Airgap Statistics for a Tension Leg Platform

The paper discusses a method for estimating extreme value statistics of the airgap for floating offshore platforms subjected to random events. Extensive model tests were performed in a large wave basin for a TLP (Tension Leg Platform) operating in the Norwegian Sea. Among several critical parameters, the airgap was measured at a number of locations under the platform deck. The wave in deck impact is a critical safety issue with respect to the deck damage and occurrence of extreme tether tensions. The authors have utilized experimental data to look at critical airgaps under the deck in random waves. Conclusions are drawn about extreme airgap statistics, and consequently about the wave impact probability in severe seas. This paper can be seen as continuing the efforts in the challenging study of the airgap issue, [2, 6–10].