My '89 Mk1 leaked out most of our diesel last week and dumped it in the bilge. It now needs a replacement of the aluminium tank. From articles and this forum, it seems this is about the age where the tank fails.
Catalina emailed a blueprint copy of the tank assembly and it shows that in April 1990, the document was revised to incorporate a vinyl covering for the base of the tank - only a few months after our boat left the factory.:o
I assume this was to slow down the crevice-cack corrosion that has now beset our tank.
My question is whether there is some other material I should consider - something possibly more 2010-era technolgy... like what if I sealed it with an expoxy?... or some paint-on material to ensure no moisture seeps up from the base to accelerate the corrosion process.
Anyone got experiance with this? ... or some other recommendations?
Triatica (GlennF)
s/v Blown Away
Sammamish, Wa
Hull #971
1989 Catalina 36
Universal M25xpb
My surveyor when I bought my boat told me the bottom of the tank should have a layer of neoprene bonded to it for this reason. Haven't done it yet, big job to empty the tank out on my own, not to mention bleeding everything again afterwards.
Jason V
Vancouver, BC, Canada
I am right in the middle of a tank replacement right now. It is also the result of a leaking tank. I've removed all fuel related components, tank , lines, filter/seperator, and fuel pump and will replace all with new.A new tank is being made and I am hopeful that it will arrive soon. Our boat is a 1983 and the tank was original equipment.
If you go to a web site called "Marine survey online" there is an article by D.H. Pascoe & co. of Destin Fla. It gives some good information and food for thought.
Good luck with the mess
Bob Serotini
Glenn,
I think you could use a number of different products. Anything you install should be designed to keep water or moisture from coming in contact with the aluminum tank. Epoxy, paint formulated for aluminum, fiberglass & resin. What you do NOT want to use is something like old carpet scraps. They would do just the opposite: they would hold moisture next to the tank.
Jason,
Isn't neoprene the stuff they use for scuba wetsuits? If so, I think that stuff absorbs water, and should not be used.
Tom Sokoloski
C36/375IA Past Commodore
Noank, CT
I had to replace the tank in my 1989 (hull 966) a couple of years ago. After researching the options, I bought a new aluminum tank from Catalina. The new tank was made of thicker aluminum than the original tank, and arrived with plastic strips to put under the tank. The strips were actually pieces of rub rail. I am convinced that the combination of ventilation under the tank and thicker tank walls completely eliminates the chance of future leaks caused by corrosion.
As a precaution, I also changed the water heater while the fuel tank was out. The old water heater was 18 years old, and I did not know how long it might last.
Gary Teeter
1989 C36 "AnnieG"
Std Rig #966, M25xp
Everett, WA
Thanks guys, this is helpful. Gary, your suggestion is a good one to tackle the water heater at the same time. On [I]Blown Away[/I], this was done just prior to our buying her, so we're good.
This may be overkill, but I am toying with the idea of coating the entire bottom of the tank (like around 1") with 5200 and letting it dry totally before installing it. This should prevent any chance of crevice corrosion from occuring between it and that wooden base.
Question is if there is any known interaction with 5200 and aluminium? ... I don't see any references to this, so I think we'd be good there. Probably overkill, but a bilge full of diesel is rather a harrowing sight to recover from.:eek:
Triatica (GlennF)
s/v Blown Away
Sammamish, Wa
Hull #971
1989 Catalina 36
Universal M25xpb
The ONLY place on a boat that 5200 belongs is the hull to deck joint. Regardless of whether it works with or again aluminum, what are you trying to achieve with an adhesive product? The trick, as so ably described, is to keep it dry, not encapsulated.
Stu Jackson, C34IA Secretary, C34 #224, 1986, SR/FK, M25 engine, Rocna 10 (22#)
Stu - what would you suggest I do to have total confidence that it will be dry all the time?
Triatica (GlennF)
s/v Blown Away
Sammamish, Wa
Hull #971
1989 Catalina 36
Universal M25xpb
Glen,
Maybe Stu misread what you proposed sealing the bottom of the tank, coating it with 5200 and letting it dry may well be a good moisture barrier. I am not certain that 5200 is the best product but would work. This will prevent exterior moistrure from attacking the tank. The other issue is water in the fuel that settles out and sits on the interior bottom of the tank.
Setting the tanks on some plastic strips that allow drainage and air flow under the tank would also prevent moisture build up, you would need to keep the area clean and dry.
Cepheus dream
C36 MK I # 825
MK I Tech Editor No Mas
Thanks, Steve, that's exactly what I was getting at. If you re-read Tom's suggestion, nowhere did he mention GLUE, which is all that 5200 is. Our 24 year old tank is up on something, maybe a couple of two by fours, but it hasn't leaked (knock on wood) (NPI!) [I]yet[/I]. The trick is to keep it up and air underneath. To do that you simply have to raise it up, and inherently by doing that, something has to be in contact at some portion of the bottom of the tank. Whatever that material may be, coating the outside of the bottom of the tank where contact is made sure wouldn't hurt, but I wouldn't use 5200 for that (or anything else on my boat for that matter).
Stu Jackson, C34IA Secretary, C34 #224, 1986, SR/FK, M25 engine, Rocna 10 (22#)
Thanks guys - I appreciate the clarification. The new tank goes in today and I will see who much room I have to set the tank on some strips to keep it elevated.
Much appreciated,
Glenn
Triatica (GlennF)
s/v Blown Away
Sammamish, Wa
Hull #971
1989 Catalina 36
Universal M25xpb