It’s not, technically, a perpetual motion machine, since if you look at it as a system, it’s relying on an external energy supply in precisely the same way as a normal sailboat.
I suspect its downwind speed will be lower than that of a normal sailboat, however, due to issues of decreasing relative windspeed and propeller/friction losses - but it should be able to sail directly into the wind, thus avoiding all that time spent tiresomely tacking. :rolleyes:
But the big technical issue is to match propeller pitch and gearing to suit the rotor.
(There is a risk, of course, should this be optimised: when sailing upwind the speed of the hull will increase the apparent wind speed, thus speeding it up even more, in a terrible positive-feedback loop - only ending when it reaches 80mph and starts to travel through time…)
I distinctly remember seeing a line drawing of an arrangement similar to your proposal, except that the aerial part was a conventional propeller facing forward, with a flexibleshaft extending down to a propeller in the water below a twin hulled boat. It was presented as an idea that had been proposed several times, but that it could not inherently work precisely because it was a perpetual motion machine. That is, the energy absorbed from the air flow past the aerial propeller would need to be transmitted in toto to the water propeller, without any losses. Even if this could be achieved by means of frictionless bearings etc., the very best that could be obtained would be that the vessel would stay still, rather than being blown downwind. As frictionless bearings have yet to be invented, I greatly fear that your model will always go downwind, at a slightly lower speed than it would if there were no actively moving components on the boat.
I have not been able to locate the reference that I remember, but will continue to look, and will present the material here if and when I do.
It just occurred to me that a Flettner rotor system, but with the rotor(s) rotated by a small electric motor might sail straight upwind. Because of the power needed to turn the rotor, it is, of course, not a perpetual motion machine.
Here’s a variation made by Halsey Herreshoff in school and now visible in the model room of the Herreshoff Museum. Halsey loves telling the story of the day Ted Turner bet him a dime it wouldn’t work. They took it out to the water, set it down, and off it went. Supposedly Ted never paid off. Just saying
I would like to see a properly researched vector diagram showing that an upwind force existed that would drive the boat upwind. I was trained as a scientist, and cannot forget my training when considering matter transmitters, Ponsi schemes, ghosties, goblins, little Irish leprechauns and all the other unlikely things we might all wish were possible. The modern sailboat with its Bermuda rig is wildly impossible ( the boat goes upwind due to the force of the wind blowing it backwards, you say? IMPOSSIBLE, SIR!!!) but the vector diagram says otherwise.
Do you know that the tunnel diode, a common electronic component, has electrons which disappear in one place and reappear in another while apparently passing through a space where they cannot be? Is that a matter transmitter or not?
Show me a vector diagram, or a good photo! Un-retouched, of course!
Signed: Doubting Thomas.
