[AncientMariner]

I can tell from all the replies that you all are riveted to the outcome, so here it is.

Once the tank was removed, it became evident the hole was corrosion from the inside caused by water in the tank. I won't bore you with a long explanation of water and aluminum, just google "corrosion in aluminum diesel tank". There is tons of info and my problem is well known.

When my (signed the papers today) boat was built (94), the norm for aluminum tanks was still .125" thick material. Since then (not sure when it changed) the ABYC recommended .250. This won't stop things but does give you longer. My new tanks will be .375. Maybe you didn't catch the change from leaking tank to tanks. My thinking is if one is rotted through, the others are soon to follow and it's way cheaper to do them both now than one at a time.

Anyone pick up on the 2 tanks being replaced when there are 3? The auxiliary tank is located under the cabin sole and would require major surgery to get out and I'll play craps with that. If it starts leaking I think I can find a way to fix it rather than replace it, or quit using it as it is only 90gals (did I say only?).

BTW, to remove the main tanks you have to pull the engines, to pull the engines you have to remove the engine cover. Hopefully you get the picture. It's not pretty.

I am sharing this info as both a commentary and also as a "head's up" on what you may be facing.

Paul