Pedal powered Paddel boat! :)

[Logic11]

Clever and cool!

At a guess I'd say it's very efficient too..?

 

[marvin78]

If pedal boat's were efficient, they would still be around commercially.

As to 'fun' -> still waiting for someone to built me a life size pop pop boat like this ->

..but then using a solar boiler.

 

[Chalo]

Clever and cool!

At a guess I'd say it's very efficient too..?

That is one of the better propulsion schemes I've seen for a pedal boat. Paddle wheels are rather splashy and slow, and screws are hard to optimize and easily snagged or damaged.

The fastest human powered boats have all used screws, though.

 

[Logic11]

If pedal boat's were efficient, they would still be around commercially.

As to 'fun' -> still waiting for someone to built me a life size pop pop boat like this ->

..but then using a solar boiler.

This is not your std water wheel.
Some efficiency testing from someone who has been testing various screw props.

 

[marvin78]

rctestflight is a fun channel, doesn't make pedal power more efficient then screws/props though

 

[Logic11]

rctestflight is a fun channel, doesn't make pedal power more efficient then screws/props though

Hmmm... maybe not, but he has tested just about every prop design out there.
The long, slower blades win again, as expected.

Then when it comes to pedaling a boat, changing the direction of rotation through 90 degrees is inefficient: ~10%

Then there's no fouling from water weed etc.

So I'd say; from ease of a construction, practicality and even efficiency POV, paddles that move down/up into/out the water perpendicularly is up there.

There's also a bit that can be done to optimize paddle shape etc:
Add a 2nd free wheeling crankset at the top of the paddle to keep them perpendicular to the direction of desired motion at all times.
Sharpen/round the bit that moves down/up into/out the water.
Round the perpendicular edges backwards in a Pelton Wheel type style.

 

[Logic11]

A boat bike contraption by the same guy.
A series of videos.

I'm surprised it didn't occur to him to close the 2 sides for the front wheel with canoe fabric, using the same technique, to make it more hydrodynamic, rudder-ey and buoyant.
At least it rotates in the water which helps a bit.

Then there's the 'old angle grinder to differential' trick:

 

[marvin78]

Even if it wouldn't be suspectable to fooling through weeds, I feel the added mechanical complexity adds to many additional points of failure, points of mechanical friction / losses and would make the contraption also space inefficient.

Add a 2nd free wheeling crankset at the top of the paddle to keep them perpendicular to the direction of desired motion at all times.

.. as I said I think it's adding complexity to fix a problem which doesn't really exist. If you're worried about weed fouling, a muddrive works excellent and only losses a bit of efficiency compared with a 'normal' prop.

With placement of a rudder and prop you also greatly increase handling over a paddel propulsion which only gives trust 50% of the time.

 

[Logic11]

Even if it wouldn't be suspectable to fooling through weeds, I feel the added mechanical complexity adds to many additional points of failure, points of mechanical friction / losses and would make the contraption also space inefficient.



.. as I said I think it's adding complexity to fix a problem which doesn't really exist. If you're worried about weed fouling, a muddrive works excellent and only losses a bit of efficiency compared with a 'normal' prop.

With placement of a rudder and prop you also greatly increase handling over a paddel propulsion which only gives trust 50% of the time.

It was more a case of: "Oh look! Novel (looking too) and easy boat propulsion, using bits lying around and hand tools "
than: "...a technically superior way of propelling all boats!"

So to me it looks more like the opposite of "...adding complexity to fix a problem which doesn't really exist.."
He got his pedal boat moving (the problem) with bits he had lying around, simple hand tools and no holes below the water line etc.

eg: If some guy with a canoe and old bicycle bits asked you to help build a pedal boat this evening; would you go with this option or start doing maths and then building gearboxes and efficient props and energy sapping below the waterline effective water seals..?

Then; for the only efficiency tests I could find offhand, the numbers look pretty good!

Worth a post, all in all!