Quick explanation of slip please?

[jaycozer]

Just want to know what this means as I read some other threads. Don't know if it is referencing the gear engaging or prop performance. A little info if you have the time.

Thanks!

 

[walleyehed]

Re: Quick explanation of slip please?

The prop is the same as a screw...The "PITCH" of the threads is the distance it moves in 1 revolution.
For the Boat prop, the "PITCH" is the distance it would travel in 1 revolution (in inches) if it were turning in a solid...but it's not..it's in a fluid, and because of that and the weight/drag of the boat, the prop only moves about 80-90% of the rated "PITCH". The remaining 10-20% is called "SLIP RATIO". The lower the slip ratio is, the higher your efficiency is.