building a propane locker...

[centerline]

Sumner, for my situation, the bottom of the locker is about 12-15" above the waterline at rest. The drain hose was run aft to about 5" above the waterline at rest. Under way, motoring, that waterline raises due to the flow around the hull and forces water into the locker. Under sail the waterline raises cuz of healing. Thought about putting a long clamshell over the hose penetration. It is compliant but not practical. The yard located the penetration when I was hauled for bottom paint. I didn't make an issue about it as I'm divorcing myself from that yard for various reasons....don't mean to hijack Centerlines post....

its not hijacking the thread, its adding a bit of information and ideas that I might hijack to solve a problem

I think a clamshell vent may actually solve the issue... if, when underway there is a venturi effect caused by the clam vent, it could keep the water out, or at the very least lessen the level of it....

also, ill have to do some checking when we go out next week, but there may be a spot on the aft part of the hull where the hull wave is lower when under way on the motor. this would be a good exit point thru the hull...

when heeling under sail, there is no hope other than the clam vent idea... thanks for that

 

[centerline]

The vent exit must be above the waterline when running under power as well as at any angle of heel. There cannot be any rise in the vent line - it has to be continuously downward for proper drainage and to eliminate any "P trap" effect that would restrict drainage of lpg.

I agree this would be ideal, but im wondering how many boats with tank lockers have some of these same issues.. possibly unknown to the owners.

I am aware that the rule does call for an unrestricted vent line from the bottom of the locker, exiting the hull at or below the bottom level of the locker....

but i will have to take my chances, i suppose, because i dont believe its possible for a boat below about 40ft to have the locker vent remain unrestricted 100% of the time when dealing with waves and heeling.....

my other reasoning is.... even as it may not be perfect, its a much better plan than i have now...
as it has been since I bought the boat, the propane tank is in the cockpit.
the cockpit coaming is 8" higher than the companionway opening. so this would mean that if the tank ever leaked while setting in the cockpit, it could flood the footwell with gas until it overflowed into the companionway and cabin, til it was saturated also.... its just as possible that it could happen as it is unlikely that there would ever be a leak of that magnatude that wasnt noticed and corrected before it got to that point.

so.. not that this is a proper arrangement for a propane tank, but many boats, especially livaboards, are using larger tanks in the cockpit without complaint by any authority..... maybe they assume the gases will exit the cockpit drains, or be blown away in the wind. or maybe it has just gone unnoticed.

so with the locker installed on my boat as it will be, there is still the possibility of the previous scenerio happening if the vent line should be passively restricted by water when underway, while a leak happens in the gas system and spills out thru the lid of the locker, filling the cockpit with gas, ect.... and, without being dissipated by the wind....

to greatly lessen the chance of that ever happening would be to create a lid/seal that could hold a couple of pounds of pressure, so if there ever was a leak in the system, it would push the passive water blockage free of the ventline to exit the gas, instead of being able to overflow out into the cockpit.
AND.... with a tightly sealed lid to the locker, it would likely prevent water intrusion during heeling under sail, due to the pressure being held in by the lid.

 

[Bob J.]

That's pretty cool. When I saw the shape of your locker it reminded me of a fiberglass basin that would be set below grade for a sump pump or in larger applications, a sewer ejector. That has me wondering if a small enough sump receiver could be adapted to use as a propane locker?

Thanks for putting that idea in my head & good luck with the project.

 

[mitiempo]

I agree this would be ideal, but im wondering how many boats with tank lockers have some of these same issues.. possibly unknown to the owners.

I am aware that the rule does call for an unrestricted vent line from the bottom of the locker, exiting the hull at or below the bottom level of the locker....

but i will have to take my chances, i suppose, because i dont believe its possible for a boat below about 40ft to have the locker vent remain unrestricted 100% of the time when dealing with waves and heeling.....

so.. not that this is a proper arrangement for a propane tank, but many boats, especially livaboards, are using larger tanks in the cockpit without complaint by any authority..... maybe they assume the gases will exit the cockpit drains, or be blown away in the wind. or maybe it has just gone unnoticed.

Propane will not exit cockpit drains unless they are above the waterline. An arrangement like that would not pass a survey. Insurance companies always listen to surveyors.

Below deck lockers always are more difficult to fit.

My locker (for 2 10lb tanks) will be draining through the transom just off center to miss the rudder 6" above the cockpit sole - the sole is over 8" above the at rest waterline. My boat is 27'.

 

[Apex]

Centerline, that is a BEAUTIFUL locker. I am looking to do something similar on the Oday soon. I look forward to seeing the finished product.
We disconnect and carry our small tank in the cockpit. Because we do not have a locker with vent, we disconnect each time....pain in the arse.

For VENTING, the stern is the place to go for keeping above waterline. MiTiempo has my same vent drain plan.

 

[centerline]

Propane will not exit cockpit drains unless they are above the waterline. An arrangement like that would not pass a survey. Insurance companies always listen to surveyors.

Below deck lockers always are more difficult to fit.

My locker (for 2 10lb tanks) will be draining through the transom just off center to miss the rudder 6" above the cockpit sole - the sole is over 8" above the at rest waterline. My boat is 27'.

the vent line WILL BE exiting above the waterline. almost 8inchs above the waterline.

