In 1628, the Swedish warship Vasa sank on its maiden voyage.
Over the centuries, many have tried to explain what caused that embarrassing and deadly mishap. Researchers in Stockholm have conducted a detailed examination of the 17th-century vessel, and they've found clues as to why it sank.
Vasa set sail on her maiden voyage on August 10, 1628. At the time, she was the most powerfully armed warship in the world, with 64 bronze cannons. Twenty minutes into her journey, Vasa was hit by two strong winds. It heeled to port, water gushed in, and the ship sank less than a mile into the journey - Thirty crew lost their lives.
Soon after, there was an inquest that concluded that the ship had been unstable. But the reasons behind the instability have remained a point of debate over the centuries.
Fred Hocker, head of research at the Vasa Museum, has been trying to find some definitive answers. "We have, over the lyears, measured every single piece of the wood in the ship. If we want to understand how the ship was built, that's what it takes."
Hocker's meticulous measurements paid off. They gave fresh insight into what made the Vasa unstable. For one thing, the ship was asymmetrical, more so than most ships of the day.
"There is more ship structure on the port side of the hull than on the starboard side. Unballasted, the ship would probably heel to port."
No wonder the ship tipped to the port side when the winds hit. But why was the ship so lopsided? While examining the ship, Hocker discovered four rulers the workmen had used. Those rulers were based on different standards of measurement at the time. Two were in Swedish feet, which were divided into twelve inches. The other two were in Amsterdam feet, which had eleven inches in a foot. So each carpenter had used his own system of measurement. "When somebody tells him, make that thing four inches thick, his four inches is not going to be the same as the next guy's four inches, and you can see those variations in the timbers, as well."
But that wasn't the only reason the ship sank. Hocker says the Vasa was also top-heavy. "The part of the ship that was above the water is too heavy compared to the part of the ship that's in the water. It makes it too easy for it to heel over."
People in the 17th century were aware of that fact, but they didn't understand what made the ship top-heavy, or whom to blame for the poor design. Some historians and military architects have blamed the King.
They thought that he had interfered with the ship's dimensions after the construction had begun. But Hocker's measurements offered no evidence to support that theory. He uncovered a simpler cause. - "The deck structure is simply too heavy. It’s heavier than it needs to be to carry the guns that Vasa was armed with."
Why were the decks so heavy? Hocker studied historical documents and found that the shipbuilder, a Dutch man named Henrik Hybertsson, had never built a ship with two gun decks or with so many guns. He thinks Hybertsson erred on the side of caution and made the decks heavier than they needed to be. In other words, "the design was simply flawed from the beginning."
Despite its unfortunate end, the ship was lucky in one regard; it sank in waters that helped preserve it for more than three centuries. Since it was brought up, the ship has provided a rare glimpse of life in the 17th century and the investigation continues.