Mercator30

My Endeavour 37 built in 1979 has aluminum water and diesel tanks. located in the bilge. The diesel tank lasted about 32 years, before the PO pulled it, and had the bottom cut off and a new one welded on. I replaced the water tank last year. It hadn't started leaking yet, but the corrosion was severe and would have leaked in a year or two. The bilge had salt water and fresh water in it for about 25 years, with the last 10 years seeing only fresh water. Condensation (water inside the diesel tank will settle to the bottom and corrode it from the inside. I think 35 years is about the maximum you can expect from aluminum tanks. I've replaced my aluminum water tank with another aluminum one, figuring I'll be 100 years old when it fails. Good luck. Paul