Alerts iconUnreliable position reference systems leads to DP incident

Comments from the report Only 2 DGNSS were online, with poor signal quality due to the location and environmental conditions.  The end effect was that the deviation from the set point in surge and sway were increasing for each oscillation. Considerations of the IMCA Marine DP Committee from the above event For DP2 operations, the … Continue reading “Unreliable position reference systems leads to DP incident”

Alerts iconDP3 drillship switchboard blacked out – DP undesired event

Case Narrative: A DP 3 6th generation drillship was set up on automatic DP engaged in plug and abandonment operations in field.  The DP design concept of the vessel was such that there were two redundant groups and the vessel was set up with power generation and thruster supplies equally split across each redundant group … Continue reading “DP3 drillship switchboard blacked out – DP undesired event”

Alerts iconMix of absolute and relative position reference systems – DP incident

Comments from the Report: It was considered that the movement towards the drill ship could have been caused by a combination of position reference system degradation and interaction from the Drill ship’s thrusters.  There was an advisory regarding service disruption from the DGNSS supplier in force at the time.  It was stated that the DPO … Continue reading “Mix of absolute and relative position reference systems – DP incident”

Alerts iconOperating outside DP equipment class 2 requirements – DP incident

Comments from the report: Although DP checklists were completed, the availability of the standby operator station was not confirmed.  The most probable cause for DPOS2 to freeze and not auto changeover was traced to a faulty IO controller on DPOS2.  The vessel replaced the controller with a spare held on-board.  At the time of the … Continue reading “Operating outside DP equipment class 2 requirements – DP incident”

Alerts iconSoftware update caused loss of generators in separate redundant groups

Case narrative A DP2 platform supply vessel (PSV) was set up on auto DP whilst conducting trials in open water after extensive upgrades.  The redundancy concept was based on two redundant groups with power generation, thruster supplies, and all DP consumers equally split between them.  Bow thruster 1 was supplied from a dual drive which … Continue reading “Software update caused loss of generators in separate redundant groups”