Fuel Tank leak

Mar 6, 2008
331
Catalina 310 Scott Creek, VA
Found a leak on my 13 year old aluminum tank. For those that may be wondering, it will come out the starboard side access panel after removing the water heater. The retaining dam for the tank holds water (and fuel) and has no weep hole. I also found that the shelf which holds the water heater is not water (fuel) tight, and has no weep holes. After removing the tank I still had weeping fuel and had to cut drain holes to get the fuel out from under the shelf. After several washings, I am hoping to be rid of the fuel smell. Will reinstall tank after Matt goes away.
 

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Nov 18, 2010
2,441
Catalina 310 Hingham, MA
Slightly unrelated but how was getting the water heater out? Any pics or descriptions of that process?

Thanks,

Jesse
 
Mar 6, 2008
331
Catalina 310 Scott Creek, VA
Step one is get the water good and hot so you can clean up the diesel fuel as you drain the tank (I disconnected the shower wand pulled it out and reconnected it below deck). Hardest part is draining the antifreeze and disconnecting all the hoses. There has been some discussion on how to drain antifreeze on other posts, but I just disconnected the rubber hoses from the flexable metal hoses by the thermostat. The water heater holds about 3/4 gallon. There are two screws on the port side which hold it down. There is a slot routed on the stbd side that the flange engages into. It slides out easily once disconnected.
 

Attachments

Nov 18, 2010
2,441
Catalina 310 Hingham, MA
Step one is get the water good and hot so you can clean up the diesel fuel as you drain the tank (I disconnected the shower wand pulled it out and reconnected it below deck). Hardest part is draining the antifreeze and disconnecting all the hoses. There has been some discussion on how to drain antifreeze on other posts, but I just disconnected the rubber hoses from the flexable metal hoses by the thermostat. The water heater holds about 3/4 gallon. There are two screws on the port side which hold it down. There is a slot routed on the stbd side that the flange engages into. It slides out easily once disconnected.
Thanks for the info. Unfortunately it looks like someone already replaced the factory water heater with something smaller on your boat. The factory heater was 20 gallons and about twice as long as the one you showed.

Thanks,

Jesse
 
Mar 6, 2008
331
Catalina 310 Scott Creek, VA
I can almost guarantee that is the factor heater. I bought the boat with 30 hrs on the engine right after the first owner died. The warning stickers were everywhere. Neither the stove safety switch for the oven nor the thermostat for the fridge worked when I bought it. I guess they were missed at commissioning. The surveyor missed both because the fridge was cool and the top burners worked. This was a 2003 model. I will look at the heater before I reinstall and check the size. I think your boat is a few years older than mine.
 

Richit

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Jun 9, 2009
25
2 310 Coconut Grove, Fl
Found a leak on my 13 year old aluminum tank. For those that may be wondering, it will come out the starboard side access panel after removing the water heater. The retaining dam for the tank holds water (and fuel) and has no weep hole. I also found that the shelf which holds the water heater is not water (fuel) tight, and has no weep holes. After removing the tank I still had weeping fuel and had to cut drain holes to get the fuel out from under the shelf. After several washings, I am hoping to be rid of the fuel smell. Will reinstall tank after Matt goes away.
Interesting. I've had an ongoing fuel seepage problem where fuel ended up in the bilge and there was what looked like a trail of fuel that dried on the fiberglass that slopes down from where the tank is located. I had a mechanic check it out, and he said the sender unit was leaking and resealed it. That seemed to take care of the problem, but every so often I'd get some more fuel in the bilge. I thought it was residual fuel stuck in various places, but it continued off and on for a year. Recently it seemed to be coming from the Racor. So I replaced the filter, and that thought that would do the trick. But I still had a bit of a fuel smell below, and there still seemed to be a small about of fuel in the bilge. So, today, I crawled back past the rudder post and looked closely at the fuel tank. There appears to be a hairline crack that runs down from the sender unit (maybe the mechanic did something to crack it) for about 2" below the top of the tank. Maybe that is leaking. But, if the retaining dam is self contained (no weep hole) even if a small about of fuel leaked form that crack, wouldn't end up in the bilge. So still not sure where my problem is, but the crack has me thinking I may need to either repair (don't know if that is even possible) the crack or replace the tank. Thoughts?
 

Richit

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Jun 9, 2009
25
2 310 Coconut Grove, Fl
BTW, hope you didn't have any damage from Matt. I'm in Ft. Lauderdale and thought we were going to get the first landfall, but then it turned North - lucky for us, but not so much North and South Carolina.
 

