Seems to me the propane is not going to push the flapper open.

Would a vent through the transom make more sense (heeling does not affect the center line)?

Does the box have a lid? Propane is not that heavy. It would not be difficult for the propane to overflow the box and go into the locker or the cockpit. I wonder if this design will be any better than simply storing cylinders in the locker, which you have ruled out.

Unfortunately, I do not believe this is a suitable location and the problems may not be fixable. Is there no place to install a new deck hatch, away from the cockpit?

Stay safe.

 

The vent has to be a minimum of 1/2" inside diameter. I would skip the valve and the flapper as the drain has to always be open. The locker, although inside, will need a tight fitting lid as well.

 

OK I failed to say it is under construction, the propane locker. We have a lid and a seal for the lid. We are fiber glassing the box now.
There is no other place for the box. It will work if we use a long hose to a through hull located in the aft port side. We are just trying to get away from that.
I figured if the through hull was located in such a place that it was pointed down the flapper would by default stay open. This was I guess another crazy idea I had to run by someone else to see if it was really crazy.

 

I am not liking this especially if you a putting this in a lazzarette which actually is inside the hull and there maybe a panel which opens to the engine compartment. Oour lockers are under the port and starboard helm seats which does not empty anywhere into the hull of the boat and is solid fiberglass.

Dave

 

SDC,

I agree with these guys to skip that flapper. I also share some of their concerns about the location of the locker. In any event, your should 'glass the inside of that locker too, not just the outside. that might require taking it apart and 'glassing the components individually before re-assembling.

The idea we have been thinking of is a scupper (to keep weight down) coming out the bottom of the locker and then a hose to a through hole with a valve on it for safety above the water line and at a slight downward slant.

Another thing: In the sentence above, when you say "with a valve on it", are you referring to the flapper? It's not clear to me, but it sounds like you might also be contemplating a seacock-type valve on that through-hull fitting, so that you can close it? If so, it's my understanding that ABYC does not permit a close-able propane locker drain, i.e. no seacock.

Some of these other guys may know the answer to that, but it is something you should clarify before adding a seacock or other close-able valve.

Sometimes, the only way to get "drainage" on all points of sail, is to have two drains.

 

There cannot be either a valve or flapper in the vent hose. It must "always be open" which also means it cannot be able to be closed. The outlet of the vent on the hull has to be a minimum of 20" from any other hull opening to the boat's interior.

From ABYC

 

Wow this is some great information about the location and the valve on the through hole.
We will not be putting a valve on the propane locker through hole then and will keep it 20 inches away from any other.
Last night I was working on the propane box, glassing the inside. It is getting glassed inside and out and the top will be glassed also, top and bottom. Then it will get a hole curt in the bottom for a vent hose to the through hole. NO flapper or valve.
Thanks for this important information, it is just what I was looking for.
Chip

 

SDC, Looks like you're doing some nice work there.

When it comes time to run the propane line(s) from the locker to the appliance(s), be sure to use something like this where the line exits the locker: Trident Vapor Tight Fitting. These are really slick and easy to install.

 

I agree with John, but try and find an electrical supply house - they cost less. After buying mine from a marine store I was at my electrical supplier one day and found them for $1.25 to $2 each in many sizes. Exactly the same product without the package.