Thanks for the reply...I've been gone for the long weekend and just picked up your response.

Yep all serious prop testing will now be put on hold until the boat is painted and loaded up.

The water test was to get my motivation up so I could get going on the rest of the fairing and sanding.

My speed was GPS and the tach is new out of the box Mercury. So I'm not sure how to really check the accurateness of it.

How did you calculate the prop slip?

Sounds like your tach should be ok. If you look around abit, you can find some good examples of how bottompaint can affect your slip. The most recent is in the BAJA forum I think.



The easy way to calculate prop slip, is to use this when possible.
http://www.mercuryracing.com/propell...calculator.php