Always Fun - Fuel Tank Leaking

Maine Sail

Maine Sail

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Feb 6, 1998
11,709
Canadian Sailcraft 36T Casco Bay, ME
So I am in the middle of my re-wire project when it gets a little warm up here in Maine, especially for this time of year. All of a sudden I notice a couple of drops of diesel in my engine compartment, just as I had seen at the tail end of last season.

At the end of the season I cleaned it and put some paper under the engine, secretly wishing that is where it was coming from, though I really knew it wasn't, but all winter NADA, no drips. Good, problem solved!:D But wait, it was only temporary, until the weather warmed up and the fuel tank again began to leak.

I don't have a good explanation other than the thicker diesel viscosity in cold weather or sludge mixed with water that froze, as to why it did not drip all winter, but it did not and now it is back..

So yesterday evening I disconnected and removed most everything on the engine, motor mounts, fridge compressor, hoses, water heater, fuel lines, Racor, gear box etc. etc. on and on. I then used my main sheet and an old boom vang with a 4 X 4 across the companion way to lift the engine out of the bay and plop it in the galley so the tank could come out. Tim R. came over for the final "plop" of the engine and to help disconnect a hose I had missed.:doh:

It all went quite smoothly and the tank is finally out of the boat and a new one is being made. It will only cost 1.2-1.4 boat bucks, plus hoses etc. and I should be back in business..

Here I come:


The engines temporary resting place:


The pin hole that caused all this BS:


All in all, from start to finish on the removal, it took me about an hour and a half to disconnect everything, set up the hoist and get it prepped for removal. When Tim showed up it took us about another hour to get the engine and fuel tank out. So 2.5 hours is not to bad. Going back in should take a little less time, except for the re-alignment. The longest and most time consuming aspect was the removal of all the hoses. Cold hoses don't like to let go of hose barbs...

Oh well it gives me a good opportunity to clean under the fuel tank as it was quite nasty and had been hidden since 1979.

The new tank will have three supply and return fittings as opposed to just one set. One of them will be for the engine, another for the polishing, recirculation system and one for a cabin heater..

It's always something with boats.....:cussing:

P.S. This boat has been using Sol-Tron/Star-Tron for over 12 years. The PO used to get it from Europe, as Sol-Tron, before it was marketed here as Star-Tron. I continued the use of the product. When I get the old tank back from the shop I promise to cut it open and see if the "claims" are true? I will be surprised if this 30 year old tank is totally clean. I have not really had any problems but something ate that hole at the low point of the tank and it was not sitting on the hull, but rather suspended with air circulation at the pin hole area. My guess is that it came from within..
 
Bob S

Bob S

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Sep 27, 2007
1,804
Beneteau 393 New Bedford, MA
I admire your tenacity and wonder how you find the time to do what you do and then document it with pictures. Got to thank you for all that you’ve taught me without ever meeting….. :dance:
 
sailingdog

sailingdog

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Oct 22, 2008
3,502
- Telstar 28 Buzzards Bay
Re: Always fun.....

Ouch 1.2-14 boat bucks... UGH... At least the new tank will be problem free for a good long time... (crosses fingers and knocks on wood).
 
Bob J.

Bob J.

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Apr 14, 2009
774
Sabre 28 NH
Re: Always fun.....

2.5 hours, that is very impressive!!

Had some time to kill & was surfing your web site, very informative. God bless you for putting that stuff out there!
 
BobM

BobM

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Jun 10, 2004
3,269
S2 9.2A Winthrop, MA
Re: Always fun.....

Now is a perfect time to paint your engine white. Then it will be easy to track leaks.

Will the new tank be aluminum again or plastic? Have you considered putting spigot at the bottom of front of the tank to allow you to easily check for water? I have been toying with the idea. Perhaps something like the drain valve on a car radiator. How about an inspection port? It could make future cleanings much easier and at least you wouldn't be guessing what your tank looks like inside.

I had pinholes in mine too and need to change it soon so I have been turning these ideas over in my head.
 
Ross

Ross

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Jun 15, 2004
14,693
Islander/Wayfairer 30 sail number 25 Perryville,Md.
Re: Always fun.....

It appears that something was in contact with that spot for long enough to get electrolytic corrosion started. All of the minor scrapes and scratches appear to have been accumulated over the years.
 
Bill1565

Bill1565

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Jan 22, 2008
1,483
Hunter 37 C sloop Punta Gorda FL
Re: Always fun.....

Nice work Maine. When you spec out your new tank get a drain welded in at the low point. Called a pickle line, it allows you to drain off the water and black sludge. If you fit a clear hose to it, you can see when you drain off all the bad and get to clean diesel.
 
Stu Jackson

Stu Jackson

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Feb 26, 2004
23,047
Catalina 34 224 Maple Bay, BC, Canada
Re: Always fun.....

Maybe I'm missing something, but Maine said the tank was UNDER the engine. Not too much room for a drain thingy, eh?

Nice job, good luck and the replacement work. Ross has a good point, somethin' coulda dropped in there and caused that. Anyway...holes found, tank's out, doesn't matter now unless something else becomes obvious.
 
sailingdog

sailingdog

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Oct 22, 2008
3,502
- Telstar 28 Buzzards Bay
I don't think the tank was under the engine, but that the engine was in the WAY of taking the tank out. It was probably either aft of the engine or to one side of it.

BTW, the most interesting thing I've ever seen was a fuel tank that had two holes in it from someone dropping a silver dime into the bilge. The dime somehow ended up on the aluminum fuel tank and ate its way through the tank. Then it ate its way through the bottom of the tank and let a lot of fuel spill into the bilge.
Stu Jackson said:
Maybe I'm missing something, but Maine said the tank was UNDER the engine. Not too much room for a drain thingy, eh?

