Double check the size. I think mine is a 16" and I thought it was at 24°. I also suggest getting a laser tach from Amazon. The Yanmar tachs are notorious for being about 200 rpm slow. Mine was.
It sounds like you already know that the pitch can only be changed in 2° increments and for every 2° you change rpm by about 10%. What do you want to consider max RPM? Mine had 3, max instantaneous = 3600 Max 1 hour = 3400 Max continuous = 3200 It is best to run at 80% load as often as possible. So for me I pitched the prop to 3200 max and try to run at ~2500. You'll also find that a dirty prop, shaft, and bottom can significantly change the load and subsequently change the max achievable rpm. If your surveyor was basing his advice on your boat with a dirty bottom and prop then you may not need to do anything other than get them cleaned. Engine/fuel problems resulting in reduced power output can also lead one to believe that the bottom is dirty or the prop is incorrectly pitched. When I adjusted my pitch I simply changed it by 1 increment (2°), with plans to do additional adjustments in future years if need be. PM me if you'd like any other guidance/advice/details. Josh Muckley S/V Sea Hawk 1989 C&C 37+ Solomons, MD I have a 3 blade Max Prop, 17". The surveyor said to adjust propeller pitch to allow the engine to reach top speed in gear. The current settings are for 24 degrees. I think I am supposed to reduce the angle. I do not know how far off the speed is, so I am thinking of starting at 22. Anyone else with a 37/40 know their pitch or angle? Brian Fry La Neige 37/40 XL Havre de Grace MD _______________________________________________ This list is supported by the generous donations of our members. If you like what we do, please help us pay for our costs by donating. All Contributions are greatly appreciated!
_______________________________________________ This list is supported by the generous donations of our members. If you like what we do, please help us pay for our costs by donating. All Contributions are greatly appreciated!
