Anyone ever had a steel fuel tank fail?

Hi All,

My ship is 40 years old this year. The original steel fuel tanks have no "rust" to speak of. Old looking steel yes. The original SS water tanks are also in good shape. Has anyone ever had one of these tanks fail? I can only imagine the monumental task it would be to yard out these steel tanks.

Dave

Worked for a company in Key West that repaired steel shrimp boat tanks. They were big enough to torch a hole in the side so we could crawl in and weld patches. Shrimpers would empty the tank while fishing, fill it half full of salt water and a jug of Joy dish soap. By the time the got to shore the tanks were super clean.

gingerly scraping off surface corrosion on sides of my 33 year old IG 125 gallon tanks. Mostly minor surface pitting that I'm hitting with scotch brite, wire brush, and 320 grit. Area under stbd fill pipe looks worse, plan to tackle that today. Plan to use a borescope to check bottom if possible, hull sides, then interior.

Monumental task to me is what do I do with 250 gal of diesel if I find serious corrosion? I'm guessing I can cut the tanks up into small pieces with a stack of cutoff wheels and good earmuffs.

Stuffing boxes throw up a fine mist so I'm going to macgyver some type of plastic cover out of milk jugs?

I helped a friend with a leaky steel tank in a older GB. Rain water leaked on to the top of the tank rusted though and then rusted from the inside. It was a mess. My feeling is if they are clean and dry they should last a very long time.

Fred P..........

I have a rusted out one now . I am weighing my options now . I'm not sure I will ever need 300 gallons.

I joined a long list of owners of 30 year old trawlers who had to replace their tanks. But a pain and a great expense.

Fredp said:

I helped a friend with a leaky steel tank in a older GB. Rain water leaked on to the top of the tank rusted though and then rusted from the inside. It was a mess. My feeling is if they are clean and dry they should last a very long time.

Fred P..........

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I had a Bruce Roberts 44 with steel hull and the hull was one side of the steel tanks. Water from the galley rusted thru the top and then thru the bottom. The choices I had were to cut the tanks out along with the side of the hull and replate the hull, or put bladders in the tanks, or sell the boat. I sold the boat.

http://www.trawlerforum.com/forums/s6/replaced-fuel-tanks-26430.html

Check out my post from a couple of years ago.

Failure of a steel tank. Originally Bay Pelican had two 350 mild steel tanks. When the starboard tank started leaking I decided to replace both tanks. I relied on the port tank until it was time for the replacement. The starboard tank had been filled with salt water to level the boat. After draining and replacing the starboard tank we started working on the port tank. Since we were using blades to cut the tank we rinsed the tank with water leaving a good 6" of water at the bottom.

When we started pulling the plywood off the engine room wall to get to the tank, the tank burst along a rust seam dumping all the water which was in the tank into the bilge. If that burst had occurred underway a week earlier when there was diesel in the tank the result could have been catastrophic.

There is a company here in the PNW called FELIX industries that coats the inside of leaking diesel tanks with a proprietary product. They have a long list of success stories and the job can be done in place.

Just finished checking bottom exterior of tanks with borescope. Two limber holes under each tank but essentially inaccessible. Wish I hadn't looked. Plenty of corrosion.

There was a lot of corrosion around the fill pipes on the top of the tanks but scotch brite and rustoleum took care of that. Unlikely a pin hole in the top will dump 125 gal into the bilge.

The ext bottom is another matter entirely. Just a question of when, not if. I think I can get several more years but hours through a pounding sea is going to have me in a state of anxiety. I might rethink next fall's project list.

tiltrider1 said:

There is a company here in the PNW called FELIX industries that coats the inside of leaking diesel tanks with a proprietary product. They have a long list of success stories and the job can be done in place.

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There is no reason such a repair cannot be done successfully: riveted aircraft structures have had wet wings for decades. Polysulfide sealants can be amazingly effective when used correctly with the proper preparation, priming and cure. The problem comes in getting access to do so, and the time needed and resulting expense of doing a proper job under very difficult conditions. It is one thing to spend tens of thousands on a million dollar aircraft, it is quite another on a TT....

My original 30 year old stainless tanks corroded from the bottom exterior due to them sitting directly on an unventilated surface and moisture collecting in under the tank.


I replaced both tanks without much trouble when I had the engine out. It would have been a much more difficult job with the engine in place.


