propeller slip calculator

[MS2tester]

in an effort to get a boat propeller slip calculator working
i first need a theoretical speed
i looped back my ms3x PT4 out to launch in for VSS1
made PT4 my tacho out at normal speed
now set up as a V6 2 stroke this should give me 6 pulses per 1 RPM
gear ratio is 1.87 RPM to 1 prop rotation
roughly speaking i should have 12 pulses per 1 shaft rotation
24 pitch is 24 * 2,54 = 0.609 mtr
now for some reason i need 36 tooth or 35 in this case as the 1.87
something to do with 2 stroke versus 4 stroke?

double check against
http://www.mercuryracing.com/prop-slip-calculator/
MS3 1.5.0 release code

[MS2tester]

but it is good fun

[DHH]

Cool idea. I'm going to save this one, but 3% slip? Is that even possible?
I'm assuming you're running a blender off the back, so not my area, but there's no way an outdrive could get those numbers.

[MS2tester]

3% very unlikely just testing on the bench with a frequency modulator testing the math
8 to 10% is very good for standard props
and those high performance overhub cleavers on catamarans run close to 20% slip
also tried out the shadow dash