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.
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.
