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" When a ship&amp;#039;s mission is to pound through ice as thick as a couple tree trunks -- in negative 60-degree weather, no less -- it has to be tough. From the power of their engines to the design of their hulls, these six icebreakers are some of the hardiest, most stand-out vessels in the world. MACKINAW   + Click to enlarge  Home Base: Cheboygan, Mich. Commissioned: Replaced old Mackinaw in 2006 Capacity: 56 Length: 240 ft. Icecrushing capability: 2.5 ft. thick (10 ft. ramming) Traditional super-horsepower icebreakers have no problem plowing straight through polar waters, but only one can pull a 360 on a dime. The newly-launched U.S. Coast Guard Cutter Mackinaw doesn&amp;#039;t use a rudder or traditional propeller shafts as it demolishes ice on the Great Lakes; instead, it&amp;#039;s equipped with two under-hull azimuth thrusters -- swiveling pods that each contain a powerful, electric motor/propeller combo. These twin propulsion units, coupled with a bow thruster, allow the vessel to apply full thrust in any direction and turn around on its axis.  The Coast Guard&amp;#039;s prized Mackinaw also responds to oil spills, and participates in buoy maintenance, search and rescue and law enforcement missions. If the ship successfully completes its icebreaking trials this month, more vessels may be designed with a similar azimuth steering designs. (Modifying existing ships would be too difficult.) You can watch Mackinaw in action here. POLAR SEA  + Click to enlarge  Home Base: Seattle, Wash. Commissioned: 1978 Capacity: 180 crew, 35 scientists and technicians Length: 399 ft. Icecrushing capability: 6 ft. thick (21 ft. ramming) One of two ships in the world&amp;#039;s most powerful class of non-nuclear icebreakers (and the first U.S. surface ship to reach the geographic North Pole), this Coast Guard vessel provides support for American bases near both ends of the Earth. To reach McMurdo Station in Antarctica, Polar Sea must break through 10 to 30 miles of fast ice (ice that&amp;#039;s still attached to shore), its curved bow riding up high on the ice, then smashing through using the weight of its hull (reinforced with 1 3/4-in.-thick steel) -- and it&amp;#039;s all driven by a computerized propulsion control system. Learn more about McMurdo ice-drilling research from our embedded blogger here. LOUIS S. ST-LAURENT  + Click to enlarge    Arctic Icebreaking    Voyage to the Top of the Earth    Slideshow: The Journey North    Podcast: Arctic Icebreaking      The World&amp;#039;s Top 5 Icebreakers   Home Base: Dartmouth, Nova Scotia Commissioned: 1969 Capacity: Up to 50 crew and as many as 60 scientists Length: 366 ft. Icecrushing capability: 6 ft. thick (35 ft. ramming) The Canadian Coast Guard&amp;#039;s steam-turned-diesel/electric research ship powers through the Gulf of St. Lawrence with an efficient icebreaking system-underwater bubblers that blow compressed air into the open sea, and a coating of a Teflon-like lubricant helps ice slip along the hull and Louis&amp;#039; pressure sensors to gather data. And in case of fog or thick cloud cover, the ship can download satellite imagery (visual or infrared) from Terra Scan technology that blows your car&amp;#039;s GPS system out of the water. Read more about the Canadian icebreaker fleet here. POLARSTERN  + Click to enlarge  Home Base: Germany Commissioned: 1982 Capacity: 44 crew, with room for up to 50 scientists Length: 387 ft. Icecrushing capability: 5 ft. thick (8 ft. ramming) Spending time at both poles during its 320 days at sea each year, this vessel, operated by the Alfred Wegener Institute for Polar Research, has a double-hull design and four engines that together produce 20,000 hp and allow it reach 16 knots in open water. Cranes and winches on deck can place research equipment at extreme depths, and the Polarstern&amp;#039;s special depth-sounding devices can reach 32,380 ft. underwater and penetrate almost 500 ft. into the sea floor. Track the ship&amp;#039;s course here. 50 YEARS AFTER VICTORY  + Click to enlarge  Home Base: St. Petersburg, Russia Commissioned: 1989 Capacity: 138 total Length: 522 ft. Icecrushing capability: 26 ft. Known in its native tongue as 50 Let Pobedy (to mark the end of World War II), this Arktika-class, nuclear-powered ship is the biggest icebreaker in the world. After high construction costs resulted in a 10-year delay for 50 -- Russia&amp;#039;s ninth nuclear icebreaker -- the 100-ft.-wide ship and its two atomic power plants finally completed sea trials last month and are ready for a maiden voyage (although officials say two diesel-powered icebreakers will assist 50 with navigation as the country rapidly expands its Arctic fleet). Some speculate that the 25,000-ton vessel may even be large enough to accommodate tourist cruises, though safety concerns are sure to be another stumbling block. Check out specs on the newest Russian nuclear vessels here. "^^<http://www.w3.org/2001/XMLSchema#string>
<http://www.popularmechanics.com/technology/infrastructure/a1479/4213361/>