Tuesday, October 25, 2011

Do I Need a CO Detector on my Boat?

Article by William L. Gills aka Bos'n Bill

Jim Hart and his wife Judy took their three sisters out for a boating overnighter.  They watched a movie with the generator running to power their air conditioning one hot evening in late July, then went to bed.  At 2:00 a.m. Jim awoke and slid off the berth to get a glass of water. When his feet his the deck his legs buckled at the knees and he nearly collapsed.  He felt like he was wearing heavy leg armor as he stumbled and lurched against the bulkhead that led to the galley.  He felt dizzy and disoriented, suddenly sick to his stomach.  Something was terribly wrong, but what?  At least he had the presence of mind to wake up his groggy passengers and crew.  Grappling with his cell phone he dialed 911. The local fire department responded immediately to his call.  When they arrived within the half hour in a fire and rescue boat they found Jim, Judy and the sisters dizzy, confused and ill.  They were rushed to the nearest hospital to be treated for CO (carbon monoxide) poisoning.

How does this happen?  What causes what seems to be so innocuous to the senses to be so life threatening?  You're being poisoned by CO, but you don't know it.  You  can't smell it, you can't see it, you can't taste it.  It takes on the specter of the macabre as it slowly, progressively overcomes your being.

If you're awake, you could pass out without warning, but usually the process is a slow one.  The first sign is usually a headache often with nausea, feeling much like the flu without the fever. As time goes on you'll feel drowsy for no apparent reason with accompanying lethargy, later breathless on exertion, with chest pain as the heart is starved for oxygen.  Low cardiac output will leave you less capable of clear thinking interfering with your usual response to danger;  escape.  With continued exposure the outcomes are often convulsions, coma, brain damage and finally, death.

So what causes this lack of oxygen medically known as hypoxia?  CO is generated by the normal operation of any fuel-burning appliance or engine aboard a boat, including and commonly generators.  If poorly maintained and/or malfunctioning or if not vented properly you run the risk of being a victim.

You've probably heard of hemoglobin.  Hemoglobin is a substance in the blood that carries oxygen from the lungs to every cell in the body.  It's needed so we have energy for growth, repair, movement and nerve conduction, all fundamental functions of life itself. When CO is present, it replaces precious oxygen in our blood causing a slow, but sure suffocation and destruction of tissue; a strangulation of life processes in the most insidious way.

You don't need to be sleeping to be overcome by CO.  In fact, there are more deaths in open air exposure when people are awake than in a confined space like a cabin, places like open cockpits or even swim platforms.  You learn in safe boating courses about the so called "station wagon effect" where gasses can be trapped and funneled back into the boat caused by a reverse air flow around the transom.  This heavy concentration of gas is further exacerbated by fiberglass swim platforms where exhaust fumes containing CO can be trapped in concentrated amounts only to flow into enclosed cockpits where it can accumulate to extreme toxic levels. Even a boat underway can pose problems at slow speeds, especially with a tail wind.

What can you do to be sure you're not being exposed to the deadly gas?  Well, the obvious answer is to get a CO detector, right?  That's what I did.  But, I assumed they were all made the same and would work equally well if they met minimum safety standards as noted on the package, so I bought two of the least expensive ones I could find at a local hardware store and installed them on my boat; one in the cabin and one in the cockpit.  The problem was, they kept sounding off at the slightest provocation; loud, ear-piercing tones designed to wake you out of a deep REM sleep.  I couldn't tolerate the excessive interruption and the attention they required, so I disarmed them to maintain sanity and keep my ears from ringing. 

Further exploratory research taught me there are CO detectors designed specifically for boats.  They're referred to as marine CO detectors and they work differently than the residential detectors I had purchased.  What I learned is that CO levels in the home are typically very low.  When they rise perhaps due to a faulty stove, heater or furnace, occupants need to be alerted right away.  In a boat, you certainly don't want to be warned every time an engine starts or runs at idle for a short period of time.  Marine CO detectors are designed to sound only when CO levels have remained high for a longer period of time, not every time spikes in CO are detected.  They're also designed to withstand harsher marine conditions.

I now have two new marine CO detectors in strategic locations on my boat.  Sure they cost a bit more, but what's the price of lost life and the peace of mind they bring.  As boaters, we're around fuel burning engines and appliances quite often.  To me,  they're a line of defense against a wily foe; an early warning system that shouts - beware of the deadly gas lurking in the shadows.

William L. Gills aka Bos'n Bill is the author of the book, Lubber's Log published by Llumina Press; a boating primer and adventure story about a couples experiences in moving up to a bigger boat.  


  1. Great advice. Not enough people realize the dangers of CO but you do a good job at shedding light on the issue!

    Keith Johnson
    Used Boats in PA

  2. Thank you Keith. That's why I'm putting it out there. It's the if you can't see it or smell it, it's not really there perspective that can get you killed.