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ChamJam 30-11-2009 07:51

Propane vs Natural Gas
I have started to kick some keels around the local marinas looking for my future boat. One boat that I was very interested in has a natural gas (NG) set up for the stove. Has anyone had any experience with NG??? Is it readily available in marinas when it comes time to refill? Is it safe? Or if need be should it be replaced with propane? Should this be a negetive when looking at purchasing a boat?

Any thoughts would be appreciated.


Mule 30-11-2009 08:30

if you find a marina that sells cng, let us know, surly there is one some where in the world.

Bash 30-11-2009 08:40

Is it safe? Yes, safer than propane because CNG is not heavier than air, and hence won't collect in your bilge. But I had a CNG system several boats ago, and was shocked at how difficult it was to replace an empty bottle. One time I ran out of CNG while rounding Pt. Conception northbound. We stopped in Morro Bay, a fairly active fishing port, only to discover that CNG was not available. We would have had to go back to Santa Barbara or continue north to Monterey to get a fill.

This is why the two boats I've purchased since then have used propane.

Reality Check 30-11-2009 08:44

I have not run across a marina with CNG and in many countries it is not easily available away from the marinas.

I find getting Propane tanks filled enough of a challange... In the Caribbean some locations will not fill certain type tanks. Some will fill only aluminum, some will fill steel tanks but Not if they are from a Boat, I have not run across anyone that would fill the new fiberglass tanks and some will only fill selected take types that have the type fitting they use. Never ran across a filling station that would fill "anything".

You need to specifically check the locations you intend to cruise prior to getting CNG and probably have a back up plan//// adapters and burners for conversion when not available. Personally I would just stick to Propane unless I was going to hang around an area I knew CNG would be available.

Pblais 30-11-2009 09:33


But I had a CNG system several boats ago, and was shocked at how difficult it was to replace an empty bottle.
I doubt you can find any marina that can actually refill tanks. It's not simple equipment. I'm not aware of any marinas actually filling propane either, though exchanges can be found in unlikely places.

Here in Hampton Roads the only place I know about for CNG is in Virginia Beach. You can sometimes get an exchange but often you leave the bottle and come back after it is filled (not that day). CNG is not easily available. It works fine enough but conversion to propane usually involves building a new propane locker and rebuilding all the fitings on your stove. Installing CNG on purpose would be a mistake.

cal40john 30-11-2009 09:47

As above CNG is safer, but there is about 2.5 times as much heating capacity in propane, almost twice as much propane in standard tanks for each, and weight of empty tank to haul around is nearly twice for CNG.

BTU/ft^3 NG 1000
BTU/ft^3 propane 2500

standard tank CNG (scuba size) 80 ft^3
standard tank propane (4 gal, 20 lb) 150 ft^3

weight empty tank CNG 30 lbs
weight empty tank propane 18 lbs


ChamJam 30-11-2009 11:21

Thanks folks for the prompt replies...You have re-enforced what I was thinking. Availability is key and although it is safer than propane, the negetives out way any positive attributes of NG. I will take that whole conversion thing into mind if I put an offer on the boat.

thanks again.

amarinesurveyor 30-11-2009 13:13

When converting to propane, you will probably have to replace the stove also. All of the Gas Systems brand CNG stoves that I have seen are not equipped with thermocouples. They shut off the gas to the burner if the flame goes out from wind or whatever. They are a very important safety feature when using propane, because propane is heavier than air and will sink into the bilge. Buying a stove is not cheap!
You may be able to just buy new burners that will fit into the stove but I have heard from clients that they could not find anything to replace them. If the burners have thermocouples installed, then you are good to go.

Ram 30-11-2009 13:53

In the Med both are availbule, and its very easy to switch from one to the other, i just change my regulator, propane is hotter - NG is only $8 for around a 40 lb bottle in Tunisia- 30 Euros in Greece for Propane

Pblais 30-11-2009 13:53

Part of the inital appeal of CNG was you didn't not need a dedicated locker for the tank and you clearly do need one for propane. It made a lot of short cuts possible and it used to be easier to get. When porpane got more popular CNG went off the radar as popular.

Subdividing a rear lazerette often can be done so it is separated and drains overboard. You can then run lines and add a solenoid valve. If the existing CNG stove wasn't very good then it may make the math add up. If you really want a good oven then it starts to make sense to convert.

Dockhead 30-11-2009 13:55

Don't consider the cost of replacing the gas system, lines, tails, regulators, IMHO, because you will want to do that anyway. A stove is pretty spendy but depending on the price category of the boat maybe not an enormous percentage of the total cost. Besides that, the price probably reflects the difference anyway. I wouldn't personally shy away from a CNG boat, although I would certainly convert it to propane.

Solitude 30-11-2009 13:57

Change to propane .

Pblais 30-11-2009 14:39


I wouldn't personally shy away from a CNG boat, although I would certainly convert it to propane.
I would agree as well. CNG is better than everything else but Propane and cooks great. It's just a PITA to refill it in most places. A good friend has a Tartan 37 with CNG and he bought the boat brand new 20 years ago. He has been lots of places and it works fine.

He does really hate the 45 minute drive each way (longer when traffic is bad) to get CNG and especially when he has to leave the tank and come back for it. The tanks don't last anywhere near as long as a propane tank does.

ChamJam 01-12-2009 05:53

Again thanks for the great input. The boat is in the 100k range, so in the scheme of things a conversion to propane will be part of the negotiations. It could be a $3K ticket item!! I just feel better using propane as I have for 30 yrs on a BQ.

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