You need to cut the foam around the tank . I have a hand saw that I bought at home depot that is rigid and has jagged teeth on it. Once you cut around the tank you need to get straps under one end of the tank . Then pull up with some kind of lifting device. (forklift, engine hoist , comealong, or whatever you got) . You must pull on one end at a time to break the suction on the bottom of the tank to the bottom of the boat. Good luck . That job is a pain in the ass. Tom.