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CNG tank fill or exchange... PNW... Anacortes, Port Townsend???

Dec 25, 2000
3,906
Hunter Passage 42 Shelter Bay, WA
To follow up on this, I found a ready supplier of CNG in the PNW... but it is anything but convenient. It is a welding gas company out in Ellensburg. I have arranged to pick up a tank in spring. That seems to be the most economical solution for me, in the PNW, at the time.
Do you have the name of the company, or phone number? Unable to find any place around here (Seattle, Anacortes, Everett, etc.) that will exchange or fill an empty CNG tank. There is a CNG filling station near Seattle, but they only fill vehicles. Still looking for a source. Anybody, anybody?
 
Nov 10, 2018
23
S2 9.2a Marblehead, Massachusetts
Lucky for me, my local chandlery still exchanges tanks. They get their supply from the Corp Brothers in Providence, Rhode Island. I guess they are now called Tech Air. Anyway. It is a national company so they might be worth contacting.
 
Jul 1, 2019
2
C&C 38-3 Telos San Diego
I just signed on and read a few pages of this; so dont flame me too badly.

There are several references to both CNG and Propane. To be clear, Compressed Natural Gas and Propane are not the same thing. CNG remains a GAS in compressed form in the tank and is widely used in Cars and Trucks. Propane less so. Propane becomes a liquid when compressed at Normal Temperatures (read room/ambient).

I dont recall boats having CNG as those small (1-2 gallon) bottles have so little fuel, they dont last long. Propane on the other hand has a lot more storage capacity since its a liquid.

If there are CNG equiped boats, Id be interested in knowing the benefits/issues using this fuel onboard.
 
Jun 11, 2004
812
Oday 31 Redondo Beach
If there are CNG equiped boats, Id be interested in knowing the benefits/issues using this fuel onboard.
Unlike propane, CNG is lighter than air. The theory is that if there is escaping gas CNG will dissipate into the atmosphere and be less explosive and propane will pool in the bilge or cabin and be more of a hazard.

CNG tanks on boats are typically the same as what you might know of as a steel 72 cubic foot scuba tank (with a different valve).
 
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Nov 10, 2018
23
S2 9.2a Marblehead, Massachusetts
I think CNG is better from a safety standpoint for sure. That said it is becoming very hard to find. It just didn't catch on, perhaps because of the super high pressure the tanks hold, mine just got filled to 2500 psi. I know people diss alcohol but that will be my next stove. That said, the standard, the Origo stoves are being phased out by Dometic, which now owns that company. I was able to locate the two burner version (Origo 3000) and bought one to put into storage. I'll install it on my boat when I can no longer get CNG. If I bought a new boat and it came with propane as they all do, I would keep it, but not going to plumb an old boat over again, especially one that has no place for a dedicated propane locker.
 
Jan 25, 2011
2,002
S2 11.0A Anacortes, WA
I think CNG is better from a safety standpoint for sure. That said it is becoming very hard to find. It just didn't catch on, perhaps because of the super high pressure the tanks hold, mine just got filled to 2500 psi. I know people diss alcohol but that will be my next stove. That said, the standard, the Origo stoves are being phased out by Dometic, which now owns that company. I was able to locate the two burner version (Origo 3000) and bought one to put into storage. I'll install it on my boat when I can no longer get CNG. If I bought a new boat and it came with propane as they all do, I would keep it, but not going to plumb an old boat over again, especially one that has no place for a dedicated propane locker.
You can hang two 1.8 gal propane tanks off the stern pulpit!
 
May 20, 2016
2,804
Catalina 36 MK1 Everett, WA
When I bought Mahalo it had 2 6lb tanks hung off the stern in fender holders. Very ugly - I made a holder out of 1” Al angle and pop riveted starboard to the outside then hung from the push pit. Looks so much better!! It goes with the white of our winter cruise
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Oct 26, 2010
781
Hunter 40.5 Beaufort, SC
All you Chemist's out there. Since CNG is primarily Methane (maybe all methane except impurities?) why can't you order a Methane tank (size 80) from a welding gas supply store and use that? Is there some reason this won't work? I have found several commercial gas suppliers that can and will sell Commercial Grade Methane in about the $100 for a filled cylinder. I know that is pricey compared to Propane and the energy density of the Methane is less than LPG. This is not a discussion of whether to convert or not. As little CNG as I use each year I could buy a lot of tanks for the price of the LPG conversion (LPG locker, new hoses, safety valves, new stove, etc). As a followup, the question might be if the valve on the top of the tank is left hand thread and the same size as on a CNG tank. I'll have to research that.

