An investigation into the implications of recent advances in knowledge of wind structure over the sea for the extreme roll motion of vessels was mounted. Data from the NMI wind measurement programme on BP’s West Sole 'A’, production platform was used, together with recommendations from the Draft Code of Practice for offshore structures, to suggest a basis for calculating the stability of vessels that is supported by experimental evidence. The method is based broadly on the "weather criterion approach, implying the application of a maximum 3-second gust at the most dangerous point in the roll cycle.

Comparison is made with experiments on a small model typical of a North Sea trawler in the NMI wind/wave facility. Subject to certain reservations, the results agree as well as might be expected, but point out the great importance of water-on-deck in dealing with the approach of a small vessel in severe wind and wave conditions to extreme motion and eventual capsize.