Marina Waters No Place for a Swim

By Jack Klang

Last summer in Northern Michigan where I live, a local teen died after going for a swim in a marina. Although officially classified as drowning, his death was caused by electrocution after he entered the water where there was a field of stray electrical current. In technical terms, this tragedy is referred to as an Electric Shock Drowning (ESD); it’s a scenario that plays out many times each year in marinas around the world.  ESD gives no warning and leaves no marks on its victims. It can happen to anyone. How can we prevent this tragedy?

Where does the electricity come from?

Alternating electrical currents (AC) can leak into the water from faulty wiring in a marina’s electrical system. When the AC comes in contact with the water, it can create an electrically charged field in the marina waters. On board, an improperly installed appliance or a defective shore power supply can create an electrified field around a boat. When faulty shore power or wiring comes in contact with a boat’s grounding system, all metal objects on the boat become electrified with 120-220 volts of shore power. Following this path, stray current can form an electrified field in the water under and around the boat. 

What should you know about ESD?

Alternating current (AC) must ground itself to complete an electrical circuit.  When a person enters charged water, the human body becomes the pathway to completing the electrical circuit. Electric shock survivors say the initial feeling is a shock followed by paralysis, which renders a person unable to swim. Most victims are unable to call for help. It only takes a small amount of current (50-100 milliamps) to quickly cause death. That’s not even enough AC to trip a ground fault interrupter.

ESD occurs almost exclusively in fresh water because it is a poor conductor of electricity compared to salt water. Of the hundreds of case histories on file, all ESDs have occurred in fresh water. 

A cooling dip in the marina may be tempting on a hot day, but it can be deadly. Never swim in fresh water marinas or around boats that have access to shore power.

What can boaters do to be safe?

It is almost impossible to know if water is free of a stray electrical current. Although you may be confident that your boat is safe, you never know about the boat docked next to you, or about the power post in your marina. Here are some safety tips:

  • Never swim in fresh water marinas or around boats that have access to shore power. 
  • Take precautions on your own boat: check for loose or damaged wires, plugs, and connections.
  • Use only marine approved shore power cords and plugs which cannot be reversed (never household extension cords).
  • Any boat with electrical wiring that has been altered, improved, or newly installed is suspect – have it checked by a knowledgeable marine electrician.
  • Encourage your marina to use devices that immediately detect AC leakage.
  • Ask if your marina has had its electrical systems professionally inspected and certified.

Electric Shock Drownings can occur anywhere water is near an electrical current. Remember to look for the potentially dangerous conditions so that you can boat and swim safely.


About the Author: Jack Klang is a Cruising Consultant for Quantum Sail Design Group. He has shared his vast experience with thousands of sailors through his seminars, a syndicated newspaper column, magazine feature articles, television and movie appearances. He is the author of  “Cruising with Quantum” a series of how-to articles covering all aspects of sailboat cruising as well as an instructional video. Jack is recognized as one of the country’s five best sailing speakers, appearing at boat shows across the country. For the past five decades, Jack has sailed the Great Lakes, Atlantic and Pacific Coasts, Caribbean, and Gulf of Mexico. He earned his first Coast Guard captain’s license at age 18 and has logged over 30,000 miles under sail as a cruiser, ASA instructor, charter captain and delivery skipper. Jack sails Michgan's Great Lakes out of of the beautiful harbor of Suttons Bay, MI. 

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