New tanks were mounted on tapered strips of plastic decking to allow ventilation, and to slope tanks towards the drain valve on the new tanks. It should be now be good for the life of the boat.

Fuel tank

Two photos should be included. The problem starboard and clean Port 200 gallon each tank.
First noticed an odor then a small stain on white oil absorbing towels. No easy access, used a tiny camera and found dirt and corrosion on the top near the fill.... saws-all removed engine-room wall and then cut tank into many hunks, all looked fine till one of the last hunk, a fifty cent spot of rust and a pinhole very close to the tank bottom.

I’ve postponed repairs.... mulling, do I do both tanks now... one looks great..... if I only do one tank it’s going to be much smaller 50 gallon est. Need to go over and around Engine and generator..... I am not going to pull engine. $$$ thirty year old trawler in great shape, but value to costs...

So if I do one tank I’m thinking I’d use it as a Day tank, pump fuel from existing 200 gallon tank as needed. My head scratcher is balancing the vessel. What do use ballast? The removed tank weight est 400lbs empty. New tank >100 lbs.
Changing Fuel max 200 gal port side, 50 gallons starboard.
Any thoughts.

So What - went through this a couple of years ago - I feel your pain. I pumped the fuel off, had the yard circulate, filter, and drum it up. After all the QA (air pressure test, etc) on the new tanks and installation, pumped the drummed fuel back aboard. Didn't waste a drop.

One of my 125 gallon tanks sprung a leak on the old boat. They were in the laz and fairly easy to remove once the generator camo out.

Sand blasted to bare metal, had the bad spots cut out and replaced and a second access/cleanout on the top. Also added pick uos and returns for a polishing systemTwo coats of mil spec. epoxy primer and three coars of white epoxy. Looked great when done.

Also had to replace the stringers under the tanks but that is another story.


Rob

Photos 1 after sand blasting. 2 Holes, this section was cut out
3 two cleanouts per tank 4 ready to install. My great brother in law Dick helping seal cleanouts.

Capecodder said:

Two photos should be included. The problem starboard and clean Port 200 gallon each tank.
First noticed an odor then a small stain on white oil absorbing towels. No easy access, used a tiny camera and found dirt and corrosion on the top near the fill.... saws-all removed engine-room wall and then cut tank into many hunks, all looked fine till one of the last hunk, a fifty cent spot of rust and a pinhole very close to the tank bottom.

I’ve postponed repairs.... mulling, do I do both tanks now... one looks great..... if I only do one tank it’s going to be much smaller 50 gallon est. Need to go over and around Engine and generator..... I am not going to pull engine. $$$ thirty year old trawler in great shape, but value to costs...

So if I do one tank I’m thinking I’d use it as a Day tank, pump fuel from existing 200 gallon tank as needed. My head scratcher is balancing the vessel. What do use ballast? The removed tank weight est 400lbs empty. New tank >100 lbs.
Changing Fuel max 200 gal port side, 50 gallons starboard.
Any thoughts.

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I had small pin holes due to rust on the top of one of my tanks. Based on your pictures it looks like you have good access. I would degrease the areas, sand if possible, JB weld big hole and then Marintex the top. Look into POR 15 rust coating. You could use in and then Marinetex the top.

Greetings,
Mr. C. Hoo boy. What are the possibilities of putting in 2 or 3 50 gal tanks and plumb them together? Perhaps a stout box with a 150 gallon bladder inside?

I see what you're trying to do but you've taken 400+ lbs out of the starboard side as well as a +/- variable of another 1600 lbs in fuel. IF you put in the 50 gal day tank and ballast the starboard side, to level the boat, as you use fuel from the port side, you'll develop a starboard list with no way to correct it other than adding more fuel to the port.

I suppose you could add a port bladder and fill it with water ballast as necessary BUT that's a LOT of fiddling around IMO.

Thank you Dave, access was not good to start... the photos were taken with a tiny camera on the end of a stick..... the holes on the top were an extra find... it was the the the one at the bottom outside against the hull behind a few ribs... that was leaking, we didn’t find the hole till the tank was removed.

Mr. RT,
That been my headache, the 400lbs is easier, it’s the variable fuel load... I don’t burn much fuel 2+ gallons an hour, and carrying >100 gallons 50 a side is not an issue, .. but it’s when I want to pop over to Bermuda or cross an ocean ;-)..
It’s the possibility of wanting to Carry full tanks Bahamas.. or some how the 200 got filled.... by the next owner...

