Fuel Tanks

brainstormers · #1 (**permalink**) 03-03-2005

A new skeleton has come out of his closet. My issue du jour: Evidently my old (galvinized) fuel tanks on Diva are deemed DOA. So, in my silver-lining kind of way, I''d like to take advantage of this situation to create the best damn fuel storage system possible.

My carpenter is extolling the virtues of wood-and-epoxy tanks. Frankly, I''d never heard of wooden tankage. Is this the best long-term solution? Is there anything to fear about rot, termites, etc. over time? Is epoxy truly diesel-proof? Is this an acceptable type of tank in the eyes of the USCG? And lastly (and perhaps most importantly someday) is there any impact on what a prospective buyer might think about wooden tanks vs. more modern approaches (stainless, fiberglass, etc.)?

My water tanks (fiberglass) are okay, though if there are reasons to go to the wood/epoxy type for them too, now would be the time, with her salon floor ripped up.

Thanks for any input!

Geoff

TrueBlue · #2 (**permalink**) 03-03-2005

I''m no expert on the topic, but IMHO, if I was a prospective buyer of your boat in a few years, the notion of wooden fuel tanks would scare the heck out of me. I think I would walk away and not look back.

What''s wrong with stainless . . . isn''t that the best material for diesel? I have twin 80 gal. mild iron tanks but sure wish they were SS.

Best, Steve

RichH · #3 (**permalink**) 03-03-2005

Go to the WEST SYSTEM website and look up "repairing fuel tanks with an epoxy fiberglass liner. Simply cut the top off the tank, install new FRG liner and epoxy the tank back together. Leave a margin where you cut so as to leave a ''flange'' to accept the modified ''top''.

www.westsystem.com then look up ''projects''.

brainstormers · #4 (**permalink**) 03-03-2005

Steve, that''s the kind of visceral reaction I was wondering about. I wonder how many more would feel that way, and fear wooden tanks even if I could swear on a stack of bibles that they were the greatest fuel tanks in the world.

Rich, that would be an excellent idea...except that the old tanks numbered SIX. It really wasn''t a great system, with a complicated set of valves between them; it was nearly impossible to tell how much fuel I had. So, it''s just as well that they get replaced. "With what?" is my quandry!

RichH · #5 (**permalink**) 03-03-2005

For me monel is the ONLY tank metal suitable for a boat - if you''re near a ship ''breaker'' /salvage yard sometimes you can find fairly economical monel/inconel. Otherwise I prefer Fiberglass with an epoxy liner followed by good old black iron.

Yup, black iron is cheap, strong, everyone and their brother knows how to weld it. It will last forever if you recirculate/polish the fuel regularly and draw it through a water ''knock out pot'' followed by a ''starch'' (hydroxymethlycellulose) impregnated filter. The knock out pot removes all the free water and the starch removes the emulsified water - simple, cheap and very effective.
..... just make sure that you ''blue'' (ferric- to ferrous) the exterior bottom so it doesnt corrode externally ... and then swab occasionally with phosphoric acid to keep the ''blueing'' intact.

elhanley · #6 (**permalink**) 03-09-2005

I agree with Rich regarding black iron tanks, however be sure to paint the bottom of the interior, also. No matter how careful you are to exclude water in the fuel, you need only 1/16" to cause rust. I used to build steel boats and ABS and Lloyd''s both required this. If you can work it in, incorporate a small sump w/ a drain **** to collect the water.

RichH · #7 (**permalink**) 03-09-2005

mmmmm .... thats strange that ABS and Lloyd''s require internal painting/coating .... as my experience in the chem process field is that once a pinhole inevitably is formed in such coatings the corrosion/rust formation is catastrophic - much worse than if left bare or passivated.

FalconEddie · #8 (**permalink**) 03-11-2005

Hmmm. Well, this is what I would suggest, because I have done it.

You get a little bit of framing ( 2x4''s ) and a good sheet of 3/4" plywood, a 4x8 sheet of white gloss formica, nails, glue, and contact cement. With this, you build a 4x8 table with a shiny, gloss formica top.

Now, with a substantial amount of 1808 Biaxial fabmat and Vinylester resin (fine for fuel tanks) and plenty of mold release wax. Ready? See where we''re going here?

You wax the tabletop well and lay out 4 layers of the cloth, then mix up resin and saturate the cloth, being sure to air-roll it, and only using enough resin to wet it out and not allow the mat to ''swim''. Too much resin is bad, not enough is bad. Get help to get started if you need.

You will now have fine strong sheets of plate fiberglass. You select a tank and lay it down on each side, mark the fiberglass, cut out the side plates, install bronze through fittings with good sealer (before assembling tanks!) then fiberglass the entire tanks together, laying plenty of extra cloth around the outside. When you''re done, the tanks should be about 3/16 to 1/4 inch thick. Plenty thick and strong, and impervious to fuel, electrolysis, corrosion, and fit right back where the originals were.

Just a thought

elhanley · #9 (**permalink**) 03-11-2005

Well, the entire steel boat was painted, inside and out, after welding, and rust was a fact of life. The tanks were integral with the hull, and the only unpainted surfaces were the interior sides and tops of the tanks, since they were assumed to be protected by the fuel.

brainstormers · #10 (**permalink**) 03-11-2005

Eddie, I believe you have suggested exactly the process my carpenter intends to follow. I will forward the link to this page for him to see, in case any of the nuances you describe might offer tips he hadn''t thought of.

I hadn''t heard of "vinylester" resin...is this better for diesel than West epoxy? Is it upiquitous enough to be found in say, Trinidad?

Also, have you made baffles in your tanks?

Mucho Thanko,
Geoff