ИСТИНА

Since 2006 new generation cargo vessels of enhanced ice class Arc7, equipped with dual-acting hull and Azipod propulsion, started to navigate along the Northern Sea Route. The vessels operate in the ice-covered southwestern Kara Sea throughout winter without icebreaker assistance, entering the Kara Sea through either the Kara Gate (seaward, central and coastal routes) or north of Cape Gelaniya. As the relevance of ice conditions depends on design and capabilities of vessels navigating them, detailed research of sea ice conditions for navigation is necessary for planning of safe and efficient navigation of this type of vessel. Route selection and operation of Arc7 ice class vessels were analyzed based on satellite images, ice charts and ship logs received during 2004-2014 from the vessels navigated between Murmansk and Gulf of Yenisei. These data were used to identify the key criteria that influenced the decision making process. Position of four main navigational routes in the southwestern Kara Sea, frequency of selection of each of them during different months and concurrent ice conditions were defined. Vessels themselves can be seen as instruments to determine the state of the sea ice cover, with the vessel’s speed serving as quantitative indicator. Based on operational reports, the average speed of the movement of Arc7 ice class vessels in drifting ice in the southwestern Kara Sea was calculated for the period 2006-2014. As a result, the fastest speed of the motion in drifting ice was achieved in winters of 2007-2008 and 2011-2012. During the whole period investigated, ice conditions that were extremely difficult for navigation had formed three times: at the end of May 2009, at end of March 2010 and in the middle of March 2011. In 76.5% cases time consumption of navigation between Murmansk and Gulf of Yenisei was within the scope of average, in 4.4% cases - below average, and in 19.1% - above average. Thus, cargo vessels of enhanced ice class Arc7 started to navigate all year round in the western part of the Northern Sea Route without icebreaker assistance, and time consumption for cargo transportation significantly decreased. Permanency of time consumption during the navigation period allows enhancing efficiency of planning of marine cargo transportation. This is a result of unique type of vessels and usage of operative hydrometeorological information.