Prop Selection

[hydro]

Nope, the cavitation plate is not a factor.

But, if the prop is running too high for it's design it may well be sucking air and that certainly can cause a "surge" in RPM. On a high speed turn that can cause "Blowout" where the prop loses it's bite on the water and bad things can happen if you are going fast enough. From your 2nd photo it looks like the jack plate is near the top of it's adjustment and maybe that is causing a problem with the prop you have.

Look at it like this: On a boat moving over 60 mph the best position for the prop is where the top portion of the blades are partially out of the water as they spin around. This reduces drag and allows the boat to move faster, to a point. The prop needs to be designed to grab the water as it goes back around the bottom of the rotation without capturing air or "cavitating". The typical prop on a fishing boat will not run well with the blades surfacing whereas the prop on an F1 tunnel boat runs perfectly with only the bottom blade in the water, both due to the design.

Your boat is a high performance hull and should be capable of at least 65 MPH with that 200 HP motor, and that puts you in a zone where you need to look at motor height completely different than on the typical 40 MPH fishing boat.