Optimal weather window for transportation of large-scale offshore structures

Offshore transportation is recognized as one of the most dominant sources of human and financial loss, among all varieties of maritime and offshore operations. The conventional deterministic approach to address the corresponding risks, therefore, needs to be reconsidered. This study aims at developing a reliability-based methodology for marine transportation analysis of large-scale offshore modules. Taking vessel stability and strength as the limiting criteria, the allowable weather window is extracted by use of Monte Carlo simulation. Comparing the results of conventional deterministic and reliability-based approaches, the efficiency of the proposed methodology is well demonstrated. The importance sampling technique is also proposed subsequently to reduce the computational time and effort. The developed framework is ultimately employed for optimal planning of offshore transportation, aiming to minimize weather-related downtime. The application of the proposed probabilistic approach for planning the installation phase of offshore projects leads to a significant reduction in costs while keeping the risk level as low as reasonably practicable.