Prop shaft powered alternator for cruising sailboats !

None of the above. The rumble comes from the stern bearing and is a totally different sound to the prop noise. The rumble stops because the alternator load on the pulley acts as a third bearing, maybe inducing some side load, dampening the bearing noise from the cutlass. The prop noise is reduced because this stops the prop attaining the higher rpm which causes the prop noise. That's how simple it is.

 

Phil,

I am curious about the electrical side of your installation. Is this a regular alternator with a field coil connector to a regulator off your batteries, or is it a permanent magnet design?


Thanks,

Allan.

 

Hi Allan,

Old thread, Phil might not be online here anymore. I'm pretty sure he just used a regular alternator - I think this was before PM designs were more readily available. You can get some low RPM PM generators these days designed for wind turbines that might work well without such a high pulley ratio.

Cheers,
Mark