Stability of floating offshore structures

Stability of floating offshore structures at intact and damaged conditions is currently being addressed by adherence to prescriptive regulations, on the basis of qualities of the righting moment curves. However, as experience shows, a prescriptive set of regulations is not adequate, especially when dealing with larger structures or complicated configurations. Following relevant developments in the shipping industry and the recent Macondo Prospect (Deepwater Horizon) incident, it is considered appropriate to propose a probabilistic framework for the stability of offshore structures. This framework will take into consideration different damage cases, loading conditions and damage extents, and will account for their probability of occurrence and potential consequences. The framework would be developed on the basis of parametric use of first-principles tools and integrated analysis of dynamic behaviour of the said floating structure in a wind-wave environment and would make use of accident data. The considerations above are directly related to risk-based design. Existing regulatory requirements are discussed, and key areas for future development are proposed.