Fuel Tank Support?

[Joe H]

I'm ready to permanently install my fuel tank, I have a slight V in the bottom of my boat so I thought I'd use a flat piece of 3/8 plywood under the tank the same size of the tank, my question is do I need to build a frame under the plywood? I think I remember seeing something in Andrew's thread, "SmokyMountain's PH18 Build in E. TN" with a frame under the tank.
I only have about 2" from the top of the fuel tank to the top of the cleats, not much room to put much underneath.



Joe H

[peter-curacao]

hang it
http://forums.bateau2.com/viewtopic.php ... 10#p188871

[chicagoross]

I built the flat shelf as you described; the size of the supports underneath will be determined after you dry fit the shelf - they sill be pretty small strips. How about glue and tape the flat shelf in, drill a few big holes in it with a hole saw, and pour 2 part foam through the holes?
That would probably be enough support to keep the shelf from sagging.

[Joe H]

How about glue and tape the flat shelf in, drill a few big holes in it with a hole saw, and pour 2 part foam through the holes?

That's a good idea, that way it will be supported evenly all the way through. I'll have to put a half piece of pvc at center underneath because I want it to be able to drain from the bow all the way to the transom between the center two stringers, I'm going to lower the floor in the cabin and it has to drain somewhere and that's the route I want it to take.

Joe H

[fastlane]

Joe

I did basically what your proposing. I used 2 pieces of 3/8 per tank.
I put it between the stringers on a large fillet underneath and same on top with 2 layers 12OZ biax
Attaching to stringers then covered again in 12 OZ biax up the stringer sides.

They are solid! I could jump my 300 LB’s up and down on them with no flex at all.

I do however like the idea of pouring foam underneath it. I think I would have done that if I thought of it.

[Joe H]

Peter, Sorry I missed your post, those are beautiful tanks but I should have mentioned, mine are polyethylene tanks, I don't think you can hang those?

Fastlane, yeah that's it with pictures too, great! thanks. Are the pieces of ply glued to the stringers for keeping the tank from going side to side or to mount hold downs?

Thanks
Joe H

[peter-curacao]

Peter, Sorry I missed your post, those are beautiful tanks but I should have mentioned, mine are polyethylene tanks, I don't think you can hang those?

Whoops sorry didn't see that

[fastlane]

Joe,

I am using aluminum tanks so not sure if this will work on the poly but
the pieces on the sides keep the tank from moving side to side. they match up with the neoprene pads on the tank. The tanks sit on neoprene strips as well.
The tank slips into the opening and fits like a glove. The floor finishes it off with some neoprene on the top. The tank has no movement once its altogether yet has plenty of open space around it for airflow on the top sides and bottom. The neoprene is bonded to the bottom of the tank then to the floor and sides once installed.

[ericsil]

Joe, Really glad to see you back at it again. I have exactly the same tank you do, in fact two of them. I did not put a shelf under the tank but did run rubber strips the entire length of both sides where they contacted the hull. After standing on my tank on the garage floor it did not seem like it needed any extra support. Seems to have worked OK.
Holding the tank sideways needs a little care. That tank will expand up to an 1" lengthwise when you fill it with gas. I used expandable foam to make corner blocks, maybe 4" square, that could slide in the compartment to accommodate the expansion. Seems to have worked OK, at least they are still holding gas after four summers in Maine. Don't forget to vent that compartment with several square inches worth of air holes. Those tanks degas quite a bit.

[Joe H]

Hey Eric, yeah, I had to take a little break, just not by choice, but I'm feeling pretty good these days.
Great ideas,I think I'll use a combination of them, put the shelf floor in and then support with the foam like you did, I though about the expansion so I'll leave Fastlanes side supports out and just use foam, did you use any brackets to secure it in place?

Well the kids are here so I'm off to cook up some Perch for everyone.

Thanks

Joe H