Human Powered Boat

[icetreader]

Bricka made it as far as Hawaii
http://www.ananova.com/news/story/sm_68850.html
Good luck to you

[JEM]

That's an interesting idea. I know when I warm up on the recumbant bike at the gym, it feels like part of my energy is being devoted to just keeping my legs up. That might be a function of the bike design though. I don't know enough about them.

A row-driven prop set up is a neat thought. You could really get some power strokes going. Could probably rig it so you can just use your legs when you want to keep moving but want to do something with your hands like eating or check a map or something. Envision a rowing machine at the gym: Just move the pull strap from the row handle to the seat.

[Skippy]

Just a few more thoughts.

• On the derailleur, I would mention windage from headwinds vs. tailwinds.
• Standard cycling frequency is usually around 80-90 rpm for most people, maybe more like 100 for trained racers.
• If you incline a rowing machine slightly, you do work with some muscles just pulling yourself up the track. Then you get that energy back from gravity as you pull back with other muscles. So it's an even more distributed workout.
• But the power to the propulsion will still be intermittent, which may not be ideal hydrodynamically.
• On the other hand, if you can time your strokes to power up the front of a wave, this could be ideal. You want to coast down the other side of the wave to even out your speed. Gosh, it's fun just thinking about it!
• My tendency would be to avoid the weight of a flywheel like the plague.
• That may also apply to an aluminum hull.
• Eric's comment on the difficulties of rowing may also favor a prop over paddlewheels.
• With a prop, the airborne crowd will have a lot of experience with transmission systems.

[SolomonGrundy]

Eric,
Again, thanks for the insights. I have been all but setteled on the prop. system. Paddelwheels and other non-traditional forms of propulsion, so far, lack one or more of the prerequsite aspects of simplicity, reliability and efficiency. I don't want to discount any options this early though if they could be shown to be effective. Prop. engineering and fabrication are daunting challenges and that aspect is starting to sound really expensive. Where would one have such a prop. manufactured?...back to carbon fiber...are those laid up? As it looks like a 2 bladed prop. is ideal, could there be a way to make several of the same blades and then fasten them somehow to a hub so that should the need arise to repair the prop. one could simply remove the offending blade(s) and replace it with a spare?
I have considered some sort of feathering device, but there I go again adding complexities into the equation...it might be easier and/or simpler to adjust the prop. at the hub manually, I mean this boat will be not much more than an over glorified rowboat anyway, maybe some sort of drop down or other form of retractable device would be good, especially as far as prop. inspection, installation and repair is concerned. I'm thinking something like either a longtail type similar to the kinds used in the southern Indian Ocean islands, or a kind of drop down/well type like for the outboard on my Thunderbird, the well has a plug closing the hull when the motor is retracted.
I think the notion of a derailer (sp?) that some have advocated is a really good idea if a chain and sprocket type is setteled on. At least it would be easily serviced and cheap to make with the available parts. I doubt if more than 4 different ratios would be needed.
Back to the prop., can anyone point me to some good resources regarding manufacture of highly specialized props such as the one we are discussing?
Again, thank you to all who have contributed so far for your welcome advice, insights and comments, they are greatly appreciated.
Solomon Grundy.

[D'ARTOIS]

An aquaintance in business of mine operates and owns the largest prop mfr plant in France. Supplies subs, boomers, and nuke carrier(s) as well as a host of comm. ships and yachts not to forget. But, does it make sense?
Alaska-France is a long way, on the other hand, there are most probably no prop
mfrs in your vicinity, maybe in Seattle?
In any case, if you can produce a design, I can have it made, probably at no cost.

[Eric Sponberg]

Solomon,

There are a number of propeller manufacturers in the country that could machine a prop, although most of these work in bronze rather than aluminum. Check your local area for propeller shops as most have some kind of NC milling capability, and also for any machine shop doing NC milling of aluminum. If you can create a propeller design, then the shop can mill it.

Building a propeller in carbon fiber would not be that difficult either at any number of composite fabrication shops that are experienced in carbon fiber laminating--I can think of a number of them right off the bat in the east here that would likely be able to do it. There may be some up where you are. The ones I am thinking of are GMT Composites in Rhode Island, Composite Solutions in Mass, Elliott Associates in Mass, Composite Engineering in Mass, Phil's Foils in Ontario, Canada, and Vectorworks here in Florida.

