Before a ship slides from its berth into the water, it must first get hit on—by a bottle of booze, usually champagne. Here’s the lowdown on the history and physics of smashing some bubbly and launching a ship.
The tradition of christening a new ship for good luck and safe travel goes way back. Many ancient seafaring societies had their own ceremonies for launching a new ship. The Greeks wore olive branch wreaths around their heads, drank wine to honor the gods, and poured water on the new boat to bless it. The Babylonians sacrificed an ox, the Turks sacrificed a sheep, and the Vikings and Tahitians offered up human blood.
These events almost always had a religious tone to them, and the name of a favored god or god of the seas was often invoked. In the Middle Ages, two friars would often board British ships before their maiden voyage to pray, lay their hands on the masts and sprinkle holy water on the deck and bow.
The religious aspect of ship christening died off in Protestant Europe after the Reformation, especially in Great Britain. Some member of the royalty or nobility would instead join the crew for a secular ceremony of drinking from the “standing cup”—a large goblet, usually made of precious metal and fitted with a foot and a cover—and solemnly calling the ship by her name. After taking a drink, the presiding official would pour what liquid was left onto the deck or over the bow and then toss the cup over the side of the vessel, to be caught by a lucky bystander (or sink into the ocean). As Britain became a maritime power and its growing navy required more ships, the practice of discarding the expensive cups fell out of favor. For a while, they were caught in a net for reuse, but eventually, the whole ceremony was replaced by the breaking of a wine bottle across the ship’s bow.
Ship christening in the young United States borrowed from contemporary English tradition. The launch of the USS Constitution in 1797 included the captain breaking a bottle of Madeira wine on its bow. Over the next century, the ritual of breaking or pouring of some “christening fluid” remained, but the fluid itself varied wildly. The USS Princeton, Raritan and Shamrock were all christened with whiskey. The USS New Ironsides was double-christened, first with a bottle of brandy and then with Madeira. Other ships were teetotalers, and launched with water or grape juice. The USS Hartford was christened three times, with water from the Atlantic Ocean, the Connecticut River and Hartford Spring. The USS Kentucky was launched with spring water by her official sponsor, but as the battleship slipped into the water, onlookers gave her a baptism more fitting of her namesake state and bashed small bottles of bourbon against her sides.
It’s not clear how champagne came to be the favored fluid. The Secretary of the Navy’s granddaughter christened the USS Maine, the Navy's first steel battleship, with champagne in 1890. The shift to that particular sparkling wine might have been meant to coincide with the new era of steel, or it may just have just come into vogue because of association with power and elegance.
When Prohibition went into effect in the U.S., ships went sober again and were launched with water, juice or, in at least one case, apple cider. Champagne came back with the passage of the 21st Amendment and has stuck around since.
Champagne bottles are basically booze-filled tanks. They have to stand up to the enormous pressure the wine creates inside them, so their glass is very thick, and breaking them is no easy task. But, as Mark Miodownik, a material scientist at King's College London, told the BBC, it only takes a small defect, a slight imperfection in the glass, to compromise a bottle’s strength. He points out that bigger bottles have a higher probability of a natural defect, but any size bottle can be prodded along towards breaking if the wine has bigger bubbles, and hence more internal pressure. If ever you find yourself stuck christening a ship with a bottle that can take a beating, P&O (the British shipping and logistics company) chairman Sir John Parker, quoted in the same piece, suggests scoring the bottle with a glass cutter to to weaken it.