I haven't found any place that can refill my onboard CNG tank (Texas Gulf coast). Lots of places to fill a truck fuel tank, but not the small propane-sized ones. Do you know of any place?
CNG refill source in Texas??
- Thread starter davjonLegend
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cng is great stuff. but if its that hard to get it seem that it,s more trouble than its worth. I know its safe and all that but you have to weigh out the benifits it,s probably easyer to convert to lpg. and let the cng guys figure it out, the county that I am in is building a station for its fleet and for the public but they have been working on it for over a year. and no where near done. looks like maybe two more years with a grant from the fed,s so going back to fuel what would you rather have ? cheap and easy to get or safe and hard to find. I would rather have alchohol than cng. oh and if you think its safe well that cng tank has at least 3000 psi in it, there is a little danger in that, the problem is it expensive to have a pump to compress the cng and no one wants to pay the price when lpg is cheaper to store and sell. good luck to you you hope you find what you need.
You might want to build your own adapter if you are feeling handy...
http://hunter.sailboatowners.com/mods.php?task=article&mid=34&aid=8316&mn=35.5
Sure is nice using the CNG, I think I spent < $150 on parts and much less $$ than a propane conversion. Gook luck.
http://hunter.sailboatowners.com/mods.php?task=article&mid=34&aid=8316&mn=35.5
Sure is nice using the CNG, I think I spent < $150 on parts and much less $$ than a propane conversion. Gook luck.
WoW cheap out on cng refilling ? the reason for epoxy is not for protection from corrosion but to hold the pressure. steel tanks are not used anymore. most are all carbon fiber with a liner, do you want to play with 3000 psi of flamable gas ? and think about it if you cant find cng in texas, try finding it in the islands. also most tanks have a colesting filter to keep not moisture out but oil from compressors and also have tprds, stands for temp, pressure release devise which must be vented out of of cabin so as not to burn or suffocate. play with fire and see if you dont get burned, dahmasing !
Not to put too fine a point on it, I do think steel tanks are commonly still used for CNG. As far as supply, I have spent a month in Mexico with just over one tank. Two would certainly allow some cruising. But Frankie's point about it not being the first choice for cruising outside of first world sources is well taken. I considered changing and budgeted $3K. However, CNG is readily available here and since it's inherently safer on a boat (but not risk-free) I elected to stick with it and just buy a reserve tank. http://www.pressedsteel.com/type-1-cng-cylinders.html
I stand corrected on steel tanks but did you see the size of the small one. what size tank are you using if I might ask.the company were I work for is changing over to cngand the tanks are as big as veh is wide. cng is safe with good practice but still not enough inferstucture.here in florida
Scuba tank size is the standard for marine CNG tanks. Can't buy them new since all the services here are leased tanks (turn one in to get another).
If you want to cruise the world, propane is better. Not my problem. I cruise where cng is available. I have 2 tanks. I bought my second tank from safgas in Los Angeles. They were original supplier, at least on my 1990.
Nothing unsafe about the cng tank in the cabin. A SCUBA tank is safe as long as you hydro and inspect every 5 years. Turn the valve off at the tank when not in use for long periods. Stove top and oven works like home. I'm a happy customer.
Nothing unsafe about the cng tank in the cabin. A SCUBA tank is safe as long as you hydro and inspect every 5 years. Turn the valve off at the tank when not in use for long periods. Stove top and oven works like home. I'm a happy customer.
cng is good stuff not putting it down just dont want people with little education playing around as it is with high pressure.( so you have a regulator at tank and run to the stove ?) I am in the industry and we are tought to always expect te worst poss sinario that can happen. I am certified in cng tank inspection and installation in veh, and the rules are very stringent. but that comes from nafta, and dot. tanks must be marked cng dated and working pressure, just resently had a sailor blow up using lpg he could not smell the mertane they put in the gas,smells like rotten egg,s it went down to the bilge and poof he died. cng goes up lpg goes down, the problem with cng is pressure. and availabilty to find it. good luck and happy sailing
Any flammable gas or liquid must be used with caution. I am much more leary of LPG than CNG. Lets look at the facts _ LPG is in common use because it is readily available, even at your local self serve station, not because it is safer as a whole. LPG is heavier than air. Lacking some forced ventilaton or a clear and open low point drain to the exterior of the boat will sink to the low point (may not be the bilge if there is a low point close to the leak). It then concentrates in that low point and if the leak is big enough, will spill over to the next low point. It doesn't take much of a spark to get the LPG ignited! Then Boom. Is it safe - sure if handled correctly just like CNG is safe is handled correctly. The thing that surprised me is how many boaters carry a small LPG "can" for the gas grill, a heater, or a camp stove inside their cabin. They have all the safeties for their LPG stove (separate low point vented compartment for the tank, auto shutoff valve, etc) yet keep a source of LPG inside the confines of a compartment that is, by design, sealed at all the low points. Anything that will keep the water out will also keep the LPG in. Not so with CNG. Very few boats are "watertight" above the waterline. Almost all have some air leakage at the companionway hatch or somewhere else. Unless the CNG leak is pretty big, it will rise and leave the boat, especially if you have a solar powered ventilator. It will vent the gas long before the mixture reaches a combustable limit, unless it is a very big leak.
