[C320-list] Bilge Diesel

Tue Apr 28 22:05:37 PDT 2015

Brian, 
I concur with Jon's assessment about the fuel tank replacement process. However, you may not have a fuel tank leak due to perforation of a seam or a tank wall if you overfilled the tank. You could now be seeing fuel seepage from either the tank fittings or most likely the fuel sender or sender gasket. I had the same issue a year ago and found that the sender gasket was leaking after having topped off the tank the previous fall while the boat was stored on its cradle with the bow higher than the stern. I experienced fuel seeping from the sender gasket when the boat was launched and sitting level at the dock.

By pulling off the starboard aft corner storage shelf above the tank, you will be able to see if the fuel is leaking from the sender or from any fittings on the top of the tank (due to topping off the fuel tank last fall).  If you do not find any fuel on top of the tank, then you probably have fuel seeping from the forward port corner of the tank.  If you are lucky, you just have a sender gasket leaking and you may be able to get by for this season by applying some liquid thread sealer to the top side leak. You will first need to remove two gallons of fuel to stop the seepage if it is coming from your sender area or a fuel fitting. I removed the 90 degree fitting used for the return fuel line barb (that fitting is on aft end, the port side of the tank,   adjacent to the larger fuel filler hose and right next to the overflow/air hose). I used a topsider oil removal pump and sent a narrow plastic tube down into tank and pumped out a couple of gallons. Do not attempt to remove fuel by removing the sender or fuel feed line fitting located at the forward end of the tank because with an overfilled tank, the fuel will just gush until it either stops or you can stop that sudden and massive loss of fuel.....imagine lots more fuel seeping under the hull liner! Next, clean the sender and gasket and tank area to remove the fuel residue on the top of the tank with a grease cutting cleaner like "409" and then dry off that area. Last step,  apply some liquid thread sealer  "goop" that is available at NAPA or any other auto supply store for a something like $4. The thread sealer did not dissolve over the entire season.  I did tweak the sender screws before applying the sealant to ensure that the gasket was tight, but I am convinced that applying the liquid thread sealer to encapsulating the sender screws and gasket is what stopped the leak was taking place ( I had installed new sender the previous season but did not apply any thread sealer.) Using two coats of sealer with several hours drying time between coats,  did the trick for me. I  topped off the tank several times without another leak last season.

 I cleaned up the fuel seepage that found its way under the bilge liner by using lots of Bounty towels to first wipe up fuel followed by leaving ample amounts of towels to wick-up the fuel. Next, I  used a generous dose of "Dawn lemon" liquid dishwashing soap with very little water followed by two very, very strong concentration and large rinses of "Simple Green" (large concentration size available at SAMs Club). I poured the Simple Green in and around and under the tank area so that it drained to the very lowest areas where the fuel traveled and then removed that residue with the paper towels where possible. The Dawn soap loosened up the fuel residue and the Simple Green removed the Dawn & fuel mix, as well as removing the fuel smell.  I could access that area where the forward most corner of the aft water tank rests by wicking paper towels in that area to first remove the fuel and then the Dawn soap residue and Simple Green rinses. Also, on my hull, I can access the area below the cabin sole where an inspection port provides access the hull below the bilge liner. I could get an arm sweep under the liner to wipe up lots of fuel and then the soap residue and rinse. After the strong Simple Green rinses and removal, it took about a two weeks for the Simple Green to completely dry up and that soap odor to cease. 

After the fuel clean-up drill last year, and with a 20 year old 320 (hull #277), I  decided to avoid another fuel leak cleanup episode by making plans to just replace the aging tank. Upon haul out last fall I ordered a new fuel tank from Catalina Direct ( I found that for me, CD had the best available price after considering shipping).  I removed the old tank last week and am going to install the new tank tomorrow.  I will also paint on a coat or two of liquid thread sealer "goop" over the new fitting threads, over the fuel sender screws and gasket edge, and, also do two coat over the inspection port bolts and gasket edges, given what I learned over the past year. 

With an aging aluminum tank, it is not a matter of "if" the tank could ever leak, but really a matter of being prepared "when" the tank is going to leak.... or better yet, anticipate a planned replacement before the tank leaks. Preventing a fuel seepage problem is much preferred when the day is out there for an aluminum tank to leak based on my extensive research last fall of several popular owner sailing blogs regarding aluminum tank leakage problems.  I learned  that most reported aluminum tanks leaks took place between 15 & 25 years.....some sooner and some later, depending on how successful owners were about removing the water or condensate from their fuel to reduce the nasty goo from forming in the lowest corner of the tank that produces a chemical interaction that perforates an aluminum tank (on a 320 it is going to be the forward most port corner). Hence, I ordered an inspection port on the new tank to provide easy access to remove the lowest lying quart or two of fuel every few years, or if necessary, to remove any nasty goo from the forward port corner. 
Hope you found this lengthy reply helpful. Feel free to contact me for more info "off  list" at my email address.
Rick;  My-Ria 95 320 hull #277

