Safe Down Below

Carbon monoxide detectors can save lives.

The proper installation and use of carbon monoxide (CO) detectors can save lives aboard your boat by warning you when this deadly odorless gas is present. CO detectors are most often installed in interior cabins and sleeping quarters and they emit a loud alarm at 85 decibels when the presence of CO reaches harmful levels.

Two companies manufacture CO detectors for marine use: Fireboy-Xintex and Marine Technology Industries (MTI). Each company’s product—Fireboy-Xintex’s CMD-4M and MTI’s Model 65—utilize sensors to detect lethal-but-odorless carbon monoxide gas. Installment guidelines call for the unit to be placed at eye level in the cabin, where it can’t be blocked by pillows or gear, and away from windows and doors. The unit needs a 12-volt power source that is wired directly to the battery so it is constantly functioning. The CO detector must also be changed out on a regular basis. In August of 2009, the United Laboratories 2034 (UL) testing standard was updated for all units, and specified that all CO detectors must have an end-of-life warning.

“That means that CO detectors have a finite period of life,” said Larry Akins, Chairman of Fireboy-Xintex. “Over time the sensor deteriorates because of dust and dirt. We received UL-approved standards for our marine-grade CO detectors over a year ago and now everything we sell meets that standard. The company that makes our CO sensor is in Japan, and we install a timing microprocessor that signals end-of-life in five years from when we manufactured the unit. Also, our CMD-4M-RLY can be wired to shut down the generator if the CO levels rise.”

MTI’s new Model 65 marine CO detector that is UL 2034 compliant should be available early this year when UL completes its testing. The 65 series will be available as a multistation alarm sounder so you can connect up to 10 different alarms, and will also be available with a three-amp relay (used to shut down a generator). The 65’s end-of-life warning will sound five years after the unit is first powered on.

New-boat manufacturers of cruisers with interior cabins must build their boats with CO detectors as standard equipment to receive certification from the National Marine Manufacturers Association (NMMA). Sea Ray uses gas generators aboard many of its boats—a common source of carbon monoxide—and new Sea Rays are built with Fireboy- Xintex units. Many people with boats not originally equipped with one add a CO detector to their boat. Costs for marinegrade CO detectors range between $80 and $110.

“The best way is to wire the sensor to the battery, but it can be wired to the battery switch, so when the engine is on, the CO sensor is on,” Akins explained. “If you are going to install a CO detector, it makes no sense to go halfway and not buy a marine-grade detector. The inexpensive CO detectors you can buy at Home Depot are built for consistent temperatures in a home and no movement. On boats, there are big temperature swings and a lot of movement, and that’s why the marine-grade CO detectors are the only way to go.”

It’s important to note that new studies show that CO can enter your boat in many ways. A pamphlet from the NMMA’s “Know More About It” brochure series includes a lot of helpful information on carbon monoxide poisoning. For example, CO can be trapped in inadequately ventilated canvas enclosures, an area you might think is otherwise safe. Blocked exhaust outlets can be a problem, as well as another vessel’s exhaust. And then there’s the infamous “stationwagon effect” or back-drafting of exhaust gases, even though the vessel is moving forward, a swirling suction develops which draws the exhaust back into the cockpit and then into the cabin. “The CO from the boat next door to you is just as bad,” said Jeff Wisniewski, President of MTI. “Your engines might be off and nothing else is running, but the CO from a nearby boat comes aboard.”

It is important to make sure it’s not easy to disconnect the power source from the CO detector. Connections that can easily be broken could tempt someone into disconnecting the alarm because it’s a nuisance in the middle of the night, believing the alarm is malfunctioning. Today’s technology has made false alarms much less likely, as the CO sensor and accompanying microprocessors more effectively monitor the CO levels in the enclosed space.

CO poisoning is hard to detect, because the feeling is very similar to being seasick. Early warning signs include headaches and sore eyes, which can be followed by dizziness, drowsiness and vomiting. Longer exposure to lower levels or short-term exposure to high levels of CO will lead to unconsciousness, brain damage and possibly death.

fireboy-xintex.com or mtiindustries.com