A Few Words on Carbon Monoxide from Boat Exhausts

Carbon monoxide (CO) is an odorless gas that is a combustion by-product of both gas and diesel engines. When inhaled by the human body it is dangerous because it interferes with the blood system and the brain. In small doses it may only result in temporary illness but in larger doses it can progress to brain damage with possible internal hemorrhaging and even death. The first symptom of CO poisoning is drowsiness and sometimes nausea, the later of which is most often associated with diesel produced CO.

CO by itself is odorless, but you can always be sure that it is present by the smell of engine exhaust. In fact this is the best way to detect CO but over a period of time people can become intolerant to the smell and cease noticing it. CO is heavier than air and will tend to collect in lower areas of the hull especially cabin spaces and sleeping quarters.

The most common method by which CO accumulates in cabin spaces is via leaking engine and generator exhaust systems. All exhaust systems need to be inspected frequently. Like on your car, they don’t last forever and require maintenance. All inboard engines both gas and diesel have water cooled exhaust systems. Any time the exhaust system shows evidence of a water leak, there is a serious potential for a CO leak therefore if it’s leaking water, it’s probably leaking CO.

Boats are also somewhat prone to what is known as the “station wagon effect”. When the vessel is moving under engine power a vacuum is created behind the boat, which can actually draw the fumes on board and into the cabin. This can occur at speeds as low as four or five knots. Even though this can’t always be prevented ensuring that all windows and hatches are open keeping the cabin well ventilated is the best insurance. Also sometimes a slight course change which can alter the wind direction can help as well.

The amount of CO produced by a diesel engine is less than half that of a gasoline engine but it is still dangerous.  With diesel you are also being subjected to poisonous sulfur dioxide which is considerably less deadly, but it has a tendency to make you feel sicker. In rough water, it can increase the effects of, and often cause sea sickness. Long term exposure to diesel exhaust can do the same thing as short term exposure to gas exhaust. In either case, the condition has to be eliminated.

The installation of CO alarms in cabins is a good idea and they do work but like anything else they need to be maintained and kept in good order to be effective. Most surveyors that I know recommend their installation as part of a survey report and in reality it is just good common sense. They have become pretty much commonplace in our homes so why not out boats. The largest problem with alarms is that they are very sensitive to contaminants and when they do become contaminated they usually sound and then are disconnected and rendered inoperative.

The good news is that by simply being alert to the potential of the risk you can reduce the odds of this happening to you to nearly zero.

 

Reprinted From “The Seaworthy Surveyor” Ontario Sailor Magazine

Original Article By David Sandford AMS®

2016 Marine Survey Season

Well, its been a busy 2016 surveying season so far here on the North Shore of Lake Ontario. We had virtually  no spring this year and went right from winter to launch season. Like I said its been very busy and I apologize for my lack of posts these past couple of months. As it usually does, business has dropped off a bit in July and this year is no different but its still going.

In between a myriad of survey inspections and reports I have actually managed to sail my own boat a bit and have that the opportunity to race on ACE a Mumm 36 up and down the north shore and across the lake. In our club’s Wednesday night series I’ve been on a board a C&C 38 so I’ve been busy. On Wednesday this week its aboard ACE again for another across the lake overnighter, the Freeman Cup and after that on Friday, Saturday and Sunday its can racing as part of the LYRA regatta hosted by The Whitby Yacht Club.

Mumm 36

ACE, Mumm 36 racer

In the picture above, standing on the side deck is Dirk Stydenga, sailmaker extraordinaire former owner of Performance Sails in Toronto and now hails from Halifax Nova Scotia.

Electroshock Drowning – Prevention

A few days ago I received and enquiry on my Facebook page (thanks Brian) asking about the possibility of testing for stray electrical current leakage in the water at marinas. To that end I thought that I’d talk that very subject in this post.  To make a long story relatively short it is possible to test for this but to do so requires specialized equipment. You basically need a Digital Multi Meter which is very sensitive on the low side of AC amps scale and it needs to be equipped with precious metal test leads.

Unfortunately these test results are  only good at the time of the test. In other words you could be ok  today and not tomorrow Unless you are testing every day or so which is probably not going to happen.

