Alerts iconSteering motor failure leads to loss of both aft thrusters – DP incident

Case narrative A DP2 cargo vessel was working close to a pipelaying vessel conducting cargo operations in a drift off position.  The current at the time of the event was 2.5 knots which, in conjunction with 10 knots of wind, resulted in an external force of 30 tons acting on the port quarter. The port … Continue reading “Steering motor failure leads to loss of both aft thrusters – DP incident”

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 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”