Fuel tank foamed in.. removal?

[erikgreen]

Hi all;
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I have a 64 gallon steel fuel tank that was foamed in place at some point in my boat's life... for pics, see <P> <A HREF="http://www.greendragon.org/boatproject/">boat project pics</A>
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Basically my problem is that I've gotten all the foam along the sides, front, and back cut away or pulled out and the thing still won't come out. I also removed the screws and/or brackets that are along the top side, FYI.
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Suggestions I've gotten so far include cutting holes in the tank and using toggle bolts to attach handles. Any suggestions here for getting the thing out? I'm not going to re-use it... too much water got to it for it to be safe any more.
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It's big... 72 inches long, 22 wide, and 10 deep (at the fore section, dunno the back yet). It's not vee shaped, since it has a stainless bilge drain running from my cuddy step to the engine bilge under it. I have enough room at the front to get a few fingers under it at this point, already tried a big crowbar (gently).
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All the gas is out at this point... 26 gallons with a hand pump :\
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Erik

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PS: I could also use suggestions on where to get a replacement tank... west marine and iboats don't have anything near that capacity that will fit in a 10 inch underdeck space.

 

[Boomyal]

Re: Fuel tank foamed in.. removal?

How much clearance between any one of the bulkheads or side stringers is there? The best way is to get a lever under one end of the tank. It should pop loose from the foam fairly easily if you aren't trying to pull the whole thing straight up at once. That would be the problem with the toggle bolt idea unless you just concentrate on one end of it.

It doesn't have to move very far to break the bond.

 

[Bob_VT]

Re: Fuel tank foamed in.. removal?

I agree on using a lever

OR

If you are positive you have all the hold down brackets removed.... get a fiend and you can use a piece of wire and it will be tough. Use a sawing motion.

 

[erikgreen]

Re: Fuel tank foamed in.. removal?

On one end (fore) there's about two inches of clearance... almost none at the aft, and the port side has about one inch and the starboard almost none again.

I'll see if I can get a piece of pipe in the fore space... I'm worried about levering it up though, since the fulcrum is basically the fiberglass keel. Time for some experimentation I guess.

If I don't get it out tonight I'll take some better pics of it and post.

Thanks,
Erik

 

[erikgreen]

Re: Fuel tank foamed in.. removal?

No luck tonight... here's a couple pics, one of each end. Excuse the foam, I was working on getting it all cleaned out wherever I could. The pics are at my camera's native resolution, which makes the files large, but you can zoom in.
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<A HREF="http://www.greendragon.org/boattank/">Tank pics</A>
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Basically I tried levering it up.. I'm afraid to use too much force at this point since it's filled with gas vapors and I don't want to accidentally crack something else. I did make sure that all the brackets holding it on its top are out/gone. Note that it sort of sits crooked between the stringers (which by the way are glassed and seem sound) so the aft/starboard has a bit of space, as does forward/port. The biggest gap is the forward end.
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Erik

 

[iwombat]

Re: Fuel tank foamed in.. removal?

Any chance of hooking something inside the fill spout and using a hoist?

 

[erikgreen]

Re: Fuel tank foamed in.. removal?

Re: Hoist Not much chance really, without taking the hardtop off the boat. I may get there eventually though.

Also...

I had two friends over tonight and we spent an hour and a half trying different things to get the tank to move. The best we did was to make it temporarily bend. It's like whoever put it in epoxied it to the bottom of the boat.

We tried getting a wire saw around it to saw the foam or whatever out, and it's so tight against the hull and stringers on one side we couldn't get it all the way around.

We also tried stringing the wire through the fill hole and sender hole, and we nearly broke a 2x4 trying to lift it.

Finally, I tried putting a crowbar under one end and levering it out... all that happened is I crushed a soft deck section (which was a good thing anyway... I hadn't noticed it was rotten).

Anyone know of a way to neutralize gas fumes? I can't use a power tool to cut it up without risking an explosion. I was thinking of cutting it out piece by piece with a hacksaw, which should avoid sparks but would take a month to do.

Suggestions desperately sought. Anyone ever take a gas tank like this out of a Sea Ray before?

Erik

 

[Yacht Dr.]

Re: Fuel tank foamed in.. removal?

fill the tank with water .. then look for some kind of glass tabbings on the sides .. grind away.

typically your tank will not hold that well just bonding to some foam were you would delaminate glass underneath it ( though it has been known to happen from time to time ). so your best bet is to get as much out from the sides as possible

look for any possible bind areas surrounding the tank..then just pry and pull and jack as much as you can.. mebbe try pouring some acetone down the sides.

but you have to make absolutly sure there is no bind point from glass wrapping or strapping

obviously protect your pry points

 

[Solittle]

Re: Fuel tank foamed in.. removal?

In picture # 2 it looks like there is a soft or rotten crossmember just fore (or aft) of the tank. Could it be removed to give you better access to the bottom.

 

[erikgreen]

Re: Fuel tank foamed in.. removal?

Yep, the forward one was soft... it got taken out today while we were working. The deck just forward of it was bad too.

I suspect the aft crossmember is gone as well... I may try taking that out tomorrow, although the engine is right there and that won't get me much more access.

My friends recommended getting a small, narrow saw to try and cut the tank free of all the foam around it, which I did tonight, and will try to use tomorrow.

I'm seriously thinking about cutting the thing up in place and taking out the pieces... I'd have to use tinsnips though, or maybe a compressed air powered sheet metal nibbler.

 

[erikgreen]

Re: Fuel tank foamed in.. IT's OUT!

Re: Fuel tank foamed in.. IT's OUT!

It's out!

I'll take some pics a bit later just for completeness' sake, but here's the story:

either the factory (possibly) or a PO had foamed in the tank, including the bottom. I say this probably wasn't factory due to the fact that A) The boat is old enough to be pre-foam era and B) there was a section of garden hose foamed in with the tank (water tank drain)

I finally got the tank out by going and buying a "compass saw" from Home Depot... it's basically a wood type saw with "induction hardened" small teeth like a fine tooth wood saw, and a blade about 1/3" across tapering to a point. It's pretty stiff. I then sawed clear the foam along 3 1/3 sides. Even though I had chopped the foam out (mostly) it was still sticking the tank in place. Once I sawed out three sides and as much as I could reach of the fourth, then I pried the tank out of the hole in my first try with the crowbar, revealing that the entire tank underside had been bedded in foam.

Of course, then I tilted it up far enough for about 1/3 gallon of the remaining tank gas to leak out of the draw tube and into the foam below it, which made a quick trip back to home depot for some spill absorbing material necessary. I'll wait for it to absorb then shovel it out, then pull out the gas soaked foam with gloves for disposal. After that a detergent washdown should get the rest of it, as well as cleaning out the remnants of gas that soaked into that section of boat while the tank leaked over the years.

I plugged the draw tube with fast hardening two part epoxy putty, so after it hardens I can get the tank out without more spills.

Lessons learned:

1) Foam is a ***** to pull out
2) Foam is tougher than you think
3) Brute force is rarely the best way to go
4) Patience is a necessity when dealing with boats

My thanks to all those who helped with suggestions,

Erik