The work discusses possibility to make transit voyages of vessels without ice strengthening on the Northern Sea Route (NSR). Exist many uncertainties for it. They are related to hydro-meteorological conditions, mostly to ice cover on the Russian Arctic. Ice conditions are under dynamic changes in time and space. Is hard to precisely predict ice conditions now, in the time range of one month and so on. Statistical historical data of daily changes same like yearly changes show a considerable scatter of the data. The author analyzed number of ice-free days of particular seas of the NSR in the latest eight years. The results of this work may be used for estimation of time frame (time window) for transport of cargo on the NSR by means of vessels without ice strengthening. The statistical presentation of ice-free days data was used in the work to develop decision supporting method related to planning vessel voyage including ice-free time frame on particular seas of the Northern Sea Route.
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