1972 20 HP Mercury prop question 2 or 3 blade

[BDbill]

Hi,
I have a 1972 20 HP Mercury currently running with a 2 blade prop. Would I gain anything to buy a prop for this motor that is a 3 blade, being the exact same pitch ect as the 2 blade? Thank you in advance.

 

[CharlieB]

Re: 1972 20 HP Mercury prop question 2 or 3 blade

You may be better off posting this in the Prop forum, or calling your local prop shop.

Generally, the addition of another blade increases the total blade area in contact with the water, requiring a DECREASE in pitch, otherwise the motor may not pull near the same WOT RPM. You want to watch WOT RPM, keep that in the mid to upper side of the recommended range for you motor to prevent excessive engine loading.