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Author Topic: Safety-propane and carbon monoxide  (Read 5420 times)

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Safety-propane and carbon monoxide
« on: May 06, 2006, 06:34:26 AM »

Sorry this article is so long. I found there to be some very useful info.

My 1994 Gemini 3400, like many multihulls, is equipped with several
propane-fuelled appliances: stove, refrigerator, hot-water heater, and
barbecue grill. When I left Minnesott Beach, North Carolina on Nov 30, to
begin my long-awaited nine-month sabbatical cruise, I had been using the
propane stove for several days while getting provisions aboard. As we motored
across the Neuse River and into the Intracoastal Waterway, I made several
unsuccessful attempts to light the Dometic AC/Propane refrigerator that I had
been operating on AC at the dock. Getting propane devices started after the
boat has been in storage for months always seems to take several attempts.
After anchoring Icon Duet in Cedar Creek, I got the refrigerator pilot lit,
cocked dinner on the Pacific 2000 propane stove, and lit the Paloma hot-water
heater for dish washing. Pete said that he'd need hot water for shaving in
the morning, so I left the heater pilot on. It was a cold night. By 8;30 p.m.
Pete, his wife Joy, Marion and I, all were in our bunks, several complaining
of headaches, and all of us feeling exhausted from all the last-minute chores
associated with leaving our homes and jobs.

The Xintex Propane/CNG Fume detector alarm awoke me at about 10:30 p.m. I ran
to the alarm and found it was a real red-light emergency and not an amber
light false alarm, opened the door to the cockpit, and collapsed unconscious
before reaching the propane valve shutoff. As I collapsed, I caught my arm in
my free-standing helm chair and went down with my arm twisted behind me -
which may have been one of the factors that saved all our lives. The three
crew members were all hearing the piercing beeps from the propane alarm, but
due to fume-befuddled minds, were not reacting. Joy heard my "unearthly
wailing" and thought maybe Marion was having a nightmare in the port aft
cabin. After Joy visited the head and was returning past the companionway to
the starboard aft cabin, she realized that the wailing was coming from the
cockpit - and found me. She roused Pete. Marion could hear the alarm
beeping and she heard Joy alternately yelling "Pat, can you hear me?" and
"Marion, come out to the cockpit!" Although Marion was aware of the commotion
in the cockpit, she was feeling too dopey and detached to respond and kept
drifting back to sleep. It all "seemed so far away."

I was probably unconscious for about 10 minutes before coming to enough to
say "propane emergency." Pete got the propane turned off at the tank and soon
made brief forays into the cabin to open hatches and get blankets for us to
wrap ourselves in.

At 11:10 p.m. I called the Coast Guard for advice in dealing with the propane
leak. When they learned that I had been unconscious they asked if I wanted
medical treatment and suggested that I motor to shore where they would
arrange for an ambulance to meet us. As befuddled as I was, I didn't think I
should start the engine in a boat that might be filled with propane... the
alarm was still sounding. The Coast Guard agreed and sent a boat to take us
to the ambulance. At 1:10 a.m. we arrived at Seagate Marina where two
volunteer-staffed ambulances waited to transport us to the hospital at
Morehead City. We arrived at the Emergency Room at 2:00 a.m., still assuming
our problem was inhalation of propane fumes.

The ER nurse took our blood pressure and pulse, and determined our blood
oxygen level with a device that we inserted our index finger into, and it
gave a digital reading on a device the size of a hand-held GPS. After
interviewing us about our nausea, headaches, etc... the ER physician
announced that he would be dismissing the three crew as soon as paperwork was
completed, but he would run an EKG on me since I had been unconscious. I
asked about the carboxyhemoglobin test the nurse had mentioned to me and the
doctor agreed to run that test also. The results of the carboxyhemoglobin
test were our first clue that our problem was carbon monoxide rather than
propane fumes.

My COHb level (carbon monoxide level in my blood) was 14; normal is 1. The
nurse told me that my COHb level probably was 25 when I had passed out, but
by this time I had been breathing clean air for nearly 5 hours and my level
was coming down enough that I did not need to be evacuated to the Duke
University's hyperbaric medicine center, although the ER physician remained
in consultation with Duke until all our COHb levels normalized. COHb levels
of the crew, at 3:15 a.m., were: Marion - 13.9; Pete - 10.5; and Joy - 5.9.
They kept us breathing through oxygen masks until 6 a.m. when all our COHb
levels were down to 2 or below.

