27 year old fuel tank is out! New tank design mod…

[Chinookie]

I tried using a winch on the front tied to the hardtop, and a cherry picker on the back, but the tank fought me something fierce to stay in its coffin. I finally said enough of this, and took a air chisel to the tank after removing one end of it. It was far easier to remove then, although I did have to take a router to the sides of the opening in the hatch. Once out of the boat, I was astonished to have to look hard for holes. I finally spotted two small 1mm pinholes that were soft although I did not press a probe all the way through them. They had to be a significant source of leak because I filled that tank with water to reduce the chance of a spark and the next day the tank was empty. As expected, the leak was where the rubber strips had trapped moisture against the bottom.
I am about to order a new tank, but I was thinking that the same thing is likely to happen again. If I glue rubber to the bottom of that new tank, then moisture is going to be working away there eventually. Has anyone ever considered welding a few rectangular aluminum pads to the bottom of the tank and then fastening rubber to those pads? The idea is that the rectangular pads would be sacrificial aluminum once the rot starts, which might extend the life of the tank many years. Thoughts?

 

[Boosted1]

I’m in the process of installing new tanks myself. My plan is to use 5200 to adhere strips of hdpe plastic to the bottom and anywhere else wood will touch the tank. I’m going to use enough 5200 to seal it 100% from any moisture to get under to prevent corrosion.

 

[Hookup1]

The way to do it is to adhere 1/4" neoprene strips to the tank with 3M 4000. Anything that touches the tank front, back, sides, bottom and mounting blocks.

Thread '268 Islander Fuel Tank Replacement'

Jul 10, 2023

Decided that this is the year to replace my 25 yo fuel tanks. No leaks. I plan to keep the boat. I'll document the process here.

Pulled the hatch. This hatch was rebuilt a few years ago with Coosa board. Looks good and feels solid. Hatch was set with 3M 4000 - kept everything sealed. Some difficulty cutting with blade to get it up. Not sure what it will go down with. Deck ports were caulked in from the underside as well. Kept the tanks dry.



I also put plastic over the fill, sending unit and pickup. This deflects any water away from the busy area of the tank.

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• Hookup1
• Replies: 67
• Forum: Tips, Modifications and Electronics

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[Ekea]

dont be shy with 5200

 

[DennisG01]

I think that's a great idea to add sacrificial Al strips.

Otherwise, I would use fiberglass stock strips as plastic/HDPE is likely to eventually break free from its glue bond. Fiberglass stock is easy to source - for example, look at McMaster Carr online.

I've always questioned the need for any kind of rubber strips used to "soften" the tank to coffin floor contact area. I just don't think it's necessary for "that" purpose.