prop pitch

[seacolt]

would any one know the proper pitch for A 1976 46 c with 871TIs, I currently have two sets of props that are 28 33 and 28 34 .

 

[Jackman]

Every boat is different as far as weight and distribution and even horsepower in some cases. So what works for one boat identical to yours may not work for yours! During my repower I followed the specs to the T for a repower of a 32' Hat FB that someone else did. Even with the identical engines. I used the same diameter wheel but my pitch ended up being 2degrees more aggressive. With that I ended up with a better top end.

With that said I'd either try a prop that Hat recommends as far as diameter and see what your WOT is. If you don't make spec WOT take the props to a propshop and tell them what you got versus what you want as far as RPM. The key to me was use the largest usable diameter prop with a pitch close to the theoretical pitch as calculated from a prop calculator like the one on boatdiesel.com. Then adjust from there.

Good Luck!

 

[SKYCHENEY]

How many blades and what gear ratio?

 

[altmed]

I am currently having a similiar dilema--according to hatteras it would be 28 x 34's. But I have 30 x 34s, but have larger injectors and more HP, but it makes the engines run a little hot--not good, you want to get 2300 rpm,s at wot, your 28x 34's should do it. By the way waht is your cruising speed and what injectors are you running??