At this point we realized that it had been carbon monoxide that had almost
killed us, but we still thought that a propane leak had set off the alarm.
Later that day, I called the Xintex Corporation for information about their
fume detectors. I learned that CO alone would set off my propane alarm, but
not until approximately lethal levels of CO - perhaps 3,000 ppm. So now our
problem had been relabeled as a carbon monoxide problem rather than a
propane leak, even though it was the Xintex propane detector that had
awakened me and probably saved all of us from dying in our sleep.

The boat was towed to Town Creek Marina in Beaufort where they sent the
regulator to be tested by the gas company. The water heater was removed and
sent back to the importer, to see whether it could be reconditioned after
finding that it was very corroded inside. It was too rusted to be
reconditioned. I decided I never wanted another water heater aboard. Not only
did the water heater seem to be the source of the CO which had nearly killed
the four of us, but it had always been my least treasured propane appliance.
I've always preferred solar showers to the alternating scalding/chilling of
my pressure-water shower. Water from the hot water line passing through the
heater activated a flame which came up with a terrifying woosh. Then the very
hot water had to be mixed with cold, to adjust the temperature for bathing -
and as soon as I'd got it mixed just right, it would be time to turn it off
while soaping up, so I wouldn't waste precious tank water. Then, with eyes
full of shampoo, I'd have to get the hot water going, add the cold to the
proper temperature again - and, by then, I'd feel a nostalgic longing for
solar showers and sponge baths.

We arranged to have a Xintex CMD-2M carbon monoxide audible alarm detector
installed. Aside from the corrosion in the Paloma water heater, the only
other clue to the possible source of the CO was that there was one mud dauber
wasp in the water heater and a small clump of mud such as those they leave for
their nests - it was in the bottom of the heater when we found it, so we
don't know where it might have been before the heater was taken apart.
Town Creek Marina checked all propane connections to stove, refrigerator,
and tanks, checked the tanks for leaks, and sealed off the line at the tank
that had gone to the water heater. No leaks were found except in the
regulator which attaches to the propane tank in the exterior vented cockpit
propane locker. We replaced the regulator.

Convinced that our problem was solved, and protected by our new CO detector,
we left Beaufort on Dec. 5, had a pleasant day motoring south on the ICW, and
anchored that night in Mile Hammock Bay. It was getting cold so we closed up
except for the usual minimal ventilation openings on my boat: one Nicro
Day/Night solar vent fan over the stove, and another one operating in the
hatch of the head, plus leaving the two companionway windows open at the 1
1/2 inch setting. With window widths of 42" and 28" this gives 70 square
inches of open window ventilation in addition to the two fans operating at
the two Nicro vents.

Within an hour of cooking and closing the companionway door, the new Xintex
carbon monoxide audible alarm sounded and the red light flashed. We headed
for the cockpit after fully opening all hatches and the companionway door and
windows and turning on all five of my 12-volt fans. Soon the Xintex CO
detector alarm ceased sounding and flashing, indicating that the CO level was
now below 75PPM. This marine alarms tolerates higher levels of CO than
household alarms and operates on a time sample system so it doesn't go off
unless there is a sustained presence of CO: How long depends on the
concentration level. At 100PPM it needs nearly eight hours of continued CO to
sound, whereas at very high levels it requires only 5 minutes.
We called our helpful BOAT/US surveyor, Tommy Suggs, from my home port of
Oriental, NC, to let him know that the CO problem had apparently not been
solved and that either the stove or the refrigerator must still be generating
CO. We slept in a cold but well-ventilated boat that night at the anchorage.
The next morning, after using the stove at breakfast and thoroughly airing
the boat after we got underway, we conducted an experiment suggested by
Tommy Suggs. We closed up the cabin with nothing operating but the Dometic
propane refrigeration to see if we could isolate the problem between the
stove and refrigeration. Seventy-two minutes after closing up, the carbon
monoxide detector alarm sounded again with nothing operating but the

In Wrightsville as in Beaufort, no gas company was willing to deal with a
propane device on a boat. On the other hand, Masonboro Boatyard was extremely
helpful despite operating under difficult conditions due to the heavy damages
incurred from a hurricane a few months earlier. When the refrigerator was
pulled out, there was a pile of corroded flakes under the pilot. On the
advice of the gas company, Walter sucked corroded metal bits with a shop vac
and then blew out the area with compressed air - and that solved the problem.
Not only did the CO detector not go off again, but we found a boater with
access to a CO measuring device who determined that there were no further CO
problems at the refrigerator - and none at the stove.

