I followed SailingCal's advice and cut a small section out of the material in the quarterberth to provide the room needed to remove it. I used a Rockwell vibrating tool and it made a very nice clean cut. You can put the piece back with a backing board and some trim strips to cover the cut, isolate the engine compartment and still be able to remove it later on. I consider it an improvement to the boat. I have a thread with some fuel tank replacement photos you can look at for some ideas. I used a 23 gallon plastic tank for replacement and built a new cradle to hold it securely. So far I'm very pleased, the new tank was inexpensive, has a built in clean out port, and a built in sender unit. The angled fill and vent molded ports align perfectly with how the hoses run in the 35/34 O'Day. As DaveM and I both found the screws for the bracket holding the fuel pump were long enough to touch the tank and caused corrosion resulting in a pin hole leak about 6 inches or so up from the bottom on the front of the tank. I also replaced all my fuel hoses as those were old and starting to crack and leak, subsequent research I saw recommendations to replace fuel hoses at least every ten years.