A propeller would be similar to a windmill blade propeller too. When I was doing manufacturing at TPI for US Windpower, we were building similarly shaped blades like on Gossamer Albatross in composites. They simply used a NACA 4415 foil section with the proper spanwise distribution and angle of attack for uniform power along the length of the blade.

In composite more so than aluminum, it would be relatively easy I think to make demountable blades, as you suggest, so that they can be replaced individually.

In the small boat that we are contemplating for around the world sailing, I anticipate that the hull will be kind of akin to a Bristol Channel Cutter (with some significant variations which I won't get into now) which has a nearly plumb stem that sweeps down and back into a full-length keel. The prop will hide behind the skeg so that when you don't need it (most of the time on a sailboat) is tucks in line with the skeg. This is one way to eliminate the need for feathering. Just mark the shaft on the inside of the boat so that you know where to stow the prop in the upright position behind the keel.

Eric

[jehardiman]

Solomon Grundy;

If you are really serious about doing this with a prop, e-mail me, and I can give you the technical rundown on what you need to do to build a human-powered propulsion system. I have all my design material from the SUBHUMAN Project (the first human-powered submarine recognized by Guinness World records), including the prop designs and manufacturing methods for aluminum and composite blades along with design and construction plans for "normal" proplusion and SUBHUMAN III's linear (i.e. "stair stepper") proplusion systems.

I'm going to be blunt about this, some of this stuff is not "nickle/dime" work, but you need a skilled machinist and proper equipment/materials. The SUBHUMAN Project was very lucky to have some good technicians/hobbiests/sponsers who had the equipment necessary to do the job. Now, a surface craft is not as complex as a submersible, but the quality needed to get a high efficency (80%+) and robust propulsion system cannot be underestimated.

[SolomonGrundy]

Mr. Hardiman,
Is there a working system or mock-up in the Puget Sound area that I could go look at?
Thanks, Solomon Grundy.

[jehardiman]

Originally Posted by SolomonGrundy

Is there a working system or mock-up in the Puget Sound area that I could go look at?

SUBHUMAN II is in the Naval Undersea Museum in Keyport. She has an eliptical crank drive and counter-rotating 33" wheels. Her prop delivers ~ 200 lbs bollard thrust at ~ 0.8 horsepower and about 50 lbs thrust at 5 knots with the same propulsor (i.e. peddler). Her blades are basically untapered and have minimal optimization in plan. RPM was about 200 at the torque limit and max Va was ~6.2 knots.

SUBHUMAN III is down in California. SUBHUMAN III's drive system was an improvement and so was her propeller. Props were very different from SUBHUMAN II's and an improvement as she got about 180 lbs bollard out of a 25" set of wheels and about 40 lbs at 6.5 knots. Her operational RPM was about 170 with a max Va of ~ 7.5 knots.

I'll tell you right now that looking at either boat as they sit will not tell you much. Most of the mechanicals are hidden due to design considerations of a submersible and for effiency. Most of the gearboxes are either compensated or protected to prevent damage and hydro losses.

[sharpii2]

Hi solomen

Just had some fun with my plyboats (r) program. I thought about the boat, and just for fun, I keyed in a hull. It was exactly 20ft long, 4ft wide, 1ft 2in deep, and displaces 2200lbs max. It was pointed at both ends with a very sharp bow. Its vertical sides project a mere 12in out of the water. It has a raised deck kind of cabin that sweeps down at the ends and is comprised of three panels. The two side ones are sloped 45degr.

It looks like a pregnant kayak. Most of its above water design is calculated for streamlining because I assume that some of your voyaging will be up wind. I guestimate that this structue would weigh in at about 400lbs including, perhaps, the pedal drive unit. This will allow 1600lbs for gear which, I presume, will be mostly food and water (the remaining 200lbs is for yourself). Much of the water could be kept in two liter bottles which can be stowed low when not being used. They can also be refilled with salt water if their weight is needed for ballast.

