Marina waters can be deadly, but not how you might think
Jan 9 2013 in Seamanship by Vincent Pica
When I wrote previously about man overboard emergencies and about whether you need a life jacket or not, the main thrust was all about safety of life at sea.
But it is a little-known fact that you can drown right at the marina — in the most shocking way. It is called “ESD” – Electric Shock Drowning.
Most mariners are not aware that such a danger even exists other than in the most blatant way. If there were an electrical cable thrashing about from a downed power wire, well, it is pretty obvious that whether that happens at the dock or in front of your house, that is a major danger. If it happens to knock you off the dock as it paralyzes you, you’re going to drown.
But how about a charge as low 10 milliamps (.010 A)?
Sources of stray currents at the dock
There are two sources of stray current at the marina – faulty marina wiring and faulty wiring on your boat. At the marina, if there is a non-functioning grounding system, or an improper grounding of the neutral-white power conductor, or just unapproved wiring near the water, there can easily be a charge snaking through the waters of the marina.
Although these are all violations of the National Fire Protection Association’s PFPA 303 Fire Protection Standard for Marinas and Boatyards, it will be cold comfort for you if you reach into the water to retrieve something and your muscular system is shocked into paralysis.
The amount of electricity entering the body can be so small that often the post-mortem doesn’t catch that stray current was the cause of death. “Poor Charlie reached in for his skipper’s cap and just kept going! He must have been dead when he hit the water because he never even tried to get back on the dock!”
And it doesn’t have to be a marina owner who missed his annual inspection. It could be you or your slipmates. As boats get bigger and electrical systems get more complicated — with generators, inverters, chargers and other such devices — chances of error compound. Add in the Do-It-Yourself’er adding a device as an after-market “enhancement” to the boat and you can see the implications. And it is all the usual errors: poor groundings, reversed polarities, mixing AC and DC wiring, etc.
While such practices are violations of the American Boat and Yacht Council’s (ABYC) Standards and Recommended Practices, the boater is not protected from himself or others by required inspections. You just have to be committed to doing the work with licensed and experienced help.
The most unnerving aspect is that if muscles are exposed to charged water, they can become paralyzed, making it impossible to swim or even breathe. Drowning happens just that much faster since obviously you can’t do anything to aid yourself.
What can I do about it?
First, stay out of the water in a marina, especially if someone is running their generator. If your cap blows off your head into the drink, get a boat hook with at least a rubber grip and snag it.
Secondly, check with your dockmaster to be sure that the boats and the marina itself are wired to ABYC and NFPA standards. It is better than even odds that the dockmaster has a charge-indicator in the shop for simple boat work.
Have him check the waters periodically, perhaps even by staging an “electrical safety day” at the marina. Have everyone that has a generator turn theirs on. Then test the waters. If it shows a charge, turn the generators off one by one until the charge drops out. That’s your guy.
He’ll thank you for it — as will everyone at the marina.
Sean Munger said on January 12, 2013
Looks like there are numerous story’s found on google that seem to support the theory that ESD in saltwater had other elements involved other than just swimming ie. the swimmer was touching their boat, or grabbed something that was part of a dock, or the person was on the dock touched the water, was shocked fell in and drowned.
That fact remains there is the potential for this to be fatal. Thanks for the heads up Vince!
I’ve seen many marinas with “crazy” looking wiring. Best to report it to someone if you see something that looks dangerous.
Vincent Pica said on January 13, 2013
water, both fresh and salt water, will conduct electricity. we need to keep sources of electricity out of any water we might bathe, swim or fall in. pretty basic and important life-safety stuff…
John Vigor said on January 11, 2013
Vincent, does this apply to saltwater marinas? I’ve read that electrical current will by-pass a human body in salt water because salt water is a better conductor. According to BoatU.S., deaths from stray current are more likely in fresh water because the human body is a better conductor than fresh water. Divers work in my saltwater marina all the time, scrubbing bottoms and replacing zincs. We haven’t lost one yet.
Vincent Pica said on January 11, 2013
John, this is about all marinas. sorry, no ability to bypass humans… glad to hear about your divers – but that just means that your electrical system is in good shape. Vin
John Vigor said on January 11, 2013
Vincent, the current issue of Seaworthy magazine (BoatU.S.) cites a question from Bob Deresz, of Miami, Fla. He asks if a swimmer can be affected by electrical current in salt water.
The magazine, which is the highly respected BoatU.S. marine insurance and damage avoidance report, replies with an unqualified “No.” It continues:
“Salt water is more conductive than the human body, which means that electricity will follow salt water to ground and bypass a swimmer.”
Can you cite any examples of officially investigated deaths resulting from electrical shock in salt water? I’m sure the BoatU.S. insurers would be interested to know.
Vincent Pica said on January 11, 2013
John, it is simply wrong to think that salt water will bypass a human being while an electrical charge is present. There is case after case of ESD on the books. The entire electrical system of boats is based on protecting boats and people from electrical charges, stray or otherwise. Perhaps the BoatUS author had an editing error.
John Vigor said on January 11, 2013
Vincent, I quote from the Huffington Post:
“Electric Shock Drowning doesn’t occur in salt water because salt water is a better conductor of electricity than the human body. Fresh water, however, doesn’t conduct electricity, but mammals do. If people or their pets swim in fresh water that is electrified by a boat or other machinery leaking voltage, they can be electrocuted.”
http://www.huffingtonpost.com/terry-gardner/esd-hidden-danger-in-fres_b_693454.html
I quote from a report prepared by Harbor Marine/Quality Marine Consultants, of Jacksonville, Fla:
“Our studies have shown that, in salt water, the high voltage gradients required for electric shock drowning could not be established with the available fault current levels. In no cases can we attribute cause of death to electric shock drowning in salt water.”
http://www.google.com/url?sa=t&rct=j&q=&esrc=s&frm=1&source=web&cd=5&sqi=2&ved=0CEwQFjAE&url=http%3A%2F%2Fqualitymarineservices.net%2FElectric%2520Shock%2520Drowning%2520Incident%2520List%25203-18-11.doc&ei=z7jwUJGUMMvliwLK5oHACQ&usg=AFQjCNF_IZMI03tFPo3-KqA0XDjVxYzyZg
Vincent, if you Google “Electric Shock Drowning salt water” you will find reference after reference to the fact that people do not get shocked in salt water.
I don’t think it was the BoatU.S. editor who made a mistake.
Vincent Pica said on January 11, 2013
John, ESD can occur and does occur with as little as 10 milliamps. forgive me if I drop this at this point as we both seem to find our own evidence compelling. I must say that I find it hard to believe that anyone could believe that a current can’t run through salt water when we protect our boats from electrolysis – and must – or the very process of electrical charges at work would destroy many of the metallic elements of our drive systems.
honest men have honest differences so I am going to leave it there.
Vin
John Vigor said on January 11, 2013
You’re missing the point. Nobody said a current can’t run through salt water. The point is that it DOES run through salt water — in preference to running through the human body.
doug said on January 10, 2013
how about a little investigation at Shilshole and Elliott Bay?
Shawn munger said on January 10, 2013
If you have an issue you’d like to have checked out, ask the Seattle Fire Dept.to address your concerns.
You may also check for stray voltage with a simple multimeter, switch it onto AC volts on the lowest readable setting, ground the negative lead to the metal power box, something metal as some marinas have plastic outer shells, and immerse the positive end in the water around the boat or where it is your checking for stray current, if there is stray current observed, the source will now have to be found.
Inform the marina of your findings, if they are not easily convinced call the Seattle Fire Dist.for more information and a follow-up, no need to be nervous, that is why they are there.