Pedal Powered Boats

Here are some pictures of Greg K's prototype which used retractable outriggers:

http://www.pedaltheocean.com/about-within-prototype.php

These were unsuitable for his purposes and were later replaced by a KEEL. But you can contact Rick W. on how these were done and for ideas of how to retract your catamaran hulls. You can google for Rick's web/email address or send questions to the human powered boat site which he and other experts post to...

P.

 

Hi Jeremy, I was wondering how your 'efficient electric boat' project based on Winsome hull proceeded? I'd love to know how that boat ended up and how effective the drive system/solar arrangement was, I've just finished reading the 32 page thread.
Thanks,
James

 

so in the type of peddle system like in Rick's where it uses the gear box or in the twisted chain type, when you stop peddling or giving effort, what happens to the prop and drive up to the peddles? Does the prop keep driving the peddles so you can't just "rest"?

 

That has been a concern with racers at full output, as the pedals could not stop immediately. If you become foul strapped to the pedals at high crank speed, might cause some kind of foot damage with large props having higher inertia. Small props probably have enough slip though. The solution is a freewheel like in ordinary bikes, but I have not heard much about it being used because it prevents reverse in a boat....

P.

 

Anyone knows the wetted area (in m²) of a boat like Rick's V15 series?

Thanks in advance, Andreas

 

I'd think that I'd use the freewheel feature more than the reverse, in my case anyway. Maybe easy enough to have with a twisted drive system vs a gearbox? It's already built into bike parts but not into the gear box. Or maybe mate the two together? hummm......... time to go back thru my pic collection and see who had what.

 

Hello folks!

I have used the weekend for extensive calculations. As it turned out, the wetted area measures only 95% of the wetted area of a 4.5m catamaran. It should also be not so much higher that that of a sleek 5.5m boat. I have also done power calculations for the hull based on the tank tests. The speed at a power input of 150W should be in the area of 10-11kph. As I think, that a HPB has better efficiency than a 14m boat because of relative propsize, my guess would be that 12kph hopefully will be achievable.


Now my questions to the community:

• How much efficiency losses do I have to expect when using an APC 12x12 instead of 16x16? How much better would be a custom made prop and is there any advantage/disadvantage in using the sleeker APC E-series?
• Dou you think that a 10:1 gearing will suit for an APC 12x12E prop for driving at cadence and is a 6mm steel shaft enough for it?
• How much weight gain will it have when I use 4mm Plywood with 65g/mm² on both sides compared to 5mm foamcore with 2x200g/mm² on each side.
• How much rudder area is necessary, if I use static rudders (non-dipping) and will it make a difference if I have two rudders with area/2 instead of one?

I am appreciating any help, but please no comments, that the project will not work out. We will see that soon enough, when the boat is ready.

Greetings, Andreas

 

Rick has gone back to using bike type sprockets in V15, post #1206. Then he added a 90 degree gearbox. But that could have something to do with making the prop easily reached for releasing weed tangles because of the Murray competition it was meant for.. If you have a lot of manuvering to do in your narrow passages, it might be better to have reverse capability considering the weight of your boat. You can tilt the prop out of water if the gently spinning cranks are a bother, since you were looking for that capability anyway.... Seems like the traditional chain twisted drive would have some stresses/wear issues compared to a straight lineup bike chain although Stuart's was essentially flawless from what I read. But now there are different types of chain such as the beaded cable type which might be somewhat better, though they have negatives of parts availability/assembly/design, etc.

P.

 

Scheny:

The electric series have been the most efficient for me for low power electric drive up to 40 watts, but they have a lot of efficiency losing flex at high power/acceleration and do not hold up to stresses very long-fragile. There are some CF electric aeronauts which are stronger in my applications, but only come in small sizes. I have only seen 16x16 APCs and larger used with human power. Rick might do a calculation for you or at least have an idea about the 12X12's: http://www.boatdesign.net/forums/boat-design/efficient-electric-boat-27996-17.html post #252 and thereabouts...

Rick Willoughby <rickwill@bigpond.net.au>

Hope this helps.

Porta

 

Thanks for the advice. I thought the E-series might perform better due to lower drag. I have flown a commercial plane with an efficient woodprop many times, which was only held in position by centrifugal forces. If you had to add in full power very fast (in emergency situations), you could see the blade area oscillate back and forth a few times.

I see, that a few hundred RPM are not enough to make the blade area less flexible due to centrifugal force.

 

Portacruise,

Do you know where there is any discussion of the V15 boat? I was very surprised to see the extensive superstructure when Rick had discussed the virtues of lightness. I have seen his "website" or photos, but I would like to see if he has some discussion outside of this thread.

 

Yes, in water, it's the pulled forward deformation of the blade as it bites into the much denser water compared to the air the blade was designed for. This deformation reaches a fatigue level that soon snaps the e- blade. Also any collisions with rocks, or even floating pencil twigs can cause immediate failure. But they are very cheap and compact to carry, so you can carry a dozen with you and rig a quick release so the changing takes only a minute or so.

P.

 

I'm liking this system! and should be easier for me to mount (somehow). Rick has been after this for quite awhile, so it's good to note what he's up to. I too am surprised at all the "superstructure" on the V15.
edit: so this didn't take long ........ I pick up my model and play with, gaze at it, fuss with it and now I think I got a mounting idea figured out! Just like in Rick's boat, the drive goes over the right side, ok, I can do the same thing on my center platform. then when I fold the hulls together I pick up the drive, as in to clear weeds and so on, fold the boat and drop the drive back into the drink but this time it' now on the outside of the hulls. I just have to make sure it far enough outside as to not have the prop hit the hull. What diameter prop is rick using?

 

Rick will usually post his activities around new year's on the human powered boats list. He responded to some questions on that list and to some PMs I sent as a follow up. The V15 boat was custom designed for a Murray marathon competition, though he did not compete in 2011. I was surprised by how fast the boat was (20+ km/hr) considering the superstructure. He went to folding outriggers probably to offset the superstructure and a slightly smaller prop with a higher gear ratio. I think there has been interest in commercial production. I believe Rick is guiding several builders including I57 from his Oz neighborhood who posts to this list.

P.

 

this is Rick's blog: (as posted earlier somewhere in the thread)
http://www.rickwill.bigpondhosting.com/V15_58.htm