36 pleasure w/ cabin weighs 8-8200 lbs 1.5 gear
want to spin it to around 6200 it made 914 peak hp @6100

Previous setup w/ 575's ran the best of 115 w/ 1.5 gear & 35- 5 blade merc props @ 5550 rpms

37 pitch prop @ 6200 would put it @ 145mph less slip of 7% would be 135mph-Sound right?

I think you are really close - maybe a pitch too high

Gregg Reichman

Sounds like you may need a gear ratio change, i think your going to spin 37s more than 6200 with the hp your giving.
The speed you gave is correct if you do end up with 7% prop slip. I'm thinking 1:35s
That said give Peter a call he will save you hours of test time and lots of money.

I am setting the boat up for acceleration

I am going to keep the 1.5's & just adjust the rpm w/ the prop-I can go up to a 38 or 39 if need be

Your thinking 36's ?

What about rake degree?

There are a couple variables here.

If the 35 Mercury props you have now are the cast version you are really closer to 37 in pitch than 35. That puts your slip at 12% with the 575 set up. What is the diameter of the 35's?

What year is your boat?

A good place to start is with your current props. Get a feel for the boat and the new power and work from there.

I think you may see more than 135 with the new power, especially with the new props on the market now.

Hey Keith , Have Randy call me about those dry sump #6s and Jeremy keeps sending p.m.s but cant send them back
ROCK ON
Bill 815-693-3031

The 35's (16 1/2" diameter) I have now are from 2001 when the boat was new they have been damaged & reworked etc... So the slip is probably higher.
I was planning to try the existing props first & go from there-

Does throttle up make #6 props now?

Yes, We make props to fit the #6 drive which are CNC machined in 16 and 18 degree rake.

Your props are the cast type and the rpm would typically fall between one of our 36 and 37 CNC. Any previous work done to your props may have an effect on the effective pitch and slip, especially if the cup has been changed.

You will need different props for the new power set up but your current props will be a good place to start.

Sure thing I just spoke to him about dry sumping mine. Skaters rule!!!