he White Star Line didn't have much luck with giant ocean liners, much as they tried to build them for safety as well as opulence. The Titanic went down in spite of engineers' efforts to build a shipwreck-proof vessel. And in the wake of that disaster, the shipbuilders retrofitted Titanic's sister ship, the Britannic, with special design features -- including a double hull -- to insure that it would not suffer the same fate. But ironically, in November 1916 it sank three times FASTER than the Titanic.
Four years after the Titanic sank, the Britannic suffered a mysterious explosion off the coast of the island of Kea in the Aegean Sea. It was during the First World War, and she had been converted to a hospital ship. Off of Kea, experts are pretty certain, the Britannic struck a submerged mine about ten feet below the waterline. (The possibility that a torpedo, rather than a mine, felled the ship has not been disproved, but most experts believe it was a mine.) The ship took on water quickly, developing a list to starboard. In only 55 minutes, she lay beneath 400 feet of seawater, fortunately having lost only 30 of the 1,125 crew and medical personnel aboard. This puzzled shipwreck researchers for a long time: Why did the Britannic go down so much faster than its near-exact replica, the Titanic, despite added safety features?
To be sure, the immediate cause was the massive damage from the explosion, which opened a hole an estimated 20 by 30 feet in size. In 1975, a visit to the wreck by Jacques Cousteau revealed an additional hole in the port side, opposite from the mine damage. Based on the fact that the shredded metal around the wound curls outward, it's possible that the ship was rocked by a secondary explosion -- perhaps from ignited gas fumes -- after the initial blast.
Making matters worse, witnesses reported that the explosion set the iron hull vibrating strongly enough to shake china off of shelves in the galleys and dining rooms. This "hull-whipping response," as it's known, might have loosened rivets all around the point of detonation and speeded the flooding in the bow.
Theoretically, however, the Britannic should have been able to stay afloat a lot longer than it did, even with such major flooding. Garzke and his colleagues think the reason for the swift demise of the Britannic has a lot to do with how and where the water went as it flooded into the damaged ship.
Almost immediately, the hull took on a 6 to 10 degree list to starboard. The cause of this was what marine architects call unsymmetrical flooding: The walls of staterooms lining the hull acted as barriers that trapped the flood on the right side of the Britannic's hull. "It's now unable to flow across the decks," Garzke says. "You have all the weight of the water on one side. When that happens, the ship takes a list, and there's no way of counter-flooding that hull to put it on a more even keel."
But what probably doomed the Britannic, Garzke says, is the decision by the crew to open the portholes of the ship to air out the staterooms -- including portholes that lay as little as five feet from the waterline. As the ship's bow nosed down and the starboard list steepened, the portholes dipped beneath the water. "All those portholes started flooding, and as the ship sank more to starboard she had all that water trapped on the starboard side."
A safety feature added to the design of the Britannic after the Titanic disaster might have also played a role: the inclusion of an extra inner hull along 60 percent of the hull. This was supposed to guard against the sort of "raking damage" that caused the Titanic to sink with 1,523 of her passengers and crew. The retrofit created hollow compartments in the walls of the ship from 2.5 to 4 feet wide. If the side of the hull took a long, slashing wound from a rock or iceberg, the flooding would be contained to these spaces. But if the damage from the mine explosion was extensive enough to breach the hollow hull section farther back, the unbalanced flooding would have grown even worse still. "If the inner hull was involved," Garzke says, "it only would have made the situation worse and made the ship sink faster."
SNAME's Marine Forensics Panel is now planning an expedition to the Britannic to clear up the remaining mysteries surrounding the loss of the ship, especially whether there was indeed a secondary explosion, and what may have been its source. But for now, it seems the single most important factor was not the design of the ship, but the fateful human error of opening the portholes in a war zone, contrary to regulations.
It's chilling to consider why they were airing out the staterooms: in preparation to pick up some 3,600 wounded men at the port of Lemnos. Fortunately, the Britannic met its fate first. "Otherwise," Garzke adds, "this would have been one of the worst maritime catastrophes this century."
-- By Daniel Pendick