Gas tank installation question

[BLITZ]

just purchaced a 76,23cc. previous owner has moved the gas tank about 14 inches forward. The tank appears to be resting on the hull. Previous owner said that this is the way seacraft installs the tank. Any info on tank installation and mounting would be helpfull.
BLITZ

[skipjake04]

I am no pro but from what I have seen on this site and the people I have spoken to on installing my tank there has to be something between the two. For one you have to have it supported and two you will wear the tank out or your hull. Fiberglass will eat through the aluminun where they rub together is what I have been told. From everything I have seen there is supports fibeglassed in and then a rubber "absorber" between the tank and supports, then braced or secured to the stringers or a brace between the stringers. Hope this is what you were looking for.

[76Red18]

I am no pro but from what I have seen on this site and the people I have spoken to on installing my tank there has to be something between the two. For one you have to have it supported and two you will wear the tank out or your hull. Fiberglass will eat through the aluminun where they rub together is what I have been told. From everything I have seen there is supports fibeglassed in and then a rubber "absorber" between the tank and supports, then braced or secured to the stringers or a brace between the stringers. Hope this is what you were looking for.

be careful with rubber, i think theres some posts in here about it being corrosive.

[strick]

rubber has carbon in it which will react with the aluminun and cause pitting.

strick

[JohnB]

Shields rubber and hose has a closed cell neopreme that has no carbon in it, that is designed to be used for that application. It comes in 2" wide by 1/4" strips, and cost about a buck a foot. It is glued on to the tank with 5200, so it doesn't really touch the tank anyways. The other alternative is foam, which I would suggest NOT using. It holds water against the tank and WILL corrode there.

As for the supports, I looked at a tank last week that came out of a buddies proline, and it was touching the hull on the corners. It didn't fail there, but it was VERY thin where it was rubbing. BTW, it had holes in it where the foam had held water against it.

When I did my tank, I put neopreme strips every 16 inches attached with 5200 on the bottom, and then 5200ed it to the platform. I have bulkheads in front and back of the tank, and put neopreme strips between the tank and the bulkheads.

[BLITZ]

Thanks for the info. But my real concern is weather the tank should be supported by the hull alone or should it be supported by the heel or some way supported form the stringers. I believe there is some rubber between the tank and the hull, is this the way tanks were installed originally??

[JohnB]

Every seacraft that I have seen that has a below deck gas tank, has a platform, usually 3/4" underneath it. The platform also adds some lateral stiffness to the hull when waves hit the hull and transfer energy inwards toward the centerline. I would NOT let the gas tank sit on the hull, since it flexes when waves hit it, and it will chaff the gas tank.

[wavelength]

This week I replaced my tank from a 1975 23 C/C. The old tank was sitting on a piece of 1/2in plywood with roving on the up side. The original tank had three 1in. strips of rubber running long ways. My issue was the filler hose rusted and leaked when putting gas in. To replace the filler hose and vent hose I figured since I was in there I'd replace the tank. The old tank had one corner that was showing signs of leaking.

I used the original plywood and put the new tank in yesterday. The new tank is 96 gallons and was built by RDS in Perry Fl. at a cost of 450.00

[BigLew]

The topic of replacing an aluminum tank has been discussed a number of times on this site. I have a 23' Scepter with a 140 gal. tank and yes I intend to pull it, at least. Probably replace it as well. All of the articles here, that I recall on the topic and the pictures I have seen, show a plywood "shelf" set between the stringers and sitting on the hull. Most of these "shelves" were glassed, or certainly their replacements were when the orginal support shelf rotted out.

As to HOW to install it, an article that disusses the issues involved and explains a "preferred" method can be found at the following website.

http://www.yachtsurvey.com/fueltank.htm

Good luck!

[htillman]

The last post accurately describes the process. Whatever you do when installing a new tank, do not use foam.