What have I learned?
1. If there are fuel-burning devices on your boat, have a specialized carbon
monoxide detector in addition to any other fume detectors you may have.
2. So few people survive carbon monoxide poisoning that symptoms may go
undiagnosed, even by ambulance and emergency room personnel. Since we were
awakened by a propane detector, we made the faulty assumption that our
problem was propane fumes and it was only an offhand remark by a nurse about
carboxyhemoglobin test that led to our being properly diagnosed and treated.
The oxygen administered after the CO poisoning diagnosis was made, no doubt
hastened our recovery and may have saved us from permanent neurological
3. What we thought was quite generous winter-time ventilation on the boat was
not enough to prevent rather rapid buildup of carbon monoxide to near lethal
4. Carbon monoxide poisoning renders you incapable of making rational
self-care decisions. We had to rely on reports from the Coast Guard,
ambulances, and the hospital, to piece together the chronology of the
night's events. In recapsulizing what had happened, we all wondered why we
had behaved so stupidly. I wondered why I hadn't immediately called out to
the crew when the alarm first sounded. The crew were at a loss to explain
their lack of response to the piercing sound of the propane/fume detector
alarm and to the "unearthly wailing": of the skipper. Poison-control helped
us to understand that carbon monoxide affects judgment and decision-making.
5. My boating schedule of living aboard and using all my propane devices
intensely during three months of the year and then letting the boat sit
unused while I return to Ohio to teach for nine months of the year, no doubt
has hastened the rate of corrosion in my water heater and refrigerator. These
appliances are only three years old and badly corroded.
6. Flakes of corroded metal can accumulate over the pilot of a propane
device, leading to incomplete burning of the propane and a buildup of carbon
monoxide. Cleaning these devices of any loose corroded material at the
beginning of each season is certainly a good idea. Getting someone to inspect
or work on propane appliances on boats, however, is difficult. Manufacturers
who state that their appliances should only be worked on by their
manufacturer's service facilities will not have anything to do with coming
aboard a boat to service these propane devices. We were told, both by the
Dometic service center and by gas companies, in three locations, that "our
insurance won't cover us for working on boats."
7. Although my boat is of the era when neither the water heater nor the
refrigerator were vented to outside as these same devices are on the newer
Geminis, venting is not the solution to CO problems. The corrosion over the
pilot clogs the normal venting channels, regardless of where the vent ends.
The only real protection seems to be the CO detector and visual inspection
for corrosion.
8. Ultimately, we have to weigh risks and benefits for each of our propane
devices. For me, the stove is by all odds my most treasured propane
appliance. It cooks well, has given me no trouble, and hasn't shown any signs
of corrosion. My refrigerator uses a lot of propane in hot weather and
sometime freezes lettuce in cold weather, but I love it. It keeps me supplied
with ice cubes as well as keeping food and beverages well chilled. I've read
that the difference between a "boat" and a "yacht" is whether you can produce
your own ice cubes. Ice cubes are the most highly rated luxury item aboard
Icon Duet. So, I'll keep my propane refrigerator. The water heater, on the
other hand, is something that I can, and will, do without.

Doug and Donna #171

Ron Hill

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Re: Safety-propane and carbon monoxide
« Reply #1 on: May 06, 2006, 06:54:00 PM »

Doug & Donna : A great ending to what could have easily been a tragic story!
I have a CO detector on my C34 and in a Mainsheet article recommended that everyone install a smoke detector on board.  You have them in your house - why not on your C34?  I recommend the one with a light - that turns on when the detector goes off.  It has already "saved" this boat - when an empty fry pan was put back on a lite burner!!
Cost of a detector? $20?   
A thought along with Doug's. 
Ron, Apache #788

Jon W

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Re: Safety-propane and carbon monoxide
« Reply #2 on: April 06, 2015, 04:26:22 PM »

Where did you install the carbon monoxide and propane alarm on your C34?

Jon W.
Jon W.
s/v Della Jean
Hull #493, 1987 MK 1, M25XP, Manson Supreme 35
San Diego, Ca


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Re: Safety-propane and carbon monoxide
« Reply #3 on: April 07, 2015, 09:17:46 AM »

It should be noted that neither the hot water heater nor the LP refrigerator meet today nor met ABYC safety standards then for when that boat was built.

