pedal powered kayak idea.

I bought my fiance a sit in kayak about 2a years ago. However due to a shoulder injury paddling any further than short distances becomes painful for her. I have been doing some reading on pedal powered boats, but they are all of sit on top design, so their drive systems are of limited help in my endevor to make a pedal powered sit in boat.

So I had the idea of using a flexible cable drive, similar to the speedometer cable in your car (non-electronic), but more heavy duty. There is a company that makes them called Elliot Industries or something like that. My goal is to use one of these cables from the pedal gear and chain setup, route it out of the boat above the waterline (less chance of leaks), to a prop mounted on the back below the waterline. Has anyone ever tried this? Trying to keep things as low cost and simple as possible, which is why I don't go with something more expensive. Not looking to break any speed records, just for her to be able to keep up with the kayak "pack".

 

There have been a number of long threads on this forum on "pedal powered boat" and the like, such as:

http://www.boatdesign.net/forums/boat-design/pedal-powered-boats-23345.html

http://www.boatdesign.net/forums/props/propellor-pedal-powered-catamaran-21911.html

http://www.boatdesign.net/forums/boat-design/where-start-pedal-powered-boat-23665.html

http://www.boatdesign.net/forums/props/pedal-powered-prop-design-34585.html

http://www.boatdesign.net/forums/boat-design/pedal-boat-propeller-specifications-data-31674.html

And these are just a few. If you do a search on "pedal powered boat" on this forum, you'll see all these links and a lot more.

I have not read them all or followed, them, but one thing I think you will find is that pedal powered propellers are very slow turning, and that means they don't produce a whole lot of power. The slower turning a prop, the bigger diameter it has to be. And the bigger the diameter it is, the harder it is to pedal because of the blade drag. But study the threads and see where it leads.

Eric

 

WP:

Begging, borrowing or renting a 2 person kayak might be a simpler solution. Your fiancee could be a passenger, and because of the increased length you might be able to keep up with the pack until her shoulder heals.

Pedal boat props need a way to remove debris that tangles in the prop periodically, as well as being able to avoid hitting the bottom/obstructions.... The cable system you are considering would require that you get in/out periodically for prop inspection. Unless you are doing completely clear, deep water???

Hope this helps.

Porta

 

I couldn't agree more.

Get a two seater.

Give her a paddle and have her paddle lightly until the first sign of pain.

Stop, ice, rest and resume.

It's the road to recovery.

 

http://h2proped.com/index.htm

They're working on an updated model with fairings.

 

There you go! System's designed. Pretty clever!

Eric

 

I know there's no such thing at the RPMs that a human can produce, but the prop appears to be weedless.

 

Hmm. Thanks for the link. Thats alot like what I am looking to build, but I am looking to build on the cheap. (E-4 pay). Pretty much using garage sale bike parts, but teying to find out where I could get a cable similar to that one. The overall design will be simple, and anything in the 4-5 kt range would be concidered a success.

 

There is also a pedal powered Paddle device, avoiding the problems of prop maintenance

http://www.abc.net.au/tv/newinventors/txt/s1816985.htm

or better yet

 

Rwatson that spidery looking, clamp on, canoe paddling, gizmo is clever as hell. He is using a simple parallelogram linkage to make the paddles work. No chains, gears, propellers or other complications. Because the paddles lift clear of the water at each stroke, they might even clear the flotsom that they have encountered. His pedals are coupled but if uncoupled they could affect steering.