How Icebreakers Work and Why They Get Stuck


Now it's the Americans' turn to help out down south. After failed attempts by ships from Australia and France, the U.S. Coast Guard has dispatched the Polar Star, a heavy-duty icebreaker that will make its way to a Russian science vessel and a Chinese ice breaker -- both trapped in ice off the coast of Antarctica.

On Tuesday, the captain of the Russian ship told news services that he was slowly moving through the ice along with the Chinese ship after a slight change in weather. Still, the two vessels are reportedly not yet in open waters.

Antarctica is a cold, harsh place with vast changing landscapes and uncovered mysteries underneath the ice. Why wouldn't we go there? Trace digs into what researchers are discovering about the ice continent.

But how do icebreakers work and how could they get stuck? It seems that even the toughest ships sometimes are no match for sea ice that can quickly surround a vessel with hull-crushing strength.

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"Once the ice has got you in a squeeze, there is nothing you can do to get out of the way," said Sprague Theobald, a documentary filmmaker who was trapped in Arctic sea ice for several days in 2009 on a 57-foot trawler with his family. "It's as if a jigsaw puzzle came into place and you were locked in. The ice will move the way it wants to move."

While Theobald was on a smaller craft, even massive scientific ships and icebreakers can become immobilized under the right conditions. That appears to have happened to the crew of the Russian scientific ship Akademika Shokalskiy, which became trapped on Dec. 24 near Commonwealth Bay, Antarctica.

A Chinese ship, the Xue Long, or Snow Dragon in Chinese, sent helicopters to ferry 52 scientists and passengers from the Shokalskiy to an Australian ship last week. But now the crew of the Xue Long, too, is trapped.

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The Xue Long is actually a Ukranian cargo ship converted to an ice-hardened transport to supply China’s growing scientific presence on the Antarctic continent. It can break 3.5 feet of ice (1.1 meters), while traveling at 1.5 knots, according to the China Daily website. In contrast, the Polar Star, which just completed a three-year $90 million renovation, can smash through 6 feet of ice at 3 knots, according to the Coast Guard.

Some ice floes around the Chinese ship are reportedly more than 13 feet thick. While the bow of the Chinese vessel cuts through ice like a knife, the American ship and other heavy duty icebreakers actually ram the ice to break it. The Polar Star uses its powerful 60,000 horsepower diesel engines to flop on top of the ice sheet, smashing it like a 13,000-ton hammer.

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