Ethanol can ruin fiberglass fuel tanks

July 09, 2006|By ANNIE LINSKEY

The debate over whether gasoline suppliers should replace MTBE with ethanol did not cause a lot of waves in the boating community, but the issue is affecting recreational vessels in ways that have not been widely appreciated, according to boating advocacy groups.

Suppliers traditionally have added MTBE (methyl tertiary-butyl ether) to gasoline so it would burn more cleanly. But the additive has leaked into ground water supplies in Maryland and other states, raising health concerns.

Many gasoline suppliers, under pressure from state legislatures and facing lawsuits (including one in Maryland), are switching to ethanol, which isn't known to contaminate water supplies.

Chuck Fort, the editor of Seaworthy, a quarterly magazine published by BoatU.S. Marine Insurance, wrote a story last year after adjusters noticed that ethanol weakened fiberglass fuel tanks in some boats. Fort spent a year studying how ethanol affects boats.

We talked to Fort about what boaters should be looking for when they gas up this season.

What can happen when gas formulated with ethanol is used in boats with fiberglass fuel tanks?

The ethanol slowly dissolves resin in older fiberglass tanks. This dissolved resin deposits itself on intake valves, and then the intake valves stick and that causes engine damage.

What can that mean?

There have been several reports of gas tanks that started to leak because they were weakened by ethanol.

The good news is that the problem affects a small percentage of boaters. There might be 10,000 boats - out of the 10 million or more that are registered in this country -with fiberglass fuel tanks.

How do you know if you might have a fiberglass fuel tank?

Most of the people [with fiberglass fuel tanks] are going to know. They are the high-end boats built in the 1960s, '70s and '80s. The fiberglass tanks were considered the best material. Most of the boats built after the 1980s won't have a problem because they've changed the designs, but there is not an actual cutoff date.

What should you do if you have a fiberglass fuel tank?

The only thing you can do is replace it, and that is a very expensive proposition. If [boat owners don't] want to do that, they should have a vapor detector added to the tank to detect fuel leaks.

What if you have a fiberglass fuel tank with a diesel engine?

This has nothing to do with diesel, yet.

There is talk of some groups lobbying to add ethanol to diesel fuel. That would be [a bad idea because many more boaters would have to replace fuel tanks]. There are lots and lots and lots of boats with fiberglass diesel tanks. Including mine.

Does ethanol-formulated gas have other impacts on motorboats or sailboats?

Ethanol does two things to boats' [engines]. It is a solvent, so it cleans the inside of the tank. That tends to clog filters. We recommend that people carry spare fuel filters and know how to change them.

Second, ethanol ... will absorb water. Once it absorbs a certain percentage of water [in the tank] the ethanol and water combination will sink to the bottom.

That leaves you with low-octane gas at the top and ethanol and water at the bottom. If your fuel line is at the bottom it may pick up the ethanol and water. It will cause stalling, difficult starts.

How do you know if you are putting gas with ethanol into your tank?

Most of the marinas don't have to post that. The only way someone can find out is to ask the people who run the marina, and some of them don't know. But the marinas can ask the distributors.

Will the boating community adjust?

All this sounds like bad news, but ethanol has been in California for a few years, in the Great Lakes for 10 years. It is not a terrible thing unless you've got fiberglass tanks. The sky is not going to fall.

Most people will not be affected very much, especially if they are careful about housekeeping and keeping water out of the tank.

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