While I was doing this, I was brain storming about possible problems. The biggest one I can think of is keeping on course. Unlike a row boat, where you can stay on course by differential oar strokes, this boat will need some sort of rudder. With a rudder it can, of course, be steered. But how easy or hard this will be is another matter. I thought that if the underwater profile can be manipulated to trim in relationship to the wind, little or no rudder use will be needed. It would be a set it and forget it system of two small dagger boards set about one third to one half the hull length apart. They could be adjusted from inside the boat. By adjusting their relative depths, it may be possible to control the boats course in relation to the wind. These dagger boards would ,of course, be fully retactable.

When going up wind, what will you do when you need to sleep? Heave to? Put out a sea anchor? If riding to a sea anchor, will you attatch it to the bow or the stern? My vote is for the stern.

As for performance, I expect a speed range of 2 to 2.25 knots with the boat fully loaded. With a half load, you may win another 1/2 knot. Supposing a 16 hour day, that would give you 32 to 36 miles of progress per day. With a favorable wind, you may go faster, perhaps 4 knots.
With an unfavorable wind, progress could be brutally slow. You could lose up to 1/3rd of your progress due to back drift. A carefully designed sea anchor will be a must. The goal should be about 1/2 to 1 knot of back drift. If thats possible, you may actually be able to get somewhere.

It will be interesting to see how far this goes.
I look forward to reading other posts.

Bob

[Skippy]

Bob, how would a really skinny sliver boat do? Say 3ft beam with a small bulb keel. Even compared to an open rowboat or canoe (maybe similar to a kayak), this one shouldn't need as much initial roll stability, since the prop won't come out of the water in moderate heel, and it won't capsize as long as it's self-righting. SG, do you mind pedaling heeled over to the side sometimes? Less wetted surface, less wave drag, and more headroom.

[mattotoole]

I haven't seen IHPVA mentioned in this thread yet. Undoubtedly there's a lot of information to be had there, on drivetrains, efficiency, and human performance.

As far as bicycle drivetrains go, you're better off with a chain than a belt. Chains can be over 99% efficient. Belts are considerably less. Every watt counts with human power.

[sharpii2]

Originally Posted by Skippy

Bob, how would a really skinny sliver boat do? Say 3ft beam with a small bulb keel. Even compared to an open rowboat or canoe (maybe similar to a kayak), this one shouldn't need as much initial roll stability, since the prop won't come out of the water in moderate heel, and it won't capsize as long as it's self-righting. SG, do you mind pedaling heeled over to the side sometimes? Less wetted surface, less wave drag, and more headroom.

Good idea, Skippy.

Draw it up and do the numbers.

I originally wanted it to be only 18ft long, but had trouble getting the right displacement. Just how much length are you suggesting. 25ft? 30ft?
And how high are you considering? 3ft? 4ft? My concept is 3ft high from the bilge to the highest point of the raised deck.

It must be remember that someone will have to live in this thing for months at a time. The space I have alotted seems paltry enough. Kind of like living in a sewer pipe. And cutting the beam by another foot may, as you have suggested, require fixed ballast. When you say 'small bulb keel' how small do you mean? 50lbs? 100lbs? 150lbs? Remember, this weight, whatever it is, will have to be subtracted from the payload. Not only that, but it adds non removeable wetted surface as well. With my concept, some of the drinking water (about 1/3rd of it) serves as ballast. It is replaced with salt water as it is consumed. Also, as the boat gets lighter from stores being consumed its wetted area goes down significantly. By about 1/3rd (at a minimum load of 600lbs).

Two primary concerns in my concept are windage (fore and aft as well as frontal) and laminar flow. The prismatic coefficient for this boat is less than 0.50. This is in best keeping with the slow speeds its designed to travel at.

Whether my concept is the right one, who knows? For me, its just a starting point.

So get your calculator and scale paper out and start sketching, maggot .

Bob

[SolomonGrundy]

Some #'s to throw out for the heck of it... "Reach" was 28' about 4' beam 1200 lbs. light and 3000 lbs. loaded and had about 6" of rocker. Swampscott style, there was 2 planks per side, the bottom and of course the dory style transom with a cabin fore and aft.
Something else I found... http//home.gci.net/~alconda/projects/projects.htm

[JEM]

Curious: Are you going to build the hull yourself?