[Fr. Frank]

Originally Posted by Moose

the prop is a mercury marine vengeance prop that reads 48 16315 17p.

First, the Vengeance is a bow-lifting prop, not a stern-lifter, and designed for light-weight hulls. That prop will turn low rpms until it begins to ventilate, then with a heavy hull, it will lose effective thrust. Pitch is about right, the rest of the prop geometry is wrong.

But start with your motor mounting height.

Then, for top end, go with a 3-blade SS.
For low-to-mid-range performance and maneuverability, a 4-blade is better.
A 4-blade will always provide more stern-lift than a 3-blade of similar blade geometry.