Rusty In-Keel Fuel Tank.

[andreaswolfman]

Howdy ho...
I have a 40 year old steel boat with an in-keel fuel tank thats rusty inside. I cant access inside it so I cant paint it or coat it with a brush.
If it rusts too much it risks the whole keel falling off.
So I want to stop using the tank and somehow stop any further rust. I was thinking if I fill it with antifreeze? Dose anyone know of a product that can deal with this without having to access the tank?

[Pete7]

If its rusty, then there is water or has been water, in the tank. Clean it out and use it as a fuel tank with clean diesel.

[tkeithlu]

You do have a diesel, right?

Is this tank, as I think you imply, the keel itself? Then there is a secondary issue of the strength of your keel.

My steel keel is actually filled with fresh water and sealed. In that case, the other component, oxygen, can't get to the steel to make rust.

[markwesti]

I have no idea if this would be worth it for you , but on the other hand if you had to buy a couple hundred dollars of this and it fixes your problem not to mention saves the boat , I'd try it . . There is a product called Evapo-Rust buy enough to fill your tank and put it in . I have used Evapo-Rust and it works .
https://www.homedepot.com/p/Evapo-Ru...R013/300223745

[boatpoker]

Originally Posted by tkeithlu

You do have a diesel, right?

Is this tank, as I think you imply, the keel itself? Then there is a secondary issue of the strength of your keel.

My steel keel is actually filled with fresh water and sealed. In that case, the other component, oxygen, can't get to the steel to make rust.

Stagnant water accelerates corrosion.
https://pdfs.semanticscholar.org/4bf...32a4673934.pdf

[Pauls]

Any steel chamber can be protected from internal rusting by simply sealing it closed. The amount of trapped oxygen inside is very small and when it is exhausted by oxidizing the steel then there will be no more rust. This is a common approach for building steel masts.

That said, I agree with Pete 7. If you need the tankage, remove the water and install something so that any future water can be removed. The diesel will then do a good job of protecting the steel. If you don't need the tankage, then suck it dry and seal it off.