Fuel Tank Leak

I have developed a pin-hole leak in my port tank. These black in tanks have lasted well over 25 years however. Unfortunately the leak is on the bottom where I cannot get to it.

Any suggestions on a simple repair.

Unfortunately the leak is on the bottom where I cannot get to it.

Lots of solutions if you can get to it .

If you cant replacement or installing a bladder is about it.

marinetrader said:

...Any suggestions on a simple repair.

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Google "CS3204-B2". Keith on this forum has used it successfully. I can post a few pictures tomorrow from another leaking tank after it used the sealer.

Marine tex works great. A friend of mine had a leak on bottom of his tank on his diesel truck. He drained the tank, cleaned the corner where it leaked and then sealed it with marine tex. It's going five years and still does not leak. It's impervious to gas and oil!

marinetrader said:

I have developed a pin-hole leak in my port tank. These black in tanks have lasted well over 25 years however. Unfortunately the leak is on the bottom where I cannot get to it.

Any suggestions on a simple repair.

Click to expand...

If you have one pinhole...how close are you to the second pinhole?

THAT would be the question that answered my repair direction.

I cant help here but this is my biggest worry with my 1989 tanks. I plan to run my tanks low, pump one over and then go in to see what I can with a boroscope camera this winter. The next step is to install manways.

Having replaced the tanks on my 1985 Krogen last year I admit it is neither fun nor cheap. However the question of repair or replace gets even more complicated when you consider the eventual resale of your boat. Even if the repair is successful and lasts for your use of the boat, prospective buyers are going to ask about the tanks. In this market buyers have a choice in boats and may discount their offering price on your boat by more than the cost of the replacement. This is the old real estate situation of the guy who puts up with a leaky roof for years, patching the roof, repairing the inside damage and then when he sells the house having to pay for or install a new roof.

As to the issue of the second pinhole developing when I replaced my tanks it was the starboard tank that was leaking (slightly). We cut it out and could see the rust. When we went to cut out the port tank we started to remove the framing and all of a sudden the port tank split along a non-visible rust line and dumped the water in the tank into the bilge. Obviously the rust had affected both tanks.

Good luck with your decision.

Marty

From what I understand, the Flamemaster CS3204-B2 is the consistency of warm peanut butter. These pictures were taken from the inside of a black iron 350 gallon diesel tank. They found the leaks/pin holes on the inside at the low spot of the tank at the seam. After cleaning, a layer of cloth tape was epoxied at the seam and then coated with the CS3204-B2. I have heard the stuff has been used to repair a bullet damaged fuel tank and also used to coat new tanks.

psneeld said:

If you have one pinhole...how close are you to the second pinhole?

THAT would be the question that answered my repair direction.

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X2. If your tanks are shot forget about the manways.

sunchaser said:

X2. If your tanks are shot forget about the manways.

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Ditto

Thanks for every ones thoughts.
The leak is in an area that is totally inaccessible to get to.
So I have resolved myself to using a few diapers for the short term and replace the tanks; if there is one hole...likely another soon. And the STB tank......probable going to leak too.
So that being said....to get to the tanks from the inside will require moving both the engine and genset...ouch!
So am thinking we cut the hull on the exterior, replace the tank and repair the glass.
As anyone done this or know of any details?

You are indicating the current tanks are too big to remove and replace without moving both the engine and the genset. This is true on many trawlers but on some you can cut out the existing tanks in pieces and then replace the two tanks with four smaller tanks. I did this with a Krogen 42 and elected to go with smaller tankage (700 US gallons to 450 US gallons) as I am not crossing any oceans.

We were able to keep the main engine in place.

Marty

Marty...though about that....my engine room is tight......but will look at that too.....thanks for suggestion

I had my starboard tank repaired with aircraft fuel tank sealer maybe 8-9 years ago. I figured if it's good enough for the FAA, then it's good enough for my trawler. Opened the existing inspection port, then installed new ones in each baffled area. Cleaned out the old gook, solvent washed then sanded and applied the coating. It's fuel resistant and flexible. A good alternative to replacing tanks.