I was planning to exit the vent out the side of the hull but going out the transom may be an option, but at this moment im not sure if the level of the transom is above or below the bottom of the proposed install position, but the shorter the vent line, the less chance there is of having any p trap effect due to a sag in the line..

im not sure if you plan a below deck locker, but if so i think once you get the depth of your locker figured in to the equation, you may have the same issues....

 

[mitiempo]

I'm not sure if you plan a below deck locker, but if so i think once you get the depth of your locker figured in to the equation, you may have the same issues....

No, not below deck but aft in the cockpit under the tiller. My cockpit footwell goes all the way aft to the transom. The bottom of the locker will be about 5 or 6 inches above the cockpit sole which is 8" above the waterline. The drain hose will be very short. The top of the box will be higher than the seats but not in the way. Plywood glassed inside and out.

I couldn't plan a locker below deck as the locker bottom would be below the waterline when sailing. Below deck lockers don't work on many boats.

 

[centerline]

No, not below deck but aft in the cockpit under the tiller. My cockpit footwell goes all the way aft to the transom. The bottom of the locker will be about 5 or 6 inches above the cockpit sole which is 8" above the waterline. The drain hose will be very short. The top of the box will be higher than the seats but not in the way. Plywood glassed inside and out.

I couldn't plan a locker below deck as the locker bottom would be below the waterline when sailing. Below deck lockers don't work on many boats.

thats a good use of the space in that area of your boat.... and the vent would definitely be above the waterline

I was at my boat today and set the casting in place.... it is on the port side just aft of the foot of the quarter berth.
the bottom of it is actually 10.5 inches above the waterline, but the bottom of the hull sweeps up to the transom and the transom is 2" above the bottom of the locker.... so its either venting out the side of the hull, or farther aft, but below the transom.

when we're out with it next weekend, I will check and see where hull wave/waterline level is when underway.

the white thing is the male mold.. ready to lay up another one.

 

[Sumner]

The mold and housing really came out nice.

The new regulator we bought had the pressure gauge on it (top arrow). Do you have something similar.

I like it as with the solenoid turned off (it is only turned on while the stove is in use) you can see if you have any kind of leak between the tank and the regulator and by closing the tank and having the solenoid open you can pretty much check the whole system. Still I soaped all the fittings after installing the new pieces but would still check the gauge from time to time. It is handy.

We bought a new continuous hose from the solenoid down to the stove to replace the old one even though it might of been ok. This stuff wasn't cheap but we felt a lot better using the stove on the boat while living in it after updating the whole system,

Sumner

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[centerline]

The mold and housing really came out nice.


The new regulator we bought had the pressure gauge on it (top arrow). Do you have something similar.

I like it as with the solenoid turned off (it is only turned on while the stove is in use) you can see if you have any kind of leak between the tank and the regulator and by closing the tank and having the solenoid open you can pretty much check the whole system. Still I soaped all the fittings after installing the new pieces but would still check the gauge from time to time. It is handy.

We bought a new continuous hose from the solenoid down to the stove to replace the old one even though it might of been ok. This stuff wasn't cheap but we felt a lot better using the stove on the boat while living in it after updating the whole system,

Sumner

Thanks.... the install will require moving the exhaust hose, but it may be time for replacement anyway.
i actually have more room in that area than I thought i would have, which will make the install much easier.

the boat is already set up for propane. it passed the survey without problems.
since then i have replaced the lines to both the gas stove/range and the force10 heater....

it had a seaward locker installed for a 1gallon propane bottle, but i wanted bigger and more out of the way.
the seaward locker was installed directly below the laz hatch... in the way of everything, and made it very difficult to get down in there to work on the engine/pumps/batts, ect....

this will be bigger, better, out of the way and virtually unseen...

 

[Benny17441]

I don't see where he needs an airtight lid but the compartment does need to be sealed from the interior of the boat and it looks like he has that covered....



.... since it will be sealed to the underside of the settee and have the vent in the bottom,

Sumner

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Summer, a lid is part of a propane locker design so that in the eventuality that the vent should become blocked it will help prevent the propane from spilling out inside the hull. It had not occurred to me that the top of the locker would be attached to the underside of the settee. It may likely be a little difficult to remove the tank every time a re-fill is needed.

 

[centerline]

Summer, a lid is part of a propane locker design so that in the eventuality that the vent should become blocked it will help prevent the propane from spilling out inside the hull. It had not occurred to me that the top of the locker would be attached to the underside of the settee. It may likely be a little difficult to remove the tank every time a re-fill is needed.

as seen in the last photo i posted, with the casting (temporarily) in place, there will be a hole cut out of the settee above it for access... the tank will be lifted directly up and out.... i will install either a ready made hatch covering the access hole, or a custom cover of my own design. either way, it will be a sealed lid, but any gas that escapes out the lid will vent to the cockpit...

 

[mitiempo]

Keep in mind that the vent exit has to be 20" minimum from any other exit or intake to meet ABYC.

 

[Sumner]

Summer, a lid is part of a propane locker design so that in the eventuality that the vent should become blocked it will help prevent the propane from spilling out inside the hull....

Ok, thanks, I can see in some situations a sealed lid might be important.

I guess I'm guilty of tunnel vision I had in mind the Endeavour...

... that has a very high coaming around the cockpit ant the locker is on the outboard side of the coaming (show with door removed above). Here even if the vent tube plugged the gas would only rise an inch or two and then spill out the door, that doesn't seal, and down over the side of the boat not into the cockpit or interior.

Sumner

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