Luc
We have the ability to lift the props close to the surface and keep operating but no point with the deep rudders. It would not be very effective once the props ventilate though.
The linked video shows a high speed paddlewheel:
The basic wheel dimension are quite good for that application. It would have similar efficiency to an outboard propeller. You can see that it takes a while to get the boat up to speed meaning they are quite high slip under load.
To get efficient operation with paddlewheel on a proa they would need to be quite large blades. The props we are using have a swept area of 0.22sq.m so equivalent to blades 300 deep by 700 wide. You would want 12 blades on each wheel and diameter up around 2m for good performance from such large blades. As you drop blade size the efficiency drops. You will need a big gear reduction for such a large wheel.
You can trade blade width for depth to get a smaller diameter wheel but the thrust will be more affected by waves.
There are all sorts of propulsion systems in this video. You get an idea of the relative performance of different paddlewheels. Notice how big they are on the boat that is competitive with the propeller driven boats.
Paddlewheels are possible but they will take a good deal of engineering to get a neat, useful system.
Rick
On 23/12/2012, at 1:12 PM, LucD wrote:
If navigating shallow waters is part of the boat's SOR's I come back to the paddlewheel idea. Using two rather standard bicycle wheels with hub drives rated at 1 kW each, one could have a pretty powerful paddlewheel "just" connecting the wheels with the right sized paddles on the outside rims. Such a paddlewheel could drive each of two Denney pivoting tender/sleds to turn the vis on a dime. There are already motorcycle wheel hub drives rated at a continuous 10 kW. There must be a good reason why I could not find not even a goofy example of such a construction yet on internet.
Luc
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