saturday for a better test, sorry no pics.

Ian

Ian
You should be able to raise the outriggers to the point where they just skim the water. If too high the boat will tend to flop although with a good ruder you can balance it dynamically.

What time do you think you will be at the lake?

Rick W

Guest625101138

01-10-2009, 06:20 PM

Was sent this link regarding a new pedal powered fishing kayak. I expect it would be faster than a Hobie:
http://www.nativewatercraft.com/media/videos/propel/ult_multi_propel.cfm

Rick W

MLampi

01-10-2009, 10:56 PM

Was sent this link regarding a new pedal powered fishing kayak. I expect it would be faster than a Hobie:
http://www.nativewatercraft.com/media/videos/propel/ult_multi_propel.cfm

Rick W

I would have to disagree, Rick. The apparently rather poor propeller and the tunnel hull, plus the relatively short hull lengths all contribute to a fairly slow boat. I expect there to be a bit of aeration of the propeller once you start going at higher speeds. This would limit the top speed to perhaps 6 mph.

Otherwise, the boat seems to be a nice craft for fishing and general tooling around.

Michael

Guest625101138

01-11-2009, 01:50 AM

I would have to disagree, Rick. The apparently rather poor propeller and the tunnel hull, plus the relatively short hull lengths all contribute to a fairly slow boat. I expect there to be a bit of aeration of the propeller once you start going at higher speeds. This would limit the top speed to perhaps 6 mph.

Otherwise, the boat seems to be a nice craft for fishing and general tooling around.

Michael

Mike
You must have a higher estimation of the Hobie than I do. Having seen a few in operation close by me in recent weeks, including another twin in the Murray Marathon, I can honestly say they do not perform well.

The one in the Murray had fresh crew at each check point and still only managed to complete the last day where they delayed the clean up sweep to try to get as many finished as possible. It completed that day at slightly faster than half my speed.

The twin Hobie that went in the 2006 race had a more dedicated crew but they were still very slow.

Rick W

mark775

01-17-2009, 10:05 PM

Rick, could a flexible shaft work with, say, 500 HP., a twelve foot run, and six inches of bend over eight feet?

Guest625101138

01-17-2009, 10:41 PM

There is another thread that covers what was called a rope shaft used in a high performance vehicle but it is different to what I do. THere is also a lot of discussion there on the allowable fatigue range.

I would need to know the rpm so I can look at the torque requirement.

My operation is predominantly in fresh water and I use spring steel. Spring steel in small section is very good material so high yield. I get Range 2 material shown in the attached. You can see it is good stuff.

The allowable stress range for infinite life is around 40% of yield. I can determine this. It is a function of the shaft diameter and the curve radius.

You can get some high strength stainless steel but they cost a good deal. Typical shaft material may be OK if the stress range is low.

You need to maximise the bending radius and minimise the shaft diameter with some margin on the allowable torque.

If you could go the full 12ft it would help. Might see what could be done with layout if the required shaft material is too exotic.

Of course the length of shaft working in air would need to be checked for resonance. I have never checked if resonance in water is possible if the shaft diameter goes up. In my application the water dampens any tendency to vibrate. Also if you put the thrust load into the shaft it could increase stress significantly and need to be allowed for so I would suggest a strut able to take the thrust in most applications.

Rick W