Pedal Powered Boats

[Scheny]

I would like to create a freely available collection of data about human powered boats including a calculator based on this values.

If you can pass me information about human powered boats, I will collect it and make the information available. This may help anybody interested in building his perfectly fitting purpose built boat.

Interesting would be:

• type of hull
• length
• width
• wetted area
• speed at cadence
• top speed

I will try to find correlations in form factor and wetted area which will lead to a formula for realistic calculation of future boats.

Best regards, Andreas

[spidennis]

Originally Posted by Coach Dave

I epoxied a threaded freewheel hub to the string trimmer gear head. Then I threaded on a 14T 3/32" track cog. That gave me forward or reverse thrust. To use reverse you need a strut to keep the prop oriented correctly. If you have a free swimming flex shaft drive the prop dives when you go in reverse. The 14T cog resulted in slightly too high a gear ratio for my setup. I unscrewed the track cog and threaded on a 16T single speed freewheel. My freewheel hub will also accept 5 to 8 speed thread on freewheels. On a bicycle multiple gears are a big advantage for going up/down hills or with head/tail winds. On a boat you don't really need the complexity of multiple gears unless your load changes a lot. I attached pictures of a single speed track cog, single speed freewheel and a 6 speed freewheel.

Dave

Dave, this is Great, thanks! you got my gears turning now! Having both reverse and freewheeling sure would be nice! I've also learned about other bikes (weird ones) that have the freewheeling in the crank.

[Coach Dave]

The APC 20x15E prop is 1.06" wide where it attaches to the hub. That is a fairly large size to fit inside a U-channel then tuck in behind a spinner. I could increase the diameter of the spinner but smaller would be better to reduce drag and not catch weeds. If I trimmed the prop root down from 1.06" wide to say 0.50" I could use a smaller spinner but I'm concerned that I would weaken the prop root too much. I'm thinking that a purpose built folding prop would be a better choice.

Dave

[portacruise]

Hi, coach:

Yes, on purpose built folder. Cuts losses from breakage and bent tips under load plus you get more efficient custom blade design and possibly smaller diameter.

I haven't found anything that is really weed free, except maybe with light vegetation. Have tried folders, weedless troll props, cutters. One of several reasons that Rick mounted the folder within arms length to clear weeds. Lifting the prop to clear the water and spinning to fling off weeds works well for me, but there is still the occasional hand clearing required.

A reverse auger built on the surface of the flex shaft might help by keeping weeds away from the prop. I never did find the right pitch and depth to the stairs in my application.

P.

Originally Posted by Coach Dave

The APC 20x15E prop is 1.06" wide where it attaches to the hub. That is a fairly large size to fit inside a U-channel then tuck in behind a spinner. I could increase the diameter of the spinner but smaller would be better to reduce drag and not catch weeds. If I trimmed the prop root down from 1.06" wide to say 0.50" I could use a smaller spinner but I'm concerned that I would weaken the prop root too much. I'm thinking that a purpose built folding prop would be a better choice.

Dave

[spidennis]

Originally Posted by Coach Dave

The APC 20x15E prop is 1.06" wide where it attaches to the hub. That is a fairly large size to fit inside a U-channel then tuck in behind a spinner. I could increase the diameter of the spinner but smaller would be better to reduce drag and not catch weeds. If I trimmed the prop root down from 1.06" wide to say 0.50" I could use a smaller spinner but I'm concerned that I would weaken the prop root too much. I'm thinking that a purpose built folding prop would be a better choice.

Dave

Too bad these aren't readily available, I'd like to start out with one from the get go. As it is I guess I'll start out with the easy to get and cheap APC and once I got a system working refine it from there. I can work on my skilz to build props after that. It would also be nice to have a spare since I'd be doing extremely long and remote trips.

[Coach Dave]

Originally Posted by spidennis

Too bad these aren't readily available, I'd like to start out with one from the get go. As it is I guess I'll start out with the easy to get and cheap APC and once I got a system working refine it from there. I can work on my skilz to build props after that. It would also be nice to have a spare since I'd be doing extremely long and remote trips.

For a light, low drag boat you could use an APC 16x16 prop. For a larger boat with more drag the 20x15E is a better choice. Or if you want a "Texas-sized" prop go for the 26x15E. In the absence of prop slip the 16" prop moves through 1.9 cubic feet of water each revolution, 20" through 2.7 CF and 26" through 4.6 CF. The bigger props are better at low speed, high thrust and are a liability in shallow water.

Dave

[portacruise]

Originally Posted by Coach Dave

For a light, low drag boat you could use an APC 16x16 prop. For a larger boat with more drag the 20x15E is a better choice. Or if you want a "Texas-sized" prop go for the 26x15E. In the absence of prop slip the 16" prop moves through 1.9 cubic feet of water each revolution, 20" through 2.7 CF and 26" through 4.6 CF. The bigger props are better at low speed, high thrust and are a liability in shallow water.

Dave

I've found that by continuously adjusting/reducing the depth of submersion for the prop, you can run at various degrees of surface piercing from full immersion and get through sections of shallows with a large prop. Seems to be better with weeds also, as you don't get a tangle on shaft since most are flung off the tips. Running at surface piercing mode for extended distance might not be practical as it would reduce the speed considerably, compared to full immersion. Maybe one place where a sprocket cluster would help with the gear ratio...

P.

[spidennis]

I like that idea of variable depth selection for shallow water! I'll be keeping that in mind. Three settings, full, shallow and stowed.

[spidennis]

Rick has just uploaded a new video.
A carbonfiber folding prop!
and I like the peddle crank system. cool.

[Submarine Tom]

Do you have a link there Spidy-man?

-Tom

[spidennis]

Originally Posted by Submarine Tom

Do you have a link there Spidy-man?

-Tom

did the youtube video not post?
it shows on my end, oh well, here's the link:
http://youtu.be/ONk3fUnHamI
http://youtu.be/ONk3fUnHamI
Rick has some slick stuff going on there!
I was thinking about using CoachDave's bicycle frame idea but it's too tall, then I see rick's peddle and crank, ooooh I like! That would be be nice and low. I got to figure that I'll have sails above my head at times, so low profile would be good. I'm even thinking about changing up my center platform idea a bit. I keep molding the clay and it's starting to take shape.

[Submarine Tom]

The space is there but no link...

-Tom

[I57]

Tom
Try typing in the search area of YouTube CF_Blade_Propeller.wmv

Ian

[Submarine Tom]

Sorry, I wasn't very clear.

The first post didn't show the link but the second one did.

I had already found it by Googling: rick carbon prop v15

What I'd be more interested in would be any dialogue that may have gone along with it.

-Tom

[upchurchmr]

Rick doesn't seem to talk much. I would like to read his comments also.