Thank you

Been there, done that. $12k later I have half the capacity in nice new aluminum tanks. It's only a matter of time and luck.

"Been there done that" too.

Have two aluminum tanks new as of 12 years ago.
Won't happen again on my watch as I pump out the water every 6 months or so. I use rubber fuel hose and a 4' piece of copper tube that I can bend so the end can be placed at the lowest corner of the tank where (if any) the water is.

The PO of my boat ran into the same issue, as well as other water damage, so to fix her cabin up structurally he had to spend quite a lot, so to remove and replace the tanks as well was going to be a bridge too far - especially in terms of resale value. This latter point needs to be kept in mind.

So, he did something I have not heard anyone else on here do, and if faced with the same issue beforehand, I'm not sure If I would have done this either, but it was the product of thinking outside the square, and proved a good solution, that did not break the bank, and kept costs reasonable, taking to account the likely price he could recover, (and I was willing to pay, of course).

He blanked off the original steel tanks, which were sound except for top rusting, left them in place, so they then became buoyancy tanks, which may well work to slow settling in a hull breach. They were too large (~ 2500L combined), and too high in the hull anyway in my view. He then converted the stainless water tanks in the forward part of the lazaret to fuel, (800L combined, and plenty for most purposes), and although he made do with bladder water tank in the lazaret, I put in two 250L food grade plastic water tanks between the fuel tanks. Both the fuel and water tanks are linked, and drain from the bottom, so self-leveling, and in the case of the fuel tanks, effectively self-cleaning, as crud cannot build up on the bottom.

The system works well, and the weight being concentrated in the after (most buoyant) part of the hull, the balance on the helm is amazing. This latter is an unexpected, or serendipitous bonus, if you like, but she will surf with finger light helm control in front of a large enough wave - I've seen her touch 11.5kn with no hint of broaching.

That conversion was over 18 years ago, and there have been absolutely no issues. So, for anyone faced with tank replacement. There are other ways...just sayin'...
Sure, purists who are anxious over resale will want to totally replace, but then consider the same issue, re-sale, versus what it will cost, compared to the best you could expect to sell for, and maybe the arithmetic comes out different.

Petro Clean in Bellingham, WA also does tank coating and repair. They opened my tanks when I bought the boat, put in access ports, cleaned the tanks, polished the fuel and declared them good to go for the foreseeable future. Dodged a bullet there.

"I have a rusted out one now ."

Rust failure from the inside , or the outside?

I had steel tanks on my N46.
I accidentally put water into one tank while trying to back flush the vent of the sanitary tank. LONG and unpleasant story. Had all fuel polished and tanks inspected. No rust, no problems in any of the 4 tanks.
The tanks were about 10 years old at the time.
Steel (black iron) tanks, if properly maintained, should last forever.

The fuel tanks on two nuclear subs I was on, never had a problem and on one sub, never refueled. Those diesels were seldom used but always very reliable when tested.
Basically, the fuel was as old as the subs..... 20 years +
They didn't worry about polishing the fuel. LOL The filters where nothing special.
We are small potatoes when compared to Navy ships.

Nomad Willy said:

... as I pump out the water every 6 months or so.

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Is condensation a big issue in PNW?

I don't think condensation is as big a problem here in the PNW. I've had three older boats with steel tanks and nary a problem. None of them had low drains, but I dip them on a somewhat regular basis with a water detecting paste made for home fuel oil heating tanks. I have never found an indication of moisture.


Tator

Question for the KK42 and GB42 folks. If you are faced with both a deck job and a tank job, is it a feasible option to pull the tanks UP and OUT? IOW, is there structural framing below deck that makes this very difficult?
I've been looking a buying one or the other. (yes, I know they are not close in performance)

Side decks on Kk42 are only 14” wide. What year are you looking at? The first few years were fiberglass tanks.

My current boat carries 2000 gallons in 4 steel tanks. 3 main tanks were built in 1942 and the day tank about 1970.
The secret to long life is a good outside paint coating and keeping water out of the fuel by using a conditioner. I entered my main tanks a couple years ago during a remodel. They were built w/o access ports and between 2 bulkheads. There was mild surface rust and some pitting in the bottom. The deeper pits I welded, but decided not to add a tank coating because so much material thickness still existed.
Commercial boats use steel tanks built as part of the structure and last the life of the vessel.