Converting from Compressed Natural Gas to Propane

[Jon Perry]

I recently purchased a 1987 C34 that has a oven and range set up to use CNG.  I am having a very difficult time accessing bottled CNG, so I am considering converting to propane.  Can this be done?  If so, what challenges would I face?  What issues do I need to be thinking about?  Or is there a way to find CNG that I can exchange bottles with and have them FedEx'ed?

Any help would be very much appreciated!

Jon Perry

[fthefireman]

I am in Louisiana and my 1988 is in Pickwick Lake Mississippi. There is just no cng anywhere close .it is not that difficult to change from cng to propane. the jets and the oven controll have to be changed. The propane locker has to be located under the stern seat, and has to be vented also air tight. There is a good description of the process in the tec notes. I used a lot of info from this site. I brought my stove home and did all the work in my shop, then tested it before i put it in. I don't recall where i got the parts but if you run a search on the net you can find everything. The guys on here are great. Where is your boat located?

[Stu Jackson]

Jon, welcome and congratulations on your new boat.

1.  Type "CNG" in the search box on the message board.  There are a number of previous posts on just what you are looking for.

2.  Seaward will need the # of the stove you have, which can be found by lifting up the top of the stove.

3.  Call Seaward with this information and they'll help you out.

You may also want to check out the C34 Knowledgebase, and then access the Tech Notes Online once you become a member of the C34IA.  See: http://c34.org/bbs/index.php?topic=3362.0

[Ron Hill]

Jon : There was a very nice article written in the Mainsheet tech notes by Dave Euing back in 1997 on converting from CNG to Propane. 
Great info in those tech notes!!   

[Jon Perry]

Frank,

Thanks for the message. I have had great info on my first posting, so I'm really excited.  My membership check is headed to Stu, so I'm hoping to be a member and be able to access the info I need soon.  And my boat came off of Lake Erie, and I just had it delivered to Eden Isle Marina on Greers Ferry Lake , Arkansas. I think the boat was pleased to get out of the snow belt!  As you know, the sailing is great in the winter below the Mason Dixon!

Jon

[dgill]

Hi Jon,   

If you check the internet for http://www.corpbrothers.com/marine.htm you will find the source for CNG.  They are the only tank exchange service that I know of.  They distribute to many states but it is an ever dwindling list.  If you decide to make the switch to propane and might be interested in getting rid of your existing CNG tank I would like to speak with you.  My email is fpoa34@aol.com.  Thanks.

[Jon Perry]

Thanks so much for the info onthe CNG suppliers!!! I think that is just what I needed.  I'll let you know how it works out.

[Lance Jones]

How do I determine if my system is CNG or propane?

[Craig Illman]

Where is your tank located? and what does it look like? CNG tanks look similar to dive bottles. Propane tanks are usually just smaller versions of what would be on your home BBQ. CNG is considerably higher pressue, but has the advantage of being lighter than air. Propane's easy to find, but a leak could have it puddling in your bilge and be an explosive hazard.

the short answer........

Craig

[Lance Jones]

Woo-hoo! Great answer! Mine is under the Helmsmans seat and looks like a BBQ mini! So, I guess it's propane. Atlanta has a CNG fill point; but, it is all the way in-town. About an hour from me.

Thanks!

[Ron Hill]

Lance : You've got a 1 gallon (4 lb) propane tank.  You might want to look in projects and convert to a 10/11 lb tank. 

[Lance Jones]

Ok, we finally ran out of gas. What type did I run out of? Who knows. I went to pull what I thought was a propane tank; but, it didn't look like one; nor, was the connection anything I was familiar with.

I looked up this link that I had replied to before and it only confused me more. Here are the images of what I found today

[Craig Illman]

Lance - It says right on the tank in the second picture. LP-Gas = Liquid Propane.

Craig

[Ron Hill]

Lance : You not only have a Liquid Propane bottle, but you have an old bottle without an OPD device!! At about 99% of the LP filling stations they will no longer fill a bottle that is not equipped with a Overflow Protection Device (it's the law)!!  The new bottles have a triangular knob (NOT round) that turns ON/OFF the flow from the bottle.
You'll need to have your bottle inspected and an OPD installed.  As I previously posted above, you might want to make a new box and just get a new 11 lb bottle rather than screwing around with that old little bottle.  Read my article, it's also in projects.  A few thoughts !!

[Stu Jackson]

Lance, propane also has a solenoid valve that should be in the galley.  CNG does not.

With your propane system, you should read this, WM Propane Systems, also in their catalogs:  http://www.westmarine.com/webapp/wcs/stores/servlet/westadvisor/10001/-1/10001/Propane-Systems.htm

Most quality boating systems books have extremely well written chapters on cooking fuels including propane.

It is very heartening to know that you now understand what system you have.  Because of the content of the sign on the tank, it is important to understand and MAINTAIN and check out the system on a regular basis.  Others will recommend CO detectors and the like for you, although those issues are also covered in the those books I suggested.  Calder's Boat Owners Manual, which many of us have recommended over the years, is a perfect example.  Between that book, the West Marine Catalog and/or their online Advisors, this website and a few tools, man, you got it made!