Diesel fuel leak

[NWpilot]

I have a 1979 30' sedan with twin Volvo diesels. I've been overhauling the battery system and when visiting the boat the other day I opened the lazarette and found about 5 gals of diesel. It appears the port side tank has sprung a leak. I pumped out the diesel I could find and laid down absorbent pads to get the remainder.

I know aluminum tanks can corrode but wondered if there is a hose connection at the bottom of the tank. The main source of the leak is directly under the tank best as I can tell. Logic tells me all connections are on top of the tank.

The smell inside is still overpowering and I'd like to set up a fan to move air outside but, will arcs from electrical equipment set off diesel fumes?

I don't know if these are the original tanks. Were originals aluminum?

 

[Comodave]

Diesel tanks can have connections at the bottom, gas tanks cannot. I would pump that tank dry immediately, fines for spilling fuel can be tremendous. Then get an assessment of the tank. Probably will need replacement. If you fix a leak in one place, soon you will likely have another leak somewhere else. Clean up the fuel as best you can, IOW get all of it cleaned up. Then use some PureAir to treak the location for smell. PM the Head Mistress on smells. Get her book on Amazon. Peggie Hall is the author. Title is The New Get Rid of Boat Odors.

 

[Cold Duck]

I had a leak in my 150gal aluminum tank. I looked for 2 years for a solution thinking I would have to cut up the tank and remove it, maybe install a bladder, etc. Aluminum tanks usually are built by forming the tank in a "U" then welding ends and top on after installing baffles. It is possible for a hole to form in the solid sheet but more likely the leak is coming from a weld joint. If your tank is like mine, you can't see squat as to where it might be. I would look at the welds at either end first. I cut an inspection hole in the top big enuff to get my arm in and reach the weld end that I believed to be the culprit. A guy recommended "Seal All", Ace Hardware carries it. Looks like and smells like a giant model airplane glue tube. It is oil/gas resistant. I smeared this over the entire bottom weld particularly where I thought the leak was. You actually cut up strips of old Tshirt and saturate it and lay over the leak like a gasket. Kid you not, this stuff works, only $6.95 a tube. My friend who recommended it says they actually sealed a gas tank in a Jeep out in the desert with it to get home. So, if you can get an inspection hole over the leaking area, give it a try. You got nothing to lose but $6.95. Do need to dry and clean area as well as you can but my leak has been holding for over a year now. I am a believer for sure.

 

[Cold Duck]

Oh, don't worry about a fan blowing in the bilge, that's why we use diesel, fumes are not explosive like gas.

 

[tiltrider1]

Most likely water has gotten under the the tank causing corrosion to eat through the bottom of the tank. It is possible that a weld has cracked. There are companies that can cut an inspection port in the tank and then epoxy coat the inside.

Removing the tank inspecting, cleaning and repairing or replacing with new are the best options but this is not always easy. 5 gallons of diesel sounds like a pretty serious leak, I am guessing you will find more corrosion than can be patched.

I have fixed several fuel tanks over the years but in all my repairs we removed the tank to get access to make repairs. While the tanks did not always leave the boat they did move far enough so that we could access all sides.

One repair was as simple as welding a patch on. Another required cutting the bottom off and welding a new bottom on. The latest repair was using 3 different epoxy’s and fiberglass to repair a drill hole gone wrong.

Run your fan, diesel fumes won’t ignite from a spark.

 

[Comodave]

I have taken a road flare and stuck it into diesel and it didn’t ignite. Unless it is already heated up it is very difficult to ignite it.

 

[NWpilot]

OK, so I'm thinking I can run for now on the starboard tank and when it warms up I will pull the tank. I'm pretty sure I can but have to remove the water tank and the port exhaust system to access it. I was planning on removing the water tank to replace the fuel lines behind it anyhow.

There is no fuel left in the tank and I pumped about 12 - 15 gals out of the hull. The leak was totally contained.

It feels good to confirm that I can't set diesel fumes off easily.

Thanks eyeryone.

 

[tiltrider1]

When the tank is pulled update us with a few pictures.

 

[Pete Meisinger]

This will scare you at first but don't worry, no danger.

To remove the tank or gain access to the inside grab your sawzall and saw away. You will not ignite the diesel fumes or residue.

Some people use a cutting torch but that would not work very well on aluminum.

pete

 

[Cold Duck]

If you can pull the tank you are way ahead. That opens a whole new area of repair possibilities. Rather than use a sealant for a cracked weld just have it rewelded for sure. Good luck.