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Aluminum Fuel Tanks

I am the original owner of a 1980 Sea Ray SRV 300 Sport Bridge with twin inboard gasoline 255 Merc Cruisers and twin 100 gallon 5052 aluminum fuel tanks with gauge thickness 0.125.  The boat has been out of water and in storage for the past 10 years.  With imminent professional retirement, I have begun the process of restoring and updating systems for an anticipated 20 additional years of boating with this boat, which will take me to age 80.  I remember from last year’s "Ship Systems, Stem to Stern" presented by Steve D'Antonio at PassageMaker University, Poulsbo, that aluminum fuel tanks are most common yet subject to corrosion.  I recently contacted the manufacturer and they recommended replacing the tanks, especially since the boat has been in storage so long.  Yesterday the boat was transported to a shop in Portland, Oregon.  The service manager said he will thoroughly check them out, but my initial impression is that they appear to be in good condition, especially since they have been located away from any moisture.  I certainly have enough expenses accounted for, yet should these tanks be replaced now since I plan on many additional years of using this boat? 

Gary

As you rightly recalled, I did say that aluminum tanks do have their shortcomings.  If they are exposed to water, internally or externally, they can and often do corrode to the point of failure.  However, many of the boats I  inspect and service are equipped with aluminum tanks that are more than two decades old.  Provided they were properly installed, not abused and remained comparatively free of water inside and out over their life, there’s no reason they should not continue to be serviceable.  In short, I wouldn’t condemn them simply because of their age.  They should be carefully inspected both inside and out (if they are not equipped with inspection ports, this may be a worthwhile addition, however, for gasoline applications these may only be installed in the top of the tank), and pressure tested.  If they pass this scrutiny, then I see no reason why you couldn’t continue to use them.  Remember, gasoline fumes are explosive (one I've seen indicated that a cup of vaporized gasoline is equivalent to a stick of TNT) and leaking gasoline presents a substantial danger.  If the tanks show any sign of weakness or leakage, they must be repaired or condemned.  Steve D'Antonio, PMM Tech Editor