Leaky fuel tank; what to do?

[yodave]

I was checking over my boat today. It has two fuel tanks that I filled up (so over 80 litres each side/tank) before crane out. On the port side I found what looks like a pinkish-coloured liquid. This doesn't seem to have escaped into the bilge or elsewhere. See below>

It seems likely to me that it’s diesel, and therefore I’m thinking that I might have a leaky tank. She'll be on the hard-standing until early April.

Questions:

• Is there any way to check this?
  
• Is there any way to fix this?
  
• Is there any urgency to take remedial action?
  
• If there is no emergency, should I use the fuel up over the coming season and then retire or replace the empty tank?
  
• Any other suggestions?

Thanks as always in advance for any and all opinions and advice.

 

[PeteCooper]

My brother had something similar so we removed the tank with a view to getting it repaired. A new tank wasn't very expensive, I can't remember the amount, and seemed the best solution. He had his made at West Of Scotland Engineering in Glasgow and they made a very fine job of it. The new one fitted perfectly.

 

[yodave]

Hi Pete,

Thanks for your response. Good to learn about West of Scotland Engineering.

Replacing the tank is an option, but I can't see how the existing tank would come out without first removing the engine etc. There are already another two large tanks down there which may be legacy fuel tanks. So there's no room to leave it in situe and add another alongside.

Thanks again for your advice : )

 

[BabaYaga]

You should be able to determine if it is diesel just by sniffing.
If so, as the leak was discovered only after filling up, suspect a leak from the tank top, a fitting or a hose.

I had a slight and intermittent leak from my diesel tank the other year. Took it out in the winter and used a bicycle pump and some soapy water to trace the leak. Turned out to be one of the bolts holding the fuel gauge on the tank top – therefore only leaked when the tank was full.

 

[CAPTAIN FANTASTIC]

I had the same problem last year. My Macwester has two large bespoke steel tanks, one has developed a leak. I considered all available options; removing the tank was not a problem; when I took the tank out, it was in good condition apart from the bottom corner where the metal was badly pitted due to corrosion. The tanks are tilted so the bottom of the tank is the corner; which is always wet and therefore more likely to corrode.

I decided to repair the tank myself; I used an electric drill with wire brush and cleaned it down to new metal. I washed the inside and the outside with acetone; so the tank was dry and oil free. I then covered it with several layers of woven cloth and used good quality epoxy (not polyester resin). I then painted the tank with several coats of oil based paint. I had no problem at all last year with the tank and I am it will outlast me. I may have to do the same with the other tank soon.

In the main, It appears that repairing the tanks is not a problem; the problem is getting access to the tank.

 

[yodave]

BabaYaga: Good point. The leak maybe at the top, or in theory it could be that the diesel (if it is diesel) has found it's way down from an overfill when we filled the tanks up just before crane-out. Next time I'm over at the boat I'm going to obviously check to see if the spill is any bigger, and also try to spot what fittings are near the top of the tank. Thank you very much!

Captain Fantastic: To be honest I hadn't even considered repairing the tank myself, as I had assumed that would involve steelwork. I guess I could consider emptying the tank, and making a repair as you have ...but the problem is going to be getting the tank passed the engine, as I'm not convinced making a repair in situe is feasible. Food for thought though, and I'll certainly keep your experience and advice in mind when I'm making a decision. Thanks very much for your input!

: )

 

[yodave]

I've been thinking about this overnight. Just a couple of points to add.

1) The last sail of the season was pretty rough in a force 8, so the boat and it's contents took a bit of a bashing ...and this means that the diesel would have been sloshing around vigorously.

2) The anti-freeze that I added during winterisation was pink.

 

[CAPTAIN FANTASTIC]

You may be lucky then; the tanks tend to corrode at the bottom, therefore, if you had a leak in the tank, it would have been very obvious by now, with diesel everywhere.

However, if you have to repair the tank, i strongly suggest that you remove it first, as in situ repairs are most likely to be temporary.

 

[PTB]

Pitted Bottom Cornrer of Tank

Captain Fantastic, did you epoxy and cloth the inside and the outside of the bad corner? I have a similar set up to you and whilst I have no leaks, the bottom corners have some minor pitting from, presumably, a bit of water settling down there from time to time.

Many thanks Phil

 

[CAPTAIN FANTASTIC]

I covered the outside of the tank only. I used 3 inch woven cloth strips to cover the corners carefully, using several overlapping layers; two hours later I added a few more layers and eventually I covered the lot in a woven cloth and epoxy.

I made sure were no bubbles, no dust, no moisture and the metal was very clean and dry using acetone. I used West epoxy system. Excellent results.

 

[yodave]

Captain Fantastic: The liquid in the photos is maybe 3-4mm deep at it's deepest. I assume that it's gathered there over time since crane-out in October. Hopefully I'll be able to identify the liquid at the weekend whilst I'm cleaning it up. Then I'll wait to see what, if anything appears over the next few weeks.

Thanks again for your help with this.