1 (edited by bernard 2012-03-21 11:11:02)

Topic: Beta Marine 13.5 / Prop Question

I have a prop question. I will be updating my current motor to a Beta 13.5 and I am trying to figure out what prop I should get. The dealer recommended the following: 12" diameter x 8 pitch, 3 blade.

I'm wondering it I would benefit from a 2 blade prop as far as less drag? What are the advantages or disadvantages of 3 blade vs 2 blade?

As always any input would be greatly appreciated.

Thanks!

2 (edited by MCo26 2012-03-21 12:48:52)

Re: Beta Marine 13.5 / Prop Question

Bernard,

I have a 1GM10 and my prop is a 3 blades 11x10rh.  It's a new prop and like you i wonder if 3 blades is a good choice...I will see.

Marc

Contessa 26 #158
Sun Wave
Montreal QC

Re: Beta Marine 13.5 / Prop Question

2 blade would have less drag that a 3 blade of the same diameter, but if you use a 3 blade then you can use a smaller diameter. So it's not a clear cut answer. You need a certain amount of prop to absorb the horsepower you have available. Since we only have a limited space in the rudder cutout, we are limited in the diameter of prop we can swing. You can absorb power with diameter, number of blades and pitch within limits.  You may be forced to go to 3 blades in order to use all the available power. I use a 12x13 3 blade prop on a Yanmar 1GM10. There is a program online somewhere that takes basic info about your boat and engine and makes suggestions. Your dealer probably has that program and can give suggestions for 2 and 3 blade props.

Re: Beta Marine 13.5 / Prop Question

I use a 3 blades 11x7 with a Petter 6.5  and it works fine even on strong front winds. So to me a 3 blades is a good way to go as we had before a 11 x 7 2 blades with very limited performance.