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josrulz 05-06-2014 04:45 PM

Two questions about new fuel tank install
 
Hello,
I'm installing a new aluminum fuel tank in our 1984 Sabre 34.

First, should I paint the tank? The old tank was painted, but I'm under the impression that this should not be necessary. There was no external corrosion on the old tank, although again, it was painted.

Second, the original tank has an anti-siphon valve in the diesel supply line out of the tank. Is this required by ABYC for diesels? It's working OK, but seems like one more thing that could go wrong.

Thanks for your help!
-J

KMC 05-06-2014 07:38 PM

Re: Two questions about new fuel tank install
 
Hi. My advice is to on no account paint the tank. Far from protecting, it can encourage corrosion. As long as the tank remains away from standing water in a ventilated area the bare aluminum is the best protection. With regards to the anti-syphon valve I am unsure if it is an ABYC rule for diesels but it would certainly make sense as syphoning a tank full of diesel into the bilge only to have the bilge pump throw it overboard could prove very expensive in fines should it be noticed. My advice is to leave it.

josrulz 05-07-2014 08:41 AM

Re: Two questions about new fuel tank install
 
Thanks KMC. I think not painting the tank seems to be the general consensus and how I'll go too.

As for the anti-siphon, I've heard but cannot confirm that it's a requirement only for gasoline, and that many diesel systems do not use one. Also that the benefits are outweighed by the drawbacks (potential point of clogging, failure, makes the fuel pump work harder, etc). However, my experience in this is from reading and I could be completely wrong. And I see your point too.

Anyone have info on ABYC and/or Coast Guard requirements on this?

CaptainForce 05-07-2014 09:14 AM

Re: Two questions about new fuel tank install
 
I replaced my two 55 gal steel tanks with aluminum tanks about 14 years ago. I agree with the comments about not painting and not installing the anti-siphon loop. I would add that it's a good practice to secure the tank with good ventilation outside and beneath the tanks. My tanks are sitting on starboard runners that are fastened with screw heads well reccessed and not other metals fixed to the tanks; however, there are tabs welded to the tanks that are then securely fastened.

josrulz 05-07-2014 09:23 AM

Re: Two questions about new fuel tank install
 
Quote:

Originally Posted by CaptainForce (Post 1814282)
...I agree with the comments about not painting and not installing the anti-siphon loop...

Hi CaptainForce. Thanks for the comments. One point of clarification is that we're referring to an in-line anti-siphon fitting as opposed to a loop. It looks something like this one below, though not identical. Same idea though.

Is your advice still the same?
Thanks again,
J

http://www.jmsonline.net/media/catal.../7/5/75053.jpg

CaptainForce 05-07-2014 04:32 PM

Re: Two questions about new fuel tank install
 
I did say, "loop". I think I just type this by rote after "anti-siphon"; however, what you present in the photo is the same item that was formerly within my diesel pick up lines from my tank. I drilled out the balls inside these one-way valves. For the first year after the install of my new tanks I was able to run well on one tank, but the other would often cause my engine to stall after about twenty minutes of running at 2500rpm. I've heard of others having problems with these valves sticking and I did not want the insecurity of having my fuel supply blocked at some innappropriate time,- like breaking an inlet at the rocky jetties!

I should add that the one tank pick-up never stuck and many may never experience a problem. I guess there may be different qualities of the production of these valves.

josrulz 05-07-2014 04:38 PM

Re: Two questions about new fuel tank install
 
Thanks CaptainForce. I thought that might be the case, but wanted to be sure.

pdqaltair 05-07-2014 06:28 PM

Re: Two questions about new fuel tank install
 
Nix the painting. I do tank inspections in my day job (API licensed inspector) and I've seen many Al tanks ruined by coatings.

The 2 big rules are to keep the base out of saltwater, and be VERY careful with dissimilar metals (no brass or bronze fittings, only SS by code) and grounds. Additionally, there are some additives that greatly reduce Al corrosion. Practical Sailor did a review. As I recall Stabil and Star Tron did best. However, internal corrosion is mostly a steel tank problem.

josrulz 05-07-2014 08:17 PM

Re: Two questions about new fuel tank install
 
Thanks pdqaltair. When you're referring to fittings, you're referring to the pickup and return lines, correct? They are SS, I believe. But the fittings that attach to those SS pieces might be something else. Is that the no-no? Or are we mainly talking about what comes in contact with the tank?

Bernie Hoban 06-01-2014 07:30 AM

Re: Two questions about new fuel tank install
 
On the subject if fuel tanks, we just discovered our catalina 309 (2008 year) tank is corroided on the bottom. We are shocked that a six year old well kept boat would have this problem and we are baffled how moisture may have gotten into the space.


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