Methodology for assessment of the operational limits and operability of marine operations

This paper deals with a general methodology for assessment of the operational limits and the operability of marine operations during the planning phase with emphasis on offshore wind turbine (OWT) installation activities. A systematic approach based on operational procedures and numerical analyses is used to identify critical events and corresponding response parameters. Identifying them is important for taking mitigation actions by modifying the equipment and procedures. In the proposed methodology, the operational limits are established in terms of allowable limits of sea states. In addition, the operational limits of a complete marine operation are determined by taking into account several activities, their durations, continuity, and sequential execution. This methodology is demonstrated in a case study dealing with installation of an offshore wind turbine monopile (MP) and a transition piece (TP). The developed methodology is generic and applicable to any marine operation for which operational limits need to be established and used on-board as a basis for decision-making towards safe execution of operations.