This article by J.G. Merritt originally appeared in the Technical Information Exchange, a publication of www.BoatUS.com!BoatUS.
Carbon monoxide alert - Is it installed correctly? Is it actually working? Are there other elements that could make a dangerous situation? Ask your marine surveyor
As often happens, a near catastrophe—two people almost being killed-- was caused by a series of seemingly small events, each of which occurred at precisely the right (or perhaps 'wrong') time. Of particular interest to me, as the surveyor assigned to do the initial investigation, was that the events taken individually were not necessarily significant, but on the whole were deadly important. Hold that thought.
The boat owner and his lady friend were both hard-working professionals with pressure-type jobs. They had planned an outing on his boat, including anchoring overnight in a nearby cove. The boat was kept in a marina on a local lake and after getting to the boat and loading their supplies for the weekend, they pulled out. Fuel supply was adequate for the planned usage, although the starboard tank was lower than port. They anchored where they would be sheltered from boat wakes or wind driven waves. Even though it was early fall, the weather was still warm and humid so before going to bed they closed the cabin doors and turned on the air conditioner. They slept, and slept, and slept.
When the owner woke up the sun was already shining and he was feeling terrible, almost unable to move. His girlfriend was still asleep in the aft cabin and looked uncomfortable as she was huddled up in the port corner in front of the air conditioner grill in order to feel the cooling breeze. Thinking she needed to wake up and move, he tried to change her position but she didn’t respond. The effort exhausted him and he collapsed back into a deep sleep again.
When he woke, it was still daylight and his girlfriend was in the same position. She was and still unresponsive. Knowing something was terribly wrong, he realized he had to get help even though he could barely move. He managed to get out into the cockpit and started making calls on his cell phone but couldn’t get through to anyone who may have been able to help. Working his way forward, he found he was unable to retrieve the anchor, so he went back to the helm and started the engines. He tried to hail two fishermen he saw—or thought he saw--standing at the mouth of the cove. They couldn’t hear his weak cries, because, he reasoned, the wind was blowing the wrong direction. Then he used the engines to move the boat forward to break out the anchor. Feeling a bit stronger, he managed to pull the anchor aboard and start toward the marina. As he passed the two fishermen, he saw they were actually two tree stumps.
Steadily improving in consciousness and strength, he called the nearby marina for help. They indicated they would call EMS and meet him at the service dock if he thought he could make it. Assuring them he could, he completed the short run back to the marina, which was in sight of where they had anchored. The EMS ambulance and crew were waiting when he pulled in at the marina. He told them he didn’t know what happened, but his girlfriend was still below and comatose. Immediate attention was given to getting her off the boat and whisked away. The owner said he felt well enough to drive home.
On his way, he decided to call his office. His secretary answered the telephone and her first question was, where in the world are you? We’ve been going crazy trying to find you! It was then he realized that it was Monday and he and his girlfriend had been unconscious on the boat all day Sunday.
A shower and clean clothes put him in better shape and he decided to calling his doctor and finding his girlfriend. His doctor listened to him on the telephone and told him to come in immediately so he could be evaluated. Arriving at the doctor’s office, he related all the things that had happened. Blood, breath, and urine samples were taken and minutes later he was flat on his back with an oxygen mask over his face and the doctor telling him he had just suffered an acute case of carbon monoxide poisoning. In soon was feeling much and the doctor gave him the OK to try to find his girlfriend.
He finally located her in the ICU of the local hospital and, hurrying down the hall to the designated room, he was abruptly stopped by a uniformed police officer before he could enter the room. The officer refused to allow him access. The following day he learned that the police department was investigating the incident because of the EMS report that stated that the woman had been received in a comatose condition with heavy bruising to her upper arms, shoulders, and neck. There was a strong suspicion she was the victim of an assault and charges would be filed against him. They had not yet realized she was the victim of CO poisoning, which would have explained the many bruises. Though they were acting in what they thought was her best interest, she had not been treated for CO poisoning.
I received the assignment from the insurance company several weeks after the incident. It was presented as a 'possible' CO case and they wanted verification, plus the conditions and source of the CO. Testing for the presence of excessive levels of CO is a regular part of my Condition and Valuation Surveys. After accepting the assignment, I contacted my close associate, Dan Ginder SAMS-AMS, to see if he wanted to participate in the vessel inspection and he agreed.
Research into the US Coast Guard accident reports and recalls had not found any CO incidents with this model boat, a 1997 Regal 322 Commodore. The boat has twin Mercruiser V-8s, a Westerbeke 4.5 kW generator, air conditioning, electric range, etc. The boat was well kept, with less than 500 hours on the engines. The current owner’s service records revealed only minor problems, along with a persistent rattle associated with the generator that had been corrected by replacing and tightening attachment screws on the belt cover. No notes were found relating to any exhaust system leaks or gasket replacement.
