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-   -   Propane on stern rail - doing it right. (http://www.sailnet.com/forums/gear-maintenance/66394-propane-stern-rail-doing-right.html)

cghubbell 07-12-2010 10:11 AM

Propane on stern rail - doing it right.
 
After much deliberation I have given up on building a propane locker in my CS27. It would take up too much locker space that I need for other purposes. With that in mind, I need to improve my "tank on the stern rail" configuration.

At the moment, I have a rubber gas lin which exits my fiberglass cockpit coaming at the stern with a lovely GOB of 5200. It looks awful and over the years has cracked, and no doubt leaks.

Most of what I can find on-line for gas standards applies to propane lockers, and doesn't apply to stern rail configurations. I'd like to make sure everyhing is as safe and well thought out as possible. With that in mind I have a few questions I'd appreciate hearing "best practices" on...

- What is the right way to have a flexible gas hose exit the fiberglass (to reach the external tank) and be protected from chafe? I've seen lots of wire "glands", but it seems like they would (1) be too small for a gas line, and (2) I don't want to compress the line, do I? Those glands are water tight by compression.

- Is there any special type of hose or fittings or treatment I need to consider for the gas line as it is exposed to the elements vs. always being protected in a locker? My current hose is showing some signs of UV damage (drying out), although minimal. Note that I am in fresh water, although future brief salt water is a dream.

- I'm assuming I don't need to use a electronic gas relay / valve with the tank on the rail since I just use the manual valve for on/off. Is this right?

- Any other "gas on the rail" best practices you can share would be appreciated. I'm ripping it out now and will be replacing it soon, so all design recommendations are appreciated.

Thank you in advance,
Chris

sailpower 07-12-2010 10:19 AM

I’ve always been told that the purpose of the solenoid shutoff is so that you close it first and allow the gas in the line to burn out before you secure the stove/cooktop. Saves having to go out to the cockpit before you turn the stove/cooktop off.

sailingdog 07-12-2010 11:14 AM

Quote:

Originally Posted by cghubbell (Post 621654)
After much deliberation I have given up on building a propane locker in my CS27. It would take up too much locker space that I need for other purposes. With that in mind, I need to improve my "tank on the stern rail" configuration.

At the moment, I have a rubber gas lin which exits my fiberglass cockpit coaming at the stern with a lovely GOB of 5200. It looks awful and over the years has cracked, and no doubt leaks.

Most of what I can find on-line for gas standards applies to propane lockers, and doesn't apply to stern rail configurations. I'd like to make sure everyhing is as safe and well thought out as possible. With that in mind I have a few questions I'd appreciate hearing "best practices" on...

- What is the right way to have a flexible gas hose exit the fiberglass (to reach the external tank) and be protected from chafe? I've seen lots of wire "glands", but it seems like they would (1) be too small for a gas line, and (2) I don't want to compress the line, do I? Those glands are water tight by compression.

Get a bulkhead gas-proof fitting for the gas line. This will be much better and easier to maintain. They look like this:

http://www.defender.com/images/400200.jpg
photo courtesy of Defender.com, click photo to see product page there.

- Is there any special type of hose or fittings or treatment I need to consider for the gas line as it is exposed to the elements vs. always being protected in a locker? My current hose is showing some signs of UV damage (drying out), although minimal. Note that I am in fresh water, although future brief salt water is a dream.[/quote]

Fit some cable loom over the gas line where it is exposed. This will protect it from chafe and UV damage.

- I'm assuming I don't need to use a electronic gas relay / valve with the tank on the rail since I just use the manual valve for on/off. Is this right?[/quote]

Don't need to have a gas relay/solenoid setup, though having one with a gas alarm is a good idea on a boat. Getting the gas alarm by itself would be a wise idea. This one can be used as just an alarm, but does have a switch for a solenoid if you decide to add one later.

http://www.defender.com/images/550039.jpg
photo courtesy of Defender.com

Quote:

- Any other "gas on the rail" best practices you can share would be appreciated. I'm ripping it out now and will be replacing it soon, so all design recommendations are appreciated.

Thank you in advance,
Chris
See below....

Quote:

Originally Posted by sailpower (Post 621657)
I’ve always been told that the purpose of the solenoid shutoff is so that you close it first and allow the gas in the line to burn out before you secure the stove/cooktop. Saves having to go out to the cockpit before you turn the stove/cooktop off.

You can easily achieve the same purpose by leaving the burner going and then going out to shut the main gas valve off and then coming back in to shut off the burner. Not quite as convenient, but does end up with the same result, and its what I do on my boat. The tank valve is shut off unless I'm actually about to use the stove.

cghubbell 07-12-2010 11:40 AM

Thanks SD - excellent information, and exactly what I was looking for. Not sure how I missed the fitting as I've spend half of the past two years with my nose buried in marine catalogs. Guess I'd better start reading them all over again!

I agree with the use of a propane fume detector, and had been looking at the same one you posted.

I like the idea of using the manual valve on the tank vs. a solenoid as it's simpler. I don't mind climbing outside briefly even if it's raining.

