Is There A Way To Reduce Prop Slippage Or Is This Something You Have To Live With. If My Calculations Are Right I'm Running About 50% Slippage
24 Pitch Prop Spinning At 5500 Gets Me About 65 Miles Per Hour Gps

24 (pitch = Inch Foward Per Revolution) X 5500 (rpms) = 132000 (inches Per Min) Devided By 12 (inches Per Ft) = 11000 (feet Per Min.) X 60 (min Per Hour) = 660000 (feet Per Hour) Devided By 5280 (feet Per Mile) = 125 Miles Per Hour (yea Right Laugh)
What Am I Doing Wrong Or Could I Be Getting That Much Slippage And If I Am Is There A Way To Get Rid Of It Or Lower It With A Different Prop Size Or Blade Count.
Very Heavy Boat 42' Welcraft Excalibur Eagle 11000 Lbs. Dry About 14500 Lbs. Loaded

Use the formula listed here: http://go-fast.com/prop_slip.htm

I calculated your slip to 22%
It breaks down to this:
5500 X 24 = 132000
132000 X 0,667 = 88044 (0,667 Being 1,5 gear ration in des.)
88044 X 0,00094697 = 83,37502668
83,37502668 - 65,00 = 18,37
100 / 83,37502668 = 1,199
1,199 X 18,37 = 22,03

What kind of power and gear ration are you running?

I got this "calculator" on a Excel spread sheet, if you send me your e-mail I will send it to you.

[email protected]

As per 88Fountain's recommendation but one click further.

http://go-fast.com/Prop_Slip_Calculator.htm

How are them blower motors running,we haven't heard much from you in a while,Smitty

You need to divide it by your drive ratio. 125MPH divided by 1.5 = 83MPH thereoritical top speed.

Hey Smitty, I post a reply yesterday but I don't see it here today I don't know what happen. motors are running good just have to start over with jetting and prop changing again to get motors tuned in, because I just got back the new reworked carbs 3 weeks ago. I haven't had time to play with it like I should. I think I'm a little afraid because of all the past problems. Almost like if it isn't broke don't touch it. The past mechanics just suck the fun out of it. I just want to thank all you guys for all your different advice over the last couple of years. Its hard to find good advice around here, I think the season is so short so everyone is just a back yard mechanic claiming to be good boat mechanic's. There where allot of times I wouldn't have known where to turn if it wasn't for this site. The main problem i'm having is prop slippage right now and don't know how to get the numbers down. I'm running about 20% slippage and think I should be around 10% don't really know. I'm getting about 10 more miles per hour out of these new motors running about 65 mph like to get in the 70's if possible. I started with a 26 4 blade and only got about 4800 rpms and was doing about 60 then went to a 24 4 and got up to around 5300, then I had a short run with a 24 3 and got up to 5500 pushing around 65 mph but slippage is high. not sure which way to go now.