Stainless Steel Fuel Tanks vs. Aluminum, anyone with SS?

[Grady Wahoo]

Hi,

Grady White still had the drawings for my tanks (1981 Grady). I started sending them out for quotes last week, and talked to a glass guy about cutting,removing, reinstalling and painting my deck. The aluminum tanks have been replaced once by a previous owner, and now one has failed again. I believe cause part of the tanks are under the hatch gutters, salt water finds it's way down there. I'm estimating a couple of grand labor, tanks have been quoted in stainless and aluminum, $2000 for epoxy coated aluminum or $3000 for stainless. Yeah I'd rather spend the $2000 but I was thinking the $3000 would be a selling point, and guarantee future problems. But now I've heard a few negative comments on stainless, one was the corrosion resistance of the welds...

Any opinions on stainless gas tanks? And would you pay 50% more for them?

Thanks,
Mike

[jorgeparagon]

My boat has now 13 years old with the same SS tank ,never had a problem ,here in Brazil we use 23% of ethanol mixed with gasoline


good luck

[76GMC1500]

The Coast Guard frowns upon stainless steel fuel tanks, I'm not really sure why. They are rare and you'll never see one in a COI compliant commercial vessel.

If done properly, the corrosion resistance of the welds shouldn't be an issue.

[bayboater1]

Can you still get Monel tanks? If so, this might be another good option.

[t3rockhall]

My 1965 Pearson 28 had stock monel tanks. Never leaked a drop in the 20 or so years I had it. They had been "salvaged" by the time the newest owner bought the boat as a hull (for $500, I think), and he put poly tanks in.

[yottyboy]

The regulations are as follows:

Sec. 183.510 Fuel tanks.

(a) Each fuel tank in a boat must have been tested by its
manufacturer under Sec. 183.580 and not leak when subjected to the
pressure marked on the tank label under Sec. 183.514(b)(5).
(b) Each fuel tank must not leak if subjected to the fire test under
Sec. 183.590. Leakage is determined by the static pressure test under
Sec. 183.580, except that the test pressure must be at least one-fourth
PSIG.
(c) Each fuel tank of less than 25 gallons capacity must not leak if
tested under Sec. 183.584.
(d) Each fuel tank with a capacity of 25 to 199 gallons must not
leak if tested under Sec. 183.586.
(e) Each fuel tank of 200 gallons capacity or more must not leak if
tested under Sec. Sec. 183.586 and 183.588.

[CGD 74-209, 42 FR 5950, Jan. 31, 1977, as amended by CGD 81-092, 48 FR
55736, Dec. 15, 1983]

Sec. 183.512 Fuel tanks: Prohibited materials.

(a) A fuel tank must not be constructed from terneplate.
(b) Unless it has an inorganic sacrificial galvanic coating on the
inside and outside of the tank, a fuel tank must not be constructed from
black iron or carbon steel.
(c) A fuel tank encased in cellular plastic or in fiber reinforced
plastic must not be constructed from a ferrous alloy.

[Grady Wahoo]

Well Bill, guess I'll be buying off a certified vendor to make sure they're tested properly. I was wondering what kind of guarantee should be checked before install..

Uhm, do a,b or c refer to stainless? LOL

Do we have any fuel tank vendors on THT?

Anyone ever get poly tanks custom built???

Thanks guys

[kerno]

About stainless tanks: I can come up with two reasons not to have them. First, I had a boat with stainless tanks and had to have both tanks repaired after welds cracked. In both cases, I became aware of the problem when the fume sensor went nuts as a result of several gallons of fuel having leaked into the bilge.

The other problem is metalurgical. When you weld stainless, the welds need to be passivated or they loose a great deal of their corrosion resistance.

Given a choice, poly sounds pretty good, but I think you'll find it very expensive to have custom sizes made. The only other easy fix I know of is to have someone like Fuel Safe make up a bladder to go inside the tanks making them into fuel cells. The big problem is there are no baffles in a fuel cell. They usually fill them with foam blocks which are supposed to survive in fuel, but it does break down after a while.

I wonder if you could have the aluminum tanks hard anodized?

[ali'i kai]

For poly tanks, check in with Moeller Marine Products. They have a large number of stock sizes where one may suit your dimensions.

[Grady Wahoo]

Thanks guys,

I'm answering some of my own questions as the day goes on here. I just found myself on the Bertram 31 site, they say poly can't be fabricated for fuel (law), it must be molded, I'm thinking that means vaccum formed/tooling, ect.-no plastic welds....

I see plenty of catalog tanks with the angled bottom, to sit centered over the keel, I need left and right hand side tanks, one angle each bottom, not a "V". For the dough involved I don't want a reduced tank capacity.

Also, the Bertram 31 site put's stainless below monel.

Thanks for the ss weld info kerno, similar to what I heard friday night (hey it was friday night)

Looks like the epoxy coated aluminum is in the Wahoo's future!

Cheers

[76GMC1500]

t3rockhall - 4/23/2007 11:22 AM

My 1965 Pearson 28 had stock monel tanks. Never leaked a drop in the 20 or so years I had it. They had been "salvaged" by the time the newest owner bought the boat as a hull (for $500, I think), and he put poly tanks in.

Yeah, I'd imagine monel would work quite well but have you checked the price lately? Copper-nickel would do the trick and is somewhat cheaper.

Copper-nickel used to be used for evaporator shells all of the time. I know of one that has been in service for 30 years and is subjected to frequent load cycling (0psi to 24 inchesHg vacuum almost daily). It's also exposed to hot salt water brine (170 degrees). These are some of the absolute worst conditions you could subject a metal to and it has only cracked a few times.