What size prop ' ?

[nala]

There is an estimated rule of what ever the total weight is....ie Boat, fuel, persons, gear and not forgetting the engine ... : )

Total all that up and you can get an estimate of what size prop', to fit. Prop' size is determined by the manufacturers recommended RPM of the engine, and the weight of your boat.

A tachometer, rev' counter is required to carryout the test

Boats total with all-in weight :-

Light boat 100 - 500lb

Moderate 500 - 1500lb

Heavy 1500 - 3000lb + up

For every inch of pitch it roughly equates to 150rpm difference.

Depending what you want as far as performance is concerned, pulling a skier quick acceleration is required ie "out of the hole shot" use a reduced pitch.

For higher top speed, ie slower acceleration you increase the pitch.

Diameter is the first size in inches ie 8.5 x 7.5 second is the pitch again in inches.

www.castlemarine.co.uk/pitch-calculator.php (this site maybe suited for larger boats check out your manufacturers spec' of their dia' x pitch sizes)

But they do excellent prop' repairs and is cheaper than a new one : )!

Also,they can repair damaged gear casings too...

[nala]

Also, 1" of Prop' Diameter is equal to 1.5" to 2" of pitch.. : )

[philpot]

I must confess Alan that I have never changed a prop from the factory size as I have not found a need but your post is an interesting topic mate.

Phil