I got a 20' fibergalss inboard/outbouard boat by United Marine. The gas tank is leaking. There is no way to get to the tank, without cutting the deck. My father and I believe the best solution is to cut the deck. Problem is we don't know the demensions of the tank. As far as I can tell United MArine is out of business so getting the skematics will be one hell of a job. Any suggestions?