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Thread: Carbon Monoxide Detectors

  1. #1
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    Default Carbon Monoxide Detectors

    Surprised I didnít find any threads on this here. Iíve never had them on Snoose but some things recently have me thinking about them. My initial research seems to indicate that a boat (like Snoose) with a diesel engine and diesel furnace isnít really in danger from CO as much as gas engined boats are. However, as we sleep on the boat and sometimes in winter cruising run the furnace all night, I thought maybe itís an easy peace of mind installation.

    But then there are some choices to make. Snoose has three distinct areas, two of which are used for sleeping. Then there is the choice between hard wired and battery types. Plus finding locations where they wonít be in the way or unsightly. So how important are they on a diesel boat?

  2. #2
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    Default Re: Carbon Monoxide Detectors

    No, you are in danger. I've written on this on several threads and sorry you missed.

    GET BOTH SMOKE/FIRE AND CARBON MONOXIDE ALARMS. Better seperate units.

    I put fire alarms in the engine space and near the galley and near any heating - oil furnace, solid fuel stoves. Complex boats with a lot of electric need alarms in a few more places. Monoxide alarms go in each seperate cabin. For both I use battery operated.

    When I had a coal stove, the CO alarm went off more often but even with the Dickinson oil heater it went off now and then. It could go off even after I finally followed directions and installed a dedicated from outside air source to the the stove. At least the alarms I buy are perhaps a bit over sensitive and go off well before you are at real risk, but that's the whole idea. A boat cabin is a very small volume and it does not take much.

    And when you're running the stove is not the only time. I know of a cruising family who all died of CO. Nice evening running under power at about the same speed as the wind, on auto pilot, companionway open, having dinner below. 'Nuff said.

    G'luck

  3. #3
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    Default Re: Carbon Monoxide Detectors

    +1
    That diesel produces less CO than gas doesn't mean lethal levels can't be reached. Get detectors and mount them in salon and in each stateroom.

    Kevin
    There are two kinds of boaters: those who have run aground, and those who lie about it.

  4. #4
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    Default Re: Carbon Monoxide Detectors

    Mount the CO detectors low, below the level of the bunks, as CO is heavier then air. No point in the alarms going of after you started a permanent nap.

  5. #5
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    Default Re: Carbon Monoxide Detectors

    CO is lighter than air. It's CO2 that's a nudge heavier than air. But CO2 is usually in a fire situation heated, so it rises, and is associated with smoke which is what you have that alarm for. BOTH CO and smoke/fire alarms should be near the overhead.

  6. #6
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    Default Re: Carbon Monoxide Detectors

    There is a bunch of semi-relevant information here: http://www.carbonmonoxidedetectorplacement.com/

    "The specific gravity of Carbon Monoxide is 0.9657 (with normal air being 1.0), this means that it will float up towards the ceiling because it is lighter than regular air. However, when a build up of dangerous levels of CO gas is taking place, this is nearly always due to a heat source that is not burning its fuel correctly (motor vehicle exhaust fumes are an exception). This heated air can form a layer near your ceiling which can prevent the Carbon Monoxide from reaching a ceiling detector."

    C0 is a by-product of combustion so if you are burning stuff it needs to be vented. And C0 is sneaky, being so close to the same specific gravity of air it will mix and move around easily. Placement on a boat is going to be tough, you don't want to be too close or too far away. You definitely don't want to have the alarms going off all the time and get complacent about what is setting them off.
    Steve

    Boats, like whiskey, are all good.
    R.D Culler

  7. #7
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    Default Re: Carbon Monoxide Detectors

    Interesting that goes against all the safety training and videos that I used to present. However looking at the density of both CO and air you're absolutely correct.

  8. #8
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    Default Re: Carbon Monoxide Detectors

    Having been a close victim of Oxygen starvation, a CO2 alarm is a must in any boat with a heater that consumes oxygen as part of the heating process, which is pretty much everything outside of electric produced warmth. Dont become a statistic, and its one headache you will always remember....

  9. #9
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    Default Re: Carbon Monoxide Detectors

    Ian, I am curious about your use of battery operated detectors. I bought some hardwired detectors yesterday then realized the difficulty of placing them where I want them. But the battery ones have the disadvantage, unlike a house, where the low battery warning may beep for days on an unattended boat. Do you live aboard? But I think I’m aboard Snoose often enough and I can get in the habit of checking them often so I might take these back and get battery ones. And is this one of those applications where a specific marine device is warranted or is a Home Depot one just as good.

    This came up because I took the boat operators test. It surprises me that there are no requirements for these detectors. Yet there IS a requirement to have a sign reminding me to not throw apple cores overboard. Odd priorities.

  10. #10
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    Default Re: Carbon Monoxide Detectors

    I get mine at a family owned hardware store but the brand is the same as most big box. I am religious about monthly testing and annual battery changing.

    Now and then I've looked for Consumer Reports reviews because some brands are considerably less reliable than others. Because monoxide mixes so readily and because I work hard at circulation at least in the main accomodation - galley, saloon, head, stateroom with an Ecofan atop the heater or wood stove - I think that a CO meter in each space gives adequate redundancy. But judging from alarms that have actually gone off, the build up is, as should be obvious, at first near the stove in question.

