Thanks Sam.
Most boats with fiberglass tanks have them as a part of the hull that was simply glassed off. Lining was rarely done - my old boat was 32 years old with its original polyester resin tank and there was no reaction until a thin layer of something began flaking off a couple of years ago for unknown reasons. I scraped it and coated it with epoxy and all was well.

Not until recently were boats built using epoxy and many are still built with polyestser resin.

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1984 300Sd 210k

Former cars:
1984 300D 445k (!!) (Strider) Original (and not rebuilt) engine and transmission. Currently running on V80 ( 80% vegetable oil, 20% petroleum products). Actually not, taking a WVO break.
1993 300d 2.5 275k. Current 120/day commuter
1981 300SD 188k (Hans) Killed by a deer