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# Waterbike

A whole new take on the words 'Tread Water'!
 (+4) [vote for, against]

We have all seen those cute little paddle boats people use to go hither and thither on lakes. These paddle boats are the tiny cousins of the steam-powered paddlewheelers Mark Twain (aka Sam Clemens) made famous. This concept is a new twist on the whole idea of paddling oneself across open water.

A platform constructed over two pontoons would have a bicycle-type chain and gear assembly mounted to its centerline. Instead of operating paddles, this system would power two caterpillar-like treads which are mounted outboard of the pontoons. the treads would be built up of planks assembled in an 'L' where the short part of the 'L' is the part actually gripping (if that is the word) the water with a minimum of counter-productive friction.

By comparison, paddlewheels create thrust only when they are oriented vertically to the water's surface. Once they start orienting at any kind of angle, they start to lose their thrust ability until it reaches zero - when the paddle is perfectly horizontal, relative to the water's surface. Most of the time the paddle is in the water, it is producing thrust, so the net effect is forward motion. But it seems the motive system (aka engine, or, in this case, the peddaler) is working harder than it needs to.

At any given moment of propulsion, there would be, say, 20 treads in contact with the water providing push. One tread might be ten centimeters wide and perhaps fifty centimeters long. As a tread goes through the water, producing thrust, it creates essentially no counter friction, unlike an oar or paddle wheel, both of which do. Only when the tread is about to come out of the water does it produce any counter friction, but that is counter-acted at a 19:1 ratio (the 19 other treads, that is) and the counter friction is very brief for each tread anyway.

I have a line-drawing of the concept (done on windows Paint) but have no idea about how to submit that for perusal.

Human motive power is always limited to the individuals aerobic capacities. The concept outlined here is aimed at making those capacities go further, if not necessarily faster.

 — Moonguy, Jun 26 2007

Designing a vehicle of pretty much exactly the same concept as described has been a hobby of mine for a year or so now.
 — Texticle, Jun 27 2007

Please post the line drawing. I think if you create a html page containing the drawing, halfbakery allows you to put a link to that in your article.
 — doanviettrung, Jun 27 2007

 //halfbakery allows you to put a link to that in your article.//

 — skinflaps, Jun 27 2007

What about some cam-like device that changes the presentation of the paddles such that as they leave the optimal 'pushing' zone, they retract, or flatten against the wheel's surface, or do something so that they aren't pushing water in unhelpful directions.
 — zen_tom, Jun 27 2007

 — nuclear hobo, Jun 27 2007

btw, welcome to the halfbakery, I like your name [Moonguy].
 — xandram, Jun 27 2007

It's the HullaPontoon!
 — elhigh, Jun 27 2007

(+) I was going to make some reference to a fleets flagella ship...but that would have just been cilia.
 — 2 fries shy of a happy meal, Jun 28 2007

WaterTank
 — Ling, Jun 28 2007

 as usual, i will suggest an alternate version of the original idea: (+) btw

 connect the pontoons to the rest of the vehicle such that they rotate when the pedals are...pedaled. in fact, make them counter-rotate.

 now carve them such that they resemble a couple of large screws, with exaggerated thread and minimal shaft. of course the ponturns (tm) will still need enough material to keep the whole issue afloat so the threads may be kinda thick.

 i suspect that this system will incur far less parasitic and turbulence losses (for at least a half dozen reasons i can think of at the moment).

 either tank tread or ponturns (tm) would be pretty useful for maneuvering if the steering was connected through some sort of drive differential rather than a rudder (another source of drag) that would remain operational even when coasting (differential drag).

another cool image (to me, anyway): if this thing was electric assist, you could anchor it in flowing water for a quick recharge, or to provide energy for off-vehicle use.
 — TIB, Jun 28 2007

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