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Ice Class Vessels

The Arctic is the region around the Earth's North Pole, that includes the Arctic Ocean (which overlies the North Pole) and parts of Canada, Greenland (a territory of Denmark), Russia, the United States (Alaska), Iceland, Norway, Sweden and Finland.
Ships and boats were the means by which the early explorers of Arctic reached the continent. They were very much the focus of Arctic expeditions which were often named after the ship that took the men, their provisions and their equipment to Arctic. Many landmarks in Arctic are named after these vessels. In the earliest days of Arctic exploration, the vessels were sailing ships, and they rarely entered pack ice as the ship's means of propulsion was the same as that of the ice itself, so unless the ice dispersed, great difficulty could be had in extracting the ship.
Vessels operating in the Arctic region are exposed to a number of unique demands. In the last decades, there has been a big increase in the number of vessels operating in icy and low-temperature waters. These range from ice class tankers employed in the booming Russian energy export trade to cruise ships taking tourists for the trip of a lifetime to Polar Regions.
An Ice breaker is a special purpose ship or boat designed to move and navigate through ice-covered waters. For a ship to be considered an icebreaker it requires three components: a strengthened hull, an ice-clearing shape, and the power to push through, none of which are possessed by most normal ships.

To pass through ice-covered water, an icebreaker uses its great momentum and power to drive its bow up onto the ice, breaking the ice under the immense weight of the ship. Because a buildup of broken ice in front of a ship can slow it down much more than the breaking of the ice itself, the speed of the ship is increased by having a specially designed hull to direct the broken ice around or under the vessel. The external components of the ship's propulsion system (propellers, propeller shafts, etc.) are at even greater risk of damage than the vessel's hull, so the ability of an icebreaker to propel itself onto the ice, break it, and successfully clear the debris from its path is essential for its safety.
Ice class assigned by a Classification standard requires a minimum level of ice strengthening of the hull structures to minimize damage from floating ice. The Hull made from special steels is designed for optimum strength at low temperatures. The vessel's extra thick steel bow is designed to reduce the effects of spray from freezing and collecting on the bow area. The rounded hull of the ship allows it to ride upwards if pushed from the sides from wind blown pack ice. Suitable materials for low temperatures are mandatory for proper functioning of the hull structure and equipment. Bridge wings and deck houses are specially designed or enclosed to protect equipment and crew.

Ice navigation poses stability concerns that require higher stability levels than open-water vessels. As the vessel proceeds in ice it is subject to movements from ramming and ice impacts. Suitable calculations are accordingly carried out to demonstrate that the ship can maintain sufficient positive intact stability.
The damage stability criterion concerns the ability of a ship to withstand flooding resulting from hull penetration due to ice damage, and to provide a condition of equilibrium after such damage. IMO Arctic guidelines give criteria for the extent and location of damage. Loading procedures include the maximum operational weight, position of the centre of gravity and the distribution of load necessary for operation in Arctic ice-covered waters.
The engines are either diesel driven or nuclear powered with extra power supplied by gas turbines for ice breaking. Controlled Pitch Propeller (CPP) or Fixed Pitch Propeller (FPP) with diesel electric machinery give better operability in ice and lower ice class power requirement. The extra strong propellers with replaceable blades are inspected to examine them in operation and the facility to change blades while at sea. An "ice horn" to protect the rudder and propeller when in reverse, and an "ice knife" in front to protect them when in forward motion are also essential features of an ice class vessel. The Life boats are enclosed and specially designed to operate in the cold.
The equipment onboard (e.g. crane) is certified for temperature less than minus 100C. The machinery and accommodation are insulated completely. To ensure the operation of machinery and equipment proper air distribution arrangements are made. Sea chests are constructed for ice condition. The special systems (anchoring, pipe laying, dredging devices etc) are designed for operating in ice and cold conditions. Safe working on open deck requires protection against slipping such as de-icing. The water system (piping, tanks etc) are insulated to prevent ice formation. The Crew and the other personnel onboard are trained to operate in cold environment. Ships operating in Arctic ice-covered waters carry an operating manual and training manual onboard at all times.
The American Bureau of Shipping has a system of ice classes which includes classes A5 through A0; B0, C0, and D0. A5 class is the strongest built of the classes, with D0 being the weakest. All other major classification societies have a similar system of ice classes, and converting between ice classes is relatively easy. In most cases only the names of the classes are changed and the specifics of the Arctic class are identical. The Baltic Ice classes consist of 5 classes. Classes 1A, 1B and 1C were created in 1932. In 1972 new Swedish-Finnish rules extended the classification with the new class "1A Super". The International Association of Classification Societies published a set of Unified Requirements for Polar Class Ships to complement the IMO Guidelines for Ships Operating in Arctic Ice Covered Waters. This will effectively unify the ice classes for all IACS member societies. Seven Polar Classes are proposed in the requirements, abbreviated as PC1 through PC7. Like the Arctic Ice Classes, different classification societies may assign different names for these classes, however, the restrictions and requirements of each class are the same regardless of the name given by the society.
The Arctic region of Russia has the world's biggest energy reserves of oil and gas resources outside the Organization of Petroleum Exporting Countries (OPEC). Russia's oil production has increased exponentially, and exports to world markets from the icy seas of the Arctic region are currently running at around seven million barrels per day. The demand for Russian crude oil exports from the icy seas of the Arctic regions is such that some USD 4.5 billion has already been invested in ice-class tonnage. Currently, 262 ships are being built to ice class standards, a total of 4.2 million dwt, with the vast majority (almost 80%), being less than 20,000 dwt. Even so, the fleet is set to double in both number and size. A large portion of Russia's oil is currently shipped by tankers. At present, about eight per cent of the global tanker fleet is ice-classed vessels, and it is estimated that by 2008 the share will cross the 10 per cent mark, to 18 million deadweight tonnes (dwt).
Scientists say that ships are adding to global warming in a big way because they are a major source of pollutants like carbon dioxide, nitrous oxide and black carbon. A Green Peace Report states that the global fleet of marine vessels is a major factor that affects global climate. It is estimated that this fleet releases between 600 and 900 million metric tons of carbon dioxide each year. Hence the ships contribute nearly 30 per cent of the world's releases of nitrogen oxides. According to the report, ship pollution can be reduced considerably by controlling the operation of marine vessels, including fuel type and vessel speed among other solutions. Actions that will help achieve the reduction of emissions are desperately needed to protect the oceans and marine ecosystems.
The Northern Sea Route is the shipping lane from the Atlantic Ocean to the Pacific Ocean along the Russian coasts of the Far East and Siberia. The vast majority of the route lies in Arctic waters and parts are only free of ice for two months per year. Several seaports along the route are ice-free all year round. They are, west to east, Murmansk on the Kola Peninsula, Petropavlovsk in Kamchatka, and Magadan, Vanino, Nakhodka and Vladivostok on Russia's Pacific seaboard. Other ports are generally used from July to October, or, like especially Dudinka are being served by nuclear powered icebreakers.
Global Warming is likely to open up new shipping routes in the Arctic Ocean. In the summer of 2000, several ships took advantage of thinning summer ice cover on the Arctic Ocean to make the crossing. It is thought that global warming is likely to open the passage for increasing periods of time, making it attractive as a major shipping route. However the passage through the Arctic Ocean would require significant investment in escort vessels and staging ports.Therefore the Canadian commercial marine transport industry does not anticipate the route as a viable alternative to the Panama Canal even within the next 10 to 20 years.