Just on a side note here, if your tanks are breaking at the top, I would say it would be a good Idea to bulkhead the hull before and after the ends of the tanks. My little boat used to crush the fuel hoses below the filler necks all the time, found out the deck was basically smashing down on the tops of the tanks causing all kinds of Goofy problems. Once I bulkheaded the hull sides, the boat actually picked up some handling and no more tank problems, I can get pics if needed.
Took about 1/2 a day and came out pretty cool.