Pedal Powered Boats

[Colin McDonald]

Hobie Cat 3.5 Galore

Welp,

I got the 11 footer! Thanks for all your help everyone! I'm all giddy and excited for my new boat I have attached a few photos...

I had to take it apart for the initial transport (just made it easier to go the 2.5 hour drive). I attached a few photos about the process of taking it apart as I could not find this information easily on the internet and thought it needed to be here. It was just 4 long bolts and a matter of using a mallet to hit the boat apart and then hit back together again - very easy and it took about 20 minutes for each process!

I plan on, as Clemens suggested, putting a kind of small top to the boat to protect from the sun and heat. I also plan on extening the platform a bit and doing a few modifications as needed for gear (which I intend to keep very light)

Now on to the next step... the drive system and the seats...

Anyone out there know a good place to find used/cheap drive systems. I am thinking of going with the sea cycle set up like many of you guys have - definitely seems like the best route

I know there is this site:

http://www.sea-cycle.com/

Selling them for $750. not bad, but I'd rather go for a cheaper used one, though I'm sure they are hard to come by because small popularity of pedal powered boats in general. I searched all the nearby Craigslist areas to no real avail...

Any advice? and advice about recumbent seats? best place to find them?

You guys are being EXTRAORDINARILY helpful in this whole process and I thank you all very much for everything.

 

[Tiny Turnip]

Hi Colin! Congratulations and best of luck!
I got reconditioned seacycle units from Meyers boat
http://www.meyersboat.com/seacycle/
IIRC they were a little over half the price of new.
I do find getting the chain tension right a bit fiddly - it is easy to overtension the chain so it binds, and easy to over tighten the cranks in an effort not to loose chain tension, and this can make them pop out of proper location, bind up the drive, and be awkward to get back into place. I'm just about getting the hang of them now.
When the units are full of oil, they do need to be kept upright despite the seals, which needs a little thought when in the back of the car.

With my dart hulls, I find a squirt or two of teflon bicycle lube spray does wonders for getting the aluminium spars in and out of their fibreglass sockets. Plus making sure they are free of sand and grit.

Keep us updated with your progress! Pictures please!

 

[Tiny Turnip]

Clemens
I'd love to see some pictures and details of your boat if you have some? I have a tent to use on my Fangle, but I wasn't going to rig it permenantly - just pitch it at night for sleeping!

 

[Clemens]

Hello Tiny Turnip,
glad to get in touch with you! We share a similar concept of waterbiking.
The smalllest of Quechua's seconds tents fits the actual deck. Next I'll fit a bigger platform - in order to have less parts, less weight and more space. I'll mount Quechua's tent "2 seconds air" - see:http://tente.quechua.com/en/tent/r-8,a-60,tente-2-seconds-air-ii.html

Its fibre glass poles are very flexible, which allows strapping down the tent on windy days to reduce drag.


Enclosed you'll find some pictures of the "cruising seacycle".

Best greetings
Clem

 

[Tiny Turnip]

Hi Clem
thanks very much for these - your boat looks great. I have a similar pop up tent, but mine is not as breathable as yours. I expect you get warmer weather though! I like the rotating seats too - this was something I was thinking about.

How are you getting on with your seacycle pedal units? Have you found any issues with the chain binding from too much or too little tension at all?

Best wishes

Adrian

 

[Tiny Turnip]

Colin - I meant to say, re: the seats. I ended up buying mesh recumbent seats from http://www.icetrikes.co.uk/home
They worked out fairly dear, but I felt that the comfort, and non water retaining nature of the mesh was worth it.

 

[Clemens]

Hello Adrian,
thank you! No, I haven't had any problems with the drive units. Could high chain tension have caused your problem? I exchanged the original pedals with cleats. Which was not as simple, since both cranks on the drive unit are threaded the same direction. Exchange of one pedal axle was the solution. I'm happy with the cleats. It is less exhausting, the spinning movement is more continuous. The seats from BikeE are clamped on the T-shaped bar. Thus they can be mounted in both directions. The downsides: the padded seat cushion is not waterproof, in addition the seat is designed for a two wheeler - where there is no momentum to the right or left side. On a three wheeler or on a boat, these seats tend to pivot a little bit.
Best greetings
Clem

 

[Clemens]

Colin,
I got my seacycle including 2 drive units second hand. Thus I had no reason to look for alternative propulsion systems. There are other options though - like Rick's more efficient configuration with folding prop.
Seat: I personally prefer a mesh seat. You should browse through the recumbent bike sites. If you choose a hard shell seat, I'd recommend to cover it with a mesh fabric - take a look at the product VENTISIT from the Netherlands. For the seat of my first recumbent bike I used 40 meters of belt strap (width: 1,5 cm) You could possibly use the steel frame of a dining chair if you go for this option.
The position of your seat should probably be just above or even in front of the forward cross brace of you trampoline.
Best wishes - please keep us up to date!
Clem

