T&T: Aluminum fuel talks

[Roger Lalonde]

I once had a fuel tank leak and I did the repair. then I reinstalled the 
tank and added a spacer to lift the tank for a day. Then I took some spray 
foam and filled the gap between the tank and the support. I seal the space, 
waited for it to dry up, then removed the blocks that were holding 
temporarily and filled this space with spray foam. Think of the logic behind 
this... This airtights the touch to the tank and waterproofs the space where 
it touches the tank, If no air touches the vulnerable spot and no moisture 
reaches either then you have no corrosion... It also prevents vibration 
wear. I really hate rust or rubbing wear or corrosion... and yes the tank 
had to be grounded with your common ground on the vessel

Roger
A problem solver...


----- Original Message ----- 
From: "Bill English" <wenglish at pacbell.net>
To: <trawlers-and-trawlering at lists.samurai.com>
Sent: Friday, September 11, 2009 7:17 PM
Subject: T&T: Aluminum fuel talks


>I have a 1973 GB 32 woodie, and as many times the case with old woodies one 
>of the fuel tanks had rusted through due to water leak around the filler 
>tube.  Three years ago both tanks were replaced with 1/8' 5052-H32 aluminum 
>tanks.  I thought I was set for the life of the boat, but no such luck. 
>One of my new tanks developed a leak due to corrosion where the tank rested 
>against a wood member and sea water had leaked on the contact point.
>
> I don't think this can be simple corrosion, but must be due to 
> electrolysis. I'm not sure what the circuit for electrolysis could be, but 
> my question is. All through-hull fittings on the boat are bonded together, 
> and might it help if the aluminum tanks were also connected to this 
> bonding circuit?
>  Any other advice would be much appreciated.  The leaking tank has been 
> repaired (welded patch) and I now have two non-leaking fuel tanks, but 
> what is the best way to prevent this happening again?
>  Bill English
>
> Woodstar, GB 32 woodie
>
> Sausalito, CA