I'm considering buying a 20 ft. Pontoon. boat. My main concern is that one of the alluminum toons has a leak(s). The seller says he fishes on a river all day and then just lets the water out of the plug when he pulls the boat out. If I buy the boat I will be keeping it in a slip on the water so would need to get the leak fixed. Anybody got any experience on how "invasive" this would be to get done?