propeller rotation

[curiouskb]

While slipping my 40 footer for bottom cleansing, I tried to turn the propeller by hand and found considerable force is needed before I can turn the propeller by hand slowly a few inches each time. I thought relatively easy "free wheeling" is the norm to minimise resistance and waste of power. Just interested to learn if this kind of resistance is to be expected or normal in most installations. It is a shaft drive 425hp Diesel. The boat and engine is running fine.

 

[Talulah]

Was the gearbox in neutral?
Is there a shaft brake system fitted?

 

[Tranona]

Can be very stiff. The cutless bearing is water lubricated, so dry when out of the water. You are also trying to turn a big train of heavy gears with your one manpower rather than the herd of horses that normally does the job.

 

[macnorton]

Does it turn ok when the boat is floating? a boat will change shape when out and it could be a simple as that.
You could disconect the shaft from the gearbox and try but it sounds normal to me.

 

[NormanS]

While slipping my 40 footer for bottom cleansing, I tried to turn the propeller by hand and found considerable force is needed before I can turn the propeller by hand slowly a few inches each time. I thought relatively easy "free wheeling" is the norm to minimise resistance and waste of power. Just interested to learn if this kind of resistance is to be expected or normal in most installations. It is a shaft drive 425hp Diesel. The boat and engine is running fine.

425hp?

Anyway, the prop should turn quite easily by hand, if the engine is out of gear.

 

[macd]

My first thought was exactly as macnorton's: the shaft may now be out of alignment due to deflection of the hull on the hard. That's certainly the most 'desirable' cause (of several), and the one I'd check first.

 

[curiouskb]

Many thanks for the advice. I shall try to turn the coupling with the boat in water and neutral. I agree that the dry rubber cutlass maybe the friction to turn.