steel gas tanks

Farout

Member
Joined
Nov 1, 2007
RO Number
28893
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4
Looking at a boat that has two 90 gal steel gas tanks will these tanks be a problem? My concern is rust causing a leak.
 
steel tanks are not ideal, the concern is not really just rusting from the outside but from the inside because of water at the bottom

It would help if you'd tell us what kind of boat, year, location of the tanks, etc... if they are easy to get to, you may want to consider making an offer based on possible replacement but if the tanks are buried in and require a lot of cutting and/or engines removal, it may not be a viable option.

depends on the boat...
 
The boat is a 1974 Uniflite 34 foot. The tanks were installed in 1999 it has twin 454 crusaders the tanks sit to the outside of the engines they would have to be pulled to get to the tanks.

Other than the gas tanks the boat is in great shape wife loves the layout.

Thanks for the reply..
 
Yes, eventually they wil fail. Most seem to last about 20 years, give or take a decade. The installation/environmental factors will have a greater determiniation on their lifespan than the material.
 
I'm surprised they would have used steel as a replacement in 1999. I still have my 1978 galv steel 50 gal tank. Every spring I inspect the outside and use a brush on anything that remotely looks like corrosion and spot paint the area. Every few years I brush the welds and paint them even though they appear clean. I'm also parranoid and check the tank for leaks all the time.
 
Hey guys go down to the local commercial docks and look at all those all welded steel tank barges carrying gasoline, etc., every wonder how they carry their cargoes? They use the steel structure of the hull for cargo spaces. They may have double bottoms and sides, but the material is all steel. Mild steel is fine for a fuel tank. Proper plate thickness, proper design and proper coatings are the key. If the tank is properly designed and built, it should have a clean out port. If you are concerned open the port and inspect. Rent a Hot Water Pressure Washer and clean the inside of the tank, removing any scale. Vent it well, check for the LEL of hydrocarbons and if gas free, knock the snot out of the tank with a chipping hammer, if the plate yields and dents it is getting thin and should be renewed.
 
The tanks are listed as epoxy coated so this would be a good thing ?
 
On steel....maybe. The problem with epoxy coating steel is that the tough surface both works for/against. It works great and is better than normal paint, right up until the day that it forms a crack or hole in its surface. That day is usually far longer than just paint. But...here's the rub. The rest of the expoxy surface remains intact and rather tough. The crack or hole allows corrosion to start and now the corrosion works UNDER the epoxy instead where you can't always see the true nature of the problem. If you can see the tanks, inspect them and the installation keeps them dry, they will live a long life. If they get wet, eventually the epoxy will "bubble" and then you need to act quickly to remove the epoxy in that area and recoat with "something". Personally I like paint. It doesn't last as long, but when it starts to fail its obvious. It stains and cracks and you can just slap some new paint on.

L.Keith is right...sort of. On a commercial boat you would think nothing of cutting out a section and welding a new plate in. Maybe same day. On a glass boat, you can't do this economically. Steel is a good material, but it has its characteristics.

If I were you I would, again, check the installation. They need to be bone dry with good air circulation. If so, the will live a long life. If you have ANY reservations on the installation, posture for a discount to allow for a pro-rated replacement. Those tanks ARE 7 years old after all and most people will consider steel to be a liability in a glass boat. Think not of the condition now, but what will YOU have to deal with selling the boat when they are 15 years old. They will probably last until the 454's give out at which time the tanks can be renewed at the same time. Prolly not a deal breaker.

bp
 
Oh, I forgot, production boat builders charge tons of money to mass produce a product equipped with fuel tanks of limited useful life that cannot be removed and renewed without major surgery to said product.
 
There's the L.Keith I'm used to. Must have been a momentary lapse of reason?

bp
 
You known Ghostie, there was time when boats were built with fuel tanks that would last longer than 10 to 15 years. The builders used a miracle material that would not corrode, would stand up to salt water, could be welded without exotic proceedures. Most yachts had fuel tanks constructed of this magic material. When this average priced yacht exceeded it's useful life and had to be run up on mud flat somewhere, it was not uncommon for the owner to cut out these fuel tanks and reuse them in a new boat. It's really too bad that man kind some how lost the formula for this magic material and due to bottom lines and profit margins begain to rely on materials that pitted in salt water and would crumble in less than twenty years. Can you guess the miracle material?
 
Ghost makes a very important point--and that is the installation of the tanks. Not only the being properly installed, so that the tank does not sit in water on its bed and air can circulate freely under the tank, but that a proper material is used to space the steel tank off the floor and that the top is slanted, so that water does not pool on the top. Steel in commercial vessels is much thicker than the metal used in recreational vessels--so in the commercial vessels a little rust doesn't make much of a problem.

I have seen many steel fuel tanks which were placed directly on plywood--and this is a recipe of failure when moisture gets under the tanks. Unfortunely many times the engine room vents are right over the steel tanks, and spray comes in and gets directly onto the tank. So it is the condition, the installation and way that the tank which has been cared for.

If a tank has been properly drained and cleaned, rust from the inside out, should be minimal.
 
Frank:

Check on the Uniworld web site. The issue has been discussed several times. The original tanks were made by Tempo specifically for your hull. They had an epoxy lining inside and tended to rust on the outside bottom because they sit directly on the fiberglass chine stringer. Any water than ran down from a faulty fill gasket would just sit under the tank along with any condensation. I replaced the tanks in my '73 Uniflite in the late '80s and used 1/2-inch thick rubber strips to elevate and allow an airflow under the tank. The only problem now is water inside the tanks from condensation that might penetrate the lining and rust the tank from the inside out. This doesn't seem to be a problem as even after a rough water trip, I don't see any water in the Racor water seperators. Like everyone says, if you monitor the tanks regularly for evidence of rust, they will last indefinitely.

Gene
 
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