sentences:  In addition, icebreaker classes have additional requirements for minimum shaft power and icebreaking capability.A class attributed to a vessel under the Canadian "Arctic Shipping Pollution Prevention Regulations" regime, which indicates that the vessel met the requirements of those regulations.Up to December 2017, Canadian "Arctic Shipping Pollution Prevention Regulations"  establish 9 Arctic classes for ship (Arctic Class 1, 1A, 2, 3, 4, 6, 7, 8 or 10) based on requirements for hull structural design, engine power, engine cooling water arrangement, propeller, rudder and steering gear and performance in ice.