Cleaning a submerged fuel tank...

[Alison Tuna]

It's not my boat. If it was I would rip it out and replace it...

But I am curious if any if you guys have had a boat go down and then had to clean out and revitalize the tank...

How do you do it?

 

[Frank]

I've only done tanks that were removed from the boat. If your buddies tank can be removed easily this would be the best way to go. You can move the tank into different positions and look through the sending unit hole to see if any crap remains after cleaning. Get rid of any remaining fuel/water in the tank. Stick a steam jenny nozzle in the fill line and sending unit holes and let it run for awhile. Empty out the water best you can and use a shop vac (diesel only) to suck out the rest. Let the tank sit in the sun or a heated area and any residual water should evaporate over a couple of days.

 

[Alison Tuna]

One if the reasons we went for a new tank in the last boat is because it was gas and I was afraid of the vacuum and explosions etc...

So there are no soaps or metal etching components involved?

 

[Frank]

I just want to stress again, vacuum with diesel only. The vacuum isn't a necessity either, just speeds things up. On gas tanks I've duct taped clean lint free rags to sticks and feed them in to sop up excess water. Move the tank around so the residual water reaches the rag.
Steam only has worked well for me. It's a very efficient cleaner. You can also pour some Gumout in and slosh it around when the tank is dry.

One if the reasons we went for a new tank in the last boat is because it was gas and I was afraid of the vacuum and explosions etc...

So there are no soaps or metal etching components involved?

 

[Frank]

How big of a tank are we talking about? Presuming it's aluminum I would want to take it out just to make sure all contact points with the hull and mounting hardware are salt free. Stagnant salt water against the tank will certainly cause problems down the road.

 

[Alison Tuna]

70 gallons

 

[Frank]

Not an inexpensive tank to replace. If it were mine I would yank it and check the exteriors condition. If there no signs of corrosion at mounting points or hull contact points I would do my best to clean it. Any deep pitting get rid of it. A lot depends on the age of the tank too. If we are talking about an older boat with a foam encased tank chances are it's shot anyway.