Richit

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Jun 9, 2009
25
2 310 Coconut Grove, Fl
Sorry to keep writing notes, but I just re-read your post and realized that maybe my problem is that fuel is trapped under the water heater shelf. I'll check it out.
 
Mar 6, 2008
331
Catalina 310 Scott Creek, VA
If the crack originates at the sender it would start at one of the forward most screw holes, and have to come forward over the rounded edge then down 2" as you describe. Doesn't sound likely, but you could rule it out in place by sanding the paint to check closely in that area, or apply 3 PSI air pressure to the tank by closing both shutoffs, removing the vent line, and connecting the vent fitting to a compressor. Soapy water will show if the suspected crack is there or not. The one pinhole I had appeared to be a random flaw in the aluminium plate localized to one area. You could also try sliding a piece of white fuel diaper in the crack between the tank and the retaining dam directly behind the rudder post and see if any red fuel wicks up the fibers when removed.
 

Richit

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Jun 9, 2009
25
2 310 Coconut Grove, Fl
Thanks. I'll check that out. Good luck putting the repaired tank back into the boat.
 
Nov 18, 2010
2,441
Catalina 310 Hingham, MA
I never pressurize to check for leaks. It can cause a break or other problems. Instead vacuum test. You still close off the tank but instead of a compressor hook up a hand vacuum pump with a vacuum gauge. You can get one at Harbor freight or Amazon for $30. They are typically used for bleeding brake fluid. Then you watch the gauge to see if the vacuum drops quickly. If it does you have a leak.
 

Tom J

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Sep 30, 2008
2,301
Catalina 310 Quincy, MA
Richit, the fuel will stay behind the retaining dam for the tank, but only when the boat is level. I had a slow leak in my tank, and finally realized there was fuel in the bilge after I had been sailing, and the boat had heeled, allowing fuel to flow over the dam at the shallower ends.
 

Richit

.
Jun 9, 2009
25
2 310 Coconut Grove, Fl
Found a leak on my 13 year old aluminum tank. For those that may be wondering, it will come out the starboard side access panel after removing the water heater. The retaining dam for the tank holds water (and fuel) and has no weep hole. I also found that the shelf which holds the water heater is not water (fuel) tight, and has no weep holes. After removing the tank I still had weeping fuel and had to cut drain holes to get the fuel out from under the shelf. After several washings, I am hoping to be rid of the fuel smell. Will reinstall tank after Matt goes away.
Hi,
Last time we communicated you were working on the repair. Did you get the tank repaired and re-installed? Any issues with that process?
I definitely have a leak in the tank - probably in the back area and relatively low and small since it leaks about 1 oz per every couple of days. How did you remove the fuel before you pulled the tank? I'm still at 1/2 tank and it will be a while before it's down to a low enough level to pump out easily.
 

gpd955

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Feb 22, 2006
1,164
Catalina 310 Cape May, NJ
Step one is get the water good and hot so you can clean up the diesel fuel as you drain the tank ...
It's nice to see that someone realized that the hinge on the door through the bulkhead is better on the side than on the bottom! I'm surprised I haven't snapped the door in half doing work back there!
 

Tom J

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Sep 30, 2008
2,301
Catalina 310 Quincy, MA
Hi,
Last time we communicated you were working on the repair. Did you get the tank repaired and re-installed? Any issues with that process?
I definitely have a leak in the tank - probably in the back area and relatively low and small since it leaks about 1 oz per every couple of days. How did you remove the fuel before you pulled the tank? I'm still at 1/2 tank and it will be a while before it's down to a low enough level to pump out easily.
Our leak was a pinhole in a weld at a seam low and on the side of the tank. I think a guy with a mobile fuel polisher would be willing to pull your fuel out and store it until you are ready to refill the tank, and the fuel will be clean!
 
Mar 6, 2008
331
Catalina 310 Scott Creek, VA
I had about 10 gallons and drained it into fuel cans at the engine using gravity and the fuel pump
 

Richit

.
Jun 9, 2009
25
2 310 Coconut Grove, Fl
Thanks. No problems re-installing both the fuel and hot water tank?
 
Mar 6, 2008
331
Catalina 310 Scott Creek, VA
No problems on reinstall. I did have an issue with the water heater not heating. Upon trouble shooting the 1500 watt heating element had 110 volts going to it and read 9.5 ohms resistance when disconnected, but only pulled .288 amps and would not heat the water. I replaced the element, than realized I also had to reset the water heater (small red button under wiring cover) to get it to work. I replaced the element before I figured out the reset button, but it is possible I somehow turned it on in the last couple months while replacing the tranny damper plate before it was filled with water and partially cooked the element. All works now and the tempering valve was a great addition,