Probability of a ship becoming beset in ice along the Northern Sea Route – A Bayesian analysis of real-life data

• Published in: Cold regions science and technology 2021-04, Vol.184, p.103238, Article 103238
• Main Authors: Vanhatalo, Jarno, Huuhtanen, Juri, Bergström, Martin, Helle, Inari, Mäkinen, Jussi, Kujala, Pentti
• Format: Article
• Language: English
• Subjects: Arctic; Automatic Identification System (AIS); Bayesian inference; Ice besetting; Ice data; Ice loads; Maritime traffic; Northern Sea Route; Polar; Shipping; Ships
• ISSN: 0165-232X; 1872-7441
• DOI: 10.1016/j.coldregions.2021.103238

Ships operating in ice-infested Arctic waters are exposed to a range of ship-ice interaction related hazards. One of the most dangerous of these is the possibility of a ship becoming beset in ice, meaning that a ship is surrounded by ice preventing it from maneuvering under its own power. Such a besetting event may not only result in severe operational disruption, but also expose a ship to severe ice loading or cause it to drift towards shallow water. This may cause significant structural damage to a ship and potentially jeopardize its safety. To support safe and sustainable Arctic shipping operations, this article presents a probabilistic approach to assess the probability of a ship becoming beset in ice. To this end, the proposed approach combines different types of data, including Automatic Identification System (AIS) data, satellite ice data, as well as data on real-life ship besetting events. Based on this data, using a hierarchical Bayesian model, the proposed approach calculates the probability of a besetting event as a function of the Polar Ship Category of a ship, sea area, and the distance travelled in the prevailing ice concentration. The utility of the proposed approach, e.g. in supporting spatiotemporal risk assessments of Arctic shipping activities as well as Arctic voyage planning, is demonstrated through a case study in which the approach is applied to ships operating in the Northern Sea Route (NSR) area. The outcomes of the case study indicate that the probability of besetting is strongly dependent on the Polar Ship Category of a ship and that the probability increases significantly with higher ice concentrations. The sea area, on the other hand, does not appear to significantly affect the probability of besetting. •An approach to assess the probability of a ship besetting in ice from real-life data.•Analysis of Northern Sea Route besetting events, AIS and ice data from 2013 to 2017.•Probability of besetting depends strongly on Polar Ship Category and ice concentration.•Support for spatiotemporal risk assessments of Arctic shipping and voyage planning.