Polar Class

The development of the Polar Class rules began in the 1990s with an international effort to harmonize the requirements for marine operations in the polar waters in order to protect life, property and the environment. The guidelines developed by the International Maritime Organization (IMO), which were later incorporated in the Polar Code, made reference to the compliance with Unified Requirements for Polar Ships developed by the International Association of Classification Societies (IACS). In May 1996, an "Ad-Hoc Group to establish Unified Requirements for Polar Ships (AHG/PSR)" was established with one working group concentrating on the structural requirements and another working on machinery-related issues. The first IACS Polar Class rules were published in 2007. Prior to the development of the unified requirements, each classification society had their own set of ice class rules ranging from Baltic ice classes intended for operation in first-year ice to higher vessel categories, including icebreakers, intended for operations in polar waters. When developing the upper and lower boundaries for the Polar Classes, it was agreed that the highest Polar Class vessels (PC 1) should be capable of operating safely anywhere in the Arctic or the Antarctic waters at any time of the year while the lower boundary was set to existing tonnage operating during the summer season, most of which followed the Baltic ice classes with some upgrades and additions. The lowest Polar Class (PC 7) was thus set to the similar level with the Finnish-Swedish ice class 1A. The definition of operational conditions for each Polar Class was intentionally left vague due to the wide variety of ship operations carried out in polar waters. == Definition ==

Polar Class notations The IACS has established seven different Polar Class notations, ranging from PC 1 (highest) to PC 7 (lowest), with each level corresponding to operational capability and strength of the vessel. The description of ice conditions where ships of each Polar Class are intended to operate are based on World Meteorological Organization (WMO) Sea Ice Nomenclature. These definitions are intended to guide owners, designers and administrations in selecting the appropriate Polar Class to match the intended voyage or service of the vessel. Ships with sufficient power and strength to undertake "aggressive operations in ice-covered waters", such as escort and ice management operations, can be assigned an additional notation "Icebreaker". However, unlike the Baltic ice classes intended for operation only in first-year sea ice, even the lowest Polar Classes consider the possibility of encountering multi-year ice ("old ice inclusions"). Requirements In the Polar Class rules, the hull of the vessel is divided longitudinally into four regions: "bow", "bow intermediate", "midbody" and "stern". All longitudinal regions except the bow are further divided vertically into "bottom", "lower" and "icebelt" regions. For each region, a design ice load is calculated based on the dimensions, hull geometry, and ice class of the vessel. This ice load is then used to determine the scantlings and steel grades of structural elements such as shell plating and frames in each location. The design scenario used to determine the ice loads is a glancing collision with a floating ice floe. In addition to structural details, the Polar Class rules have requirements for machinery systems such as the main propulsion, steering gear, and systems essential for the safety of the crew and survivability of the vessel. For example, propeller-ice interaction should be taken into account in the propeller design, cooling systems and sea water inlets should be designed to work also in ice-covered waters, and the ballast tanks should be provided with effective means of preventing freezing. Although the rules generally require the ships to have suitable hull form and sufficient propulsion power to operate independently and at continuous speed in ice conditions corresponding to their Polar Class, the ice-going capability requirements of the vessel are not clearly defined in terms of speed or ice thickness. In practice, this means that the Polar Class of the vessel may not reflect the actual icebreaking capability of the vessel. == Polar Class ships ==

