How to deal with aging fuel tanks-

Most of our Lymans are getting older and the galvanized fuel tanks are starting to show their age. When filters start to become clogged with a sandy, rusty type of substance, it indicates that the inside of the fuel tank has started to corrode. Have you noticed a fuel-like odor in the bilge? Check fuel line fittings. Have you noticed damp areas around the corners or at rivet locations on your tank? If any of these answers are yes, it might be time to consider doing something about it.

There are a couple of options to consider: pull the tank and have it cleaned inside or out. Then have it coated with some type of protectant. This might be okay; however, if the galvanizing flakes off, it usually takes the new protectant with it.

Another option is to replace the tank altogether. The National Fire Prevention Association (N.F.P.A.) has established guidelines for fuel tanks in publication 302, Pleasure Craft and Commercial Motor Craft. The table below is copied from that document.

If you are not sure what to look for, have a qualified surveyor look over your boat. He should be able to tell the type of tanks and if there are any problems with the fuel system. If the system is not up to code, the insurance company will refuse to insure the boat until the boat meets certain standards set.

If there is a problem with the fuel tanks, it would be best to have it repaired or replaced as soon as possible. If you are considering to have new tanks made, it is best to have them made in the off season so as to not disturb your boating season. Remember, you and your family are not as easily replaceable

Ken Grobelesek
Lyman Navy
Material Specification Minimum Nominal Sheet Thickness Gage
Nickel-Copper ASTM B127 

class A

0.031 IN 22
Copper-Nickel ASTM B122 0.0125 IN 17
Steel ASTM B122 0.0747 IN 14
Aluminum ASTM A463 

Alloy 5052

Alloy 5083

Alloy 5086

0.0747 IN 

0.090 IN

18
Stainless Steel 316L 0.031 22

Minimum Plate thickness for Fuel Tank Corrosion Resistance

Deterioration Hazard To Rubber Fuel Hoses

The Coast Guard is cautioning recreational boat owners with inboard gasoline engine to watch closely for damaged or leaking fuel hoses which could cause a fire or explosion. The danger comes from alcohol-gasoline blends which have replaced leaded fuel. Alcohol, which increases octane ratings, also causes deterioration or rubber fuel hoses and eventually the fuel leaks through. On boats with enclosed engine compartments, such leaks create fire and explosion hazard.

To help boaters solve this problem, a new alcohol resistant fuel hose has been developed, and the Coast Guard is permitting its use immediately, pending regulatory changes to the Coast Guard's fuel System Standard.

Anticipationg the effect of the alcohol gasoline blends, the Coast Guard and its National Boating Safety Advisory Council requested industry to develope a new standard. Prompt action by the Society of Automotive Engineers Marine Technical Committee resulted in standard SAE J1527DEC85. The new standard sets a permeation rate - the rate at which fuel passes through the walls of the hose - which is one-sixth of that specified under the present plasticizers (wax) in the hose.

Because of the deterioration hazard, the Coast Guard urges all owners of inboard, inboard-outboard, and jet drive, gasoline powered boats to inspect their fuel hoses frequently, especially near the engine where heat can acceleratere deterioration. Damaged hoses may be dry and cracked orsoft and mushy. A hose that has failed should be replaced immediately, preferably with one meeting the new standard. If that is not available, owners should use any hose marked "USCG Type A."