-----Original Message-----
From: C320-list [mailto:c320-list-bounces at lists.catalina320.com] On Behalf Of Jon Vez
Sent: Tuesday, April 28, 2015 5:34 PM
To: C320-List at Catalina320.com
Subject: Re: [C320-list] Bilge Diesel

Brian,
I would say with some certainty that your tank is leaking given where you're finding the fuel, the age of the tank and the fact that it continues to leak. Mine started leaking at 12 years. Jeff Hare just commissioned a larger tank that will fit a 320 and you may want to speak with him about that option. As to some of your questions:
--it's a straightforward replacement. The tank will only come out from the aft berth access hatch with the wood trim removed, not the lazarette.
--you will not have to delay your launch as the leak is very slow and you will be able to do this anywhere. The biggest issue will be removing the fuel. I used a pump attached to a drill and emptied into jerry cans through the sender hole.
--According to Nigel Calder, an aluminum tank can be expected to last 8-12 years. Of course they can go much longer. The new tanks have much thicker walls .90 vs .125, however your leak is most likely at a seam.
Once the tank is removed, getting the fuel cleaned up is pretty easy as long as you keep it contained in the aft berth area with absorbing socks. Once the tank is removed you can clean up the area pretty easily with a detergent like simple green and Pureayre. If the area is dirty, you can consider re painting with an epoxy based paint like bilge paint. However I did not find this necessary.

I know several others have done this as well, so I'm sure you will get further advice.
I know when I went through this, I denied it was the tank in my own mind and that was a mistake as all it did was create more fuel to clean up...kind of like going to the dentist at first sign of a toothache....

Good luck....

Jon
 formerly #582

Sent from my iPad

> On Apr 28, 2015, at 4:56 PM, Amiraults Family <amiraults at sympatico.ca> wrote:
> 
> All:
> 
> 
> 
> When removing antifreeze from the bilge on Sunday in preparation for 
> launch May 02, I found a little diesel in the aft section of bilge 
> exposed when lifting the inspection plate on the floor the main cabin. 
> I cleaned this. I was at the boat again today (Tuesday) to do the hull 
> wax and buff to find a ½ cup more fuel in the same area. Where I can 
> actually trace back the leak, it is coming from the starboard side and from under the floor of the head.
> In the aft cabin the leak is further back than the plastic water tank. 
> It is coming from the area of the fuel tank, and not the engine.
> 
> 
> 
> I filled the tank on the hard in cold November. It is now +22 C in Ottawa.
> It is possible that there is expansion of the fuel and a resulting 
> leak other than in the actual tank wall. Launch cannot be delayed, and 
> I must go in with club launch Saturday so I cannot further address 
> this until Monday May 04. At that time I want to move quickly. 
> Currently the leak is slow, and I have a bilge sock positioned in the way of the flow.
> 
> 
> 
> In the event that it proves to be the tank, if someone reading this 
> has already addressed this matter and done a tank replacement, I would 
> appreciate insight into the process, tips to make the remove/install 
> progress more smoothly, and ‘should have dones’ that I should be 
> considering.
> 
> 
> 
> Source of the replacement tank. A quick look online shows a 19 gallon 
> US aluminum from Catalina Direct for 536$, with a 50$ packaging fee 
> and call for special shipping charges (all amounts USD). Is there a 
> better source? A different tank material? Should I consider options 
> like an inspection plate (which deletes the internal tank baffle)?
> 
> 
> 
> Removal of the old tank. How is the tank swap physically done? Can it 
> be moved out of the starboard stern locker hatch?
> 
> 
> 
> Install of the new tank. Is there additional securing or isolation 
> that should be installed between the new tank and the boat to increase 
> the time to next failure?
> 
> 
> 
> Clean-up. There are products which can be used to clean up the spill. 
> Is there a superior product? There are areas (such as under the head 
> floor) where I have no access. Is there a technique which can be used 
> to clean these difficult to access areas? Will I need to be looking at 
> some form of sealing paint to eliminate diesel odor?
> 
> 
> 
> Might as wells. With the fuel tank removed (as well as all of the 
> locker detritus displaced to allow access) is there some other 
> unrelated maintenance that I should be considering given that the area 
> can now be accessed for the first time since new?
> 
> 
> 
> I am also curious. My previous boat experienced failure of its 
> aluminum fuel tank after 28 years. Bear originally went into service 
> in 2000. Is 15 years unusual for a tank failure?
> 
> 
> 
> Regards;
> 
> 
> 
> Brian Amirault
> 
> 797 Waltzing Bear, too
> 
> 
> 
> ---
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