Just an out of the box thought - any perspectives (other than change to LPG) are welcome. The conversion has been beaten to death! :deadhorse:
 
Jul 1, 2019
2
C&C 38-3 Telos San Diego
Nooo.... its not quite dead yet! Its not as easy to blow up your boat as one would think. Here is a video from Yachting monthly.


They finally had to resort to bottled CNG. :)
 
Jun 11, 2004
812
Oday 31 Redondo Beach
Nooo.... its not quite dead yet! Its not as easy to blow up your boat as one would think. Here is a video from Yachting monthly.
They finally had to resort to bottled CNG. :)
Nothing about CNG in that video. Looked like two portable propane tanks.
 
Oct 22, 2014
10,172
CAL 35 Cruiser Portland OR, moored EVERETT WA
Methane... I bet there are a couple of Dairy Farmers who could supply you with all the methane you could handle. They may even pay you to remove it from their farms. Some have taken up heating their barns with the stuff.
 
Apr 9, 2019
7
catalina 27 TR Bay Dancer southport nc
Tech Air has been taken over by subsidiary of Air Liquide (French parent). They are not involved in CNG. The only relatively widespread use of CNG is for vehicles, especially buses and the like -- meaning State and local govt. Such local sources here are very reluctant to get involved with a cylinder for a boat, even if it has been properly pressure tested and declared OK. One guy explained that it is a matter of liability (lawyers again).
I acquired CNG, with a Catalina 27 attached. Large bottle. Works well and doesn't seem to use much for v limited on board use.
I am used to high-pressure oxygen cylinder use in aviation; as already explained succinctly here, lighter-than-air CNG is a lot less dangerous, compared both with O2, where a leak can lead with a spark to uncontrollable burning rates, and especially propane which is heavier than air so leaks concentrate in the bilge until get to explosive levels. That Yachting World demo should be included in all boat training courses (hint to ASA and USSailing).
It should also be seen once a year by all sailors (not that there is anything like aviation insistence on some sort of repeat safety exercises for boat use, and even the aviation versions can be, and are, criticized as minimal).
I will now try to find someone who is knowledgeable about substituting methane from available industrial suppliers. Interesting suggestion .... thanks.
 
Oct 26, 2010
781
Hunter 40.5 Beaufort, SC
From what I can glean from open source materials Methane is the main, if not sole active component of Natural Gas. Its a bit difficult to get a clear answer of compressed Methane can be used in what we commonly call Natural Gas appliances like a marine stove/oven. Methane can come from a lot of different sources including, as was noted, cows, decaying material in landfills, and from underground wells. So is there anyone there that can confirm that you can use compressed Commercial Grade Methane, which is reasonably available, where you use what we commonly call CNG? Hope somebody with expertise in this area can weigh in. I don't mind the jokes and wise cracks but would really like reliable information on this. It solves a lot of problems for those of us with CNG systems on our boats.
 
Oct 26, 2010
781
Hunter 40.5 Beaufort, SC
Nothing about CNG in that video. Looked like two portable propane tanks.
Look closely at about 4:45 and you'll see those are two portable Propane Cylinder's like you can buy at Home Depot. All the more reason, even if you do have all the safety shut off valves and safety gear for you Propane stove from you sealed propane lockers, don't carry portable propane cylinders for your portable coleman cook stove or your grill inside your cabin. It is hard to get the right mixture for a true explosion like that, but it is possible and if it occurs, it can be pretty serious.
 
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May 20, 2016
2,804
Catalina 36 MK1 Everett, WA
Methane probably doesn’t have the chemical that gives Natural Gas in the US it’s distinctive odor. Not in NG in Europe.