davidpbo
Well-Known Member
Hi folks
Having failed in my attempts to be reunited with the prop for my outboard which appeared to give me more control at lower revs I am looking to replace it.
The spec of the prop I lost was 9" Dia 6 1/2" Pitch Mercury outboard Part no 48-42524A12 (maybe ....A11) (If anyone has one they want to sell please email me with a price)
How is pitch measured,
Is it angle of the blades?
Size of the blades?
Angle and size?
Other?
Is it that the higher the pitch the more thrust it is likely to give at a given speed?
Would a 7" pitch prop be likely to give similar or slightly more thrust forward and in reverse compared with a 6 1/2" pitch prop? at a given (lowish) speed.
My boat is a sailing boat weighing approx 1900Kgs max speed under engine 5+ knots. What I found with the lost prop was that it gave more thrust at low speed which made docking easier, but I believe I lost a knot or so when motoring.
I don't know what the prop is that is on it at the moment, I suspect it was the standard one supplied with a Mercury OB in 1989 (anyone know what that was?). The blades are smaller in area and the angle is not as steep although I believe the diameter is the same, does that mean they have a lower pitch?.
Would fitting larger anticavitation plates improve the thrust? It would give me some problems as the outboard sits in a well and can currently be lifted out for maintenance if needed (Just). Larger plates would probably make this impossible
Thanks
David
Having failed in my attempts to be reunited with the prop for my outboard which appeared to give me more control at lower revs I am looking to replace it.
The spec of the prop I lost was 9" Dia 6 1/2" Pitch Mercury outboard Part no 48-42524A12 (maybe ....A11) (If anyone has one they want to sell please email me with a price)
How is pitch measured,
Is it angle of the blades?
Size of the blades?
Angle and size?
Other?
Is it that the higher the pitch the more thrust it is likely to give at a given speed?
Would a 7" pitch prop be likely to give similar or slightly more thrust forward and in reverse compared with a 6 1/2" pitch prop? at a given (lowish) speed.
My boat is a sailing boat weighing approx 1900Kgs max speed under engine 5+ knots. What I found with the lost prop was that it gave more thrust at low speed which made docking easier, but I believe I lost a knot or so when motoring.
I don't know what the prop is that is on it at the moment, I suspect it was the standard one supplied with a Mercury OB in 1989 (anyone know what that was?). The blades are smaller in area and the angle is not as steep although I believe the diameter is the same, does that mean they have a lower pitch?.
Would fitting larger anticavitation plates improve the thrust? It would give me some problems as the outboard sits in a well and can currently be lifted out for maintenance if needed (Just). Larger plates would probably make this impossible
Thanks
David