Now I just need to invesitgate some canvas work to tame the aesthetics a
bit.

sailingdog 07-12-2010 11:56 AM

Glad to help. :D

JohnRPollard 07-12-2010 12:23 PM

The vapor-tight compression fitting that SD showed is definitely the way to go. By the way, they are VERY easy to install, so no worries in that respect.

I would still advocate for a remote solenoid shut-off. In fact, I'm not sure if ABYC makes any distinction as to where the tank is mounted -- I think the remote switch is required regardless for any propane installation. If so, you should follow the requirement as it can affect insurability of the vessel, and it's the best practice anyway.

As an aside, I don't believe closing the propane valve (whether at the tank or solenoid) while continuing to operate the appliance "empties" the line of propane. I think this simply stops the flow of propane and extinguishes the appliance. If new propane is not entering the hose from the supply end, a vacuum is created and the flow simply stops.

But there isn't enough volume of propane in the line to worry about anyway. The worry comes from not closing off the supply. Which is why the remote shut-off is so important.

Make sure your hose is continuous all the way from the tank/solenoid to the appliance. No splices or extensions.

As for mounting your tank to the stern rail, you might consider an arrangement that looks a bit cleaner. These folks mounted two small tanks in brackets to the transom:

http://farm3.static.flickr.com/2105/...dff1ac354f.jpg

Faster 07-12-2010 12:34 PM

Here's how we did it on our previous boat... We made SS tubing hoops that the bottom ring of the tank fit into, attached to the pulpit uprights, and dropped the tanks in place then bungeed them secure. The line for the stove lead through the transom via a gland fitting after a solenoid valve.

Don't underestimate the convenience, (and hence, increased safety) of having the remotely switched solenoid. It's a much quicker, easier way to kill the propane source should something go terribly wrong below - and as it's so convenient human nature say's you'll use it more appropriately.

http://i213.photobucket.com/albums/c.../cockpit-1.jpg

josrulz 07-12-2010 12:38 PM

Quote:

Originally Posted by JohnRPollard (Post 621699)
...As for mounting your tank to the stern rail, you might consider an arrangement that looks a bit cleaner. These folks mounted two small tanks in brackets to the transom:

http://farm3.static.flickr.com/2105/...dff1ac354f.jpg

Wow, all things considered, that's a slick installation at least on that particular boat. With rudder and self-steering back there anyway, it's hardly noticeable.

sailingdog 07-12-2010 12:50 PM

JRP—

Leaving the burner lit when closing the valve on the tank or the solenoid will allow the stove to burn off most, if not all, of the propane that is in the line.

I agree that having a solenoid is a best practice, but don't believe it is a requirement.

I don't think that's a very clean looking installation. The tanks are far more likely to get exposed to salt water there and the regulator is hanging by the hose by the looks of it. Of course, if you're going to do an installation similar to that, you're really best off using COMPOSITE tanks rather than aluminum or steel tanks.

Also, I don't know if having the tanks mounted where they can bet hit by the rudder is such great idea.

Quote:

Originally Posted by JohnRPollard (Post 621699)
The vapor-tight compression fitting that SD showed is definitely the way to go. By the way, they are VERY easy to install, so no worries in that respect.

I would still advocate for a remote solenoid shut-off. In fact, I'm not sure if ABYC makes any distinction as to where the tank is mounted -- I think the remote switch is required regardless for any propane installation. If so, you should follow the requirement as it can affect insurability of the vessel, and it's the best practice anyway.

As an aside, I don't believe closing the propane valve (whether at the tank or solenoid) while continuing to operate the appliance "empties" the line of propane. I think this simply stops the flow of propane and extinguishes the appliance. If new propane is not entering the hose from the supply end, a vacuum is created and the flow simply stops.

But there isn't enough volume of propane in the line to worry about anyway. The worry comes from not closing off the supply. Which is why the remote shut-off is so important.

Make sure your hose is continuous all the way from the tank/solenoid to the appliance. No splices or extensions.

As for mounting your tank to the stern rail, you might consider an arrangement that looks a bit cleaner. These folks mounted two small tanks in brackets to the transom:

http://farm3.static.flickr.com/2105/...dff1ac354f.jpg


JohnRPollard 07-12-2010 01:40 PM

Quote:

Originally Posted by sailingdog (Post 621708)
JRP—

Leaving the burner lit when closing the valve on the tank or the solenoid will allow the stove to burn off most, if not all, of the propane that is in the line.

Dan, I have heard that claim, but I think it's erroneous for the reasons I mentioned above.

I would argue that if your line evacuates when you close the valve off and leave the appliance running, you probably should run a pressure check of your propane system. Because something has to replace the propane that is passing through the hose to the appliance, or else a vacuum would form. If it's not more propane from the tank, it would have to be atmosphere from outside the system being sucked in.

I do turn off the solenoid before extinguishing the appliance, but only to confirm that the valve closed properly. On our boat, the appliances extinguish almost instantaneously. And I've never noticed any lag when the valve is turned back on within a short period of time, suggesting the line remains full of propane.

Compare that to the lag noticed if the appliance hasn't been used for a while (days/weeks). But that is due to the permeability of the propane lines themselves -- a certain amount of the gas passes through the hose walls over time.

Either way, closing the valve is a good idea, and as Faster said -- because of human nature -- making it convenient to do so via a remote solenoid is the best approach.


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