Fiberglass Fuel Tanks. Keep or replace?

[Booby Trap]

I am a new owner of a 1967 34' Convertible with original fiberglass tanks. The old owner was having problems with the original tanks last season and was blaming it on the ethanol in the fuel reacting with the tank resins resulting in the valve seats 'gummimg' up. I have read all I can over the internet on this issue and everyone seems to agree that older tanks (pre 1980) are not suitable for use with the new fuel mix.

However I just spoke to a company who removes old gasoline, filters it down to 0.5 microns and then blasts the fuel back into the tank. This process is repeated until both the tank and the fuel are clean.
He is telling me that there is no inherent proplem with the older tank but instead what the ethanol is doing is suspending all of the 'crap' that has been sitting on the bottom of the tank for the last 40 years. He makes a very convincing argument that the tanks only need to be aggressively cleaned and filtered instead of replacing.

Does anybody have real world experience with this type of procedure?
Any thoughts/suggestions/history would be appreciated.

Thanks in advance,

Bill

[Genesis]

I'm not sold either way.

Boat/US appears to now have evidence that polyester is being found in the gasoline. If so that's the resin itself and the tanks will eventually delaminate.

You definitely do not want to discover this 30 miles offshore when suddenly you have 200 gallons of gasoline in your bilge!

BOOM! :eek:

My first suspicion was as this guy claims - that it was the solvent action that was causing the trouble. Now I'm not so sure. Were it my boat I'd be thinking long and hard about what to do in regards to this problem.

Testing the fuel with a GC/MS run is EXPEN$IVE ($500 or so for a full analysis!) but I'd probably do it because the risk of being wrong can equate to being dead.

One problem is that if you DO find out that your tanks are being eaten what do you do about it? If you cut up the deck to replace htem what do you replace them WITH? Aluminum is not a good choice because it too fails over time (although properly installed "over time" is probably 10 years) and plastic tanks aren't made in that size due to baffling requirements.

There are other problems with ethanol in gasoline with regards to marine engines too. One of the bigger ones - and one that is being ignored by most people - is that ethanol will mix with water. Gasoline will not. When the water content in the gasohol gets high enough the ethanol/water mixture will separate out from the gasoline!

This is extremely bad (as in "may ruin your engines") because (1) the remaining gasoline has insufficient octane and will cause severe detonation in the engines, likely holing pistons and other nasty problems and (2) if you suck up the water/alcohol mixture in the bottom (where it will go) the engines will lean out horribly as ethanol requires a much richer mixture to fire properly (can you spell holed pistons again?) and if it happens under power.....

Anyway, I don't know what the answer is for marine engines when it comes to gasohol.... but there's definitely a lot to think about here.

[dougl33]

He can filter the gas as much as he wants, but he can't filter out the ethanol which is probably eating away at your tanks. I'd save my money.

Boats with later tanks (i.e. 1980's and up) may not be safe either. I can't speak for Hatteras, but I've been getting conflicting reports from people currently at Bertram, and people that used to work at Bertram. Some have said that Bertram changed to ethanol safe resins "around 1985". Others have said that Bertram didn't change their resins until early in this decade.

Go figure. Whom do you beleive?

Regards,
Doug L.

[34Hatt]

The Guy that said filtering the gas and then to use the tank does not have a F*&%$&^% Clue to what he is talking about. The Tanks are N.G Have TO Be Replaced I have a piece of tank in my back yard from a 34' Hatt it is No Good All gel coat is gone and the gel coat is what makes the tanks seal glass alone does not work.

[smoothmove]

One thing about all this ethanol/fiberglass business has always bothered me. We keep hearing that there was a formulation change in the 80's and that tanks made after that date are immune to the effects of ethanol. (not sure I believe that either) Was this change made in response to a perceived problem with ethanol compatibility, or was it made for other reasons and it's just a happy coincidence that it is compatible? If it's the former, why wasn't anyone notified? If it's the latter, how do they KNOW that it is compatible?

[67hat34c]

There must be a safe resin because all underground fuel tanks are fiberglass. Still cant see why you cant pull tank, sand blast and recoat it with a safe coating.

[dougl33]

For one thing, no one is completely sure what that safe coating actually is.

Second, I think it would be very difficult to strip the baffles of all the old gel-coat. Not to mention the fact that the tank would have to be cut to remove the old gel coat and re-glassed after it was re-coated. It's probably cheaper to replace with aluminum tanks.

Regards,
Doug L.

[34Hatt]

We keep hearing that there was a formulation change in the 80's and that tanks made after that date are immune to the effects of ethanol.
Yeah I have heard that too but also know that is Bull if that is true why is it that two boat company here on the Island are redoing tanks that are 1-2 years old.


There must be a safe resin because all underground fuel tanks are fiberglass. Still cant see why you cant pull tank, sand blast and recoat it with a safe coating.
There is a resin this is what these companys are doing but it is a royal PITA and $$$$ Yeah I now a new tank is no bargain. When I asked my friend if it will hold up he said only time will tell and had that look of :(

[ELECTRA VI]

I was wondering, since aluminum will be susceptible to corrosion, what about having tanks made out of monel? I know that monel is expensive, but I have seen no discussion points on monel tanks and wonder if they might be the solution.
George Jeandheur
ELECTRA VI
1966 34 C #068

[67hat34c]

Aluminum no good the alcohol will destroy it also. only tanks that will hold up are polyethelyne. a tank of this size is going to cost, no one is making them for off the shel installation yet, boat builders have them made by Moeller. tanks will cost min of 1k each.

thought of this is eating at me as i just dont have the money to do this work right now. spending a great deal getting the thing repainted as we speak.

no reason to have alcohol in marine fuel, it is mixed at the tank farms when it goes into the truck, i shure hope boat us and others can get the government to restrict alcohol gas to cars, write your congressman.

