do you use the same figures for slip on a b3 as on a b1, and is there any difference for twin application, working on a 32 searay cruiser and can't figure out what the slip is or if the numbers I have are correct.4300rpm,1.81gr,22p,30mph, slip comes out to 39%, is that right. boat weight,12,500lbs, T-vortec 350's with 4bbl's, It's a pig out of the hole.
any Idea's?

come on b blades and throttle up, you guy's have to have some input here.

Sorry for the delay.

Your calculations are correct. We do use the marked pitch in the equation. I don't know why your slip #'s are so high. It is unusual for any Bravo 3 boat to run that high. Verify the tachs and speed are correct. Also the gear ratio.

adjust yer carb, bo