Prop for flat boat Yamaha 115

[madman2021]

Just took out my 18x60 flat boat with the new motor. Has a 17 pitch SS prop on it. Top speed is 51 with the motor over reving. I need to go with a higher pitch prop but how big. Will have a tach soon

 

[steelespike]

Re: Prop for flat boat Yamaha 115

When you get your tach setup we can tell better how your setup works.
Is your speed by gps? Guessing some of the calculation(not a good idea) your speed indicates about 7,000 rpm.

 

[etracer68]

Re: Prop for flat boat Yamaha 115

Until you have a wot rpm reading, how can anyone say? The only way someone can recomend a pitch change is with rpm reading.

 

[etracer68]

Re: Prop for flat boat Yamaha 115

Steel beat me to it, WOW 7K, that motor wont last to long at that rpm. You may need to go to a 23 pitch or higher.

 

[madman2021]

Re: Prop for flat boat Yamaha 115

This boat turned out to be much lighter than I anticipated. Anything over 40 is scary. Also the boat pourpuses really bad even at full trim down.

 

[etracer68]

Re: Prop for flat boat Yamaha 115

On the transom bracket, there should be a set of holes (4 or 5), what set is the pin in? You may be able to put it in a set closer to the transom, that will let the trim go down, or in farther.

 

[steelespike]

Re: Prop for flat boat Yamaha 115

Is the boat rated for a 115? Sometimes a boat porpoises because its over powered driven beyond its intended speed or or even under powered stuck at a critical speed.
Smart tabs lightly applied may help. Also weight placement.

This boat turned out to be much lighter than I anticipated. Anything over 40 is scary. Also the boat pourpuses really bad even at full trim down.

 

[Star]

Re: Prop for flat boat Yamaha 115

madman your a better man than I. If that was a real fifty I can't even imagin... I flipped a small flat bottom ply skimmer at close to 40
It wasn't fun! At 60' wide it should act like a kite.