Cutting Through Precious Wood for Fuel Tank Removal....HELP!!

[BenBowSirocco]

Just another idea here, but you could have the old tank lined in fiberglass.

I have seen this done to a couple tanks, though I have only inspected one in person- the owner helped in the process so we talked it through.

Essentially they cut access into the aluminum tank as much as possible (two small-ish rectangular holes) and then prepped its interior as much as possible with big grinders, then little die grinders.

I remember seeing huge (2"+) fillets on all tank joints of epoxy and the glass was laid over these while green.

They glass was cut into small manageable pieces and saturated before going into the tank.

If I remember correctly he said it was 3 layers for a total of about 30oz of thickness.

They then followed Gugeon Bros "tank building" technique and did 6 rolled coats of epoxy while everything was still "green".

The access holes had fiberglass plates mounted on the inside of the tank with machine screws from above on the outside and typical rubber gasket/sealant.

It seemed to me like a lot of labor: but much less disrupting of the interior than any other idea I had seen mentioned.

I also known it worked as the boat had had the tank liner for years at that point.

Obviously this is a solution that requires a number of factors to work out before its really worth the work, but wanted to share the idea in case it seems plausible in your situation.

[asmith2378]

Thank you all for your responses! We have come up with an idea that I'd like to run by you guys, because it might be too crazy. I've read of people putting fuel bladders in and I'm intrigued by this idea. Our fuel tank is really just too old and rusty to trust with a bladder, however, there is a 200 gallon water tank to the left of where the fuel tank is and it's completely empty due to having some pin holes in it. Otherwise the plastic is in good condition. We have good access to this tank and I'm wondering what y'all think about placing the fuel bladder in there? What should we be considering here?

[asmith2378]

Originally Posted by rls8r

asmith2378 -

Yes, it will be a big job, no matter how you approach it. But ... it's really not that complicated. You just have to take a lot of things apart - remember how they go together (take pictures and mark the pieces) - and then put things back.

Some soles have the screw holes plugged - like 5BTM mentioned. They're easy to remove with a small screwdriver - and easy to replace. Buy teak plugs at any chandlery - or online is cheaper. A possible hiccup may happen if the sole is screwed down with bronze screws (as many boats of your boat's age were). Some of the bronze screws may have corroded - in which case you'll have a heck of a time getting them out. That's just life. Buy a pair of vice grips.

I recommend putting things back together using 316 stainless steel screws. The stainless steel screws you find at most chandleries (including West Marine) are 304/18-8, which are OK, but they are less corrosion resistant than 316. McMaster-Carr is your friend here. Many Ace Hardware stores also carry 316 stainless steel fasteners.

Another thing to be aware of is the floors under the sole. The tank may be under the floors, so you'll have to remove the floors. Make sure that you remember how they go back. Number them, and mark port and starboard ends. Depending on how your boat is built you may have stringers to deal with, too. Same advice as for the floors.

While you have things apart - it's a good time to check any wiring and hoses that run under the sole. Perhaps you'll take the opportunity to clean the bilge and give it a nice, fresh coat of paint.

As I mentioned before - it's also a good time to refinish the soles.

ahun showed you a photo of (I suppose) his boat with the sole removed and the tank exposed. The picture below is my main cabin with most of the sole removed to expose my fresh water tanks. The tank on right has been removed; the tank on the left is on its way out. Please excuse the mess of hoses and cables in the space where one of the water tanks used to be.

Like we said ... it's a big job, but not one that's technically complicated. Good luck. Have fun!

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Join Date: Apr 2022
Posts: 6
Re: Cutting Through Precious Wood for Fuel Tank Removal....HELP!!
Thank you all for your responses! We have come up with an idea that I'd like to run by you guys, because it might be too crazy. I've read of people putting fuel bladders in and I'm intrigued by this idea. Our fuel tank is really just too old and rusty to trust with a bladder, however, there is a 200 gallon water tank to the left of where the fuel tank is and it's completely empty due to having some pin holes in it. Otherwise the plastic is in good condition. We have good access to this tank and I'm wondering what y'all think about placing the fuel bladder in there? What should we be considering here?

[toddedger]

First of all, is your tank really made out of aluminum? Aluminum doesn't rust it corrodes. If it's rusted steel then it's probably done. If it's stainless or aluminum I might be salvaged. When cleaning out my aluminum tank I found corrosion in the very bottom where any water in the fuel sets. Scraping the white corrosion away I quickly ended up with a small hole. Luckily I had some access to the bottom of where the hole was. With the consultation of the West Systems tech department I was able to fill the hole snd glue an additional aluminum plate to the bottom of the tank covering the area. That was several years ago and that nightmare was forgotten.

