1971 Hatteras - Original Fiberglass Tank

So I am days from pulling the pin to purchase this 31’ Hatteras; I know I have previously posted my concern but here it goes; same owner for past 20 years; never had an issue related to file and has always ran ethanol free fuel; spoke with mechanic that has been servicing / winterization boat for 15 years; no issues that would be symptomatic of fuel tank degrading; engines have approx. 600 hours; owners seem like great older folks that have taken pride in ownership; I understand nothing is 100%; but due diligence is on me; mechanic also states the only way after doing homework and checking filters and for obvious “soft spots” on tank, would be to pressure test.I am almost convinced to purchase just checking boxes; thanks again!

Pressure testing will not do anything for you but risk inserting issues.

Sadly, no body can tell you what resin was used or if your gas tank would really be affected with alcohol.

The only way to ensure many more years of happy motoring is to avoid taking on any grain gas.

Who knows, You may install diesels in another 10 years and this concern will go aweigh.

One option I viewed might be an ATL Fuel Bladder; they make custom sizes that require a supported tank (shell) might be option to remove portion off top of old fiberglass tank; insert bladder and have new tank essentially; might avoid have to cut out any decking for new tank?

The tank shell likely would withstand pressure testing however the baffles inside probably wouldn’t. If the tank expands even a little from pressure testing the baffle tabbing will be torn and you’ll end up with a tank top that bulges when filling from the air going out slower than the fuel coming in. This will make any burp from the fill deck fitting or hull side overflow a very dramatic event.

Doesn't matter if the boat was built 40 years ago or 4 months ago, the use of ethanol fuel will cause problems with fiberglass fuel tanks. Ethanol is a solvent and turns the resin in the fiberglass into a mushy gelatin-like substance globs of which come loose into the fuel and will continually plug up the fuel lines, fuel filters, and carbs/injectors. It is a neverending problem, you can clean it out and it will just happen again. It was a nightmare about 10 or 15 years ago when ethanol first became a widespread thing and people didn't know any better.

But after that initial sh!tshow where everybody had problems and figured it out, now at least where I live (Florida) virtually all marina gas is ethanol-free. You'd really have to be looking to find a place here that sells ethanol on the water anymore. Consequently, you don't hear about any problems lately. But it may be different in other places, so YMMV.

Call a handful of marinas around you and ask if they sell ethanol free fuel. If they all say yes you'll be fine, just use that. Fiberglass fuel tanks are the best, they don't rust, they don't rot, they don't get pinholes. The one and only downside is you can't use ethanol.

Somewhat refreshing to hear; I k ow per the current owner and a captain assisting them with sale; you can not really find non ethanol free fuel in the MI area; the owner made it a point to always use ethanol free since ownership; he has had NO fuel related issues with his boat, carb issues ect…; at this point I feel Inhave done my homework and all should be as good as I can calculate; my home port all has ethanol free; will have to be careful traveling back home to make sure my stop all carry it….

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Originally Posted by cww

Doesn't matter if the boat was built 40 years ago or 4 months ago,

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You would be amazed that some FRP tanks still survive with grain gas in them.
Without knowing the future, some mfg / vendors used a different resin and still have no problems.

Pending what side of the street (different local shops) made the Bertram FRP tanks, some are still fine 40 years later.
The original Bertram corp could not tell you what tanks were from where or made with what resins.
There are replacement FRP tanks with grain proof resins that have been available for many years now. I know of these for a few old Bertrams.

Would of been nice for Hatterass or a Hatterass vendor to step up, admit there was an issue and make replacement FRP tanks for ole Hatts.