EDMONDS — If you were a lightning bolt, what could be more attractive than a big green-and-white boat on the water?
A ferry at the Edmonds-Kingston dock got zapped around 1:30 p.m. Saturday right after all passengers had disembarked and before the next group boarded.
There were no serious injuries, though a ferry terminal attendant, Leslie Saber, got the shock of her life. Saber was alone at the time in the overhead passenger loading walkway that runs from the terminal to the boat.
Other than damage to the navigation system, the vessel was unscathed thanks to what is known as a Faraday “cage,” a way for lightning to dissipate its energy to ground or, in this case, water.
“The ferries are made to take it,” Washington State Ferries spokeswoman Diane Rhodes said. “The ship’s mast takes a hit sort of like a lightning rod.”
Ferries, though easy targets, don’t get struck often, in part because lightning is rare in the Puget Sound area. The last major jolt was some 25 years ago on a vessel with a wooden mast that was marred by the lightning strike.
In Saturday’s strike, Saber was in the long enclosed passageway known as “the plank,” making sure all walk-on riders were off in preparation for the next round, when it started hailing. Then came a boom.
“It was an instantaneous flash and sound,” Saber said. “It’s the biggest explosion I ever heard. The world exploded around me. I was knocked off my feet from the shock wave and slammed down on my knees.”
The energy blast was like being hit by a tremendous punch, she said. It didn’t make her hair stand on end.
“It knocked the covers off seven light fixtures and broke the fluorescent tube,” Saber said. “The captain came on the radio and, as I recall, he said, ‘Our electronics got fried.’”
Saber finished her shift and was back at work the next day, but not on “the plank.” She’s been in the auto ticket booth since.
“Bruised knees is the diagnosis. And shaken nerves,” she said. “But I didn’t enjoy getting shaken, that makes me opposite of James Bond.”
On Thursday, she was “still a little sore all over,” she said.
The Coast Guard allowed the ferry to resume service for a few more sailings the day of the strike, but the vessel docked before dark due to impaired navigation. Then the route was on one-boat service through Monday afternoon.
Faraday “cages” are named after 19th-century scientist-inventor Michael Faraday, who in 1836 built a large box and lined it with wire mesh to show that the excess charge on a charged conductor resided only on its exterior and had no influence on anything enclosed within it.
A “cage” is formed by bonding together, with heavy conductors, the vessel’s mast and all other major metal masses. According to boatsafe.com: “A marine electrician must tie in the engines, stoves, air conditioning compressors, railings, arches, etc., with a low resistance wire which would ultimately provide a conductive path to ground (the water), usually via the engine and propeller shaft, keel bolts, or better yet, a separate external ground plate at least 1 square foot in dimension.”
Found the #lightning that would have struck the M/V Puyallup. A ton of electricity flowed from the cloud to the ferry – the likely stroke was a 133,000 amp stroke! For reference, most electrical outlets are 15 amps. #WAwx https://t.co/MrnY04uXQN pic.twitter.com/XcW8yPG2jA— Ch☈is Vagas|☇y (@COweatherman) October 11, 2020
A tweet by Chris Vagasky with Vaisala, a Finnish company that develops, manufactures and markets products and services for environmental and industrial measurement, said his company’s lightning sensors estimated the bolt delivered 133,000 amps.
“For reference, most electrical outlets are 15 amps,” he wrote.
According to the National Weather Service, the odds of being struck by lightning in your lifetime is about 1 in 15,300.