Aluminum Fuel Tanks

[jaws]

I remember reading A thread about fuel tanks A while back but couldn't find it, so I'm starting another one. As I remember Jawz12 said that the life of an aluminum tank was 10 years give or take A few years. the pictures are of A tank out of A 1977 SeaVee and wanted opinions whether this is from electrolysis, deterioration or both. This is the port tank, don't have the other one out yet but sure it's just as bad. Thanks Jaws.

[billschwabe]

Were they foamed in place? Sure looks like the crevice corrosion that results from water being trapped against the surface of the metal allowing it to eat away. There must be tens of thousands of boats built just like that and they all will suffer the same fate. Contrary to what some may tell you, that two-part expanding foam DOES absorb water and if the tanks are surrounded by it it WILL happen sooner or later.

The new ones should be properly supported by hangers or brackets, with Nitrile rubber 5200'd to the tank between the supports and the tank. Allow air to circulate all around them and make sure the compartment has drains to keep water from standing on or under them. A good coating of coal tar epoxy will help immensely too and be sure they are bonded!

[jaws]

It was foam inbedded, and good to. Took the fork lift and broke it loose pulling on it. The foam was pretty saturated towards the back of the boat. All the glass and wood seems to be in very good condition.