As Dan and I started our systematic checks of the equipment we were both struck by how many defects we noted, none of which was especially noteworthy by itself but together they added up to a deadly combination. Mr. Murphy was certainly correct in his dictum 'whatever can go wrong will.' What we found should never have happened, but it did; surveyors, shop owners, and boat owners need to pay heed and not get complacent or overlook these items during inspections or operation:
A. The owner informed me there was no survey performed. He was an experienced boat owner and his inspection and the broker’s assurance the boat would be checked over by the brokerage shop was adequate to complete the sale. No professional inspected the generator or safety systems.
B. The carbon monoxide alarms (Xintex CMD-2) would not emit a test signal or warning light, although they had a faint green light visible behind their covers. The test button could not be pushed because the covers were installed upside down. Installation of the base plates for the units was horizontal instead of the normal vertical orientation and it was easy to put the cover on in the wrong direction with the slot permitting access to the test function on the wrong side. We found that the red alarm light and 'beep' would come on when first depressed but when held down the red light went off after a few seconds and the green light would show a dim glow that was visible through the vent louvers in the covers. The owner said he was aware the units did not test properly but he did not have a manual. Xintex® discontinued the model several years ago and they were effectively outdated when the owner bought the boat.
C. The air conditioning intake air filter was clogged and the grill was located where bedding or persons can easily block it. This created a negative pressure in the evaporator compartment that would draw air from any openings into the area, including the engine room. Air conditioner filters on boats fitted with generators must be kept clean to avoid pulling air from the engine compartment.
D. In this boat, the machinery space housed the air conditioning unit, water pressure pump, and water heater all in the same space with their various hoses and cables all entering and exiting the space. Connecting ducts should be installed between intake grills and fan/evaporator assemblies if the compartment shares space with other equipment or is used for storage.
E. All bulkhead penetrations between engine room and living spaces must be effectively sealed against air movement between the areas. CFR-33 permits a ¼-inch annular space around cable and hose passages. The ABYC standards recognize this as a hazard where air conditioning or other equipment is installed and does not allow it. This boat met the federal requirement at the bulkhead/living space penetration but had a nearly ½' opening between hoses and top of a circular cutout, which was contrary to ABYC. With the air conditioning on, there was a ready transmission from engine compartment to living space. We proved that by introducing smoke in the engine room and noting it came in the machinery locker immediately. In this particular case, the woman was sleeping in a position that partially blocked the intake grill, increasing the inflow from the engine room.
E. The owner said he had noticed a slightly different sound from the generator the last few times he used it but attributed the difference to another loose item, as had been previously found. We found a section of the exhaust manifold gasket on one of the cylinders blown out, probably the cause of the 'different' sound he noted—and the CO-- but did not check to find the cause. Generators need to be checked every time they are started for exhaust leaks and any unusual noises investigated.
G. This boat had all its ports and hatches closed when the couple went to sleep. A closed living area is in much greater danger of bringing in potentially dangerous gases from the bilges or engine areas so some ports or hatches should always be slightly open. This is particularly true if the boat has air conditioning or other vent fans in the living areas.
H. Engine room blowers were not in operation during this incident and the owner did not think they were needed; he only used them prior to starting the main engines. The blowers should always be on when the generator is in operation by itself since they produce a negative pressure in the engine compartment, which can offset any intakes around bulkhead penetrations or other openings leading into living spaces.
Remember the owner had made a conscious decision to not put more fuel in the starboard tank? When we first got on the boat the starboard tank was registering empty. The generator is fed from a shorter pick-up tube than the propulsion engine in that tank, and the end result was the generator ran out of gas at some point, probably during the day on Saturday and stopped producing CO. The air conditioning would also have shut down and prevented any further interchange of air between engine compartment and cabin. That’s the only thing that saved their lives!
The boat owner has apparently recovered fully but his girlfriend is still seriously disabled with a loss of feeling and control of muscles and nerves in her lower extremities. She is improving with continued physical therapy sessions but may have permanent disabilities as a result of her more severe exposure. Medical expenses are into the six-figure range and there is pending litigation. Further tests were made on the boat after putting the generator back in operation and getting quantitative readings of CO levels.
The lessons here? Carbon monoxide is deadly and ignoring seemingly inconsequential and unrelated issues—a rattling generator, unreliable or incorrectly mounted CO detector—along with gaps in engine room bulkheads and poorly mounted air conditioner units can add up to kill. Surveyors would do well to look for issues that could create the potential for CO poisoning as well as informing owners of the proper way to use equipment that can produce CO. One more thing to note: surveyors need to remember that diesel-powered boats are not exempt from this hazard since gas generators may be installed.
Carbon Monoxide (CO) Poisoning:
Carbon Monoxide (CO) is a by-product of fossil or organic fuel burning and is present in the vapors released during combustion. The gas is colorless, odorless, and has nearly the same weight as the nitrogen/oxygen mixture we normally breathe. We smell all the other noxious gases present in burn vapors and will do something to get out of the area or shut down the source of the odor, but CO has nothing to announce its presence and starts becoming deadly with exposures of just over 50-60 parts per million (ppm). The carbon element combines with the blood, effectively blocking the oxygen exchange. The end product is called carboxyhemoglobin; it can quickly go from minor discomfort to headaches, dizziness, unconsciousness and death.