Environmental factors in iceberg collision risks for floating systems

Abstract

When designing systems for regions through which icebergs travel, it is necessary to estimate the probability of iceberg impact events and the load distribution given an impact. An important consideration is the distribution of environmental conditions present when confronted with an iceberg. The ability to detect icebergs using radar is largely affected by the amount of capillary waves generated by the wind. Overall sea state, precipitation, fog, and lighting also affect detection. The combined wind, sea state, and current regime determine the drift and wave induced velocities of the icebergs and influence the operators ability to manage icebergs. In this paper, methods are presented for determining the distribution of environmental conditions associated with and iceberg encounter event. Emphasis is given to storm conditions when detection of smaller icebergs is difficult. First, the seasonal variations in the population of icebergs and in the environmental conditions are accounted for. Then the influence of the environmental conditions on the probability of an encounter, through their effect on the drift velocities of icebergs, is incorporated. Example calculations are given for a turret moored floating oil production vessel (FPV) situated on the Grand Banks off Canada's east coast.