Access
Your tank must be way forward of where the one is on my 73' 27. I have plenty of access through the quarter berth. When my son was smaller he could lay on his back, upside down in the lazerette and hold the box while I loosened the locking nut. You may have to loosen the tank and move it out of the way. Hope its not glassed in. Al Frakes, Port Kent, NY.