Mooring Stiffness Impact on the Survivability of MODUs
Additional Document Info
During 2004-2005, three consecutive category-5 hurricanes (Ivan, Katrina, and Rita) hit the central region of Gulf of Mexico (GOM) and damaged numerous drilling and production platforms including Noble Jim Thomson (NJT) drilling semi-submersible. In the present study, the progressive failure of the mooring system of a Mobil Offshore Drilling Unit (MODU) similar to NJT during the hind-cast non-collinear hurricane Ivan wind-wave-current environment is numerically simulated. A time-domain vessel-mooring coupled dynamic analysis computer program is used to simulate the sequence of the progressive mooring-line failure of the original steel mooring system. The numerically simulated results are compared with the available NJT forensic-analysis data. An alternative polyester taut mooring system was also analyzed to determine if it could have survived the same extreme environment. The polyester system generally performed better and unexpectedly survived. Copyright 2008 by The International Society of Offshore and Polar Engineers (ISOPE).