Captain Hamilton’s Impeccable Instinct for the Ice
On deck with the captain of a U.S. Coast Guard icebreaker
Trenches tear open, powerful plates slide over each other, and mile-high ramparts suddenly freeze into place: No airplane is able to land here, and helicopters normally have a range of only a few hundred miles.
HOW MUCH ICE DOES AN ICEBREAKER BREAK?
Most icebreakers make the frozen waterways passable for other ships. Particularly stable and strong types such as the Healy can navigate the Arctic and the Antarctic, mainly for purposes of research or supplying polar stations. But how do you find your way across a landscape that’s constantly being re- created in slow motion, and some of the obstacles produced in the process are as hard as steel? “The ice leads us across the sea, we must follow its course,” says Hamilton. As the ship moves tentatively through the ice, Hamilton can estimate the thickness of the broken floes by using an ice level at the bow of the ship. Two sentinels 100 feet up help him: One looks for obstacles in front of the bow and the other keeps an eye on the horizon. “Gaps in the ice can be recognized by gray haze hanging over the sea: Moisture rises up from the gap and condenses in the air. On the other hand, ice blinks, which are luminous streaks in the sky near the horizon, indicate where ice floes are because ice reflects light better than water,” says Hamilton.
But what if there are thick ice floes everywhere blocking the way? How do you find the hidden path of least resistance? “If the ice is up to 5 feet thick, we’ll go through in a straight line. If it is any thicker than that we have to navigate along cracks and crevices in the ice, even if that can sometimes mean a 90-degree turn, and, in exceptional circumstances, it can even lead up to a dead end,” Hamilton explains.
But the decisive factor isn’t just the floes’ thickness—it’s the type of ice.
THE ICE LEADS US ACROSS THE SEA, WE MUST FOLLOW ITS COURSE
“Fresh bright white ice is easier to break than old ice that shimmers blue,” says Hamilton. “In addition, fresh water from rivers and glacial slopes freezes much harder than seawater. Ice made of fresh water is porous and, especially after it has just been formed, almost rubbery.” That’s because seawater contains crystals of salt, which dissolve and ultimately make the ice brittle. And though there is no land at the North Pole, freshwater ice is found there much more frequently than it is in the waters surrounding Antarctica. Reason: The huge rivers of Siberia carry a lot of ice to the Arctic Ocean.
CAN ICE ACT LIKE AN EXPLOSION?
Whereas in the container shipping industry speed and timetables are of paramount importance, for those colleagues who navigate the poles, arriving at all means the voyage was successful. Even the most powerful nuclear- powered icebreakers can get stuck in the pack ice. This exerts an incredible amount of pressure, as Captain Uwe Pahl of the icebreaker RV Polarstern had experienced off the coast of Spitsbergen in Norway: “The tides, currents, and wind move floes that squeeze a ship upward by 3 feet like a cork—a ship that weighs 17,000 tons.” The pressure exerted upon the hull can be greater than in the barrel of a gun or on the deepest sea floor. So it stays intact, the hull’s outer skin is forged from 2 inches of special steel, making it three times as thick as a conventional ship’s hull. Even that is no guarantee of safety: “Patience is our highest virtue,” says Hamilton. Most accidents in the ice happen because of inattention and excessive speed, especially at night when only the ice radar and two or three strong headlights show the way forward. “A high-speed collision with an iceberg can put lives at risk. Then we really have a problem…”
ICE FLOES PROPPED OUR 17,000-TON SHIP UP BY 3 FEET