HT32BSX115
Supreme Mariner
- Joined
- Dec 8, 2005
- Messages
- 10,083
My Rinker cuddy has a single 7.4L Bravo 1 at 1.50 ratio, weights 4800 dry and will hit 60 with a 21 pitch 4800 rpm
Sounds like you might have one of your numbers off.......1.5:1, 21p and 4800 results in a theoretical speed of 64mph
http://www.go-fast.com/Prop_Slip_Calculator.htm
To get to 60mph with the above numbers, you would need a slip of 6% ............seems low for a single prop running behind a fairly heavy boat.....
I have found when I get a speed that results in a unusually LOW (or impossible) slip, My RPM or speed measurement
Not saying your numbers are completely wrong, it just seems that the calculated slip is low......
http://www.go-fast.com/boat_speed_predictions.htm
When I had the OMG 460 King Kobra installed in the LIB, the boat did 60 (radar) at 5000 RPM with a 1.43:1 drive and a 20p 3blade ss prop. (19p repitched to 20)
(slip was 9%)