Prop Shaft Generators

Hi Dashews, Have 3 of your great books and getting a great deal from them. My yacht has a free-wheeling engine shaft and I understand someone has developed a system whereby you can mount an electrical generator inside the boat to the engine shaft via a belt and a set of pulleys–have you any information on this system, or contacts where it could be obtained? Regards, Mike

Hi Mike: You will find most of what we know about shaft generators in Offshore Cruising Encyclopedia. In short, what you need is an alternator which is wired for low rpm output–such as are used in deligery and emergency vehicles. Most alternator manufacturers make these.

Beyond this, it is a question of space–fit the biggest pulley you can squeeze in on the shaft and “overdrive” the alternator as much as possible.

Make sure that your gear box is happy turning without the engine being on (check with the mfg.), and be prepared for some noise from the rotating prop shaft. “Soft” mounting the alternator will also help with noise. Good Luck–Steve


Posted by Steve Dashew  (November 30, 1999)



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