Does Revolving Prop trickle charge batteries?

[ccscott49]

Thanks to all for replies - I had previously checked with Autoprop re suggested prop brake but my space is not sufficient for that one.

Will investigate other makes of brake- otherwise a "heath robinson " improvis.


Regards,

Duke.

Shaft brake, rope wrapped around the shaft as a "spanish windlass" tied off to something strong ie engine bed. with the engine key tied to it, so you cant start the engine with the rope on the shaft. I have two ropes permanently installed for my shafts.

 

[davidej]

I am not familiar with this particular set up but in most cases stopping the engine with it in gear is enought to stop the prop rotating under way.

 

[scottie]

It is possible to turn an engine from the propeller if the size of prop is big enough but unlikely in aux yacht installation.
I believe that some commercial vessels have bump started engines on occasions!
Therefore a shaft break may well be essential in some cases or variable pitch to allow the prop to feather.

 

[Ludd]

It is possible to turn an engine from the propeller if the size of prop is big enough but unlikely in aux yacht installation.
I believe that some commercial vessels have bump started engines on occasions!
Therefore a shaft break may well be essential in some cases or variable pitch to allow the prop to feather.

Done the bumpstart bit with Gardner 6L3 . Had to decompress cylinders to get enough speed on the shaft. when levers dropped ,engine started.
Huge prop required!

 

[rob2]

I like the idea of a bicycle brake - real lateral thinking! Please don't use Mole grips, that's like leaving the key in the lathe chuck. Although once the blades pitch in the shaft will generate quite a bit of torque, but it won't take anything to hold the shaft once the blades have feathered.

Rob.

 

[Wandering Star]

Done the bumpstart bit with Gardner 6L3 . Had to decompress cylinders to get enough speed on the shaft. when levers dropped ,engine started.
Huge prop required!

Off topic but I remember reading about a racing guy who drained his batteries and couldn't start the engine. He rigged up a HR contraption between his boom and the engine flywheel and successfully started the engine by an controlled gybe which spun the flywheel. Not too sure of the details but ingeniously done!

Cheers, Brian.

 

[Deleted member 36384]

I like the idea of a bicycle brake - real lateral thinking! Please don't use Mole grips, that's like leaving the key in the lathe chuck. Although once the blades pitch in the shaft will generate quite a bit of torque, but it won't take anything to hold the shaft once the blades have feathered.

Rob.

The mole grips work very well, are easy to use, and present no risk if mounted on a piece of leather. After the engine is stopped a piece of leather (from an old belt) is placed around the shaft while it spins away. The mole grips are adjusted to a a couple of millimetres larger than the shaft diameter. As shaft spins, pinching the leather together with one hand and squeezing the mole grips, over the leather with the other, slowly brings the shaft to a stop. Rest mole grips against hull or bulkhead.

If the engine is started the shaft spins quiet happily in the leather and the mole grips usually slide up to the larger opening or pop open safely in the bilge. Its very undramatic.

I have a hydraulic gearbox and this tip was taken from these forums; simple to do and surprisingly easy.