LPG locker filling with seawater

[mitiempo]

I believe the flap fills the exit hole except when the weight of water opens it. Propane will not open it and it is a restriction a surveyor wouldn't approve of.

[0verdrive]

Originally Posted by mitiempo

I believe the flap fills the exit hole except when the weight of water opens it. Propane will not open it and it is a restriction a surveyor wouldn't approve of.

I'm not entirely sure how that specific flap works, so you may be right. But if the scupper is always open (not a close-able flap), the water moving past it actually creates a vacuum, which will suck water (and any gas) out. On my boat, if there's little or no water to be sucked out, you can actually hear the vacuum - it sounds like the saliva-sucker tool in a dentist's office.

That said, the reqs for a larger boat may not allow this sort of mechanism, unless it had some sort of stop-valve that could be shut in case of emergency?

[mitiempo]

From ABYC propane regs:

[KeelHaulin]

While those ABYC definitions are considered the industry standard; they don't always work in sailboat installations; especially on boats with low freeboard. The locker vent exit should be high enough up above the waterline so water from heeling or boarding seas can't get in. That's a primary consideration. The specifics of the ABYC code for 'draining' the propane is secondary. If you have a dedicated propane 'locker' on your boat; the locker should have a sealed lid and hose ports so that if any propane gas escapes it will only exit via the vent. In this configuration there is no place for the gas to vent other than through the tube, which means that it does not matter how high it is in the locker (or at the exit) so long as the exit is to an overboard location. This configuration is similar to a gasoline tank vent or diesel tank vent. Since the locker is sealed it simulates a fuel tank and will vent in the same way.

[mitiempo]

I understand what you are getting at.

But surveyors go by ABYC and insurers go by surveys. One boat I worked on had the locker drain a few inches above the locker bottom. The surveyor stated it had to be changed in his report and the insurer listened to the surveyor.

[Hartley18]

Originally Posted by MarkSF

Right now I can't come up with a better plan than raising the tanks an inch or two, getting fibreglass ones, and hosing out the locker after a sail!

Mark, for all practical purposes, that's probably a reasonable plan.

If you're buying new fibreglass tanks, first check that you're allowed to fill them wherever you intend to go. Alternatively you could possibly fibreglass ordingary glavanised steel ones yourself to within an inch or so or the top. It's crude - and ugly - and doesn't stop you needing to hose out the locker after a rough day on the water, but it will make them last a little longer.

[mitiempo]

The composite tanks are approved in both Canada and the US. I doubt you will have a problem filling them anywhere.