In my opinion,  prevention is  much better and a more practical solution to the problem than trying to continually monitor for any stray current leakage. The good news is that it’s not difficult to do just that. There is a devise on the market which is easily retrofitted to just about any boat’s on board  shore power AC electrical system. It’s called an Electrical Leakage Circuit Interrupter or  ELCI . It’s simply a high capacity Ground Fault Interrupter (GFCI) which breaks the circuit if it senses stray current leakage to ground or in our case into the water. You all know what a GFCI is. It’s that AC plug installed in our kitchens and bathrooms in our home that have the little red and black push buttons in the center. If the red button pops you simply press the black button to reset the devise. If it continually trips then you obviously have a problem which needs to be corrected.

To understand how these devises function we need to go back to our basic electrical theory which states that on a properly functioning AC (alternating current) circuit there should be equal current flow on both the hot (black) and the neutral (white) wires. Any current leakage on the circuit, however small will cause an imbalance in this current flow and the ELCI will automatically open and break the circuit.

The main difference between the ELCI and the GFCI are the current levels at which they trip at. The GFCI trips at 5 milliamps which is really too low for to be any use to us and  the ELCI trips at 30 milliamps. Enough to serve our purposes but not enough to be harmful. (Remember .6 amps AC = heart failure). The reason  that GFCI’s are ineffective for this is that all boats plugged into shore power on any one dock are electrically connected through the shore power grounding circuits and properly functioning boats will usually leak small amounts of current into the water, even under normal conditions. In most cases these current levels are too small to be of any concern. The problem is that they are cumulative (they add up) and can increase to levels, that while are still not dangerous can cause nuisance tripping of the GFCI’s and be a real pain.  This is also why, in North America AC power services at the docks rarely have GFCI’s installed. I understand that in other parts of the world GFCI’s are sometimes utilized on docks.

Ok back to the ELCI. Installation is relatively simple. In many cases the main 2 pole circuit breaker at the AC main panel can simply be replaced with one that incorporates the ELCI into it. Otherwise they can be installed as a stand-alone in the main AC feed circuit between the vessel shore power receptacle  and the 2 pole main circuit breaker at the on board  AC panel. They also are not costly, average  about $2-300 USD. Additional  information on the ELCI can be found at www.bluesea.com

In addition to the installation of the ELCI it is recommended that the on AC and DC grounding circuits be connected aboard the boat. This is easily done right at the panel.

Electroshock Drowning in Freshwater Marinas

This is a topic in which myself and many others have been very vocal about these past few years and I have written about it many times in my magazine articles. It is a phenomenon which has been occurring in fresh water marinas, cottage docks and anywhere boats are moored and plugged into shore supplied AC (alternating) electrical current. It occurs when AC current, by way of faulty electrical wiring or appliances either on board the boat or on the dock leak current into the water and if persons or animals (yes pets and wildlife are susceptible to this too) are in the water nearby, the current travels through their bodies causing paralysis and even death.

Here is the equation: AC electrical power is supplied to boat shore power systems typically in the range of 15-30 amps   ……   .6 of an amp of electrical current is enough to stop your heart almost instantly if it travels through your body in an effort to reach ground.

How does this occur: It occurs when, through a wiring fault or a fault with an AC appliance allows stray current to  travel through the boats DC ground circuits which include underwater metallic components such as the prop shaft or stern drive. Think of your boat when plugged into shore power as similar to a hair dryer plugged in and floating in the bathtub. This in effect electrifies the water in the immediate vicinity of the affected boat. Anyone swimming nearby can be affected by this as the electrical current moves from the charged water to ground. If you remember your basic electrical theory electricity always moves from the source to ground and if your body gets in the way it will pass right through you and your heart.

Another point that you need to be aware of is that this occurs mostly in fresh water situations, much more so than in salt water. This is because salt water is a better conductor than fresh water and any current dissipates rapidly after it enters the water. In fresh water it remains at a concentrated level in the immediate area surrounding the boat. And when you take into consideration that the high salinity levels of the human body actually make it a better conductor than the water itself, just by being in the water we actually provide the best path for the current to move to ground.

This is a very brief overview on how this can occur and is occurring. I will have much more to say in future posts. For more on this I invite you to visit a couple of websites dedicated to this phenomenon.  I will add them to my links page as well.

http://www.electricshockdrowning.org/    This site is operated by Kevin Ritz who has a very deep connection to this issue.

http://www.boatus.com/seaworthy/magazine/2013/july/electric-shock-drowning-explained.asp       A very good article by Boat US which offers a very good description on how to inspect for electrical leakage aboard boats.

http://www.boatingmag.com/how-to/electric-shock-drowning-prevention      More good information.

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