Sunday 26 October 2014

Fitting a shaft alternator on a sailing yacht

I have had this on my last two yachts, both being the Endurance 37 design by Peter Ibold.
does  it work? well on a two handed return from Rio Do Janerio, Brasil, Notty and I were leaving the lights on 24/7 as the Lucas 30 amp marine alternator did not have a regulator on it, at times we  saw 16 amps indicated on the amp meter.

So yes it works!


We had intended to make for Hout Bay which was our home port, even Cape Town was ok but the South Easter got the better of us and the sea was huge, when it all calmed down we were close to Saldanha YC and were still happy to arrive there.

I was asked this week about a similar yacht, what miles per day will it do? around 135 is easy enough and we nearly topped 180 in that current off the Amazon river in Brasil.




Ocean Planet (Tal Gal) about 1985 and on the slip at the Royal Cape Yacht Club near Cape Town, note the three bladed propellor. This will have been after or thirty two day trip back from Rio in Brasil.

Lucas Marine? thats a white epoxy paint on the alloy outer casing and possibly a lacquer over the internal wires?

Numbers wise I used (i think) a 12" alloy pulley mounted on the propellor shaft aft of the gear box, this idea will not work on a hydraulic box by the way.

Then a normal V belt was fitted and remained so all the time.

The propellor was a 16" x 13 three blade and while this causes drag, the gain in free 12volt DC power was fine by me. The Endurance 37 has the propellor shaft level with the waterline, this gives a maximum drive output from the engine and also suits the shaft alternator idea. If your shaft is set on an angle expect less output?

To kill a myth, locking the shaft slowed the boat down and when we had really rough and hard weather I would use this to apply drag to the boats speed.

We now have a boat with a Max Prop Classic folding twin bladed propellor, so the idea will not  work, sad, of well it was great while we had it.

I have found one here, which does have a regulator, contact them direct to purchase.

My thanks for use of their picture.


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