I have a 15' pontoon boat with 20h Honda motor and 80lb trolling motor. It has 2 lounge chairs in the back, a console seat and 2 seats next to the console seat. Also has 3 marine batteries. The boat sinks in front with two people up front. Really bad with 3 people on the boat. The boat and motor are 2012. Can you tell me what may be causing the dipping in the front of the boat?