What Is an Ice Class?

An Ice Class refers to a classification denoting the capability of a ship to navigate through varying levels of sea ice. Defined by specific standards, these vessels are fortified against frigid conditions, ensuring safe passage in polar regions. Intrigued by the engineering marvels that brave icy waters? Discover how these ships are designed to conquer the frozen frontier.
Lori Kilchermann
Lori Kilchermann

An ice class ship or hull has several provisions and special build qualities that help the vessel to operate in icy waters without sustaining damage. A thicker hull material is one of the main differentiating features of an ice class vessel. Increased spars and bulkheads also aid in providing strength to the icy cruiser. Other special components that are present in an ice class ship are special rudder and propeller features along with heated fuel and ballast tanks. Improved and protected sea chests are also included on the special frozen water sailing vessels.

While not as heavily fortified as an actual ice breaker, the ice class ships are equipped to better withstand icy waters than a common ship. Beginning at the onset of the build, an ice class ship receives special, high-tensile strength keel and hull materials. The thicker skin is better prepared to withstand direct contact with heavy ice. Closer positioned girders and beams provide added strength and protection for the ship, while increased and tighter-sealing bulkheads provide a measure of protection should a hole be punctured into the hull of the ship. The ships can, however, still become stranded in the frozen waters and require the assistance of an ice-breaking vessel to aid in the removal of the ice.

Man with hands on his hips
Man with hands on his hips

Any ship operating in frozen water is subject to freezing ballast tanks and gelled diesel fuel. The ice class ships place special heating elements inside of the ballast and fuel tanks to eliminate or slow down this process. Oil heaters allow the engines to turn over easier in the cold climate, while warmers on shaft bearings and seals maintain a constant flow of lubrication and pliability to the seals that prevent water from seeping in around the shafts. Special propeller reinforcement in the tip area aid the ice class ships in protection against ice damage to the propulsion system.

Several types of protection are used in the rudder area of the ice class ships to prevent rudder damage from disabling the ship while at sea. Even with all of the upgrades and safety items and precautions taken to guard against ice damage, the special ships undergo a rating procedure that identifies the vessels from the lowest to highest ice safety classification. Often, a lower safety-rated ship will be converted to a higher rating to fulfill an obligation by the shipping company. Insurance and freight contracting are common reasons for an upgrade to any ice class rating.

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Discussion Comments


It still amazes me how ships can navigate even the harshest weather conditions. I saw a program on TV about ships that travel in freezing and icy conditions. My jaw was on the floor. It seems like the ships could get torn apart or frozen in ice at any moment and yet they make it through most often.

This is really a feat of both engineering and courage. First you have to design a ship that can withstand these kinds of conditions. Then you have to find a crew that is willing to brave the risks that can never be engineered out. I admire those men and women and I'm glad its them piloting those ships and not me.


I read a book once about a trip to try and explore the north pole carried out in the late 19th century. As you might be able to guess, things did not go very well.

The book was filled with crazy anecdotes, but the ones that stood out most in my mind were the ones about the perils of sailing in the arctic ocean. There were at least a thousand chances for disaster and for many ships a voyage that far north was certain destruction.

I think we take it for granted today that any ship can sail anywhere in the world. But that is a fairly modern ability. For a long time ice was the biggest obstacle to any ship.

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