So the big argument is availability, not safety. If its safety alone then its CNG hands down. By the way, all boats that I have seen have the regulator at the tank with only low pressure gas downstream of that. I can't imagine having 3000 psi lines all the way from the tank to the stove and the regulator there - "it wouldn't be prudent." There are years of experience with pressure vessels such as the "scuba like" tanks that are commonly used on boats and if properly maintained, inspected and hydro'd have a fairly large margin between rated pressure and failure. I'm not sure of that number but I'd bet it is at least 150%. In fact, I think they are hydro'd to at least 125% of rated pressure. if not more (someone chime in on the hydro requirements if you know them).
So for me, as long as I can I'll keep the CNG. If I was out of the country I'd probably convert to LPG but as hard as it is it get, it is still cheaper to stick with the CNG than convert. If it ain't broke, don't fix it.
By the way - I just looked up the hydro pressure requirements for scuba tanks and I think it is probably the same for CNG tanks. it is 5/3 the working pressure. So a 3000 psi tank would be hydro'd to 5000psi!!! This is not even the "burst pressure" but the pressure the test is conducted at so the burst pressure would be considerably higher. So as long as a tank is properly maintained and hydro'd then I would not be concerned too much about it rupturing on me! Lets take that out of the equation on safety.
Here is the link to the scuba tank hydro
www.pyramydair.com/.../scuba-tank-testing-hydrostatic-and-visual-inspe...
Feb 15, 2006 - A common hydrostatic test is to pressurize the scuba tank to 5/3 of its working pressure and to measure the flexing of the tank walls. Five-thirds of a 3,000 psi working pressure means that the tank will be pressurized to 5,000 psi.
Here is the link to the scuba tank hydro
www.pyramydair.com/.../scuba-tank-testing-hydrostatic-and-visual-inspe...
Feb 15, 2006 - A common hydrostatic test is to pressurize the scuba tank to 5/3 of its working pressure and to measure the flexing of the tank walls. Five-thirds of a 3,000 psi working pressure means that the tank will be pressurized to 5,000 psi.
Thanks everyone. It's good to know there are sources that cruisers might utilize. My immediate issue is that driving to the east or west coast from Texas (and back) to get CNG is a tiny bit out of the way. My original question was where to find a source along the Texas Gulf coast. Anyone have info on that?
Checking again, the CNG numbers are probably a little different (I'm getting a little conflicting info) but as a minimum the burst pressure of a CNG tank is at least 2.4 times the rated pressure so we're talking 7200 psi for a 3000 psi rated tank. Again, a significant margin for safety. Again, any flammable gas or liquid in the hands of a fool is dangerous so caution and maintenance are the key elements in safety.
Picture didn't come through. I used a PVC pipe with a screw on cap on the top and a glued on round cap on the bottom with several holes drilled in the bottom. Three cans will fit in the pvc holder and it straps to a rail.
nice set up Rick D thats good work and give me a great idea for mine thanks for the picture. Frank
What killed the practicality of CNG in small tanks is the high pressure at which CNG has to be compressed and stored. Compare CNG at 3,000 PSI with Propane at 150 PSI. The tanks have to be that much stronger and the pumping equipment that much costlier just to maintain similar safety safeguards. The use of homemade adapters at automotive CNG filling stations is a risky proposition which could lead to bodily harm to the user and others and perhaps charges of criminal nature as the great majority of these stations do not allow their use for liability reasons.