Reliability assessment and integrity management of data buoy instruments used for monitoring the Indian Seas

• Reliability model based on failures from 7.3 million offshore instrument hours.
• Cyclone monitoring sensor suite has a Mean Time Between Failure of 0.6 years.
• Achieved 96% data returns from meteorological sensors with 4 slot annual maintenance.
• System complies with IEC 61508 SIL4 with implemented 3 hour reporting interval.

Reliable performance is the key requirement for instruments used in offshore moored buoys for cyclone monitoring, as under performance of the sensors can have a serious impact on the societal protection, and in addition, lead to costly repair and reinstallations. The instrument selection and application practices are based on the experiences of the global scientific community, and their performances are monitored based on IEC61508 standards. Reliability modeling based on experiences in the operation and maintenance of moored surface buoys for approximately two decades has identified that the sensor suite used for cyclone monitoring has a Mean Time Between Failure of 0.6 years, which is the basis of the implemented reliability centered maintenance strategies. As this is the first attempt to study the performance of such moored buoy instruments which have cumulatively clocked more than 7.3 million demanding offshore instrument-hours, the data presented shall serve as input for the offshore environmental instrument system design.