[Maynard Rupp]

Aluminum and steel are no good due to corosion. Stainless and monel are better, but the welds are almost impossible to make leakproof. Plastic without baffles is not acceptable. Guess what folks; Hatteras selected the best material when they chose fiberglass. What the mid 80s resin change has to do with the problem is a joke. They never heard of ethanol being added to gasoline then. The cost, grief, and destruction of a good cockpit just isn't worth it. We already have the best tank material. I think gas engines are great as long as your boat is small enough for the available horsepower engines, but if we start to have a problem with "Unity", our '86 36C, I will change the engines to Diesel. The tank label says "gasoline"' but the plate has 3 pipe plugs for return lines. Our shafts are 13/4" and our exhaust system aft of the engine's y fitting are 5". The engine room is so well insulated that you almost don't know you have engines running when in the salon. I guess the smelly and noisy diesels would change that for sure. By the time you carve up your cockpit, rip out the tank, install new ones that won't last either, and put the whole cobled mess back together, you could have paid for diesels. That is true only when you account for the increased value of your boat due to the engine change.

[smoothmove]

[QUOTE=67hat34c]Aluminum no good the alcohol will destroy it also. only tanks that will hold up are polyethelyne.

I have heard the statement that ethanol is corrosive to aluminum and have been guilty of saying it myself. I pulled out a chemical index and have not found any evidence to support it, however. There WAS mention that METHANOL was corrosive to alumininum and I have seen evidence of that in the past. Pascoe addresses the subject of aluminum fuel tanks pretty cogently in his book. He seems to feel that while it may not be the ideal material, there really isn't anything better either. He expounds on the fact the the manner of installation is CRITICAL.
Eric

[GaryNW]

I think we need to settle down a little. My boat w/alum tank is (14) years old now. I have been running E10 for at least 10 years; I use no additives. Exactly when is the tank going to fall apart? Fortunately, the builder installed the tank under a removable section of deck so I can have that sucker out in about 3 or 4 hours. There are many thousands-if not-millions of vessels with steel tanks out there. Steel generally corrodes predictably- 20 to 30 year life is considered economically viable by most operators. I believe with proper design (sumps, no flat surfaces that can hold water, etc) and epoxy coatings, a steel tank could be made to last the life of the boat. Has anyone priced monel? I think it would be scary. Even alum is getting scarce. I read that this is a major issue for Boeing. They can sell more a/p's than their suppliers can feed them alum and titanium.

Seen some of the recent t.v. news segments on E85? No one had anything bad to say! And as we suspected, the population of folks with tank issues is too small to even get mentioned.

Gary

[Boatsb]

I replaces 2 tanks in my 28 pearson express cruiser with tanks from Moeller in Tn. They manufacturer OEM tanks and have the "rights to some of them plus some of their own. The cost for the 79 gal tanks was nothing compared to alum but that was the largest they had to fit in my boat. If boat manufacturers can have larger ones made why not see if they will do a plug for a couple of the sizes needed and see if baffles can be added. It beats burning up and they make a nice tank.

[spartonboat1]

I saw a mention of Monel. In the 50's and 60's Chris-Craft's ran Monel fuel tanks I believe. Of course, whether Ethanol affects Monel I am in no position to say. But at least there is a history of Monel and gasoline. The Mariner's Museum in Virginia might have some history on the Monel. They are good about doing research.

I wonder what material is in the Indy car fuel cells, since they run a mixture of ethanol and methanol. They have publicized that in future years they will run nearly pure, if not completely pure ethanol, which actually has a higher BTU content than methanol. I remember they went to the methanol because of the reduced fire hazard to drivers. Some were badly burned in gas fires and then when alcohol was run, it burned but the fires were not very visable. You burned and danced, but no one could see the flames. True of methanol..I don't know. Nomex came out of a major chemical company, when a friend of an executive was burned in a race car accident...but I digress.

Final note on the Chris-Crafts, I own a 1953 40' Chris-Craft (yes, my wife is after me big time to part with it!), but the fuel tanks at this age still hold fuel. Their construction is similar to a 50 cal drum laid on its side and I do not know if it is Monel, but I do not think I observe surface rust on it. I can't tell if the the ends are crimped in place or what the form of fabrication really is. Maybe an old experience tin-knocker on this site would know.

[jim rosenthal]

Monel tanks are pretty good... a lot of quality older boats had them. I think Matthews, Trumpy, and maybe a few others.

They are very expensive. I think they would cost more than plastic tanks and not hold up as well. I am not a fan of aluminum tanks for anything- I think they are proven to be trouble-prone and dangerous for fuel, and unsuitable for anything else, in boats.

Bertram made 1400+ 31s, most of which still run gas engines. Maybe one of the plastic tank molding companies will make up a set of molds for that boat's tanks- I think all the 31s were made before the change in resins that make the old tanks compatible with ethanol. Perhaps this will set a precedent for good plastic aftermarket tanks in the sizes Hatteras owners would need.

While no one could have anticipated the problems that boaters would have with ethanol eating FRP tanks, the indifference of fuel companies and everyone else- except boaters- to this is impressive. Clearly, hardly anyone gives a damn. I doubt that marine gasoline will continue to be offered with MTBE in it instead of ETOH, which means the problem is not going away. A shame for all involved.

[ELECTRA VI]

Years ago I had a 1962 36" Chris-Craft Constellation and she had monel tanks that sat on there sides. They were painted grey and never had any rust on them. She was 16 years old when I bought her.
George Jeandheur
ELECTRA VI
1966 34C #068