sentences:  In the Finnish-Swedish ice class rules, merchant ships operating in first-year ice in the Baltic Sea 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 Swedish Maritime Administration and the Finnish Transport and Communications Agency (Traficom).International classification societies have incorporated the Finnish-Swedish ice class rules to their own rulebooks and offer equivalent ice class notations that are recognized by the Finnish and Swedish authorities.Ships of the highest ice class, 1A Super, are designed to operate in difficult ice conditions mainly without icebreaker assistance while ships of lower ice classes 1A, 1B and 1C are assumed to rely on icebreaker assistance.