Mooring Whips Avoid electric shock Drowning
Even the name is horrific. It’s literal overkill. If electrocution doesn’t stop the heart outright, instantaneous muscle paralysis drowns even the strongest swimmers, often kids, when they float into this indiscriminate trap. Last June, a 21-year-old man died in Missouri. The year before, a 13-year-old girl died while a 17-year-old girl narrowly escaped in Louisiana. In 2013, a man in Kentucky pushed his 2-year-old son to safety before being overcome himself. This stealthy assassin was unknown prior to 1999, but the clarity of hindsight shows that electric shock drowning (ESD) has been claiming lives in freshwater marinas for decades.
The good news — if I can call it that while looking at the case facts of six-dozen waterborne electrocutions reaching back to 1986 — is that ESD deaths are preventable today. There are three basic ways to stop ESD: A certified marine electrician can head off problems with a 30-minute visit aboard. A quick test, which boat owners can conduct themselves, ensures that a ground connection is diverting lethal current from the boat to shore. (The damaged end of an easily replaced shore cord is often what causes that ground to break.) Further protection comes with an equipment leakage circuit interrupter retrofit — installed on new boats since 2011 — that shuts off alternating current power at the slightest instance of an ESD-causing fault.
What is ESD?
“It takes less than 1 amp through the body to kill,” says Ed Sherman, education director for the American Boat and Yacht Council, Boating blogger and contributor, and author of two books on marine electrical systems. “The heart stops. The body locks up.” Even a nonlethal dose — just 50 milliamps — paralyzes muscles needed to swim. “It doesn’t show any of the visual characteristics of electrocution,” Sherman says, which is why so many coroners, who rely on burn marks on the skin from the point of electrical contact as evidence of electric shock, often see ESD deaths as simple drownings — a cramp or exhaustion, not an electrical snare that could still be awaiting another potential victim.
Here’s how it happens: An alternating-current appliance aboard a boat “leaks” a bit of power to the boat’s green-wire grounding system, which then electrifies nearby water through the boat’s underwater metal connected to that same ground via the bonding system used to prevent corrosion. That current reaches across the water’s surface and gradually dissipates. Since our salt-filled bodies conduct electricity better than fresh water, current flows through swimmers who enter that electrically charged water. Seawater, on the other hand, conducts electricity far better, so it quickly dissipates ground-fault current and mitigates the risk to swimmers.
Source: Boating Magazine