130+ mph Flatbottom!

[T-Bag'n]

I ran consistantly 8400 rpm at 137-140mph 22%gears and a 11x16 prop with a 523" BGF.

[stix818]

Just for sake of arguement about gearing or lack of...it is all about horsepower..plain and simple! The more power you have and are able to attain a higher rpm range at a safer level you can drop the gear and also grab the ET. We have run 143 with 22 gears and yes the motor was "running through the roof" at over 9000 rpm.
Ahhh...the good old days!....Stix!...tell your Dad I said Hello!
Will do. He's pretty excited for this year as I am also!!! Are you the one he talked to the other day about one of your boats??
Scotty, class is going great so far. Bummed that I won't be able to race the whole season this year but I guess I should be happy to still have a job!! How's everything going??

[Flat Hall'N]

Getting a BBC to rev 8300 under power with 23s (22s or 25s), aint all that simple. I think that would be the issue with that boat/motor/gear combo. And Art, you may be a little kind with the 10% slip factor............Just a guess, MP
How does one calculate prop slip?

[Moneypitt]

How does one calculate prop slip?
By the seat of your pants......Or, IF you have the other numbers you can figure it out from there. IF you know the Rs, and you know the speed, and you know the prop pitch, it's in the math. Trying to do it backward is just a guess.........The slip factor is how wet or dry the boat runs, how much drag the prop has to overcome to hook to the water, up river, down river, with the wind, against the wind all play a small part. Fresh and salt water are different too..........Different boats with the same prop will be different, just as different props on the same boat will be different.......Ask Dave Rankin why he spent two days at Irvine testing props!!!!!........Then ask yourself why his boat is always up front..............MP

[Flat Hall'N]

By the seat of your pants......Or, IF you have the other numbers you can figure it out from there. IF you know the Rs, and you know the speed, and you know the prop pitch, it's in the math. Trying to do it backward is just a guess.........The slip factor is how wet or dry the boat runs, how much drag the prop has to overcome to hook to the water, up river, down river, with the wind, against the wind all play a small part. Fresh and salt water are different too..........Different boats with the same prop will be different, just as different props on the same boat will be different.......Ask Dave Rankin why he spent two days at Irvine testing props!!!!!........Then ask yourself why his boat is always up front..............MP
I knew I could count on you to make it easy for me! Just Kidding and thanks for the input.

[Lookin for Liquid]

By the seat of your pants......Or, IF you have the other numbers you can figure it out from there. IF you know the Rs, and you know the speed, and you know the prop pitch, it's in the math. Trying to do it backward is just a guess.........The slip factor is how wet or dry the boat runs, how much drag the prop has to overcome to hook to the water, up river, down river, with the wind, against the wind all play a small part. Fresh and salt water are different too..........Different boats with the same prop will be different, just as different props on the same boat will be different.......Ask Dave Rankin why he spent two days at Irvine testing props!!!!!........Then ask yourself why his boat is always up front..............MP
Dont forget that little equation of gear ratio too

[Moneypitt]

Dont forget that little equation of gear ratio too
I could say that was included in the "math", but that wouldn't be true. An oversight on my part to not include the gears........No, No wait, it was a test, yeah thats it a test, and you passed!!!!

[GofastRacer]

I ran consistantly 8400 rpm at 137-140mph 22%gears and a 11x16 prop with a 523" BGF.
That's with a slippage of 10-12%!..

[mouzer]

its BUY IT NOW IS $9999..HMMM I BETTER RUN OVER THERE ITS 1/2 HR FROM HERE..

[FLYTE RISK]

I could say that was included in the "math", but that wouldn't be true. An oversight on my part to not include the gears........No, No wait, it was a test, yeah thats it a test, and you passed!!!!
T Bag said it all READ HIS POST!
I am sure Guru will attest alot of the comp flats, ski flats, progas flats, depending on weather and water (phoenix) run no more than a 22 and as low as a 12 and still run 130 plus. The Looky lou boat(an old Hondo) picked up E.T as well as M.P.H a few years back at the drags something like an 8.18 @ 134 m.p.h going from a 22 to an 18. You simply cannott compare a K boat to a drag boat!! IMHO