Electrical Storm

Anna is currently at anchor at Las Brisas anchorage, Panama,
alongside the research vessel Planet (circa 1927) and the work
boat Birdie. There are dozens of cargo ships, tankers, work boats
and barges that surround us, and we are fond of their company.

THE VHF ANTENNA WHIP ATOP THE ALUMINUM MAST HAD VAPORIZED and a rather high percentage of our circuit-board driven electronic components were instantaneously toasted. The static electric discharge given off in close proximity to the center of an intense electrical storm had been unbiased when it came down to the selection of its targets. From electronic components, which were mounted on the mast head, 53 feet above the waterline, to those that resided below decks in the cabin and lazarette, circuit-board damage had been indiscriminate and complete. And it didn't matter whether the equipment that was affected was connected, powered up, disconnected, or isolated. If it had a circuit board it was fair game, simple as that. On a bad day, you can be miles away from a direct strike and still sustain heavy damage. On a good day, you can be directly under the epicenter of the electrical storm and come through unscathed.

We were aboard Anna, in a work boat anchorage adjacent to the Panama City skyline when a wild electrical storm passed directly overhead in the early morning hours. We could see strokes of lightning forking to the waterline close by, accompanied by a continuous loop of rolling thunder that had been offset from the flashing by perhaps 10-20 seconds. The eye of the storm was within 2 to 3 nautical miles of our position and closing from the southeast. Five minutes later a blinding white light was followed up - with virtually no time delay - by a deafening clap of thunder, heavy, prolonged rumbling and a sizzling crackle. Our immediate surroundings had been no less than a war zone, as a highly-charged field of static electricity had blanketed the entire anchorage and painted a bead on at least half a dozen vessels, that we know of, which had been spread out over a wide swath of water and hit simultaneously. It was immediately obvious that we had sustained electronic damage: the LED galley light dimmed to 10 percent of its power and the VHF radio that we had powered up at the time, blew out when the simultaneous flash and shock wave hit. Upon later inspection we discovered that the stainless VHF antenna whip, mounted atop the mast, had vanished. The LED navigation lights (circuit-board driven) also at the masthead, were blown out in addition to the mast-mounted Raytheon radar antenna. Down below the radar display-head failed to acquire targets, the VHF radio was fried, the GPS lost functionality, the AIS receiver lost communications port recognition, the engine's alternator regulator failed, and the charger/inverter's three circuit boards and remote LCD display were all blown out as well. Our tough magnesium-encased Think Pad, the nucleus of our electronic navigation system blew its motherboard and power supply. Our Canon DSLR was another in a list of equipment casualties. What survived the electrical surge, were any electronic components that we had put into the oven (our mini Faraday cage) prior to the storm (i.e. backup laptop, external hard disk drives, handheld VHF, cell phone, modem...whatever would fit - it's a small, stainless-steel oven. Also, our solar array, wind generator and respective regulators were unaffected. The autopilot and depth sounder had escaped injury, too. Our i-Pod and Sony FM tuner and Kindle were curiously still working.

Lightning is truly enigmatic and unpredictable and there isn't a lot which can be done to avoid it or guarantee that damage will not result, other than not being in an area where lightning is likely to occur (and in Panama, there are no such places). Short of building a Faraday cage around the entire vessel, to redirect the electrical charge directly overboard and to ground (the water), without passing through and blowing out the hull along the way, it's primarily a question of isolating the mast from the boat's DC power grid and directing the charge overboard, by either running a 4 AWG cable from the base of the aluminum mast to an external grounding plate, or nearby keel bolt if the keel in not encapsulated, or in our case running chains overboard from the base of the upper shrouds, or base of the mast at deck level...but all this assumes that lightning will follow theory and travel along the path of least resistance to ground. In the real world, however, lightning isn't always so cooperative.

We did at the time of the strike happen to have chains out, with a long ribbon of two-inch-wide copper foil bolted through the last link of each of the chains, which were attached to both the port and starboard upper shrouds, at the deck, where they met the chain plates. The chains with their long copper ribbons hung overboard and were submerged beneath the keel so as to divert a direct strike from the top of the mast - our de facto lightning rod - down the upper shrouds, and directly overboard at deck level. The idea was to give lightning a more direct path to ground without blowing a hole through the boat's interior and hull. In theory, this is a good idea; at least it couldn't hurt. But direct strikes are not the only form lightning takes; the discharge from a widespread, indirect, super-charged static-electric field can overwhelm any grounding system we could devise to protect the vessel. And it's a roll of the dice when it comes to electrical storms and the fate of on board electronics.

The good news is that Anna did not sustain a devastating direct strike, the hull remained in tact, and no one was injured. Never the less, a static electric discharge, from a severe lightning storm, is no picnic. It is a lot of trouble, it is scary when it happens, and it is expensive to replace critical navigation equipment. We weren't the only boat to suffer damages. At least five other vessels that we are aware of sustained significant equipment loss, some much worse than us, and on multiple occasions over a short period of time. One vessel we know of lost all their electronics including their engine's starter motor. Interestingly, before their starter motor blew out it had fused with the ignition switch and spontaneously started their engine.

We have since taken the opportunity to reconfigure and simplify our electrical system. We've isolated the mast from any DC power, installed redundant, ready-to-go backups for critical components; relocated vulnerable, mast-mounted electronics for easier maintenance and repair (closer to deck level and away from the lightning rod that the mast represents); switched to standalone electronic components and display heads to reduce the potential for 'all-in-one' catastrophic equipment failure.

Additionally, some of the electronic damage that we sustained, on the mast, would be difficult to re-install (e.g. radar) without unstepping the mast and rewiring it. These items could be more readily and inexpensively repaired or replaced if, for instance, the equipment was located closer to deck level, near the cockpit. And so, with this in mind, we fabricated a new stainless bracket to mount our new Furuno radar to the same beefy stainless pole that already supports our AeroGen4 wind generator that resides at the stern of the boat, about 10 feet above the cockpit sole and 15 feet above the waterline.

The heavy electrical storm season will begin to wind down here, in Panama, soon. It begins in April and grows in intensity until about October before fading away in December. So one or two months yet to go. Notwithstanding the electrical storms, our plans have not changed. After completing repairs due to the lightning strike we hope to depart Panama and the Perlas Islands sometime around, say, mid-December or January, for Ecuador and South America.

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Lightning Strikes Worldwide by Season

Lightning strikes worldwide in September, October and November.
Panama sees severe and frequent strikes until December.

Lightning strikes worldwide in December, January and February.
Panama begins to see less strikes beginning in December.

Data compiled by NASA

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Visible Water Vapor - GOES East Current

IR Satellite Imagery and Analysis - Unisys Weather

Above is a real-time  infrared image enhanced to highlight the cloud areas and the coldest cloud tops. Since IR images could be used to determine cloud height, these images are enhanced to highlight the highest, coldest cloud tops. Areas of strong precipitation will show up as shades of cyan. Thunderstorms will show up in blue and green. In addition, the contrast of warmer clouds is increased so that low clouds will show up. The image clearly shows - at the bottom and center of image - thunderstorm activity (blue and green areas) circulating in the area around Panama. This is a typical representation of thunderstorm activity in the vicinity of Panama from April to about mid- December. The animated loop, over time, shows heavy green and yellow activity (thunderstorms) constantly building and dissipating over the Gulf of Panama. 

This image was downloaded a  few hours later than the image above.
The thunderstorms had intensified and covered a broader swath.