LPG tank vents not located properly

[paulj]

Any other Catalina owners have this problem....

http://forums.catalina.sailboatowners.com/showthread.php?p=629331#post629331

paulj :troll:

 

[Dan H]

It would be interesting what ABYC says with regards to propane storage. I would like to store some of those little propane cylinders in a cockpit locker. I want to install an overboard drain and wonder what the specs are for drain to locker size, ect. I realize that it is a complete system, point of use and all that, so storing it is the only part of the standard I'll meet, but none the less. Anybody have a copy of that handy?

 

[sailingdog]

Basically, any locker used for LPG storage is supposed to be air-tight to the interior of the boat, and have a vent that drains overboard at the lowest point for the LPG to drain out of.

 

[Bill]

Yes I have had the problem, more so with the opposing locker in which I keep backup ropes and small cylinders of grill gas. The problem with mine is that there is a screen at the discharge end to stop bugs from getting in and clogging the drain. Reverse that though and add a little dirt and you have a clogged drain due to the screen loaded with dirt. Mine is a bitch to clean. Not well thought out. Most likely the next time it occurs I will reconfigure without the screen and with a larger discharge. At least then I can stick a hose on it, turn it on and blow it clear.

 

[Banooma]

Paul -

Sorry, but the problem is not clear? I have a similar design on my 28mkII, where the propane tank has a dedicated locker in the cockpit coming. I believe propane is a "heavy" gas, and if there is a leak, it would follow gravity down the hoses and out the transom. If the drains were much lower, they would be submersed and unable to vent at all. Is your propane tank stored lower than those vent holes?

 

[Jim Parks]

C-310 Propane Storage

Any other Catalina owners have this problem....

Paul:

Call Catalina.

I recall a couple of years ago this was a topic on the old C-310 mail list that Sailnet used to host. Per the discussion at that time, Catalina was sending a retrofit kit and instructions to owners who were unhappy with their propane locker venting. I never followed through on mine, so I don't know exactly what Catalina sent.

 

[paulj]

The LPG tank bottoms are 2" below vent holes shown in photo.


Jim Parks
Thanks for the information..............



Dan H

1.8
LPG LOCKERS

1.8.1 Lockers used to contain LPG cylinders, cylinder valves, regulating equipment and safety devices shall be
designed to minimize the likelihood of use as a gear storage locker and shall be,
1.8.1.1 vapor tight to the hull interior, and
1.8.1.2 located above the waterline, and
1.8.1.3 constructed of, or lined with, corrosion resistant materials, and
1.8.1.4 shall open only from the top with
1.8.1.5 a gasketed cover that shall latch tightly, and
1.8.1.6 shall be capable of being quickly and conveniently opened without tools.
1.8.2 Installation
1.8.2.1 LPG lockers shall be installed so that the locker opens only directly to the outside atmosphere, and
1.8.2.2 If a LPG locker is installed inside a boat locker, the LPG locker shall be located as high and as close to the
boat locker’s opening as possible in order to comply with
A-1.8.2.1.
1.8.3 When means of access to the LPG equipment locker or housing is open, the cylinder valves shall be
capable of being conveniently and quickly operated, and the system pressure gauge dials shall be fully visible.
1.8.4 Lockers shall be vented at the bottom by a dedicated vent, with a minimum diameter of any component in
the vent system that shall be not less than 1/2 inch (12.5 mm) inside diameter.
1.8.5 Locker vents shall be led outboard, without pockets, through the hull to a point lower than the locker bottom
and above the waterline with the boat in the static floating position.

NOTE: See
ABYC H-27 Seacocks, Thru-Hull Connections and Drain Plugs, for requirements for seacocks.

1.8.6 Locker vent openings shall be located at least 20 inches (508 mm) from any hull opening to the boat interior.
1.8.7 LPG lockers shall not be used for storage of any equipment other than LPG cylinders, cylinder valves,
regulating equipment, and LPG safety devices. See
A-1.8.1.
1.8.8 Storage provisions for unconnected reserve cylinders, filled or empty.


paulj :troll:

 

[Dan H]

Thanks Paul J, that's what I was looking for.

 

[SoSound]

What do I not understand here with regard to this standard? My previous hobbies and activities have involved some very explicit and very technical rules and specs... This one says that every boat built to it must have a vapor proof container, which may only open from the top, which must then have a vent installed in the bottom... Which virtually guaranties that in the event of an obstructed vent (which is likely if there is only one gravity fed exit from the compartment), that gas will accumulate inside the propane locker?
Dave

 

[Stu Jackson]

Tank vents

What do I not understand here with regard to this standard? ...Which virtually guaranties that in the event of an obstructed vent (which is likely if there is only one gravity fed exit from the compartment), that gas will accumulate inside the propane locker?

Dave,

Um, think about it a lot more. The vent size is MIN 1/2 inch. Even though the top is specified to be sealed, the vent line itself is big enough to let air in and propane out.

 

[SoSound]

Maybe I'll just mark this one down as being overly paranoid and inexperienced. I'm not likely to have to deal with a newly built boat any time soon. But the photos posted in the Catalina forum don't seem to have very large vents. One set of photos shows that the vent turns 90 degrees at the point that it exits the locker. I can just see a number of very reasonable circumstances where the system could still accumulate enough gas to be a huge hazard...

Proper inspections must check for a system which functions properly, not simply that it exists, or this post wouldn't have been started to begin with? Still, how many posts have you seen where a person is advised to check for an obstructed vent hose in various systems?
Dave