Nice job, good luck and the replacement work. Ross has a good point, somethin' coulda dropped in there and caused that. Anyway...holes found, tank's out, doesn't matter now unless something else becomes obvious.
Click to expand
 
Tim R.

Tim R.

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May 27, 2004
3,626
Caliber 40 Long Range Cruiser Portland, Maine
Re: Always fun.....

The tank rests behind the engine under the cockpit sole. They practically built the boat around it. There was no other option but to pull the engine. Others had claimed that it could be removed from the lazarette but they had not actually done the work. I always fear this kind of online advice. There are many folks who will describe a procedure inaccurately because they have heard of someone else doing it.
 
Ed Schenck

Ed Schenck

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Jun 2, 2004
5,802
Hunter 37-cutter, '79 41 23' 30"N 82 33' 20"W--------Huron, OH
Re: Always fun.....

Thanks for the education AND reminding me that my aluminum fuel tank was installed in 1979. :cry:

P.S. Isn't that a clutch plate that I am seeing on the flywheel? What is up with that?
 
Maine Sail

Maine Sail

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Feb 6, 1998
11,709
Canadian Sailcraft 36T Casco Bay, ME
Ross said:
It appears that something was in contact with that spot for long enough to get electrolytic corrosion started. All of the minor scrapes and scratches appear to have been accumulated over the years.
Click to expand
Not possible, at least on the outside. That pin hole is in the V in the bottom of the tank. The V is about 6" off the sump of the vessel at that location and in plain old air.




It does not rest on anything where the pin hole was. The scars are likely from Tim & I rolling it around in the gravel at the boat yard while examining it or from the removal process. The whole tank had to rotate 90 degrees to come out and it was a Crisco fit that required a persuader, some butter and even some chipped gelcoat..;)

The spots on the tank where it rested on fiberglass are perfectly fine showing no signs of pin holes. I can reach my hand under it where the pin hole was. I suspect that there could have been an errant piece of dissimilar metal, a cutting shaving etc., resting in this spot on the inside but won't know until I cut it open.

I will not be installing a drain, but agree in principal, just not in this application. There is no way to do it on this tank and have access to it any way, as the water lift muffler sits right where the drain would need to be. The ABYC really frowns on drains anyway and with the polishing system I will be installing I really should not need it. I also don't want to create a dissimilar metals soup at the bottom of my tank mixing brass adapters & valves & aluminum..
 
Maine Sail

Maine Sail

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Feb 6, 1998
11,709
Canadian Sailcraft 36T Casco Bay, ME
Ed Schenck said:
Thanks for the education AND reminding me that my aluminum fuel tank was installed in 1979. :cry:

P.S. Isn't that a clutch plate that I am seeing on the flywheel? What is up with that?
Click to expand
Not a clutch plate just a damper plate & flywheel..
 
Ross

Ross

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Jun 15, 2004
14,693
Islander/Wayfairer 30 sail number 25 Perryville,Md.
Re: Always fun.....

A metallurgical flaw could also lead to such a failure. Just an inclusion of a contaminate in the manufacturing process could get it started. Not likely starting from the inside , Diesel fuel doesn't make a good electrolyte.
 
B

Benny

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Sep 27, 2008
1,149
Hunter 320 Tampa, FL
Re: Always fun.....

That is a lot of work for a couple of drops of fuel. I would have taken a rag and wiped them up, but perhaps I'm missing something.
 
Ross

Ross

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Jun 15, 2004
14,693
Islander/Wayfairer 30 sail number 25 Perryville,Md.
Benny said:
That is a lot of work for a couple of drops of fuel. I would have taken a rag and wiped them up, but perhaps I'm missing something.
Click to expand
It would only get worse! How would you feel in a storm knowing you had a leak that could set the boat on fire.
 
sailingdog

sailingdog

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Oct 22, 2008
3,502
- Telstar 28 Buzzards Bay
Ross said:
It would only get worse! How would you feel in a storm knowing you had a leak that could set the boat on fire.
Click to expand
The chance of fire with diesel is fairly minimal. With gasoline...that's a different story. However, it is generally prudent to repair all leaking fuel systems as soon as possible.
 
Bad Obsession

Bad Obsession

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May 23, 2004
3,319
I'm in the market as were . Colonial Beach
Re: Always fun.....

I have heard that the aluminum fuel tanks have a "life expectancy" of about 20 years or so. The metal will eventually develop a hole like that and finding the hole may be an absolute pain too.

Is this true?
 
Tim R.

Tim R.

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May 27, 2004
3,626
Caliber 40 Long Range Cruiser Portland, Maine
Re: Always fun.....

That's about how long mine lasted although it was in contact with the hull where it developed a leak from condensation. It has been repaired and leak free since 2004.
 
jibes138

jibes138

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Jan 27, 2008
3,086
ODay 35 Beaufort, NC
Re: Always fun.....

How about going with a tank half the size so you rotate your fuel more frequently and gain some storage space. then you just bring a few 5 gallon jerry jugs with you to keep the capacity. The jerry jugs are sealed so should keep fresh fuel clean? A smaller tank might be easier to remove also. Why not a plastic tank instead of aluminum?
Now about metallurgy, you can get galvanic cells within the metal itself. This can be caused by an inclusion, a non-homogeneous mixture of the alloying elements, or even imbedded contaminants. I once had to shotpeen an aluminum part for fatigue resistanc and they would just correode sitting around the shop. We implemented an iron decontamination process and then things were fine. The shotpeening was pounding iron into the material and it was then reacting with the high humidity in the shop. You would never see it because we are talking about atomic level defects.
 
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