    In general, systems that regulate the heat by restricting the air - solid fuel stoves mainly - are more likely to have the sort of incomplete combustion that can lead to CO and at low burn may have inadequate exhaust. Systems like the Dickinson pot burners that regulate heat by fuel supply, rarely have incomplete combustion unless they are also on the verge of going out.

    I have no experience with heat from propane as I am afraid of it except in supervised settings - nothing like a propane cook stove.

    I am this year and last not living aboard but did from 1981 on and will be again next year. I am not leaving any heat running on Marmalade or Meg when I am not staying aboard. In the past I had no qualms about leaving the heat running when I went off to work.

    G'luck

  11. #11
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    Default Re: Carbon Monoxide Detectors

    Thanks all. Most of you probably know this, the newer detectors are available with a permanent 10 year battery. They are a little more expensive ($35-40) but it solves the problem of a low battery warning beeping for days on an unattended boat. In 10 years, I’ll be 84 so will one of you please remind me to replace the detectors in my boat at that time? Thanks.

  12. #12
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    Default Re: Carbon Monoxide Detectors

    I would be happy to but who will remind me to remind you?

  13. #13
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    Default Re: Carbon Monoxide Detectors

    As long as we are on the subject, smoke detectors have a useful lifespan of about 10 years maximum, less in dirty conditions.
    Steve

    Boats, like whiskey, are all good.
    R.D Culler

  14. #14
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    Default Re: Carbon Monoxide Detectors

    Quote Originally Posted by skaraborgcraft View Post
    Having been a close victim of Oxygen starvation, a CO2 alarm is a must in any boat with a heater that consumes oxygen as part of the heating process, which is pretty much everything outside of electric produced warmth. Dont become a statistic, and its one headache you will always remember....
    Yes, red blood cells take up CO in preference to O2.
    '' You ain't gonna learn what you don't want to know. ''
    Grateful Dead

  15. #15
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    Default Re: Carbon Monoxide Detectors

    Carbon monoxide (CO) and carbon dioxide (CO2) are profoundly different. The biggest difference on the body is that CO is more readily absorbed in the blood than oxygen (O2) and subjective symptoms of CO poisoning are rare. CO is called 'the silent killer' for good reason. CO2, on the otherhand, is a product that our bodies naturally expell, so it does not so much poison us as suffocate. CO2 can poison you if you are in such a concentrated environment that the atmospheric CO2 overwhelms the body's ability. But, as anyone who has been subject to a lot of CO2 can tell you, it's a really obnoxious experience. You feel like you're being suffocated.

    If your only problem is CO2, you will probably know that you need fresh air. If you were asleep, you'll wake up.

    However, in most hazardous situations there is also a good deal of CO and that will kill you.

    You really need a CO alarm. You also need a fire/smoke alarm. You don't generally need a seperate CO2 alarm.

  16. #16
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    Default Re: Carbon Monoxide Detectors

    An addendum: CO poisoning is not something you can easily recognize in yourself but it may be visible to others. When Dad did test flying for Grumman, his main jobs took advantage of his incredible precision. In the late fifties they were testing anti-sub and positioning systems and loved Dad's ability to duplicate a pattern within just a few yards of the time before. So the day his flight pattern was off by a hundred feet, they got him on the radio and, based on his responses, told him to immediately open a window. Once on the ground, they found a small exhaust leak getting into the cockpit air.

  17. #17
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    Default Re: Carbon Monoxide Detectors

    RE CO2 and oxygen starvation death, it isn't necessarily the case that you will feel very uncomfortable prior to being overcome. Different levels of CO2 have different effects, and a slow build up can be very sneaky and deadly. I don't recall the concentration levels, however a slightly raised CO2 level in air will likely have an analgesic effect first, in other words you'll find yourself somewhat relieved of pain and may in fact comfortably doze off. A slow rise in concentration will likely have an anaesthetic effect, and will slowly put you in a sleep state. A further increase will cause suffocation death. A more rapid increase in CO2 concentration will certainly cause a person or other animal suffocation discomfort, choking and a panic state. Don't ask me why I know this.
    When I first joined WBF they made me write a book to prove I was a real yachty. I was so gullible.
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  18. #18
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    Default Re: Carbon Monoxide Detectors

    I have had the unhappy experience of carbon monoxide poisoning. It was on a tourist yacht I worked on and was the result of a cracked exhaust manifold on our single Cat diesel. All passengers and crew were affected...some more than others...and it was miserable. I also see it regularly in the Emergency Department at the hospital where I work.

    I recently went through the process of selecting and installing CO detectors on my boat, which has a Lehman diesel and a Dickinson diesel cook stove. I chose a 10-year battery-powered combination CO/smoke detector for the main cabin and hard-wired marine CO detectors in both sleeping cabins. One of them was defective and so I enjoyed a long, informative conversation with one of the tech guys at the manufacturer. Yes, carbon monoxide is marginally less dense than air, but not enough to stratify in the atmosphere of a boat. In the two sleeping cabins, the detectors are installed at the level of our heads while we're sleeping. My surveyor and insurance company required these as the battery-powered one, which is from the hardware store, does not meet the AYBC spec.

    No, diesel engines don't produce nearly the amount of CO that gasoline engines do, but it's plenty enough to be toxic.
    --​Anson, M/V Kingfisher

    Be kind whenever possible. It is always possible. ~The Dalai Lama

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