[Goodxcharly]

Lots of good suggestions in this post and from what zi gather it is not a hurry up job.
Go slow and take your time as you do not want to loose your seller with a bad looking repair.
Take it apart verse sawing it apart is a good suggestion. Hide the seams when you can if you have to use a saw.
Just look at it as puzzle.

Enjoy

[Cheechako]

One option is to accurately cut the floor out above the tank. Then do your tank work.

Then make the cut out floorboard into a floor hatch cover, or two covers if it's too large.

You trim the floor opening and trim the cover with teak trim. It will look like it was made that way, and probably should have been.
I hope this makes sense, without more details on the construction there may be other things you need to do, but it's almost always doable.

[sinnerman]

For breaking fownthe diesel spilled inthe bilge:

https://hydrocarbon-degrader.deoilit.com

My two cents

Cheers

[TrentePieds]

2378:

Cheechako has it right in his tidy little drawing.

I just want to make sure that you know that the component of the boat you walk on, which ashore we call a "floor", is called a "sole" aboard a boat. The component that supports the part you walk on is called a "joist" ashore, but in a boat it is called a "floor"

Simple enuff, but can create confusion until you've grown accustomed to the "sailorspeak" :-)

Good luck with the project!

TrentePieds

[asmith2378]

So we got some better pics and videos of the area. I think we've decided to cut the sole and replace the entire tank. We will then create a hatch for the future tank. I'm probably going to outsource a carpenter to make the cut and hatch and do the rest ourselves. Mainly we are just worried about knowing what size to cut the hole. We can see how wide the tank is as the top. I'm thinking of just cutting a hole in the top of the tank to get a camera in the and measure how wide it is. It's about the only solution I can think of. We are really trying not to butcher the floor here. Let me know what y'all think

[TrentePieds]

That looks like a very conventional installation.

In your second picture it looks as if you've already got the dimensions of the tank established by the pink tape. If I were doing the job, I think I would keep working out towards the ends of the tank until you clear them and thus define the ends of the new hatch. The scraps of the old sole and floors can go in the garbage.

Then after having exchanged the tank, I would build a new sole on the principle shown in Cheechako's sketch.

For the substantial sole I would use MARINE plywood because it has two essential attributes: 1) It is laid up with water-PROOF glue twixt the plies, not just water "resistant" glue which won't cut the mustard in this application. Plywood laid up with glue that is only waterRESISTANT will eventually delaminate! 2) It has a smooth surface onto which you can glue things.

The surface of the sole in your boat, judging by your pictures, is a faux-teak&holly, a kind of vinyl flooring (only better). Something like this:

https://www.plasteak.com/plasteak-re...looring-glossy

There are several makes of the stuff, so you may have to hunt a bit to find material that matches your existing "plank pattern". You stick it on by sealing the surface of the ply with a sealer, then setting the sheet of vinyl faux-teak&holly just like you lay vinyl flooring ashore.

Bonne chance :-)!

TrentePieds

[Rotten Ricky]

I suggest that although you have had one large tank in the past, you could find it much easier to install two smaller tanks in the same space, though leave room for connecting them together and to elsewhere. Two tanks will automatically create a baffle to stop excessive surging. They are a particularly smart option if one smaller tank needs to be placed in position first and then slid along to get under a cross member, etc., that would otherwise have to be cut through for a single large tank.

Also consider using fibreglass tanks, either professionally made or build your own. When lined inside with "food-grade" epoxy, there is no smell, taste or corrosion. These are surprisingly easy to make if you have just a few skills, and they cost a fraction of an aluminum or poly tank. You can often find it easier to make them to fit strange shapes in the boat to maximise storage, as I did with mine.

Fibreglass tanks are also excellent for waste, or fuel, but for gasoline, line the interior with epoxy or vinylester. Not a problem with diesel.

Cheers, RR.

[mako]

Just don't forget to perform the 3psi - 24 hour pressure leak test when you're done.

[Cheechako]

Originally Posted by asmith2378

So we got some better pics and videos of the area. I think we've decided to cut the sole and replace the entire tank. We will then create a hatch for the future tank. I'm probably going to outsource a carpenter to make the cut and hatch and do the rest ourselves. Mainly we are just worried about knowing what size to cut the hole. We can see how wide the tank is as the top. I'm thinking of just cutting a hole in the top of the tank to get a camera in the and measure how wide it is. It's about the only solution I can think of. We are really trying not to butcher the floor here. Let me know what y'all think

Unless you use plastic tank(s), be sure to place the tank(s) on supports that allow air underneath. Typically a metal tank fails where it sits on something that stays damp or wet between the tank and the support, or at a weld that stays wet a lot.