Propeller rotation under sail?

The best explanation I have seen uses the unpowered Gyroscope/Gyrocopter analogy.A Gyroscope with a locked blade will plummet to earth:a Gyroscope with its blade rotating will glide to earth.It is clear that the rotation increases resistance. From all points of view,the answer must be to lock your prop in gear,or by other means.

Doesn't anyone use it for turning an alternator anymore.....or did I miss something???

According to practical sailor which did some extensive testing in the US there is less drag with a rotating prop.I have a Hurth gearbox and except for the noise its just fine.

and the noise means WEAR! bearings shafts etc god knows what its doing to a hydraulic box !

Now that WOULD cause drag !

My friends used the shaftgen om transatlantic cruise om PRM transmission.

When the velocity is so high that wavemaking drag is is significant, the generator will not slow the boat much.

Don't do it!!!!!!

I have just had to buy a new Hurth gearbox! It was only a little more expensive than refurbishing the old one. 2500 Oz dollars! The plates wore out because the previous owner let the prop spin.

The new gearboz works wonderfully!

Fair Winds Captain Mudbank

A gyrocopter with its blade rotating to cause LIFT and DRAG will slowly descend. However think about the blade spinning the other direction, driven by the medium through which it is travelling, as is a freewheeling boat prop. I suggest you go up in a helicopter and ask the pilot to try it. It is called "autorotation". Now kids, don't try this at home!! Captain Mudbank