What to do with CNG ?

[CATBOAT WILLY]

I am considering a 1990 Hunter 36 and it looks like a nice boat. The Boat is equipped with a stove system using Compressed Natural Gas CNG which was standard and furnished with boats of that time period. I can't seem to find anyone in my area who sells the stuff since it appears everyone uses propane. (Looks like CNG lost the battle and propane won)

I've searched the forums and can't seem to find an answer to my questions and hope someone here can help:

Should I reject this boat cause this is going to be an expensive conversion ?
Do I just buy a new stove that runs Propane ? Or just change the burners and install a propane shut valve ?
Will regular propane tanks fit in the space allotted for CNG Tanks ?
Is this a simple conversion process or does it require a professional ?
What do people do in this case ?
Thanks in advance for your help.
Willy

 

[Marco Garcia]

http://wisegasinc.com/wg-marine.htm

see if they are available to support you.

I have not tried them yet. I have two bottles in my boat. Filled them in MD before bringing the boat to Miami. I am still on bottle 1.

I Use a bit less than a bottle per season. Perhaps two if busy. I do use the oven and cook often aboard, but i also use the grill on the stern rail.

I have no issues with CNG. Since My boat is new to Miami, I am not sure if I will need to make an adapter to refill myself, but at least there are a couple of refill stations in S. FL.

http://poweredbycng.com/florida-cng-stations/

 

[Don S/V ILLusion]

CNG is very popular and widely available where we live in Florida. I'd be surprised you have a problem finding it but not sure where you looked. Being safer than propane, I'd be reluctant to change.

 

[Benny17441]

No simple matter, it is a costly conversion. Propane is a gas heavier than air and when it leaks it will flow like water and pool at the lowest point of any partition. In its favor CNG is a gas lighter than air and should it leak the gas tends to dissipate in the air. Against it CNG is stored at a pressure 20 times larger than propane and requires stronger tanks and equipment to refill those tanks. Why propane became the fuel of choice if it seems to be more dangerous? The answer is one of economics, the great majority of the fuel consumed by portable tanks goes to the outdoor BBQ grills found in almost every home. The tanks are cheaper and so is the equipment to refill them. The consumption of CNG gas by boats was just negligible in comparison forcing the Marine industry to adapt to the market forces as CNG portable tank filling stations snowball to a close. In order to counteract the dangers of propane the boat manufacturers adopted some guidelines to make the use mostly safe even for the careless and uninformed. Boats of yesteryears carried propane tanks in the cabin tops or hanging overboard but todays boaters demand clean lines uncluttered looks so now the tanks must be placed inside a sealed locker vented to the outside at its lowest point and such a locker to fit inside one of your lazarettes will set you back a few hundred dollars. Mind you that if you want your tank inboard this is a necessary safety expenditure. Then you can add remote switch solenoids, stove with thermocouple valves, pressure switches, continuous gas grade hoses and even electronic sniffers for leaks. A proper conversion will cost around $2000.
From a boat buying or selling point the statement that CNG was standard for boats of a certain era does not change anything. The seller has a galley with little value and the buyer will have to make a costly upgrade.

 

[bryan crites]

cng propane alcohol

My first hunter 34 had an alcohol stove in it an was very reliable. My next h34 came with a cng stove. I was going to convert it to propane but replaced it with an alcohol oven purchased on ebay for 400.00$. I will convert my cng oven to propane an use it in my garden outdoor kitchen . Denatured alcohol is readily available.

 

[Bill Roosa]

If you have the CNG system you can convert for the cost of the propane locker and some plumbing parts. The CNG regulator is a duel type, high pressure and low pressure. The low pressure one is the one you need. it is the larger diameter gray one that comes second in line off the bottle. plumb a propane quick connect to the inlet, and reroute the hose to the stove to the stern. find a convenient palace to store the tank and a way to secure it. I just eye bolted mine to the stern step port side. connect the hose and turn on the tank valve. Light the stove and check for proper pressure. It will be a bit high with yellow tips to the flames. There is a plastic slotted screwdriver cap on the regulator. Take that off to access the pressure adjusting screw. while a helper watches the flames turn the nylon screw under the cap out to decrease the pressure or in to increase it. I did not go with a solenoid as all the plumbing is open to the air. We just turn the tank valve off when we are not using the stove.
Converted this year and have not had any problems except the Rube Goldberg pressure valve I plumbed in (not really needed) popped the hose and offered itself to Posiden. Lucky I was messing with the tank at that time and could turn off the tank valve.
You do not have to re-jet the stove or oven BTW

 

[Doug in Lakeview]

Hi all,

I am considering the opposite - going from propane (LPG) to CNG. I started a separate post looking for guidance.

I may be wrong, but I would have guessed that it might be necessary to re-jet the burners since the heating value of LPG vs. CNG are different. I know that gas stoves (in a house) and gas furnaces (in a house) typically need to be re-jetted. Anyone out there in the residential cooktop or HVAC business who can provide input?

 

[Marco Garcia]

If you have the CNG system you can convert for the cost of the propane locker and some plumbing parts. The CNG regulator is a duel type, high pressure and low pressure. The low pressure one is the one you need. it is the larger diameter gray one that comes second in line off the bottle. plumb a propane quick connect to the inlet, and reroute the hose to the stove to the stern. find a convenient palace to store the tank and a way to secure it. I just eye bolted mine to the stern step port side. connect the hose and turn on the tank valve. Light the stove and check for proper pressure. It will be a bit high with yellow tips to the flames. There is a plastic slotted screwdriver cap on the regulator. Take that off to access the pressure adjusting screw. while a helper watches the flames turn the nylon screw under the cap out to decrease the pressure or in to increase it. I did not go with a solenoid as all the plumbing is open to the air. We just turn the tank valve off when we are not using the stove.
Converted this year and have not had any problems except the Rube Goldberg pressure valve I plumbed in (not really needed) popped the hose and offered itself to Posiden. Lucky I was messing with the tank at that time and could turn off the tank valve.
You do not have to re-jet the stove or oven BTW

Hello Bill,

Did you run a separate line for the LPG, and do you mean that to go back to CNG you would only need to adjust the regulator and connect it to the original plumbing lines? Could you send pictures of the installation, and the LPG tank you got.?

Thank you

 

[ben solomon]

I have CNG on my legend, and enjoy the relative safety of it. We have a family of five and cook on the boat frequently. I have a magma propane grill on the rail, so most of the heavy meat cooking is done in that. The stove, however, gets a workout. We haven't gone through a tank in a season and a half. I can get replacements, locally (rock hall, md), though. I have read that CNG is very hard or impossible to obtain outside the US.