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Diesel tank pitting

PostPosted: Sat Apr 14, 2018 12:58 pm
by mike cunningham
Anyone who has read my saga regarding white smoke and injectors will know I have had water in my fuel tank. This has resulted in pitting of the tank interior in a small area around the fuel uptake where the tank is deepest. Those pits are eventually going to turn into leaks. The vast majority of the tank is in perfect condition. I am wondering if the community thinks it is feasible to remove the tank and ask a fabricator to cut out the small pitted area and re-weld a replacement plate in there. It seems crazy to have to replace the entire tank to fix about 4 square inches of pitted interior surface.

Re: Diesel tank pitting

PostPosted: Sat Apr 14, 2018 9:38 pm
by rvivian
Hi Mike -

Before you cut into a non-leaking diesel tank maybe you should consider coating the affected area (if you can reach it) or try coating the tank innterior with a specialty lining material like: ... lletin.pdf to try and prevent leaks from developing.

My tank started leaking a few years ago and I took it out and replaced it with a new one from the original tank manufacturer used by Freedom located in Florida. They still had the original specs and dimensions and shipped me a new tank matching the original for about $750.

Re: Diesel tank pitting

PostPosted: Sun Apr 15, 2018 2:35 pm
by mike cunningham
Yes, I can get into the tank and get at the pitted area. Thanks for the link. I will check this out. I was wondering, but forgot to ask, about possible interior coatings.

Re: Diesel tank pitting

PostPosted: Mon Apr 16, 2018 1:17 pm
by Lionel7
My surveyor a few years ago told me about a liquid paint like product that you can use to line the interior of fuel tanks. It is a product designed for the aviation industry so my thinking was if it worked in that highly regulated environment it would work in a marine environment. You might be able to just "paint" the area of pitting at the low spot in your tank if you have a suitable access port to reach it.

Freedom 21 Maketea
Previously Freedom 28 Free at Sea

Re: Diesel tank pitting

PostPosted: Mon Apr 16, 2018 2:00 pm
by JohnReinagel
Hi Mike,

On my last sailboat, a 1973 CAL 29-2, I used KBS Coatings on the leaky aluminum diesel tank with great success. The tank does need to be removed from the boat and is quite a process, but the results were impressive. The coating felt hard as a rock but when I bent some test patches that I painted onto other surfaces, they flexed without issue. As a matter of fact, I kept bending to see if the coating would crack, it did not. The inside of the tank looked brand new of course and I had enough material left over that I coated the exterior also. The tank held pressure as expected. If I recall the kit I needed for a 20 gallon tank was under $100.00.

Re: Diesel tank pitting

PostPosted: Tue Apr 17, 2018 6:38 pm
by Erik
To All
I am currently removing my fuel tank in a 1983 Freedom 33 Cat Ketch. What a PITA the tank is beyond repair. The tag on the tank is unreadable does anyone know who made the tank. Any help would be appreciate.

Thanks Erik
33 Cat Ketch # 74

Re: Diesel tank pitting

PostPosted: Tue Apr 17, 2018 10:53 pm
by drcscruggs
I don't have any idea who made the tank. Having said that I think it would not be too difficult to find a fab shop to make you a new one using the old one as a pattern. I think I would do that. I am near Houston and there are many fab shops around here. I believe due to the petrochemical business. Best

Re: Diesel tank pitting

PostPosted: Wed Apr 18, 2018 10:35 pm
by rvivian
The tank for my 1986 Freedom 30 was manufactured by"

Aluminum Fabricated Products
PO Box 1088
Perry, Fla 32347

904 584-6898

I ordered a new tank from them in 2011 and they still had the tank specs and dimensions. The new tank matched the original and dropped right into place.

Re: Diesel tank pitting

PostPosted: Fri Apr 20, 2018 7:57 pm
by Erik
Thank you will give them a call Monday