50-Year old galvanized fresh water tank in bow

[JoshDad]

Fresh water tank in 1970 40' Morgan Cruising Ketch has to be replaced. It will not fit through any existing openings, and must be cut up for extraction. Any ideas for a good replacement? Tank is 40-50 gals, and very corroded internally. Space is under V-berth, and conforms to bow curve on the bottom. 4" depth forward, 26" depth aft. I can have an aluminum tank created from the "bones" of the old tank, but it would not fit through boat either. Maybe two interconnected tanks? Ideas welcomed!

[BlueH2Obound]

I had a similar situation in a '59 Monk. also in the front of the V berth. I cut a large "inspection hole" in the top of the tank, inspected the inside of the tank. There were numerous little columns of rust coming out of spots of rust on the inside of the tank, each starting at a pinhole in the steel. I cleaned out the entire tank, sanded, and laid in food fiberglass mat, effectively using the original tank as a stay in place "mold" while the fiberglass actually provided the seal. Cost was minimal (under $200), time was minimal (1 weekend). Sold boat 5 years later. Ran into buyer many years later who said he sold boat after 12 years, never any problems. Make sure that the fiberglass is FDA Compliant for direct and indirect food contact. MaxClr, at $105.00 for 1.5 gallons is one brand, (no affiliation) there are others. Do a google search.
I made a SS inspection port cover plate (could have used AL as well, but went with SS). Then installed Rivnuts to the tank, using the holes in the inspection plate to template the holes in the tank. Made a neoprene gasket to seal the port cover, screwed it down and drove on! Filled and drained the tank a few times to get rid of residual fiberglass taste, and no further issues. . . Or you can cut up the tank, spend boat bucks to have two interconnected tanks built and installed. Just a thought . . .