repowering, proper prop sizing?

[wantokex]

I have been offered a good price on a 6 cyl 120 hp Lehman diesel motor to replace my 4 cyl 80 hp Lehman for my newly purchased mess of a 72 gulfstar 36 motor sailer. what is the proper way to figure out the right prop size and pitch for the motor?

Wantok

[Pblais]

You can go to any decent prop shop and give them the numbers of the engine and transmission. They can take into consideration of the hull shape and that it is a sail boat to compute what should be the proper pitch and diameter based on the desire for a two blade or three blade prop. The combo of the engine and transmission are the key numbers needed.