Just because a builder installed it DOES NOT mean it is safe!!! There are numerous builders who completely ignore the safety standards we have in place to hopefully prevent such incidents. That particular builder installed RV grade appliances that never should have been installed on a boat....

Every boat with a cabin hould have a CO detector and a smoke alarm as well as an LPG sniffer....
-Maine Sail
Casco Bay, ME
Boat - CS-36T


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Re: Safety-propane and carbon monoxide
« Reply #4 on: April 07, 2015, 09:52:20 AM »

I installed a Fireboy LPG switch and fume detector on my C34. The switch and alarm are at the nav. station and the sensor is under the floor in front of the engine. The Fireboy sendor is not waterproof. I found this out the "hard way",  so keep it low enough to register heavier than air LPG but high enough in the bilge to stay dry.

For CO detection i am using a battery operated residential CO detector mounted in the aft cabin. Although residential is not ideal, I have not had any false alarms (yet). I may switch to a marine unit someday, but they are approx. $100 and need to be hardwired to 12v.  I have battery operated smoke detectors in main salon and V-Berth.
« Last Edit: April 07, 2015, 09:56:39 AM by Noah »
1990 hull #1014, San Diego, CA,  Fin Keel,
Standard Rig

Ron Hill

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Re: Safety-propane and carbon monoxide
« Reply #5 on: April 07, 2015, 02:34:49 PM »

Jon W : I mounted my CO detector under the bottom step companion way, as CO is heavier than air!!

A thought
Ron, Apache #788


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Re: Safety-propane and carbon monoxide
« Reply #6 on: April 07, 2015, 03:38:54 PM »

Ron, I beg to differ with you. CO is not heavier than air. In fact, it is very slightly lighter than air, but not enough to dictate placement either high or low. It is just important to keep the dectector away from open hatches or wind channels, or on the otherside, trapped dead-air spaces, in order to get a true reading on contamination levels.
« Last Edit: April 07, 2015, 03:39:36 PM by Noah »
1990 hull #1014, San Diego, CA,  Fin Keel,
Standard Rig


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Re: Safety-propane and carbon monoxide
« Reply #7 on: April 10, 2015, 06:19:16 AM »

Hi...  interested in a LP sniffer...  how did you guys hook it up to 12 volt power?  My thought is if it's directly wired to the batteries, it constantly draws it down all the time.  Did anyone run it to a breaker on the panel?  Where did you locate the sniffer sensor? 

Roc - "Sea Life" 2000 MKII #1477.  Rock Hall, MD


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Re: Safety-propane and carbon monoxide
« Reply #8 on: April 10, 2015, 10:25:51 AM »

Not much good if it doesn't have constant power. Put sender low as possible without it getting wet.
1990 hull #1014, San Diego, CA,  Fin Keel,
Standard Rig

Steve McGill

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Re: Safety-propane and carbon monoxide
« Reply #9 on: April 10, 2015, 12:16:21 PM »

When I installed the propane sniffer on CLARITY I wired it into the cabin light circuit. The first thing we always do when we come onto the boat is turn on the
lights. The last thing we do when we leave the boat is shut off the DC power, minus the bilge pump.

Just another different opinion.

CLARITY 1988 #588 TRWK
Chesapeake, Herring Bay, MD


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Re: Safety-propane and carbon monoxide
« Reply #10 on: April 10, 2015, 07:32:40 PM »

That works if you have your "turn on the switch routine down" 100% of the time. I have the luxury of not worrying about battery power as I am always on A/C charger when at the dock and my four T105s are good while at sea and at anchor. Although I don't know off the top of my head how many amps the Fireboy LPG sensor draws, I wouldn't think it is much, compared to my piece of mind.
1990 hull #1014, San Diego, CA,  Fin Keel,
Standard Rig


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Re: Safety-propane and carbon monoxide
« Reply #11 on: April 10, 2015, 07:33:04 PM »

Did you wire it to the light circuit breaker at the panel?  If so, I'm not sure if it's proper to put two wires on one breaker.  
Roc - "Sea Life" 2000 MKII #1477.  Rock Hall, MD


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Re: Safety-propane and carbon monoxide
« Reply #12 on: April 11, 2015, 02:30:50 PM »

Did you wire it to the light circuit breaker at the panel?  If so, I'm not sure if it's proper to put two wires on one breaker.  

Four are allowed per connection on a terminal block -- haven't found anything in ABYC re: # on breakers, but two would seem reasonable.  Two are ok in a/c breaker panels.

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