Prop Slip

[badMackrel]

I just calculated my prop slip on the mercury website as 15%. what is an acceptable prop slip? What can be done to reduce the prop slip?

here are my details:

2014 Z118C
Mercury 150 hp fourstroke
21P Bravo 1 FS
max rpms 5800
gear rations 1.92:1
top speed 51-52 mph

** I have tried a 21P Rev 4, a 19P Trophy Plus, a 21P Trophy Plus, a 21P Razor 3 (Croxton) and the 21P Bravo 1FS performs the best. I have also spoke to Scott Reichow (spelling?) at mercury racing and he is the one that suggested the Bravo 1 FS.

[OldTimer57]

10% is a good target. But you need accurate speed and RPM at the SAME time. Preferably GPS speed. 51-52 is not very accurate. That changes the slip by 2%. More importantly, if your prop has significant cupping, you should add 1" of pitch on the calculators... That would increase your slip.

[John Jackson]

Bravo's usually calculate to a higher slip number as they are low on pitch. (A 28" Bravo is like most other 27" props).
A 28" bravo, 27" trophy, and 26" performer 4 will all turn about the same RPMs at the same speeds, so the bravo would "calculate" to a higher slip number while the P4 a low slip number. It's not an exact thing.

[EuropeanAM]

+1

See if you can get extremely precise numbers (ie: RPM's to the exact single digit, Speed to the "10th" of a MPH). Also good to ensure you are "normally loaded" with 1/2 tank of fuel.

Then let's see how it calculates out.....

Note: Water pressure would also be helpful.

[BBW]

where do you go to cal slip i looked at site did not see

[EuropeanAM]

http://www.mercuryracing.com/prop-slip-calculator/