With thousands of amps surging in a split second, lightning can wreak havoc on a yacht. Here's what really happens when lightning strikes...
Dawn was yet to break. It was still pitch black out at 5am over the Silver Bank, as 130ft Alteza made her way to St Thomas to pick up a charter. The mate and deckhand were on watch, listening to Enigma playing over the patter of rain outside and occasional flash of lightning.
Suddenly there was an intense “ka-boom.” The captain, asleep in his cabin behind the bridge, was lifted off his bed. “I was in the air. I felt my body go up, and white light was all around me,” he says. On the bridge he found the watch crew looking like deer in headlights. “They were stunned, they couldn’t even talk, smoke was coming out of the fire alarm and every alarm we had in the boat was going crazy.”
One look at the radar mast, with its antennas split and satcom balls tinged black, confirmed what they knew — they had suffered a lightning strike. They lost all electronics, both engines died and the generator’s AVR blew, so there was no house power.
This worst-case scenario happened to Captain Carl Sputh in the late 1990s. Now a charter and sales broker with Northrop & Johnson, he recalls that they were able to bring power back on board with the other generator, but the A/C circuits were fried. A spare ECU processor got the mains back running on half of their 16 cylinders, but they could only be controlled from the engine room. Carl could only steer from the bridge and had no wing station controls or autopilot. One radar came back with spotty service, and neither GPS worked; even the handheld failed to get a position. Before Carl had to dust off his celestial navigation skills though, he got a call on the handheld VHF from a nearby sailboat in distress that had run out of fuel and he negotiated a trade: 20 gallons of diesel for a handheld GPS. With this, they managed to limp their way to San Juan.
While Alteza (now Sweet Escape) was supremely unlucky, the chance of a yacht being struck aren’t that remote. BoatUS Marine Insurance analyzed 10 years of claims and came up with odds of one out of 145 for multihulls, one out of 263 for monohulls and one out of 667 for motor yachts. It should be noted, though, that it insures smaller boats and the larger the yacht, the higher the odds.
Alteza had no lightning protection system — which, at its most basic, comprises an air terminal, conductor and ground plate — yet yachts with this have also been damaged. One motor yacht struck at the dock recently took a direct hit to its air terminal, and in the captain’s words, “the lightning rod didn’t do a damn bit of good…everything quit working.” They are in the middle of a nine-month repair.
They were able to bring power back on board with the other generator, but the A/C circuits were fried
“Air terminals work if they’re properly installed; the problem is properly installing them takes knowledge and skill,” says ABYC-certified master technician James Cote of Cote Marine, which, among other services, provides lightning protection evaluations and forensic investigations worldwide from two offices in Florida. “They’ve got to be at the highest point on the boat. Sometimes you need to have two or three air terminals. The thing that is always the bugaboo for the builders is that the wire you run from the air terminal down to a lightning protection strip on the boat bottom below the waterline has to be routed as straight as possible, and as far away from other conductors as you can, and on a boat that’s very difficult, if not impossible.” Cote explains that it is feasible if the system is laid out during the initial build, but retrofitting can be less effective. Multihulls are particularly difficult to protect because of their geometry, he adds. “There’s no way to get the lightning down-conductor straight down to the water easily.”
Captain Carl managed to get Alteza operational in just 12 days to make his charter pick-up. Nowadays things are more complicated, both because of flag state nonconformity requirements and the nature of yachts. For instance, digitalization. “If you get a strike in one area of the boat, or one piece of equipment gets a voltage surge or current spike, it’s going to affect many, many other systems because everything is interconnected,” Cote says.
His advice after a strike is to be really thorough. “You need to get experts in (both) electrical and electronics. Check everything,” he says, listing air conditioning, watermakers, refrigeration, nav-
comms, engine controls, entertainment electronics, up the mast, behind the electrical panel, under the helm station, and a haul-out to inspect the bottom.
“One point you need to worry about is carbon fiber masts. Carbon fiber is not a great electrical conductor, but it is a conductor, and it gets hot when it conducts. If you get a direct hit on a carbon fiber mast, you may have to repair or replace it.” Li-ion battery banks are another issue, Cote says, as the electronic battery management system, which prevents overcharging and catching fire, can be damaged in a strike.
“First thing you do is call your insurer, he says. “Some insurers are cheap. Most of them are pretty good. Go through everything. You have to be frugal, but you don’t have to be cheap. And if you have a problem with the insurer, you are probably entitled to hire your own surveyor to come in and make sure they’re doing it right.”