how to mount a fuel tank properly?

penst8grad · Sep 4, 2007

I am nearly finished taking the mulch that use to be stringers out of my '85 Sea Ray Seville. It looks like the whole problem started when the PO screwed the fuel tank cover into the stringers.

I would like to have the tank mounted properly between the stringers. Is it attached or does it rest on the foam under the floor? I'm also considering whether to move the tank forward a few inches to balace the weight better, but that would require tearing up the foam that is under the tank now and replacing it.

I'm really sick of pulling out foam.

penst8grad · Sep 4, 2007

Re: how to mount a fuel tank properly?

Anyone? Anyone? Beuhler.

erikgreen · Sep 5, 2007

Re: how to mount a fuel tank properly?

At least for the replacement tank I bought, you could also buy a strap kit from the same place to mount it. My understanding is that the tank was mounted on pads made from neoprene or some other material that won't rub a hole in the tank if it shifts, and strapped down or foamed in place.

With a poly tank you need to leave a little space around it so it can expand and contract with fuel fills.

Erik

penst8grad · Sep 5, 2007

Re: how to mount a fuel tank properly?

Thanks Erik.

The pad(s) at the bottom is what has me confused. I know that it isn't flotation foam, but am not sure what it is.

Can that be bought?

erikgreen · Sep 5, 2007

Re: how to mount a fuel tank properly?

I was just going to use a couple of neoprene mouse pads for mine

I think you can actually mount it on anything that's sufficient to support the weight involved, and that won't punch a hole in the tank if it rubs. A couple of fiberglassed or epoxied wood blocks of the right size would be fine.

A lot of people want to mount the tank off of the hull bottom because they want a drainage space beneath it, which is the usual reason for the pads. Some people foam the tank in place (no straps) and some people don't (strapped in).

To clarify, I mean "pads" in the structural sense, not a specific off the shelf item. I could also have said "pedestals" or "mounting points".

Erik

penst8grad · Sep 6, 2007

Re: how to mount a fuel tank properly?

I guess I'll keep my eyes open for some sort of foam that won't absorb water. It looks like there is currently no drainage in that area since the space under the tank was full of a foam pad. It wasn't around the tank, just under it.

penst8grad · Sep 18, 2007

Re: how to mount a fuel tank properly?

Update...

What I thought was a neoprene pad turned out to be rotted plywood. It was spongy like neoprene, but when I cut away floor/stringer around it I found that it was just plywood with a space underneath it.

Chris1956 · Sep 19, 2007

Re: how to mount a fuel tank properly?

My '88 Sorrento had the 35 gal tank mounted in a boxed in area just in front of the motor. SeaRay used some rubber blocks screwed into the side stringers and front and rear frames to hold the tank down. The tank compartment had a flat plywood floor.

seafrog · Sep 19, 2007

Re: how to mount a fuel tank properly?

When I installed my plastic tank, I used a bunch of dollar store mouse pads (neoprene), epoxied in several spots under the tank. I also placed some around the perimeter of the tank to cushion against the stringers. Neoprene is pliant enough to allow for expansion, yet rigid enough to prevent any excess movement. I personally would not foam any tank in place and doing so, goes against any documentation/information I've seen referencing tank installation. I wonder though.......if a tank is properly vented, does it matter if there's not enough room for expansion? Won't any excess expansion be relieved by the vent? Hmmmm....

Nova II 260 · Sep 19, 2007

Re: how to mount a fuel tank properly?

Pennst8, you should pull the tank. 1. get the foam out from underneath. 2. Check for corrosion since it sat on wet foam. Pin holes in the bottom of the tank, after your all done, would not make for a happy boater.

penst8grad · Sep 19, 2007

Re: how to mount a fuel tank properly?

Nova II 260 said:
Pennst8, you should pull the tank. 1. get the foam out from underneath. 2. Check for corrosion since it sat on wet foam. Pin holes in the bottom of the tank, after your all done, would not make for a happy boater.

There was no foam. That was the update above. What I thought was neoprene under the tank turned out to be rotten floor covered by glass. Tank was pulled as part of the stringer project and looks just fine.

how to mount a fuel tank properly?

Petty Officer 3rd Class

Petty Officer 3rd Class

Captain

Petty Officer 3rd Class

Captain

Petty Officer 3rd Class

Petty Officer 3rd Class

Supreme Mariner

Cadet

Senior Chief Petty Officer

Petty Officer 3rd Class