Tank Failure

[Witzend]

Catalina really screwed this one up, by forming the fiberglass floor around the bottom of the fuel tank and then lipping it up to create a shallow basin. This traps moisture which inhibits O2 and has caused the Aluminum to crevice corrode. So what a mess... fuel oil in the bilge. Getting the tank out was a real nightmare. I would really like to replace it with a stainless one, but $$$$. Anyone know of some sources for custom tanks?

 

[RichH]

Suggest you consider to simply build an epoxy fiberglass tank inside the aluminum tank .. good instructions on the WEST (epoxy) website.

Cut a large access hole in the old tank, clean/sand out the innards, lay-in ~3/16" of cloth and epoxy. get a new piece of aluminum to cover/overlap the access hole, set/epoxy-in studs for the closure of the access hole, get BUNA gasket material from Granger, or other industrial supply, etc. ... done.

MUCH cheaper than a tank 'rebuild', MUCH MUCH cheaper than a SS tank; and, you use the inside surface of the old tank to build/laminate-in a new epoxy-fiberglass tank.

 

[Witzend]

Hey Rich,
Had not considered this option, seems a bit involved, but doable. I have a lot on my plate right now with installing a solar system on my roof and other work related projects. So this has come at a bad time. I may end up having the tank repaired (relatively clean inside and no other evidence of corrosion other than the lower corner) and then putting a drain in the basin and chocking the tank up to allow some air flow to prevent this from happening again.

 

[RichH]

.... or just have an entirely new and 'heavier' bottom welded on. Aluminum is still relatively cheap in comparison to SS or even roto-molded.

 

[tommays]

I would call it a BAD install the tank shoud be placed on plastic Or I get natural rubber with no carbon and not able to collect water

1994 tank was shot on filler neck from leaks and I needed a 90 neck to relocate the fill up to the rail outside the boat


Just curious what the specs on the tag are ? Material and thickness

As I am on the third one due to the first two bad installs with the original fuel fill in the cockpit and always wet and allowing water inside the tank

1970/1994/2011

 

[jibes138]

Tank is made from 1/8" thick aluminum. The aluminum is grade 3052

Wrought Aluminum Specifications. The wrought alloy group is shown as: 1xxx-pure Al (99.00% or greater); 2xxx-Al-Cu alloys; 3xxx-Al-Mn alloys; 4xxx-Al-Si alloys; 5xxx-Al-Mg alloys; 6xxx-Al-Mg-Si alloys.

Pure aluminum is alloyed with many other metals to produce a wide range of physical and mechanical properties. The alloying elements are used as the basis to classify aluminum alloys into two categories: non-heat-treatable and heat-treatable.
Most of aluminum specifications designate aluminum alloys in the following way:

• First digit – principal alloying constituent(s),
• Second digit – variations of initial alloy,
• Third and fourth digits – individual alloy variations (number has no significance but is unique).

 

[Witzend]

Jibes has it correct.
I'm thinking on having a thicker new bottom laid on.

 

[Winkfish]

Suggest you consider to simply build an epoxy fiberglass tank inside the aluminum tank .. good instructions on the WEST (epoxy) website.

Rich, just wondering from all the ethanol threads. I'd heard that ethanol fuel can eat away at the coatings of fiberglass tanks.

 

[RichH]

Epoxy is safe.
The failures have been in POLYESTER (Styrene based) resins.
Check out the Gougeon Brothers (WEST SYSTEM) website for latest updates and recommendations - lots of good info.

 

[woodster]

Catalina really screwed this one up, by forming the fiberglass floor around the bottom of the fuel tank and then lipping it up to create a shallow basin. This traps moisture which inhibits O2 and has caused the Aluminum to crevice corrode. So what a mess... fuel oil in the bilge. Getting the tank out was a real nightmare. I would really like to replace it with a stainless one, but $$$$. Anyone know of some sources for custom tanks?

try www.bestfab.com in Largo FL 863-519-6611 or 800-788-4577

hope this helps

regards

woody

 

[Bob S]

Looks like Catalina used 5052 aluminum. 5052 will bend without cracking, probably why they use it to fabricate these tanks. I'm not a chemist and have no knowledge of how diesel reacts to different grades of aluminum. I used 6061 to make an access cover but it's gasketed with Buna N rubber.

 

[Mikem]

And when you reinstall either get rid of the lip or make some rat holes so water cannot collect no matter what tank you have.

 

[Witzend]

"and then putting a drain in the basin and chocking the tank up to allow some air flow to prevent this from happening again."

Aye Aye Mate

 

[Witzend]

$200 to have the tank cleaned, patched and the back port corner cut off so I can get it back in.

 

[Witzend]

The tank was still contaminated from the re-work guy, so I washed it out again and put some paint on it.
I went to re-install and it, had rained some with the front action, low and behold there was a small amount of water in the basin where the tank goes. Looks like the hinge plates for the original swim ladder were leaking. So, I re-bead them with butyl before I put the tank back and chocked the tank up so it would not be sitting in the water if it ever happened again. C310 owners you have been warned.