Carbon Monoxide and Houseboat Deaths


Carbon monoxide (CO) is a colorless, odorless and tasteless gas.  In human beings, the symptoms of CO poisoning mimic fatigue, excess alcohol consumption, heart attack, and stroke, - and CO can kill in a single breath. 

Over the past decade or so, the US Coast Guard and numerous other organizations have become particularly concerned by the number of lethal incidents related to CO in houseboats.  The primary focus is the single hull houseboat, which has a swim platform that extends behind the transom or back of the boat.  Essentially, CO-rich exhaust gases from the propulsion engines collect in the space under the swim platform and can reach concentrations in the tens of thousands of parts per million.  The result is a lethal environment created by high levels of carbon monoxide and a breathable oxygen deficit.

Up to this point, the solutions have included a US Coast Guard-mandated recall of houseboats to redirect the generator exhaust outside the swim platform space, most often to the side.  The houseboat industry has also created a wide variety of warning labels to advise houseboat users to stay away from the swim platform when the main propulsion engines are running.

These solutions, however, have proven less than adequate.  Deaths associated with the main propulsion engines have occurred, particularly when the houseboat engines have been shut down to inspect, repair, or un-foul propellers.  The lethal CO cloud does not immediately dissipate and can remain trapped by structural constraints.  The most lethal situation occurs immediately after shutdown of an idling or cold-started engine.  The great majority of warning labels tell houseboat users to stay out of the water when the engines are running, but say little or nothing about waiting for the exhaust gas cloud to dissipate with the natural action of wind and water movement.  (Unfortunately, nobody really knows how long is long enough because the effects of wind and water movement differ from one moment to the next.)  There are other solutions in place today.  Some houseboat manufacturers are using stacks rather than side exhausts for the generators.  There are advances in engine technology that reduce the amount of CO in the exhaust.  However, at this time, the majority of monohull houseboats are still manufactured and used with the lethal configuration unchanged.

Within the past year, a proof of concept study was done that showed a substantive reduction in the CO concentrations under the swim platform.  The concept used a blower to force air into the space to dilute and dissipate the CO- rich exhaust.  The reductions in CO concentrations were striking, with as much as a 30 to 1 reduction in parts per million of CO.  The result was a livable but not ideal CO environment.  One of the advantages to this blower concept is that there is a long history with the use of blowers to scavenge explosive gas fumes from engine compartments.  The blowers can be interlinked with any running engine, and that includes the generator.  The blowers can be part of new construction but also retrofitted.  Because the exhaust is diluted, the likelihood of injury or death in the immediate surroundings at the back of the boat, but outside the swim platform, is also logically reduced.

It is important to note that the CO lethality problem is not just restricted to monohull houseboats.  All combustion engines produce CO, and powerboats depend on combustion engines for propulsion and electrical power generation.  Testing has shown that outboard motor running at idle can produce lethal levels of CO.  The well-known station wagon effect has led to a number of deaths.  Rafting boats together or against a dock can trap CO.  Sometimes the CO problem is internal to the boat itself.  A small leak in an exhaust fitting or hose can produce enough CO to create a lethal environment in the engine compartment and the cabin.  The use of portable generators, even on the open deck of a boat, can prove lethal if the CO migrates into the cabin through drains, air conditioning, or even apparently closed hatches and doors.

In conclusion, CO is one of the significant and now-recognized problems within the boating industry.  Advances in engine technology, and the use of pro-active solutions like blowers, when combined with effective warnings and consumer education, will help.  However, today's bottom line is that this is still a major concern for the boating industry - and recent tests have begun to reveal just how serious this problem is. 

This article discusses issues of general interest and does not give any specific legal or business advice pertaining to any specific circumstances.  Before acting upon any of its information, you should obtain appropriate advice from a lawyer or other qualified professional.

This article may not be duplicated, altered, distributed, saved, incorporated into another document or website, or otherwise modified without the permission of TASA.

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