April 2002 — By Capt. Patrick Sciacca
Fuel Tank Failure
|If you haven’t been paying attention to your boat’s fuel tanks, you may be in for a nasty surprise.|
Last summer I watched a fellow boater cut the deck of his boat open to remove a leaky aluminum fuel tank. He’d been fishing offshore when he noticed diesel fuel leaking into his bilge–not a good sign. It turned out that years of water in the fuel and exposure to the harsh saltwater environment had taken its toll. It took two weeks for a new fuel tank to be delivered and installed in the boat, but he might have avoided all that if he’d paid a little attention to maintaining his boat’s fuel tanks.
Fuel tank failure doesn’t play favorites. It can happen to those made of aluminum, fiberglass, or even monel. Why? First, because no matter how conscientious you are in your fuel monitoring, there will always be water in your boat’s fuel. Joan Appelt, owner of Quality Yacht Services, a Florida-based company that specializes in maintaining marine fuel tanks, explains that when diesel fuel leaves the refinery, it carries with it an "acceptable" water content. Water in gasoline is equally commonplace. When you add summer heat to dark fuel tanks, you get condensation buildup, and quickly exceed that acceptable water content, which results in the growth of algae and other contaminants. (Steps like adding a fuel polisher, fuel-water separators, tank inspection ports, and a tank drain valve to remove water can alleviate but not eliminate the problem.) Aside from the corrosive properties of water, the algae produce hydrogen sulfide, which eats metal like termites eat wood. The result is a leaky tank, not to mention poor engine performance and even engine shutdown. If you add biocide to your boat’s fuel to kill algae, you’re not necessarily off the hook. You may have an "algae mat" of dead material in your tanks, opening the door to corrosion as well as clogged fuel lines.
This article originally appeared in the January 2003 issue of Power & Motoryacht magazine.