Prop Question?

[nor2345]

I have a 20' pontoon boat with a 2009, 50 hp High Thrust Yamaha, 4-stroke. The prop is a "Dual Thrust" 15" with 11 pitch. I'm having the prop rebuilt (hit a rock), I'd like to have another for a spare but it costs about $180.00. I can get a prop with the same dimentions except for the "Dual Thrust" for about $110.00. My questions are: What exactly does the Dual Thrust do? Could I safely run a standard prop? On a Pontoon boat, would I realize any signifgicant performance difference? I've heard lots of different opinions and I'd really like to hear from guys who have run into this same situation.

 

[usskydvr]

Re: Prop Question?

The patented Yamaha design pushes the exhaust gases out of the through hub in forward gear so that the propeller "bites" undisturbed water. In reverse, the Yamaha design re-directs the exhaust gases through special chambers towards the leading edge of the lower unit (away from the propeller). The result is that, in reverse gear, the propeller "bites" undisturbed water eliminating cavitation. Michigan does make a prop that is could be used, (992401, 992402, 992403) but it dosen't come in the cirrect pitch for your application. I know it costs more, but I'd stick with you Yamaha Dual Thrust prop.

 

[steelespike]

Re: Prop Question?

A 4 blade prop like a Solas Amita will also do well around the dock, maybe not as well as the Dual Thrust but better than a typical 3 blade. Would need your present max rpm and speed to figure what pitch.

 

[nor2345]

Re: Prop Question?

Thanks for the info!

 

[nor2345]

Re: Prop Question?

Well I sent off myDual Thrust prop for re-building and purchased a Solas Amita. You are right, around the dock I did not notice any difference except maybe a "little" less noise. The Solas ran very smooth however, my maximum rpm is approximately 150-200 less. I guess because of less water flow. When the Dual Thrust gets back the Solas will become my reserve prop. Again, thanks for the info.