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Gale in the Pacific, off the coast of Chile
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HOW MANY ships – not yachts and boats, but big ships - do you think are lost at sea each year? Ten? Fifty? A hundred?
Each year freak waves, up to 10 storeys high, sink quite a few. And freak disasters do the same.
The losses, even in our technologically-
governed world, are surprisingly high. |
A clue might to the numbers might be the map that hangs in my study depicting one tiny area of rough seas and shipwrecks. The map is of the Falkland Islands in the South Atlantic, where between 200 and 300 wrecks are recorded. But that includes sailing ships from the 1850s, 19th century whaling ships, and battleships like the Scharnhorst sunk by the British Navy in 1914. The Falklands are notoriously dangerous waters – not far from the immense Southern Ocean seas where Shackleton’s castaways survived a giant wave, so high they mistook its crest for a cloud.
No, we are much safer in this 21st century, with technology that wraps the planet in an electronic cocoon and reaches to the Moon. Technology that can actually predict how the forces of the sea will affect a vessel.
So, in this state-of-the-art protective environment, how many ships are lost each year?
The last official planetary count was between June 1995 and April 1998, when 1,120 vessels went down, with much loss of life!
That means an average of nearly four hundred modern ships were lost at sea each year. None of the ships that were sunk was tiny. There’s one which has been examined at the bottom of the ocean which weighed 165,000 tons – an iron ore carrier whose stern was ripped off by a giant wave in the China seas.
Quite recently, on a summer’s day in June 2005, a modern 40,000ton ferry was hit by a 25metre wave off the coast of France! It was a monster of a “freak” wave rising to the height of an eight-storey building. The powerful ship and its hundreds of passengers were lucky to survive.
Perhaps the most spectacular photograph ever taken of an encounter with a freak wave was an aerial shot of the Queen Mary - in its time the greatest ship afloat - steaming at 30knots with sixteen thousand troops aboard. That was at Christmas, in the midst of war in 1942. A Canadian air patrol was watching as the ship approached the end of its air cover and was outrunning the enemy’s fastest pocket battleships across the Atlantic. As the aircraft was about to turn for home it photographed the 300metre-long liner as it crashed into a giant wave – and seemed to be disappearing. The bow of the ship normally stood 21 metres above the sea. The ship’s bridge was normally 12 storey’s above the sea. Both were smothered by the immense wave.
I wish I could show you the photograph – hushed up in those war years – but I have seen it only once. It was shown at a lecture on oceanography by Professor Michael Orren – who was himself witness to a similar event on a much smaller scale when a “rogue” wave suddenly hit a ship’s bridge sideways and left him, the captain and crew in darkness as a thousand tons of water smothered the vessel. Fortunately, every hatch and porthole was firmly shut at the time.
How common is “freakish”?
Prof Orren says that scientists have discovered that so-called ‘freaks” happen much more often than people once thought. They are wind-driven over hundreds of kilometres, and the higher they grow the faster they travel. The power they gather is exponential. For instance a 10 knot breeze can create a half-metre high wave – but a wind of 50 knots (5 times as strong) creates a wave twenty times as high. At 80 knots, waves are spawned that rise up 26metres. They will crash into cliffs every 15 seconds and, eventually (though in universal time it is “in a flash”) they will undermine and destroy the hardest rock.
The liner QE2 has a bow about the same height as her older sister Queen Mary. and her bridge sails 30metres above the sea. In 1995 the great ship encountered a 29metre wave. In 2004, it dealt with another ten-storey high ‘freak” wave.
Not only are the “freak” or “episodic” or “rogue” waves fairly common, they can be simulated today in a tank, and their behaviour and force can be measured (though never, of course, tamed). . They can be predicted. . . but they have no pattern. Some may travel in series. Others may rise 20metres out of the blue – come from nowhere in destructive fury – and be followed by a normal calm sea.
Prof Orren explains that numbers of counter-forces determine a wave’s shape and behaviour. Tsunamis, however do not build big waves. Instead, like “tidal waves” they shift big, often calm, seas that are enormously destructive when they reach land.
Other causes of true waves include volcanic eruptions, submarine avalanches and asteroid impact. For instance, though it may never have been witnessed by mankind, scientists have plotted a scenario in which a volcanic eruption on the ocean floor could be great enough to thrust its heated water to the surface for several hours. . . and create an immense hurricane – a ”mega-cane” so great that it could cause waves big enough to cover much of our planet’s landmass.
That scenario should remind us how delicately balanced Earth is, and how magnificent and powerful are even the local forces of Nature |
