ENVIRONMENTAL-FACTORS IN ICEBERG COLLISION RISKS FOR FLOATING SYSTEMS

When designing systems for regions through which icebergs travel, it i s necessary to estimate the probability of iceberg impact events and t he load distribution given an impact. An important consideration is th e distribution of environmental conditions present when confronted wit h an iceberg. The ability to detect icebergs using radar is largely af fected by the amount of capillary waves generated by the wind. Overall sea state, precipitation, fog, and lighting also affect detection. Th e combined wind, sea state, and current regime determine the drift and wave induced velocities of the icebergs and influence the operators a bility to manage icebergs. In this paper, methods are presented for de termining the distribution of environmental conditions associated with an iceberg encounter event. Emphasis is given to storm conditions whe n detection of smaller icebergs is difficult, First, the seasonal vari ations in the population of icebergs and in the environmental conditio ns are accounted for. Then the influence of the environmental conditio ns on the probability of an encounter, through their effect on the dri ft velocities of icebergs, is incorporated. Example calculations are g iven for a turret moored floating oil production vessel (FPV) situated on the Grand Banks off Canada's east coast.