Prop Slip Calculator

Islandtrader · #1 06-05-2011, 06:38 PM

I think this deserves a separate post by itself.

Prop Slip Calculator

77SceptreOB · #2 06-05-2011, 06:47 PM

According to the website calculator mine was 8%. is that good or bad?

Tiny · #3 06-06-2011, 12:01 AM

8%...very good!

Islandtrader · #4 06-06-2011, 09:57 AM

Quote:

According to the website calculator mine was 8%. is that good or bad?

With those numbers you should be out racing

Fr. Frank · #5 06-06-2011, 11:15 AM

Quote:

According to the website calculator mine was 8%. is that good or bad?

8% slip is astonishingly good. People pay THOUSANDS of dollars to get a single prop with less than 10% slip at WOT and less than 15% slip at cruise.

Now go run at your favorite cruising speed, and record speed & rpm, and see what your slip is then. A very good prop will have 15-20% slip at cruise. Less than 15% slip at cruise is very rarely heard of, although back when new SS props were $375-$500, I once spent over $700 on a completely custom prop from PowerTech, and got 12% slip at cruise, and 8.8% slip at WOT with Merc 2.0L XR4 V6 on the back of the boat below.

basswacker · #6 06-11-2011, 03:26 PM

mine came out to be 25%

77SceptreOB · #7 07-11-2011, 03:19 PM

I made a mistake. My prop is a 17" not a 15", so my numbers are off. I thought 8% was way too good.

It's now 18%

Islandtrader · #8 07-12-2011, 08:37 AM

Quote:

I made a mistake. My prop is a 17" not a 15", so my numbers are off. I thought 8% was way too good.

It's now 18%

Goes back to the old saying "If it sounds to good to be true...

"

eggsuckindog · #9 07-12-2011, 05:34 PM

If and I think it is - my gear ratio is 1.87
Stilletto 19"

Then at cruise 3400 I'm at 14% - 27/28mph

amazingly at 4200/4400 it drops to 10% 38/39mph, it stays about there at WOT
Motors too low also would like to go up 2 holes - only get 5300/5400 would like 5600/5800

Thats also with the Big Ol'Fat Houndog( 100lbs) sitting in the bow with ears a flappin - can't get him back when I go fast either, no matter how many times I try and explain the speed factor and getting the bow up

I have been very happy with this prop, amazing trim response and makes the boat ride very dry - other one was very wet, actually very very wet. Never did the slip before though so guess I'm happier

Beware it is very aggresive and will knock down the RPM, I had a 19 on it and it took off a solid 300 RPM for the same size.

Fr. Frank · #10 07-12-2011, 05:58 PM

Dixon, are you running a 200 or 225 on your MA?