Gas Odor Below Deck

[sandycohen]

Hi!

I recently purchased a 23' cruiser - it has a small 2 berth cabin which is basically open to the below deck area under the cockpit, and locker in the stern which is basically a bunch of empty space above the bilge with a shelf for the 6 gallon plastic gas tank next to the tiller shaft.

Whenever I open the cabin or locker there is a very strong gas odor and the gas tank itself is 'wet' with what appears to be gasoline. The vent is closed to the tank, and the boat has minimal ventilation - just through a louver on the companionway boards.

I realize better ventilation is in place, but why would gasoline be condensing onto the tank in any case? If there is some gas in the bilge (it's very dry) wouldn't it eventually evaporate and escape and work itself away if there is no ongoing leak (which i see no evidence of)?

Thanks!

sandy cohen

[sailvayu]

Hold on, Time out you need to take that gas tank out of that locker like now!

you are building a not so small bomb here!

Gasoline vapors are very explosive. Unless I miss understand your description the place you have for the gas can is not properly vented or designed for gas storage.

I would remove the gas can NOW! then contact the builder and see if this area is rated for the storage of gas. Really this is nothing to mess with one small spark and you can blow up I have seem it happen twice and it is not pretty.

If you cannot contact the builder PM me and we can see if we can figure this out in the mean time take the gas can out of that locker!

Not kidding here

Wayne Canning, AMS
projectboatzen.com
projectboatzen.com

[Vasco]

Your gas tank may be leaking probably at the hose connection or a pin hole in the hose. The only condensation on the tank should be water. Take it out, clean and test it. Not a desirable situation in a poorly vented locker.

[sandycohen]

Thanks - what is the procedure to test it?

[FSMike]

Another idea is to keep it off the boat for a few days to see if the odor leaves. On a new to you boat you may have an undiscovered source of gasoline, like a small can hidden away somewhere.

[Chief Engineer]

Do you have an outboard?

Sounds to me like the 6 gallon tank is an outboard tank (portable) and the vent fitting was left open.

Get-it-out-of-there-p-r-o-n-t-o

[SkiprJohn]

Aloha Sandy,
Congratulations on the new boat. Yes, definitely remove the tank.
Your tank is plastic and let me tell you what I've discovered on two of my most recent tanks. There are factory voids in the sidewall or bottom of a few. The last time I took my plastic tank for a ride in the back of my pickup the sun expanded the tank and caused the very small pinhole to start leaking. As soon as I backed off the pressure the leak stopped. The point is I've had this tank for 4 years and it had never leaked before.
There is an easy fix but first you have to find the leak. Easy fix? Screw a small stainless panhead screw into the little hole with a bit of silicone on the screw head after you've cleaned up the tank really well.
regards

[Solitude]

Is this tank just for storage or is it the fuel tank to the motor. You must remove it. my outboard tank to my dingy will leak gas when the vent is closed and its pressurised by forcing the gas up the PU pipe and out the fitting. Its never stored on the boat.

[Ex-Calif]

If you are going to keep gasoline on the boat it must be properly vented. There are plenty of resources to determine how to properly vent the locker and to isolate it from the rest of the boat.

The wetness on the outside of the plastic tank is likely condensation, especially if it is all over the tank. I suspect you have significant temperature swings from day to night and you in a relatively humid climate. Overnight the air cools and the relatively warmer fuel will allow water to condense on the outside.

During the day the air expands in the tank and it is forcing itself to vent somewhere. Probably a clamped rubber hose connection.

You have an extremely dangerous situation on your boat that must be fixed immediately. The suggestion to remove the tank from the boat when not in use is the best immediate action.

[senormechanico]

I once saw the results of a boat/gas explosion. It was a wood cabin cruiser that he had spent a couple of years restoring. The only thing he hadn't finished to perfection was the carburetor on his inboard engine. It always started up nicely when cold, even without needing to use the choke but he never ran it for more than a few seconds until today.

He loaded his wife and baby aboard and headed down the Sammamish Slough. They hadn't gone more than a half mile when it exploded. The baby was blown out of the boat and both parents managed to swim to shore with minor burns. The boat sank but was recovered the next day. Every single seam was opened up, and when a crane lifted it, they deposited the whole boat into a dumpster.