Propeller Sizing legend 33.5

[Norman Wroblewski]

Anyone have recommendations for the correct propeller sizing for 33.5 LegendYanmar 2GM20FProp was replaced by dealer, but, seems incorrect.Diessel will go to 4,000 RPM out of gear.While running under power maxes at 3,200 RPMRPM should run up over 3,600ThanksNorm

 

[Pete]

15 x 14

as per boat spec on this web site.

 

[Brent Headberg]

335 Prop Size

I have read a lot here about changing to a 3-blade prop. My boat always has vibration about 2000 rpm. I would like to hear from any 335 owners about changing to 3-blade.

 

[Steve Dion]

4000 rpm

Norman:If your engine is trully reving to 4000 rpm in neutral that may be a little high (this may be the tach so it may not be worth worring about). If you can only get 3200 in gear I would think you really do have either a prop problem or some other drag (fouled prop and/or bottom). Normally 1 deg of pitch +/- will change the RPM's by 200-300 rpm. So in your case you would probably need to have 1 deg of pitch taken out of your current prop. If you decide to go to a 3 blade prop you would take it would be a 3 blade prop with an additional degree of pitch. Now let's assume that you have a 15 x 14 two blade now and it is over propped, You would end up with about a 15 x 12 3 blade.My advise is to go to a prop shop and let them do the calc's. If something does not work out they can be responsible for makeing it right.