bertram31.com

O.K. As you all know I have spent a little time and trouble trying to get to the bottom of the glass tank ethanol thing, and I have proported in the past that the tanks with the gelcoat interior might be better than those that do not have the gelcoat.

My tank has the gelcoat. I cleaned out all the old fuel, sloshed a little new fuel around in there and claened that out too. Then I put in about 3 gallons of E-10 and let it sit a couple of weeks.
The gelcoat has failed. It is blistering in the presence of the ethanol fuel. It can only be a matter of time until it flakes off,exposing the raw glass to the ethanol, and then that will fail too.

The only hope for any of the old fiberglas tanks is that the oil companies stop using ethanol after it no longer becomes a requierment this fall. Unfortunately, that is unlikely to happen because of the tax subsidies.

If you have not changed out your tank yet, plan on doing it soon. If you have changed it already, well you made the right bet.

I wonder what the plan is for the fiberglass tanks used for underground storage at marinas and gas stations? Some of them must be at risk too.

Peter

Peter
Tanks in Marinas, Gas Station and Chemical Industry are made from different fiberglass and resins. There is suitable fiberglass cloth, resins and coatings to redo the inside of your tank if you choose. I don't have my file on this handy at this time or I would give you some info.

Keep Smilin

Peter,

What year is your boat?

I have a 1976 '26 FBSF.

BTW has anyone tried to get an old tank out of one of these? It sits snugly between two longitudinal stringers and up against a half bulkhead aft. All but about 8" of the forward part of the tank are accessible through a large deck hatch. There is no getting underneath it to see what it might be attached to on the bottom.
I'm considering just cutting the top off and laying a new tank inside the old shell, but that might be just as difficult as puling the whole tank. It is hard to say without knowing what is underneath....and getting a wedge under it, or a lifting strap seems to be a long shot.

As for the resins designed to stand up th ethanol, that is true of some of the recent stuff, but I believe that the Fiberglass tank and Pipe Institute, who is in charge of checking on these things, points out that there are fiberglass undergraound storage tanks (usd's) in use that were built in the late 60's and early 70's that were not constructed with ethanol use in mind. The FTPI claims that some of these tanks were tested and recently approved for continued use. I question that decision, because of the type of failure.

The problem is the issue of permeability. The gelcoat failure is a blistering failure...which has to do with the permeability of the ethanol exploiting weaknesses in the gelcoat layer and getting under and into it.... Not with the resin disolving. The same permeability problems are going to exist in any frp layup. Technique in building tanks, even with the new resins is going to be a big part of assuring success.
I'm thinking vacuum bagging and hot post cure are a good idea!

Not So Fast....

Actually as I prepped the tank for removal today I found that it is in the form a a big extruded "T". The sadle tank parts, that is the parts that are the cross on the "T" have just as many blisters as the base of the "T". What is important is that the saddle parts never saw ethanol.

The blistering is NOT ETHANOL RELATED.

Still, my tank has failed and I am on the road to replacement, but if you have a gelcoated-inside tank, maybe there is hope.

And I believe there is a good chance that over this winter pure ethanol will be replaced by ETBE..... that is an oxygenate additive that hasn't got problems of ethanol, but is made from ethanol.

Way back a year ago I was talking to a friend with a B-31. He had to replace his tanks because of blistering. The thing was, though that he had a Diesel....

30 years is a long time for any tank to last...maybe some of the ones that are failing are just simply old.

Peter

I've heard of other cases where the gelcoat in the tanks came off in small 1/16 to 1/8" inch bubbles. Was that you that had that happen Vic? I agree that that is probably not ethanol related. I know that I have a rubber pad on my dash that occassionally gets wet from a windshield leak and I have smallbubbles in that gelcoat under the pad that is caused by the constant presence of moisture. They haven't gotten to the point of popping yet, but they are obvious to the touch and cover the entire area.

I am way out of my league here since I have diesels, and while I am interested in this subject I am not as directly involved as many of you and my fellow 33'rs I do try to keep up with the subject..

All the above comments are directed at gas tank FAILURE. This is certainly a serious concern.. but from what I have read there are at least two main issues.. the failure concerns and the concern that one of the chemicals used in the original fiberglas tank construction being dissolved in the gasohol, passing through any filters present, and subsequently causing the black gunk that leads to valve problems and engine failures.

Originally I read that Lee Dana was reported to have said that tanks made after the mid 80's were not expected to cause black gunk problems.. very recently he made the following statement, which I extracted from Capt. Ed's post elsewhere on this forum...
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"One well intentioned writer extracted some data from the Fiberglass Institute stating that the industry changed their resin in the 70’s to accommodate Ethanol. What they failed to explain, was that the Institute represents only the commercial fuel storage tanks and piping. Even Bertram failed to get it right when they were telling owners that they had changed resin in 1985 and boats built after that date would not have a problem. Wrong! We did change the resin supplier for the fuel tanks in the 80’s to satisfy UL Marine. This required only a certified flame retardant resin which, at that time, was Hetron 26252. Specifications for the UL certifications were approved in 1982 but records show we were still using bulk ortho. resin and adding the Antimony Trioxide as late as 1985. Records also show that by 1986-87 we had switched to the Hetron resin.

I have since gone on record that all Bertram fiberglass fuel tanks from 1961 to 1990+ that will use Gasohol are venerable to some level of degeration, How long it will take for failure to occur remains a mystery. The belief, that if a fiberglass fuel tank is constructed with Vinyl Ester or Epoxy resin the problem would not exist is simply not supported by any industry data that I am aware of. The truth is, not all Vinyl Ester resins are suitable for Gasohol. In fact the resin that is suitable for pure Ethanol is not suitable for Gasohol.

There is also a real concern for metal tanks with the possibility of corrosion and or galvanic reaction due to the water content and character of Ethanol. It is no secret that Ethanol is a solvent and is ionic conductive, even though it is considered a poor conductor."
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So.. it would appear that there is no answer that addresses all parts of this issue. Dana's comments seem to be directed at tank structural failure.. not the black gunk issue. But.. if he is saying that ALL fiberglas tanks are likely to be damaged by gasohol the black gunk problem is reduced to a lower level of concern, since it makes no difference whether or not your engine is happy with what it is fed if the tank you are using is likely to fail.

I am not really sure what I would do if I had a gas boat.. it seems that with the info available today, which is not complete and comes from multiple sources, each very likely trying to be helpful but sometimes contradicting each other, you are "damned if you do damned if you don't."