Prop for 115 Yamaha on 17' Actioncraft Flats

[ftltarpon]

Can you help with the correct prop for a 17' Actioncraft SE with 115 Yamaha 4 stroke? Tried a 13x17 SS and only got 40 mpg at 5500 rpms. Seems to have too much torque and not enough top end. WOT was 5800 rpms but actually seemed to be losing speed.

 

[steelespike]

Re: Prop for 115 Yamaha on 17' Actioncraft Flats

I'm no flats expert but from my limited reading it appears some are hard to push.Have you checked your setup?Motor vertical height can result in 2 to 3 mph if you can gain an inch up.Don't assume max trim is the best for speed.

 

[ivar]

Re: Prop for 115 Yamaha on 17' Actioncraft Flats

The F115 has a recommended max top rpm of 6000, you 're close at 5800,

Losing speed at 5800, sounds like the prop is losing grip...?
Which prop is it?

 

[ftltarpon]

Re: Prop for 115 Yamaha on 17' Actioncraft Flats

It is a 13 1/2 x 17 Ballistic. The standard aluminum prop has a bevel that prevents the exhaust from escaping outside the prop. This prop does not have the bevel. Is it possible that the exhaust is escaping outside the prop and causing turbulence in the water that causes the loss of power?

It seems that I should be able to get better than 40 mph out of this engine at WOT.