CNG to Propane?

Apr 24, 2020
99
Hunter Cheribini 37 South Portland
My Boat has a nice stove with an oven that runs on compressed natural gas. It's getting very very hard to find that gas. I'm considering converting the boat to propane. Can I convert the stove and oven to propane without much trouble? Has anyone done this? I understand I'd have to put together a propane locker and solenoid.
 

TomY

Alden Forum Moderator
Jun 22, 2004
2,768
Alden 38' Challenger yawl Rockport Harbor
My Boat has a nice stove with an oven that runs on compressed natural gas. It's getting very very hard to find that gas. I'm considering converting the boat to propane. Can I convert the stove and oven to propane without much trouble? Has anyone done this? I understand I'd have to put together a propane locker and solenoid.
I converted my stove from CNG to LPG a few weeks ago, Dan. The stove is an old Tasco but in perfect condition. Tasco no longer exists but the stoves gas pieces are pretty generic. This stove is pre- thermo couple burner, except for the oven.

I found the parts to convert on a Seaward dealer's website. All I needed is here - photo are the CNG orifices:

3 LPG orifices for the top burners(these simply bolt onto the burner valves).
1 LPG orifice for the oven burner (larger hole for larger burner).
1 LPG oven pilot orifice (you have to remove the flare joint to get at that - photo).

IMG_5117.jpeg


That's it for the stove conversion. Once installed, I connected a test LPG tank , regulator, and hose and tested it. It works great, it looks hotter and all three burners and oven going worked fine.

I'll install a new gas line, regulator, and tanks. I'm lucky, I have a deck box that will easily hold up to 3, 5-pound (1.2gal - about 20% more BTU's than one CNG cylinder) LPG tanks.

I can forego dealing with a vented locker.

I'll also install an LPG sniffer.

My last tank of CNG, after trucking, inspections, 1 failure, cost $350 for the 20 hour tank. Almost cheaper to go out to dinner.
 
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Likes: kloudie1
Dec 25, 2000
5,855
Hunter Passage 42 Shelter Bay, WA
Hi Dan. Similar problem, but a different model boat. Checked several sources for an oven conversion kit for our Seaward brand stove. Burners yes, oven no. Good thing I waited until my last tank was emptied, because I learned of a regional CNG supplier in Fife, WA. So now I'm good and no need to convert to propane at this time.

Converting would have set me back a few thousand. A new stove/w oven, two five gallon tanks, a tank storage bin, etc. If you store the tanks in a locker, it must be properly vented to allow any gas to escape. Otherwise, there is a risk of an explosion/fire as propane is heavier than air, so it tends to seep down to the lowest point of the boat. Not so with CNG as it is lighter than air.

Do some further digging before you convert. Natural gas is pretty common, especially with industrial companies that use vehicles powered by CNG. That is who filled my two tanks for $30 each. It also cost $60/each to have the tanks re-certified, good for five years.
 
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Likes: jon hansen
May 7, 2012
1,476
Hunter e33 Maple Bay, BC
:(
I converted my stove from CNG to LPG a few weeks ago, Dan.
Out of an over abundance of curiosity, for insurance purposes, @TomY, would there be a need to have a boat surveyed after such an installation?
 

TomY

Alden Forum Moderator
Jun 22, 2004
2,768
Alden 38' Challenger yawl Rockport Harbor
:(

Out of an over abundance of curiosity, for insurance purposes, @TomY, would there be a need to have a boat surveyed after such an installation?
Not that I know of. My insurance co. calls for an insurance survey every 5-6 years. As long as the LPG is correct, I doubt an older stove without thermo-couple burners would be an issue .

ABYC doesn't allow fireplaces, but mine passes with flying colors, everytime.

Fireplace.jpg