The IACS Polar Class rules apply for ships contracted for construction on or after 1 July 2007. the American Sikuliaq in 2014, and the British RRS Sir David Attenborough in 2020. In addition, a PC5 Antarctic vessel Almirante Viel was commissioned for the Chilean Navy in July 2024. In 2012, the Royal Canadian Navy awarded a shipbuilding contract for the construction of six Arctic Offshore Patrol Ships (AOPS) rated at PC5. , the first four vessels (, , and ) have entered service, the fifth () has been delivered, and the sixth () is being fitted out. Two additional ships, and , are under construction for the Canadian Coast Guard. , four cruise ships have been built with PC5 rating: National Geographic Endurance (delivered in 2020) and National Geographic Resolution (2021) for Lindblad Expeditions, and SH Minerva (2021) and SH Vega (2022) for Swan Hellenic. Polar Class 4 , built in 2016, is rated Polar Class 4 with an additional notation "Icebreaker(+)" denoting additional strengthening. The 2012-built drillship Stena IceMAX has a hull strengthened according to PC4 requirements. However, the long and wide vessel does not feature an icebreaking hull and is designed to operate primarily in pre-broken ("managed") ice. The Canadian shipping company Fednav operates two PC4 rated bulk carriers, 2014-built Nunavik and 2021-built Arvik I. The 28,000-tonne vessels are primarily used to transport nickel ore from Raglan Mine in the Canadian Arctic. In 2015, the hull of the Finnish 1986-built icebreaker Otso was reinforced with additional steel to PC4 level to allow the vessel to support seismic surveys in the Arctic during the summer months. The Finnish LNG-powered icebreaker Polaris, built in 2016, is rated PC4 with an additional Lloyd's Register class notation "Icebreaker(+)". The latter part of the notation refers to additional structural strengthening based on analysis of the vessel's operational profile and potential ice loading scenarios. The interim icebreakers CCGS Captain Molly Kool, CCGS Jean Goodwill, and CCGS Vincent Massey, built in 2000–01 and acquired by the Canadian Coast Guard 2018, were upgraded to PC4 rating as part of the vessels' conversion to Canadian service. In December 2024, the Institute of Deep-sea Science and Engineering of the Chinese Academy of Sciences took delivery of the PC4 rated icebreaking research vessel Tan Suo San Hao. The new PC4 polar logistics vessel of the Argentine Navy intended to complement the country's existing icebreaker ARA Almirante Irízar in Antarctica is currently in design stage. The Japan Agency for Marine-Earth Science and Technology (JAMSTEC) is in the process of acquiring a new PC4 rated icebreaker for researching the Arctic region. The Swedish Maritime Administration is in the process of acquiring a new icebreaker rated PC4 Icebreaker(+). The vessel is expected to enter service in 2028. The new Canadian Coast Guard Multi-Purpose Vessels (MPV) will be rated PC4 Icebreaker(+). Sixteen vessels will be built by Seaspan in the 2020s and 2030s, and the first vessel is expected to enter service in 2028. Polar Class 3 is operated by the Norwegian Polar Institute. The first PC3 vessels were two heavy load carriers, Audax and Pugnax, built for the Netherlands-based ZPMC-Red Box Energy Services in 2016. The long and wide vessels, capable of breaking up to ice independently, were built for year-round transportation of LNG liquefaction plant modules to Sabetta. Although usually referred to by their Russian Maritime Register of Shipping ice class Arc7, the fifteen first-generation Yamalmax LNG carriers built in 2016–2019 as well as the arctic condensate tankers Boris Sokolov (built in 2018), Yuriy Kuchiev (2019) and Anatoly Lamekhov (2024) also have PC3 rating from Bureau Veritas. In April 2015, it was reported that Edison Chouest would build two PC3 anchor handling tug supply vessels (AHTS) for Alaskan operations. However, the construction of the vessels due for delivery by the end of 2016 was later cancelled following Shell Oil's decision to halt Arctic oil exploration. , three polar research vessels have been built with PC3 rating: Kronprins Haakon for the Norwegian Polar Institute in 2018, Xue Long 2 for the Polar Research Institute of China in 2019, and Nuyina for the Australian Antarctic Division in 2021. Kronprins Haakon also has the additional notation "Icebreaker" while Nuyina notation includes Lloyd's Register's "Icebreaker(+)" notation. The new South Korean polar research vessel will also be built to PC3 rating. The Finnish multipurpose icebreakers Fennica and Nordica, built in the early 1990s, were assigned PC3 rating as part of the vessels' Polar Code certification in 2019. South Korea is in the process of acquiring a new Polar Class 3 research vessel for Arctic and Antarctic regions. Polar Class 2 , the only PC2 rated vessel in service is the expedition cruise ship operated by the French company Compagnie du Ponant. The 270-passenger vessel, capable of breaking up to thick multi-year ice and taking passengers to the North Pole, was delivered in 2021. The United States Coast Guard has ordered two out of three planned PC2 rated heavy polar icebreakers referred to as Polar Security Cutters. The first contract was awarded in April 2019 and the second in December 2021. Construction of the first vessel, , has been delayed by several years and now is not expected to be delivered to the U.S. Coast Guard until at least 2030. While the vessels these Polar Security Cutters are intended to replace, and , are sometimes referred to as s, these mid-1970s icebreakers are not built in accordance with the IACS rules and do not carry a PC rating. In December 2024, the German research institute Alfred Wegener Institute contracted ThyssenKrupp Marine Systems to build a replacement for the 1982-built research icebreaker Polarstern. The new vessel, scheduled for delivery in 2030, will be rated PC2. In March 2025, the Government of Canada awarded construction contracts for two PC2 rated polar icebreakers for the Canadian Coast Guard under the National Shipbuilding Strategy Polar Icebreaker Project. The first vessel will be built by Seaspan Vancouver Shipyards and the second, slightly smaller, by Davie Shipbuilding in co-operation with the Finnish Helsinki Shipyard. The vessels, named and , are expected to enter service in the early 2030s. Polar Class 1 , no ships have been built, under construction, or planned to PC1, the highest ice class specified by the IACS. == Notes ==