Foamed in fuel tank? USCG requirement?

[greyg8r]

I am going to replace the 123 gal and 73 gal fuel tanks in my 1989 Grady White Sailfish.

I was vacillating between aluminum and stainless steel, both are about the same price. Then, after doing a THT search, I have decided to go with aluminum.

But, the stainless tank manufacturer says that the USCG requres that all (I don't know if he meant all stainless tanks or maybe he meant all fuel tanks) have to be foamed in and that if they are not I will take a beating when it is observed by a marine surveyor when I go to sell it. In http://www.thehulltruth.com/forums/t...mode=1#M551451 thread, which cites a marine survey page, they stress the importance of preventing crevice corrosion by keeping air between the tank and the sides and makes no mention of foam. This makes sense to me.

In other articles, it seems that stainless is more vulnerable to stress and weld cracks forming from jostling. So, foaming them in may make more sense. But, I have not read where aluminum tanks are vulnerable to cracks from jostling.

So, my question is: Does the USCG mandate that all stainless steel tanks be foamed in, or does the USCG mandate that all fuel tanks be foamed in, or is this manufacturer full of cr@p? I have done an extensive search on Google and found 33 CFR Subpart J but I don't see any clear requirement to foam in any tanks.

I would just as soon re-install the tanks the way GW did in 1989 (which lasted 16 years) but using plastic as suggested in the marine survey article instead of glassed wood.

And, once more, is going with aluminum over stainless the smart idea?

Thanks

[BW23]

I didn't have enough time to read each document but you can try this link.

Most of it might pertain to "large" vessels.

http://frwebgate.access.gpo.gov/cgi-bin/multidb.cgi

Keep us posted.

[jobowker]

I was always under the impression that foaming a tank in was a bad bad idea. The best way to wreck a tank is to surround it with a hydrophilic substance. Unless the foam is chemically bonded to the tank, capillary action will ensure that the tank is always wet.

In terms of aluminum vs stainless, I forget if it pertain to gas or diesel, but for one of them stainless is a big no-no. Most fuel tanks today are either aluminum, FRP, or cross linked polyethylene. Go aluminum, and don't foam it in. I would never buy a boat with a foamed in tank.

[warthog5]

Ah then you wouldn't buy 3/4 of the boat's out there. In the smaller boat's that a lot of us have foaming is the way to go and the manufactures have done this from the factory.
I'm not talking about a big battle wagon where you have gob's of room.
Most of these smaller boat's have no way to get air transfering thru the bildge. It's just the nature of the design.

Here's your list when renewing a foamed in tank.
1st do what ever it takes to keep water away from it.
This mean's making sure that the deck hatch is sealed properly and the pie hole cover's don't leak.
This is not a hard thing to do, but how do you know a couple of year's down the road if it's still really sealed? You don't unless you tear it apart. That's not going to happen.
So the solution is to seal the tank. Seal it with Coal Tar epoxy and it doesn't matter if a little water get's in there. Still you don't want the water in there.

Next is DO NOT use rubber aginst a alum tank to insulate it.
Rubber has Carbon in it. That Carbon will coroide a alum tank and has been the downfall for many a alum tank. The only corrosion was where the rubber made contact.

You can get Coal Tar Epoxy from Sherwin William's paint store.

You Do Not Foam in a poly tank! They breath and expand. They also perminate the smell of gas right thru the tank. They also have no baffles.

[jethro1]

Here is the law:

http://www.uscgboating.org/safety/bo.../183-516-a.htm

[WB2101]

I'm a big fan of Poly tanks, after having metal tanks for years (with the normal problems).

There is a slight odor, but it's very minor, IMHO. The lack of corrosion issues more than makes up for that. Mine only 3 years old, but I expect it to be a lifetime tank. Will let you know 20 years from now.

BTW, even with a Poly tank, the first thing I look at on a new boat is fuel tank access. Can I pull the tank without getting out a saw ?? I had one salesman tell me at a boat show, the factory had molded in "cut lines" to make the saw work easier. Not a problem on your Grady or my Striper.

[NothnButTheTruth]

What WartHog5 said. Most small boats today(30 feet & under) & for the last 20 years or more have been foamed in place. NothnButTheTruth

[SayYes]

I owned a Cape Horn with poly tank... I always smelled gas, strong smell but not leaking. My worry was that the lighter elements of gasoline were passing through the tank sides thus changing the fuel's chemistry. There's no doubt SOMETHING was escaping the tank. So, how about spraying "Rino Liner" on an aluminum gas tank, then foaming it in??? Could that solve the corrosion problem? Given my CH experience, I'm not a fan of poly tanks. Tom.