props

[captadamr]

I bought a 220B Angler that I was looking at for a few weeks. It has 2 115hp 2002 Merc EFI 4 strokes.
The problem is with 120 gal of fuel, and 2 people on board, I cannot get over 4800-5000rpms, depending on sea conditons before they begin to slip. Both motors have the hydrofoils on. They also slip on sharp turns with the engines trimmed all the way down.Currently runnnin 15P Blackmax. Are the fins causing the slippage during turns and while running.
My mechanic is telling me to put on honda 4 blades. Any Suggestions on props and pitch??
Thanks