Christopher Columbus arrived in the Americas 516 years ago this month. For five weeks in 1492, the mainmast of his Santa María was the tallest point on the Atlantic Ocean. Weren’t the wooden ships of the Age of Exploration susceptible to lightning strikes?
Absolutely. Tall ships did get struck by lightning quite often, but just because a ship is struck by lightning doesn’t mean it will be completely destroyed. In 1852, British inventor Sir William Snow Harris published the first systematic study of lightning strikes on wooden ships. He collected data from 235 strikes on British navy vessels from 1793 to 1839. The damage typically consisted of “shivering” or splintering of the mainmast: Long shards of wood flew in every direction, sometimes wounding a sailor or knocking him off the deck. Sails and rigging might catch fire, requiring officers and crew to smother the flames with the aid of the rain and wind. None of the ships in Harris’ sample was recorded as being totally obliterated, and the vast majority were repaired by their crews and continued sailing.
More terrifying for the sailors was the possibility of individual harm. According to Harris, a sailor on an 1802 voyage who hid from a lightning strike near the mainmast was burned through five layers of clothes. A Mr. R. Mawgridge sent his account of a 1696 lightning strike on the galley Trumbull to the Royal Society. The bolt first struck the deck, knocking down two sailors (one of them “had one Side of him stupefied for three Days”) before traveling below. Mawgridge wrote that when the bolt traveled through his cabin, “a great weighty Nail was started out of said Ceiling, and fell over my Head, and lay upon my Pillow, and I thought my Head with the Lightning had been in a Flash of Fire.” The bolt exited through a wall, eventually burning the hair off of the head of a gunner and blistering his feet.
By the time Harris published his observations, protective lighting rods—sometimes called Franklin’s “thunder rods“—had been around for a full century. But lightning protection for sailing vessels was primitive, including prayers and the running of a length of chain from a mast to the waterline. If the chain did not connect with the ocean, dangerous electrical explosions could result. In 1820, Harris devised an improved method by affixing copper directly to the mast and running it through the ship into the water. The captain of the Beagle—the ship on which Charles Darwin made his famous voyage in the 1830s—was an early adopter. Despite being struck by lightning at least twice (surrounding the ship with a “blaze of fire“), the ship was unharmed. Even with success stories such as this, the British navy resisted fitting ships with state-of-the-art lightning protection until 1847.
Fortunately for modern explorers, large metal boats offer excellent protection from lightning strikes. Bolts continue to be a problem, though, for wooden and fiberglass boats. Lightning protection systems for these vessels, still using variations of Harris’ method, offer only partial protection, and some boaters fear they only attract more lightning. The most dangerous boats in a storm are small, mastless boats, especially when the operator is holding a fishing rod.
For his part, Columbus managed to avoid bad weather for half of his voyages to the New World. On his final return, he twice jury-rigged a mast after it broke in four places during a storm on the Atlantic.
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