Converting CNG stove/oven to propane

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Scott N.

I have decided to convert the CNG stove/oven to propane because the nearest CNG supplier is a 3 hour drive away and also because I hope to get to the Bahamas next year where CNG is not available at all ( or so I am told ). Can anyone help me with the following questions: - I am told that the conversion is straight forward. Apparently you can purchase new burners/jets. Is this true? Where can I purchase this? Cost? - Is it a simple change? Should I get a pro to make the conversion? - Any other considerations with the change? Tank placement, venting, etc. Thanks! Scott
 
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Don

venting

I have a 35.5 and would like to change at some point as well. The main issue as I see it is findind a location for the tank which can be externally vented and still look relatively clean. Propane is heavier than air and sinks and CNG (safe gas) is lighter and less combustable and therefore the tanks can be internally mounted. I do not believe the stove top or oven would require changes but they would produce significant more heat which would be useful. I personally wouldn't fool around with it and would hire an expert.
 
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Del Wiese

need to change stove and oven

The stove and over require changes for propane. I bought a kit from the manufacter and had a local expert intall. Glad I did, it was not simple. I have an 89 Legend 37 and located the propane locker in the aft cabin, on the shelf on the port side. Bought a stock locker and two 10 pound aluminum tanks. Got the tanks at Ace Hardware for much less than marine store prices. Hardest part of installation was running wires to the switch which controls the shut off solenoid in the locker.
 
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Paul

Did it also...

We upgraded out 37 Legend. The kit from the oven/stove manufacturer was pretty basic, new nozzles and new oven valve. We also replaced the knobs and grates with new. The oven looks like new once again. It took a few hours to replace the components abd do a leak test. We then mounted a tank under the removable stern seat cover. I made a tank holder and mounted on the side wall. You can still easy walk thru the area if the seat is removed and one wants to use the swim platform area and take a dip. This keeps the tank outside and any propoane leaks go right over the stern, away from the cabin. ps...I used the old CNG vent as my AC water discharge....just installed the new thru hull in the old hole.
 
Jan 2, 2005
779
Hunter 35.5 Legend Lake Travis-Austin,TX
Doing the same...

on my '94 model 35.5. Kit for stove/oven is $120 US from Seaward, call them at (562) 699-7997. They will want your stove model # and serial #. Mine just came today and I haven't had a chance to look at it, supposedly not too big a project. Running hose and deciding on tank location is another whole can of worms. My existing cng hose runs underneath the holding tank, aft berth, and under aft hanging locker. Yours could be different if it's an older model with tank forward of galley. It must be switched out, cannot us cng hose with propane install. I'm finishing a holding tank swapout, so I've already cut out aft bulkhead and have access to the area. I'm looking at a rail mount option. After reading Paul's post, I may consider his location of under the helm seat. Other consideration is wiring the solenoid. Lots of info in archives, dig deep!
 
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T J Furstenau

Honeyman - Spare CNG tank?

Marc - So what do you plan on doing with the old CNG tank? :) Mine's in the shop right now getting hydrostat tested so that I can refill. I honestly think it's the first time it's been filled since the boat was delivered. The stove didn't look used when we bought it. As the fill process is inconvenient to say the least, I thought having a spare on hand might be nice. T J
 
Dec 3, 2003
2,101
Hunter Legend 37 Portsmouth, RI
TJ?

Hydro tested? In the NE, tanks are exchanged (empty for full) and hydro testing is automatically done by the retailer at the time that it becomes due. You shouldn't have to pay to have it done.
 
Aug 20, 2005
6
Hunter 37.5 Olympia, WA
Spare cng tank

I'd also be interested in a spare cng tank. Email: glen@networksre.com
 
Jul 17, 2005
586
Hunter 37.5 Bainbridge Island - West of Seattle
I wanted a spare CNG tank also, so I .......

Around here, we swap tanks as well. A local company that fills the tanks and supplies the tanks to the local stores. You then just swap with the store. However, if you wanted to keep your own tank instead of maybe getting a rusted one, you may, but you will have to take the empty tank to the company, leave it, and pick it up another day. A big pain. I did that for a few years, then decided to start swapping instead. I wanted to have 2 tanks for long trips, so I just went to the company and purchased a new tank (expensive), but the new tank was swapped as soon as it was empty. So the purchase price was in reality a right to have a 2nd tank. As for the price of getting your own tank filled vs. swapping a tank, they were identical. Based on my experience, if you want a 2nd tank, don't bother buying a new tank. Go find a used one as cheap and as beat-up as you can, (beat-up = cheap) since you will swap it away shortly. By the way, if you have natural gas for your house, you can fill your CNG tanks at home, for almost free. The problem is finding and buying the connecting regulator valve and compressor, plus the safety issue.
 
Dec 25, 2000
5,703
Hunter Passage 42 Shelter Bay, WA
I picked up a used CNG tank from Pacific...

