Leaking Steel Diesel Tank

[peterbeale]

I have a 38 year old Magellan 36 with a 30 gallon steel fuel tank which is leaking. It appears to be leaking from about 1/4 from the top of the tank. There is an 8inch diameter inspection port. I plan to empty to tank and see if I can find the leak. If I do find the leak what can I use to repair it? The tank is firmly installed and I will have to remove cupboards and quarter berth etc., to remove it.

[brianlara 3]

I really wish you had a crystal ball because repairing a steel fuel tank is likely to be a rather temporary thing. As you're asking for advice, a bit more info re: type of breach, a split, a rust hole, a localised baffle weld failure.
IF, it IS worst case scenario, given that you've mentioned the work required to remove it, then depending on your skills and/or depth of pockets, don't assume that ONLY another metal tank is your only choice.
WEST SYSTEM's book on boat building go to lengths to describe how ply, glass & epoxy have been used very successfully to construct tanks for both water and diesel fuel.
What I'm saying is, don't think that ONLY MIG, TIG welding (fires, sparks??) etc are your obvious choices.
If you consider yourself a bit handy with timber and glass then have a browse thru the Gougeon Brothers book.
A new and far better tank than the origional may be as good as a new stainless tank.
Fwiw.
Good luck.

[brianlara 3]

Advice required Dear people. :

[a64pilot]

I would use aircraft fuel tank sealer, as its purpose is to seal wing that are full of rivet holes and make them fuel tanks, but that is because I am used to doing aircraft.
It comes in different specs A is thinner and more watery but will run into cracks etc., B is thicker and will stick to walls, then comes a number from 1/2 to 2 , the number corresponds to pot life, all of it should be given 24 hours to cure out. It is a two part adhesive / sealer very similar to 5200 except for the color and of course its two part, but it is at least as tenacious as 5200, maybe moreso.
PRO-SEAL FUEL TANK SEALANT P/S 890 B2 from Aircraft Spruce

[Cheechako]

Possible to cut the top off and install 1 or 2 plastic tanks inside? Might be a better long term fix.

[DeepFrz]

Doubtful you will be able to do a successful repair on a 30 yr. old tank while it is installed.

West systems does have information about building tanks and also a warning that its not a great idea.

[brianlara 3]

Originally Posted by DeepFrz

Doubtful you will be able to do a successful repair on a 30 yr. old tank while it is installed.

West systems does have information about building tanks and also a warning that its not a great idea.

Deep, are you saying that epoxy inn't in fact impervious to diesel? It was 7 years ago I gave away my last WEST book.
I'm interested. Reason being that a ply/fabric/epoxy tank is something I may have to fabricate one day.
Please, enlighten me if you will. I really do ( meaning ..honestly) love being proven wrong. I see it as a learning opportunity.
Cheers Brian.

[brianlara 3]

Midnight in Winnipeg, 5pm in Sydney Oz.

[GILow]

Originally Posted by brianlara 3

Midnight in Winnipeg, 5pm in Sydney Oz.

4:30 pm in Adelaide! As I've always said, 30 minutes and 50 years behind the East Coast.

Brian, I recently built a diesel day tank using pre-made polyester resin panels. It has turned out a treat. It has only been in the boat a couple of months and may yet explode like a stick of TNT taking out me and a marina full of luxury power boats, at least according to some advice here on CF, but if you like taking insane base-jumping, spelunking, extreme ironing type risks it may be a thread of interest to you.

No help to the OP in this case, so apologies for the thread drift.

To compensate, to the OP, I liked the idea of hacking off the lid off the steel tank and putting in a suitable rigid poly tank. Note I say rigid. Having spent a number of days removing once flexible and now rock-hard and rigid tanks from the keel of our boat I am not all that keen on the bladder type of tank.

Matt

[GILow]

Originally Posted by Cheechako

Possible to cut the top off and install 1 or 2 plastic tanks inside? Might be a better long term fix.

^^^^^^ This!^^^^^^^

[brianlara 3]

Sure Matt, I watched your day tank developments with interest.
Provided you assembled the components with epoxy & woven tape it will outlive the planet (strewth, mocker).
That spelio.... thing, is that caveing/ diving? If so, crazier that rounding The Horn in a c something t. Woops!!
And I can't remember what the rest.....yes I can, found my way back....Matt, that link says that the server is buggered.
How about the "sail or wallow" thing ?

[GILow]

Originally Posted by brianlara 3

Sure Matt, I watched your day tank developments with interest.
Provided you assembled the components with epoxy & woven tape it will outlive the planet (strewth, mocker).
That spelio.... thing, is that caveing/ diving? If so, crazier that rounding The Horn in a c something t. Woops!!
And I can't remember what the rest.....yes I can, found my way back....Matt, that link says that the server is buggered.
How about the "sail or wallow" thing ?

Dude, I didn't use epoxy. I used the extreme-ironing version. Polyester only. Which is why you need to be nice to me now because tomorrow.... BOOM! The trick is, the panels are only there to make it look nice, there's a continuously formed tank inside the shell made from uncured polyester.

If I am right I am in for years of happy motor sailing. If I am wrong you'll be reading about me in SMH obituary column.

Sail or wallow? Oh that one. Yeah, well, you know an old bit of Shakespeare that comes to mind... "Me thinks he doth protest too much".

[brianlara 3]

You used the right stuff obviously, from the right people....easy peasey.
Yes, protesteth......
At the age of 16 Jessica Watson weren't dooin' too much "wallerin'" in Don McIntyres boat off Cabo Hornas & and the other great capes.

[DeepFrz]

Originally Posted by brianlara 3

Deep, are you saying that epoxy inn't in fact impervious to diesel? It was 7 years ago I gave away my last WEST book.
I'm interested. Reason being that a ply/fabric/epoxy tank is something I may have to fabricate one day.
Please, enlighten me if you will. I really do ( meaning ..honestly) love being proven wrong. I see it as a learning opportunity.
Cheers Brian.

No, that's not what I'm saying at all. The instructions for building a tank with epoxy are on the West System web site. They put the instructions there because they knew that people would be building fuel tanks from their products, no matter what the precautions, and so wanted it done right.

I do not know if the precaution is still there.

[DeepFrz]

Yes, the instructions and precautions are still there.

WEST SYSTEM | Modifying and Customizing Boats - Wood/epoxy composite tank guidelines