The Seaworthy study found that aluminum fuel tanks are the most common source of leaks, and the most difficult, if not impossible to inspect. A 1992 Underwriters Laboratory study on aluminum tank corrosion found the average service life for aluminum tanks is only 6.5 years. If you can gain access to your tanks, regularly inspect them for the telltale sign of corrosion - white powder - before the tank's integrity is completely breached by a pinhole. Often tanks corrode from the bottom, which makes holes difficult to spot.

If you can't visually inspect your fuel tank, do the next best thing every time you fill up -- use your nose. The UL study notes that 76% of leaks were discovered only after the owners smelled fuel.

One cup of gasoline has the same explosive potential as five sticks of dynamite. If you are at the gas dock and find gas in the bilge, let the professionals handle it. Get everyone off the boat, don't operate anything electrical, including the blower, even if it is ignition protected. Don't try disconnecting the batteries.

If you are on open water with fuel in the bilge, first shut off battery switch and summon help with a cell phone, if possible. Keep in mind that VHF radios do not have to be ignition protected, an obvious risk if it's located in a cabin filled with fumes. If you decide to abandon, don't go far -- you don't want a Good Samaritan to stumble upon your time bomb.

Finally, refamiliarize yourself with proper refueling procedures: remove all persons from the boat; shut off everything including the battery at the main switch; have an extinguisher handy; keep the fuel fill nozzle in contact with the fill to prevent static electricity; close all compartments, ports, and windows to prevent vapors from creeping in (open them once refueling is completed); use the blower for at least four minutes after refueling; and then sniff the bilge and engine compartment.

For more information about Seaworthy magazine or BoatU.S. marine insurance, call 800-283-2883 or visit http://www.BoatUS.com.