Cracked Fuel Tank 22 Cruiser

[CAVU]

I had a interesting and scary experience today. In the fall of 2006 I winterized CAVU and totally drained the tanks since I knew I would not be using it during 2007. I removed both tanks since I had to repair the tank hold-down screws pulling out of the floor. This past week I completed repairs and reinstalled the tanks. I towed the boat down to local station in fuel up. I put 10 gallons in the starboard tank, then moved to the port tank. I had 5 gallons in it when I noticed I was standing in a puddle of gasoline. The port tank was leaking very quickly. Since I only live about a half mile from the station, I towed it back home a parked in my gravel parking area. I unhooked it and raised the tongue as high as possible. I was able to drain most of the gas out the drain plug hole. A lot had collected in the bilge pump sump under the galley. I removed the tank and found a large crack in the middle of the bottom panel of the tank. In the pictures below the red color in the crack must have come from the dye in fuel. My last fishing trip to Canada I fueled many times on the water where you get red dyed fuel.
Has anyone else experienced a cracked plastic tank? I would never have expected a crack in the middle of a panel. More likely at a corner or along an edge?

 

[john schuler]

Sounds like you were lucky this story didn't go down hill from the leaking fuel
and standing in it at the gas station part. Good to have you still around Ken.
I have had plastic H20 crack but it usually involved freezing H2O and cows.
Not very likley in your case. Did you happen to tow the boat when it was
real cold? Or could it have got filled with water frozen cracked and then leaked out the crack? Good luck solving this.
:smiled john schuler :smiled

 

[Sea Wolf]

Ken-

My first instinct is that I think you're right about a tank being more likely to crack along an edge, but then the corners are stronger in some ways than flat panels where more flexion can take place. The corners get support from two or three panels intersecting, whereas the flat panels could bent and bowed out of shape more.

I'm wondering if water didn't freeze under the tank, forcing the bottom of the tank upward against the weight of the gas until it cracked from bending?

Looking at the same photos in your album in larger scale, it looks like you have another crack system developing nearby to the left of the one that leaked:



I guess you'll just have to replace the tank. It might be weldable with the propane torch system they use with polyethylene water and sewage tanks if it can be done with the gas tank temporarily filled with water, but one would always be hesitant about trusting a patched up gas tank. Ditto about repairing it with the Loctite 3030 Adhesive that glues plastics like HDPE (High Density Poly Ethylene).

Glad you didn't have any serious problems with the dangerous leak!

Joe. :teeth :thup

 

[CAVU]

Joe,
you are right about other cracks developing, they just haven't leaked yet but they are deep cracks. The boat is always stored under a carport and with the mooring cover on. I don't think any water ever stood under the tank. Sure glad it didn't start while on the water or with a full 20 gallon tank.

 

[westward]

I know that C-Dory had serious QC problems with their fuel tank vendor around 2002. I had the factory retrofit our old 1991 Cruiser with new fuel tanks then and had all kinds of problems. Ours had small pin-holes in the area around the filler neck, and the overall tank volume was inaccurate. I discovered both of these problems in an emergent way at a gas station in Anacortes. The factory stood behind their work. I suspect the factory would either give you new tanks or sell them to you at cost if you bring it to their attention and reference the era of yours. Good luck; I'm glad you weren't filling the tanks in-water! Mike.

 

[Dora~Jean]

Tough situation, glad you got through it unscathed. Also VERY GOOD the bilge pump didn't come on (if you have one between the tanks). I'd probably have disconnected or shut off the battery to ensure nothing electrical would be turning on. Thanks for the information, something else to be ready for, for all of us.

 

[Sunbeam]

...The port [fuel] tank was leaking very quickly... I removed the tank and found a large crack in the middle of the bottom panel of the tank. ... I would never have expected a crack in the middle of a panel. More likely at a corner or along an edge?

This is an older thread, but I happened upon it while searching for something else, and given my recent doings I thought I would comment. I have recently removed both my two fuel tanks (replacing them with new ones and a better installation), and my water tank (had it out to replace old hoses; now due to what I found also improving installation but with existing tank).

What I found to some degree with the fuel tanks, and to a higher degree with the water tank, is that the tanks were only supported on their edges, with the middle of the bottom unsupported (somewhat with the fuel tanks; moreso with the water tank). Plastic tank manufacturers generally recommend that these tanks be supported fully on their bottoms (i.e. everywhere).

In the case of the fuel tanks, the bottom of the tanks was flat, and of course the hull curves. It's a minor curve, so more than just the very edge is supported, but there is some tank "hanging" in the center. Maybe it deforms (bulges) enough to eventually gain support, but perhaps this helped contribute to the tank in this thread cracking in the center of the bottom panel. Obviously it doesn't happen to every (or even very many) tanks in our boats, but it may have been a factor.

In the case of the water tank, it was slightly too wide for the compartment, and so it was "installed" just hanging up on the hull side, and the only parts of the bottom of the tank that were touching anything were the very inboard and very outboard edge (which was resting on the hull side). By placing a panel under the tank (1/2" thick), the tank now sits fully supported on the hull (and the stowage above isn't reduced; it's just a bit flatter because the tank is sitting more level).

Just thought I'd add to the thread since I was here anyway - I hope it's not considered bad form to "dredge" an old thread up like this.

Sunbeam

 

[hardee]

I realize this is a fuel tank thread but the info in the last post about the water tank is highly interesting. Sounds like it is time to go looking under my tanks, unless anyone has more encouraging info the 2006 versions of the 22 Cruiser.

CAVU, any chance there was something under that tank, (ie a wire, nail or screw that could have worked it -- some sort of foreign body -- and left a "rust" stain mark?)

Thanks,

Harvey
SleepyC:moon

 

[Sunbeam]

I realize this is a fuel tank thread but the info in the last post about the water tank is highly interesting. Sounds like it is time to go looking under my tanks, unless anyone has more encouraging info the 2006 versions of the 22 Cruiser.

Just to give some perspective: Yes, unless C-Dory started using a different sized tank (which they may have), then your tank is probably "propped up" on the hull side like mine was. But, I haven't heard of any cracking, and of course it'd be water and not fuel. My guess is that the bottom of the tank bulges out enough (eventually) to contact the boat hull and give some additional support. I don't want to give the impression that there is something that direly needs attention.

Not that there is anything wrong with checking and improving it if it is unsupported. I was simply going in to replace my water hoses, and to eliminate the angle-bracket screw penetrations into the core under the tank; but of course once I saw how it was sitting in there then I wanted to take care of it. Having something installed "non-ideally" is one thing, but putting it *back* that way.... I just couldn't.

CAVU, any chance there was something under that tank, (ie a wire, nail or screw that could have worked it -- some sort of foreign body -- and left a "rust" stain mark?)

I'm not CAVU, but....I'd venture a guess that a "rusty look" could be from old/fuel in the crack. I say that because the fuel that had been in my (old) tanks for some years was dark/rusty looking like that, and often when things are dye tested and there is a crack, the crack "traps" some of the color and it looks kind of like that. I don't think the unsupported gap under the fuel tanks is anywhere near as large as the the one under the water tank was. On my new fuel tanks I'm going to start by testing out some medium durometer 1/4" thick rubber that I bought as an "underliner"; that alone may be enough to take care of the slight gap. Also, the new tanks are a bit thicker which will help. As usual... I'll see how it goes when I get into it.