Check out the motor pod on a Manitou. The .160" thick motor pod is bolted at 20 locations to extruded hat crossmembers. Others with flimsy construction know better than to subject their motor pod construction to these forces. For long-term durability, today's high horsepower motors need the adequate support that only Manitou offers. cavitation plate an inch below the bottom of the boat would be the same on a pontoon boat at the bottom of the motor pod. You didn't say what pontoon boat you have nor did you say what motor you're running, but 15p seems to be part of your problem with rpms, probably should be 11 or 13.