Ice-breaker (IMAGE) University of Helsinki Caption The Polar Ship Category of a ship has a crucial impact on the probability of besetting. Ships of a lower category are most at risk, and many of them become beset in ice each year. Credit Photo: Arctia Ltd Usage Restrictions Photo: Arctia Ltd License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.