 

[pmdproject]

Hi all,

I'm one of three business students working with a small engineering company with a patented pedal-powered boat drive system. Videos of the system in action are available through an end-user survey at http://qtrial.qualtrics.com/SE?SID=SV_7Vu2eHrCwSwhwqM&SVID=
(this has already been posted in a separate thread)

Beyond your feedback on the design (it's quite clear that there is an impressive level of expertise here!), I was wondering,if anyone had any particular experience in commercialising such technological innovations? It seems that whilst some innovations have achieved commercial success (Hobie Mirage being the example noted by our designers and coming up repeatedly in our survey), there are significant barriers to any particular invention becoming marketable. If anyone has ever attempted to take a similar technology to market, knows of any examples, or is simply knowledgable about the market for such products in their area, we'd love to hear from you.

I'm contactable at curling88@gmail.com and would love to hear your thoughts.
Cheers,
Richard

(a similar message has already been posted in a thread concerning our own boat drive design, apologies for the cross posting.)

 

[MLampi]

Pulse Drive

The Pulse Drive looks quite similar to the Pacific Tailboats drive, except the Pulse Drive uses two opposing fins rather than one, and the steering seems to be better incorporated into the fin angle of attack.

http://www.tailboats.com/propulsion_technology.html

I'd be interested in seeing what sort of efficiency figures the Pulse Drive obtains, i.e., watts in vs. thrust.

Michael Lampi

 

[Dennis A]

High Friction In Curved Drive Shaft System

I have a plain bearing from nylon/steel in the support strut on my new drive system. The twisting action of the spring steel shaft 8 mm dia. increases the friction in the bearing to a very high level.
Am I doing this wrong, should the support strut not have a bearing but just a loose fitting guide so that it will not bind up caused by the spring bending.

Dennis

 

[Jeremy Harris]

I found that nylon was a poor choice for a bearing running in water, as it swells slightly in water and tends to bind.

I use PTFE, which seems to work well.

Another tip for a bearing like this might be to make the bore chamfered internally, so that the clearance is greater where the shaft enters. This may help reduce the friction caused by the slight bend in the shaft.

Jeremy

 

[Guest625101138]

I have a plain bearing from nylon/steel in the support strut on my new drive system. The twisting action of the spring steel shaft 8 mm dia. increases the friction in the bearing to a very high level.
Am I doing this wrong, should the support strut not have a bearing but just a loose fitting guide so that it will not bind up caused by the spring bending.

Dennis

You do not need any strut but the shaft will hang until you spin it in the water.

You can use a loose fitting sleeve that just stops the shaft from hanging. It will have drag in air but once the prop spins in water the prop lifts and unloads the strut.

If you use tight fitting bearings on a semi-rigid or rigid strut then it is best to use two small roller bearings spaced about 80mm apart to force the bending moment into the shaft. Likewise you should force the bending moment at the gearbox so the shaft follows a circular arc. This induces the lowest cyclic stress.

If the strut is only semi-rigid then it will move forward slightly under thrust so you can have the prop angled down a little. You can check the response by applying thrust with your hand.

So there are many ways to make it work. The lowest drag is to have no strut but it is a nuisance when the shaft dangles down for lifting and launching.

I mostly use the double bearing. I use small stainless flanged bearings. From memory the OD of the ones I use most often are 16mm per attached. If you are using spring steel it could be a little oversize so sand down the shaft until the bearings are a neat fit. If you press them on a tight fit they are likely to get damaged raceways.

A few pictures of what you are doing would be useful for giving a more specific answer.

It is probably worth trying without a strut so you know what no drag feels like and then try the loose sleeve to compare. Beware that the prop can hit the hull if it is totally unconstrained. The two bearings on a thin semi-rigid strut is the best I have found for the prop beside the hull.

 

[Dennis A]

High Friction in Bearing

Thanks Rick and Jeremy for your advice.
Due to the fairly light nature of the bearing bush, I think I could not push it out to modify it without damage. The strut is hinged so that it can move up for easy docking and launching but is a welded asembly. I will therefore simply open it out and let it float around for about 2 to 3 mm by drilling it out with a larger drill and then test.

Dennis

 

[I57]

Spring Steel Shaft

Dennis
I don't know what your setup is like but I use the spring steel shaft without a strut. For setting up on the beach I hook the shaft onto a beam and drop it into the water when the boat is afloat. I hold the shaft up with my hand until I am in deep water, holding the shaft also gives me limited reversing. The proa setup makes using the shaft this way easy, as long as you don't mind getting wet. Weed is less of a problem as there is no skeg to wrap around and the prop springs up if you hit something. The shaft snapping is a worry but I keep a count of the amount of times I use it, I carry a spare mild steel shaft and prop which would be enough to get back if disaster struck. Don't know Ricks opinion on this but I think having no skeg places less stress on the shaft as the bend is less when going slow.
Hope this may be of help.

Ian