Islander gas tank support

[Croge]

I have tried searching but can’t seem to find any ideas about the cradle under the gas tank. It is aluminum that had wood attached but the wood was all but gone from rot. I think it was 1/2 inch plywood but not sure. Does any one have any ideas if that is correct and if there is anything else I could use that would last longer under the tank for better support?

 

[sidingguy]

My Islander had 1/2" plywood also.If I remember correctly it was about 12" wide and as long as the fuel tank.I painted 2 or 3 coats of oil based paint and rivetted it to the ribs. Stayed to the outside of the plywood with the rivets because the bottom of my tank is only 8" wide at that point and tapers out from there.I did lay some rubber strips down where the tank sits on the plywood.Be careful with what you use on the bottom because you only have so much room between the bottom of the hull and your floor surface for your filler neck and hose.

 

[Croge]

Ok then I will stick with 1/2 so I don’t run Into clearance issues. I have some left over 2part epoxy from the transom I could possibly coat the ply with. Thanks for the info!

 

[mattsteg]

It was 1/2 in ply. Wrap in fiberglass as well if sticking with wood...

 

[Croge]

Will do!!

 

[Watermann]

What's your tank look like, is it a V bottom or flat?

 

[Croge]

Not sure what u would call it.

 

[mattsteg]

Not sure what u would call it.

Not flat.

 

[Watermann]

Not sure what u would call it.

I would find some way not to use wood in the very bottom of the hull that supports fuel. Wrapping in glass is not going to keep away the rot forever, I'd use aluminum with padding as part of the tank sits on the ribs.

My 18' V5 had a 2x4 under the aluminum tank bed that laid on the center of the the ribs, bad plan as it rotted. I just added angle AL supports across the span. My tank is a totally flat rectangle and the bed looked like this.

 

[mattsteg]

I would find some way not to use wood in the very bottom of the hull that supports fuel. Wrapping in glass is not going to keep away the rot forever, I'd use aluminum with padding as part of the tank sits on the ribs.

My 18' V5 had a 2x4 under the aluminum tank bed that laid on the center of the the ribs, bad plan as it rotted. I just added angle AL supports across the span. My tank is a totally flat rectangle and the bed looked like this.

Man that 2x4. What were they thinking? "Let's lay some wood right where we KNOW it's gonna wick up water, and use it to support the fuel tank"

 

[Croge]

I like the idea of aluminum because I am worried about the wood rotting. When I pulled my tank there was hardly any wood left under it. I might make up some supports from aluminum like I did for my cabin floor.

 

[sidingguy]

Starcraft used untreated unpainted plywood in my 86 Islander.It lasted 35 years.By the time my plywood rots the rest of the boat will probably be ready to make soda cans.

 

[mattsteg]

Starcraft used untreated unpainted plywood in my 86 Islander.It lasted 35 years.By the time my plywood rots the rest of the boat will probably be ready to make soda cans.

That's the one truly idiotic place that the put crap, apparently untreated wood. I'm no anti-wood zealot but that's just bad, especially snuggled up against water-retaining foam. I fiberglassed and epoxied over replacement ply, and did NOT rivet it down (no penetrations).

Removing the mulched original bottom with a shovel and seeing the tank practically resting on protruding rivets was a huge WTF moment.

 

[sidingguy]

No foam in the tank compartment in my boat,rivets were 3-4 inches away from tapered bottom of tank which fit snuggly in compartment.

 

[mattsteg]

No foam in the tank compartment in my boat,rivets were 3-4 inches away from tapered bottom of tank which fit snuggly in compartment.

Fared much better than mine!

 

[Croge]

Yeah that’s similar to what mine looked like. Not good!!

 

[Croge]

Well after taking a good look at the aluminum gas tank there are lots of corrosion pits and I def do not feel safe using it. There are probably 30-40 of these pits. I have been looking at replacement tanks but can’t find one that is a direct fit. Before I buy something that requires me changing stuff I wondered if any of you know of any places off hand where I could try looking that I might have not checked. The tank is a 43 gal 23 wide 52 long and 8 in deep. I looked at moeller etc.