We are replacing the holding tank on our 1995 336. The big challenge we are having is finding a tank that's a comparable size--30 gallons--that will fit in the odd space on the boat. Has anyone done this? We will be taking the tarp off the boat in a couple weeks and head down below with the tape measure (again), but I thought I'd ask so we don't have to 'recreate the wheel' if someone out there has found a solution! We really don't want to downsize since we are a family of four sailing on a lake.