3396 Auxiliary Fuel Tank

[simon20.69]

Looking for some guidance on the location of the auxiliary fuel tank (57 gallon) on the 1980 33' Mariner. I have been told it is under the cabin floor on the starboard side. If so, does the floor have a hatch? More importantly, is it likely that this aluminum tank is still in good condition after 30 years in a boat that has always been located in fresh water?

It would seem to me it should still be in good condition.....????

 

[awboater]

The biggest problem with aluminum fuel tanks is corrosion. If the tank is in a dry area, there should be little chance of corrosion. But if it has gotten wet on occasion, the tanks should be bonded to the ground grid (They are on my Carver), so if the sacrificial anodes have been maintained over the years, any galvanic current should have been shunted to the anode rather than corroding the tank.

I do recall one boat builder used to spray foam insulation around their aluminum tanks. But water would end up in the crack between the tank and foam, and severely corrode the tank. I don't know for sure, but I have never heard Carver using this technique. I think it was pretty much isolated to one boat builder.

 

[simon20.69]

Is pulling the floor up the only way to check the tank? Seems like an expensive/labor intensive thing to do if the tank is ok. I would have to replace the carpet in the entire cabin.

What signs would I have if the tank is beginning to fail?