Prop size

  • June 29, 2021 11:20 PM
    Message # 10713079

    Hi there, 

    Doing a reno on a 1977 Westie. We purchased her last year. She had a new Beta 38 installed in 2006. It is a 3000rpm model with roughly 2:1 reduction. I believe the 3 blade prop was never altered when the Volvo was removed. It is currently at 16x15. Best rpm achieved was 2000. Would appreciate any input. Reading through old posts I didn’t find this specific topic. Thanks!

  • June 30, 2021 9:22 AM
    Reply # 10714564 on 10713079

    You have a problem if the boat has a Beta 38 engine, and the original Volvo prop.  The Volvo used a left hand forward prop, and the Beta uses a right hand forward transmission and prop.  Consequently you would be running the transmission in reverse to go forward.  This is possible, but detrimental to the life of the transmission. 

    If the transmission is actually a 2 to 1 reduction, you should be using a 16" diameter by 12" pitch right hand prop.  Most of the Beta 38 engines I have installed (over a hundred of them), use either a 2.5 to 1, or 2.83 to 1 reduction transmission to get better performance out of the engine in a Westsail 32, with the engine running in its proper RPM range for optimum performance.

  • June 30, 2021 2:00 PM
    Reply # 10715318 on 10713079

    Thanks Bud. I was down there today and it is a 2.5:1. Was just guessing about the prop from the Volvo! Will pop it off next time we are on the hard and pull a few inches out of the pitch. Have a good summer.

  • July 13, 2022 2:48 PM
    Reply # 12847882 on 10713079


    Do not try to repitch a used bronze prop because heating and pounding on it to repitch will almost always cause a blade t break off.  Besides, the Volvo prop is probably left hand forward, and your Beta engine with a 2.5 to 1 reduction should use a 16 x 13 right hand forward prop.