Over proped?

[d design]

Yacht: 22ft, 18ft LWL, canoe stern, 1.56 tons.

Engine: Yanmar 1GM10 (Been fully serviced starts on first compression every time)

Prop: three bladed don't know dimensions

Engine revs to 2600 rpm at 5.5 kts SOG before black smoke. Should I be revving higher with this engine?

Cheers

[atoll]

Originally Posted by d design

Yacht: 22ft, 18ft LWL, canoe stern, 1.56 tons.

Engine: Yanmar 1GM10 (Been fully serviced starts on first compression every time)

Prop: three bladed don't know dimensions

Engine revs to 2600 rpm at 5.5 kts SOG before black smoke. Should I be revving higher with this engine?

Cheers

sounds slightly over pitched if this is with a clean bottom and clean prop.

reducing 1degree of pitch should increase rpm by 200 rpm.

3000 rpm is top end for that engine, at about the 6knots hull speed

reving higher is likely to lag the engine as it is overloaded

[d design]

Originally Posted by atoll

sounds slightly over pitched if this is with a clean bottom and clean prop.

reducing 1degree of pitch should increase rpm by 200 rpm.

3000 rpm is top end for that engine, at about the 6knots hull speed

reving higher is likely to lag the engine as it is overloaded

Yes clean bottom and prop.

Cheers thanks for that