Marine Fuel Tank

Marine 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 marine fuel tank 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 marine 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 marine fuel 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 marine fuel tanks, opening the door to corrosion as well as clogged fuel lines.