Boat too slow to get on plane, rebuild structure?

[robcurtiss]

I have a 1979 Imperial 15' fiberglass tri-hull with a 55 Evinrude. The engine runs great. It was a dog when I bought it, but a new prop of a different pitch made it run. Here is the issue. With one person in the boat, it will top out at about 27 mph; with two people, about 25-26 mph; a third person brings it down to only 22-23 mph. However, if I add a forth person, or if the three people are men, the boat with NOT get on plane and only travel 10 mph. This boat is obviously made to support more than three people!

After talking to some people, there is a thought of a water-logged frame/support system that is making the boat much heavier than it should be. Any thoughts on this? The floor is in need of major repair, so if I spend the time to do that right, I'd like the boat to run as it should.

 

[SKIBUM1M]

Re: Boat too slow to get on plane, rebuild structure?

If the floor is rotted then the foam is more than likely full of water and slowing you down. It is also possible the pitch of the prop just cant handle the load of 4 people but not as likely. if the floor is rotted you are going to have to replace it anyway so rip it up and see whats under it. You will more than likely find rotted stringers and transom also. So plan ahead.