Alternator in propeller shaft

[LORDRAKE]

Hello, Im a spanish sailor. I ask you over an alternator mountied in the shaft of gear to propeller.
Skill, and advises are good for me.
Thank
LORDRAKE <span style="color:blue"> </span>

 

[RobWales]

I think he is asking if you can run an alternator off the main shaft before the prop!?

 

[ccscott49]

Yes, you can mount an alternator on your shaft, however, there is no point if its a motor boat, as you have the engine running.
If a sailboat, then if the shaft is rotating, its maybe worth it, but again, you could use a towed alternator, which would be more efficient.
The shaft alternators are expensive and quite difficuolt to rig up.

 

[RobWales]

What I meant was mounting a pulley on the shaft to run a belt to an alternator!

 

[LORDRAKE]

Yes before propeller, in the shaft put a Pulley and with a belt move an alternator, so sailing get electricity by the natural movement of propeller.

 

[magichands]

it wouldn't work with a standard type of alternator as the shaft wouldn't spin fast enough. A standard alternator needs to spin at at least 700rpm to initiate a charge, at which point it builds a resistance to the input torque creating the power. Even if it did work, Depending on the size and pitch of the prop the speed under sail its quite possible that the resistance could slow the prop enough to cause drag and reduce the speed of the vessel. Then the alternator would stop charging, loose resistance and free up the prop. then boat would increase speed again and the cycle would continue.

 

[LORDRAKE]

What tipe of alternator is good in this case?
Thank