2017-1- DP Class 3 MODU exceeded WCF while operating with open busties during a heavy weather event
Learning From Incidents
A DP Class 3 MODU carrying out drilling operations, and operating in a 3-split bus configuration, had a near simultaneous trip of 3 generators from two of the independent power systems during a heavy weather event.
Each of the vessels redundant power systems had the two generators and two thrusters connected and operating correctly. Due to the simultaneous trip of two generators from one of the redundant systems the vessel suffered blackout on one of the switchboards.
The vessel had been pushed off station by a large wave, but had remained within the yellow watch circle, and was recovering position when the blackout occurred and then continued to return to and maintain station while the technical team restored the power system.
The vessel at no time required to be disconnected from the wellhead and had been operating in accordance with the Class approved shipyard DP FMEA and within the requirements of the WSOG.