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CNG to propane

NCBrew

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Feb 22, 2010
3
Hunter Hunter Legend 35.5 9335 Albemarle Plantation, NC
I know this must have been discussed many times. I need the complete instructions fo converting CNG to Propane, with estimated cost.

Hunter Legend 35.5
 
Feb 21, 2013
3,774
Hunter 46 Point Richmond, CA
Jan 11, 2014
7,824
Sabre 362 113 Fair Haven, NY
Cost is hard to predict because each boat is different.

To do this safely at a minimum you will need to install new gas hose, regulator, solenoid, and sniffers.
You will need to have a locker that drains above the waterline so any leaking propane will not enter the boat.
The stove/range will need to be replaced as conversion kits have long ago dried up. There is a slim chance conversion kits are still available for your stove, just don't count on it.

A new stove will run $1k to $2K.
Propane tank cost vary, 6lb tanks will run about $325 each.
New plumbing, sensors, and regulators will set you back $200-300.
The cost for an ABYC compliant propane locker will vary based on your boat and the current CNG locker.
 
Feb 21, 2013
3,774
Hunter 46 Point Richmond, CA
............I need the complete instructions fo converting CNG to Propane, with estimated cost......
That would require a detailed survey of what you have and your specific conversion requirements. If I was close by I would be happy to do it. Suggest contacting an experienced "boat mechanic" on Craislist or at your local marina and have them do that as an alternative.
 
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Likes: jssailem
Feb 26, 2009
591
Oday 30 Anchor Yacht Club, Bristol PA
Basically if you need to ask, you don't know how, based on that you probably should go to the expense if buying a new stove and installing proper propane equipment and accessories as mentioned above for those that know something about this stuff it's a matter of changing orifices and regulators because CNG and propanr arrive at very different pressures to the appliance manifold
 
Jan 11, 2014
7,824
Sabre 362 113 Fair Haven, NY
Basically if you need to ask, you don't know how, based on that you probably should go to the expense if buying a new stove and installing proper propane equipment and accessories as mentioned above for those that know something about this stuff it's a matter of changing orifices and regulators because CNG and propanr arrive at very different pressures to the appliance manifold
It is more that just changing the orifices and regulators. Because LPG is heavier than air and will settle in the bilge, the requirements hoses, leak detection, and storage are more important and more stringent than those for CNG.

Additionally, if an insurance survey is ever required or the boat is sold the surveyor should note the non-complaint LPG installation. I would expect most buyers and most insurers would reject a boat with a noncompliant LPG system.


 
Feb 26, 2009
591
Oday 30 Anchor Yacht Club, Bristol PA
It is more that just changing the orifices and regulators. Because LPG is heavier than air and will settle in the bilge, the requirements hoses, leak detection, and storage are more important and more stringent than those for CNG.

Additionally, if an insurance survey is ever required or the boat is sold the surveyor should note the non-complaint LPG installation. I would expect most buyers and most insurers would reject a boat with a noncompliant LPG system.


Did you actually read what I wrote, or did I just waste my time?
I said:
"if you need to ask, you don't know how, based on that you probably should go to the expense if buying a new stove and installing proper propane equipment and accessories as mentioned above"

for just the appliance it is a matter of orifice pressure and regulators, that was never meant that LPG safety requirements don't apply!
 
Last edited:
May 24, 2004
6,790
CC 30 South Florida
I'll give you a list of what you will need;

A Propane stove with thermocouple switches. (most stove conversions are DIY and are not able to be certified)
a propane tank locker (Installed above the water line and vented outside the hull)
one or two 5 to 10 lbs propane tank to fit in locker
a pressure gauge (Important to periodically check for leaks)
a solenoid with a remote switch (remote switch to be installed at arms length but away from stove)
a single length propane hose from tank to stove with fittings to protect it from chaffing
electrical wiring from Electric Panel to remote switch and from Remote switch to solenoid
Propane sniffer or sensitive nose
Gas pressure regulator ( Connections ,Tank-pressure gauge-regulator -hose-stove)

You are probably looking at $4,000 plus installation costs of another $1,000. Don't forget that switching to a propane system may have Boat Insurance implications. This is where shortcuts and conversions could fail a survey. If I had to do it nowdays I would probably look real good into non pressurized alcohol stoves. Of course it would depend on how much do you cook aboard.
 
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Likes: Hello Below