Question of prop direction....?

[DiverDan]

Ok, maybe a stupid question...

My Lehman diesel turns CCW as you are looking at the flywheel. Which means that the prop would turn CW when looking at it from behind. My question is, is this a Right handed wheel or a Left handed?

Thanks,

d

[Ian McColgin]

That's not sinister at all.

Seriously, a right hand screw is clockwise when looking at the prop from astern.

[nedL]

Ditto, clockwise from the stern (in forward)is "right hand".

[Ross Faneuf]

Imagine grasping the shaft with your thumb pointing forwards (that is, the boat's forward direction) and your fingers curled around the shaft in the direction it is rotating. If this works with your right hand, the rotation is RH; vice versa, of course, if it works for your left. Same rule for threads, etc.

[Henri]

Its even simpler that this. If you hold the prop edgewise, or any screw thread for that matter, if it climbs to the right, its an RH; if it climbs to the left, its an LH.

[mmd]

Sorry to muddy the pond, but please note that due to the configuration of the transmission gears, the output shaft may or may not turn the same direction as the engine crankshaft. Check the gearbox documentation or casing for indication of output shaft rotation direction.

[John B]

A friend of mine pulled the gearbox on his fathers boat only to discover that the problem was that the gearbox had been running in reverse for the last 20 years( finally ruptured something)It was loading bearings which weren't supposed to be under constant load I believe. I suppose a previous owner had a prop he wanted to use. LOL.

"THAT's why the gear lever goes back for forward"