Marine Exchange for $50. I now keep a spare full tank. We cruised the Discovery Islands for seven weeks this season and used 1,500 pounds of CNG. I purchased it full at 2,000 pounds. BTW, I do not think your household gas service connection has enough pressure to fill these tanks. I exchange my empty tank with a full one at Harbor Marine at the Everett marina. Terry
 
Jul 17, 2005
586
Hunter 37.5 Bainbridge Island - West of Seattle
Where is Pacific Marine Exchange?

Is it in Everett? I gotta go there and get another one. It is true that residental gas does not have enough pressure, that's why you will need a compressor.
 
Dec 25, 2000
5,703
Hunter Passage 42 Shelter Bay, WA
Pacific Marine Exchange is in Bellingham...

on the waterfront. Ask for Mike the owner. Call him and tell him what you are looking for and if he does not have it in stock he will call you when one comes in. He wanted $100, but it included the regulator, which I did not need. I offered $50 without it and he accepted. A bit of a hike from Bainbridge. There is another marine exchange at Shilshoe, but I cannot remember the name of the business. Also right on the waterfront, been there a long time. Both places have lots of marine stuff, much of it on consignment. Good luck. Terry
 
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Mike McKendy

CNG Consumption

I too am considering conversion from CNG. I have two tanks but I find the consumption is quite high. I did a four week cruise this summer and started with a full tank (about 2200 psi). Ran out in three weeks. I don't think our cooking use is that high (coffee/tea, one or two dishes for dinner). With this rate of consumption and the difficulty obtaining fills I'm considering switching. Does this consumption seem high? I've heard others claim they would not use a tank in a season,
 
Jul 17, 2005
586
Hunter 37.5 Bainbridge Island - West of Seattle
The one at Shilshole

Yes, there is a fill supplier at Shilshole, well, it is in Ballard before the locks. They are the supplier for most of the tanks in the Puget Sound area. That's where I bought my 2nd tank, new, and was expensive. Thanks for the info on the Bellingham shop.
 
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Scott N.

CNG consumption

Mike, I bought my H35.5 in Mass. in June and sailed it to St. Andrews over 6 days. We started with a full CNG tank and with expectations that it would last a full season of cooking and baking. Wrong. It was down to 500psi after the 6 days. I watched the pressure closely and noticed that the oven was a real drain on fuel. I think this is simply because the oven requires alot of heatfuel to maintain its temperature and because cooking time is usually longer in the oven than stove cooking. I plan to get a cng tank refill to finish off the season. I also have a single burner bulkhead mounted gimballed stove (diposable propane cannister)to use as backup. Next spring I will make the conversion to propane. Where do you get your tank filled/exchanged? I plan to UPS the empty tank from Calais to a Road Island supplier and they will UPS a full tank back to the Calais ICS depot.
 
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Mike McKendy

Scott, I saw your boat a month ago

Scott, I was in St. Andrews for a couple of days and saw your 35.5 - I think she's the liberty edition? We should contact directly to discuss conversion. My e-mail is mckendym@nbnet.nb.ca
 
Jul 17, 2005
586
Hunter 37.5 Bainbridge Island - West of Seattle
UPS on CNG tanks?

I may be wrong, but I am not sure if UPS will even ship a empty CNG tank, let alone a filled CNG tank. Also, even if they do take it, it is going to be very expensive.
 
Jun 7, 2004
944
Birch Bay Washington
Full CNG tank is 2200 psi or more

if not, you should take it back and get one that is full. We get about twenty max flame burner hours per tank. JC, you can exchange tanks at the Shilshole gas dock. It is the same cost as Sure Marine. They fix the price for the whole area. The cost of the fuel through the usual suppliers is extremely high. Sure claims that they have to test the tanks and that justifies the price. If you can get an adapter and fill it at an automotive supplier, it is about a dollar or less to fill a tank compared to $25 at Sure or $75 US in Canada. I tried to find an adapter to do that with and was told by the supplier in the University district that they had been threatened with a law suit by Sure Marine if they ever filled a marine tank. It seems that they have a monopoly in the Seattle area but you might get one filled somewhere else. I am converting to propane just as soon as that project gets to the top of my list.
 
Dec 2, 2003
4,245
- - Seabeck WA
Patrick, when reading your post I was eager to

suggest that you switch to propane. Then I read the last line. :)
 
Jul 17, 2005
586
Hunter 37.5 Bainbridge Island - West of Seattle
Yep, they have the price fixed.

Patrick, I have used the one at Shilshole, and yes, the price is fixed for the entire Puget Sound area. At least every place I have swapped. Before we head up to Canada, we always make sure we have 2 full tanks. Even though one tank may still have some CNG left, it is still worth it to swap for a fresh full tank before Canada. IMHO, it is a rip off. especially since the CNG gas is quite inexpensive to begin with. As for the tank testing, they don't do it every time they get a empty tank back. I believe by law, they only have to test it every 5 years or so. You can find out all the test date on a tank because they have to stamp the side of the tank everytime they test it, and it is not every year.
 
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