Finnish-Swedish ice class

Finnish-Swedish ice class is an ice class assigned to a vessel operating in first-year ice in the Baltic Sea and calling Finnish or Swedish ports. Ships are divided into six ice classes based on requirements for hull structural design, engine output and performance in ice according to the regulations issued by the Finnish Transport Safety Agency (TraFi), which overtook the responsibilities of the Finnish Maritime Administration in 2010, and the Swedish Maritime Administration.

Traffic restrictions in the Baltic Sea during winter months are based on the Finnish-Swedish ice classes. These restrictions, imposed by the local maritime administrations, declare the minimum requirements for ships that are given icebreaker assistance, for example "ice class 1A, 2000 DWT". Finnish fairway dues, a system of fees charged for the use of sea lanes to cover the costs of management and icebreaker assistance, also depend on the vessels' ice class. Since ships of lower ice classes generally require more assistance during the winter months, their fairway dues are considerably higher than those of ships of the highest ice classes. For this reason the majority of ships regularly calling Finnish ports are built to the highest ice classes. In the beginning of 2008, 47% of the Finnish tonnage were of ice class 1A Super.

Many international classification societies have incorporated the Finnish-Swedish ice class rules to their own rulebooks and offer ice class notations that are recognized by the Finnish and Swedish authorities. These ice classes are, in turn, used by nations such as Estonia and Latvia to assign traffic restrictions. Since the ice class rules have been revised and amended several times over the years, a list of equivalent ice class notations is used to assign the correct official ice class for older vessels when they visit Finnish and Swedish ports. Although mainly used in the Baltic Sea, the Finnish-Swedish ice classes and the equivalent ice class notations from classification societies are sometimes used when discussing ships operating in other ice-infested seas of the world.

While the Finnish-Swedish ice classes can be assigned to icebreakers for the purpose of collecting fairway fees, the rules are intended primarily for merchant ships operating under icebreaker escort. Because the engine output and the level of ice-strengthening in ships designed to operate independently in ice-infested waters, especially in the presence of multi-year ice, usually exceeds the requirements of the Finnish-Swedish ice class rules, the classification societies use different ice class notations, such as the IACS Polar Class, for icebreakers. The two highest Finnish-Swedish ice classes, 1A and 1A Super, are somewhat equivalent to the two lowest Polar Classes, PC 7 and PC 6, respectively.

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