Ice-Strengthened Vessels: An Overview of the Ice Class

Shipping vessels that travel in polar-like conditions or Antarctic or Arctic waters should be ice-strengthened against damage. This structural quality enables a shipping or other vessel to safely travel in waters with visible or non-visible hazards, such as submerged or surface ice. A non-ice-strengthened ship that travels in polar waters risks holing or incurring other catastrophic damage.

Routine Features of an Ice-Strengthened Ship

There is no international standard to define the term “ice strengthened.” This definition may vary from country to country and even vessel to vessel, depending on the class of the ship.

There are, however, some common characteristics of ice-strengthened ships, including:

• a double hull – typically there is a gap between the hulls, filled either with air or a water ballast. This provides an extra layer of protection in the event the outer hull is compromised by a collision with ice;
• a flat hull – a hull with a flat design and rounded bow allows a vessel to rise above an icy surface. The ship’s weight then comes down to crush the ice, thereby allowing the vessel to move forward;
• a hull that is clear of protruding fixtures – the hull cannot have external stabilizers or other fixtures that may get “caught” on the ice or forcefully removed during impact with obstacles;
• specialized engine technology – the water intake must be designed to ensure the engine will not encounter ice blockages. The same principle applies to the water outlet system;
• protected rudder and propeller – the design of the hull should be such to absorb contact with ice, thus protecting the rudder and propeller from potential damage;
• constructed of durable materials – an ice-strengthened vessel should be made with steel that is thicker than typically found on a non-ice-strengthened ship. This is especially important at key contact points, such as the bow; and
• an ice belt – an area on the hull that has a particularly thick later of steel and additional interior structuring.

An ice-breaker is a different category of ship. It shares many similarities to an ice-strengthened vessel but also includes additional special features and design properties. For instance, an ice breaker ship was recently dispatched to Antarctica from Britain to rescue the MV Akademik Shokalskiy as it was trapped in the ice despite the fact that the Expeditions Online company profile lists it as “world-renowned for polar exploration.” Thus, ice-strengthened ships are important both for professionals and tourists.

Categories of Ice-Strengthened Vessels

There are three primary categories of vessels that may have ice-strengthening features. They are categorized based on the type of waters in which they can safely travel.

Ice-strengthening vessel categories are:

• polar ice covered waters – may safely operate in water that has 10 percent or more ice;
• polar open water – may safely operate in water with less than 10 percent ice; and
• polar open water (including waters without ice) – may safely operate in waters with zero to 10 percent ice cover. This class typically will not have ice-strengthening measures.

Does your ice-strengthened vessel require special logbooks? Download our free Logbook Quick Reference Guide, and place your orders online or call (888) 468-3757.