Alerts iconSeparate problem with two thrusters caused loss of DP

Comments: The bow thruster gave an alarm that pitch was at maximum showing 114% on DP display. Investigation concluded that the full starboard maximum limit command/set point of the bow thruster proportional valve had been adjusted to 70%. During maximum pitch request the valve had to be permanently opened with constant and continuous hydraulic oil … Continue reading “Separate problem with two thrusters caused loss of DP”

Alerts iconUnintentional deselection of a DP control function

Considerations from the above event: This event highlights the possible consequences of deselecting critical DP system buttons. Significant changes to any system should not be made during critical phases of an operation. It was considered highly likely that the DPO was performing multiple tasks when the surge button was unknowingly deselected. Tools are available within … Continue reading “Unintentional deselection of a DP control function”

Alerts iconDifferences between operator stations

Considerations from the above event: Whilst it is not clear what caused this event it does stress the importance of field arrival and set up tests designed to identify operator station differences.

Alerts iconThruster fault

Considerations from the above event: All available means should be used to identify the faulty thruster and then shut it down as deselecting it from the DP system might not be effective. Depending on the time frame, it is recommended that the bulk transfer hose is disconnected prior to engaging manual control of thrusters. It … Continue reading “Thruster fault”

Alerts iconInstability of position reference systems

Considerations from the above event: It is not clear from the report whether it was the differential correction signal or satellite constellation that was  shielded, however operators need to be aware of shielding and shadowing in similar situations. The GNSS constellation screen should be consulted and considered prior to moving closer to a possible obstruction. The … Continue reading “Instability of position reference systems”

Alerts iconThruster unavailability

Considerations from the above event: From the information provided it would appear that the vessel is set up so as to allow for the worst case failure (WCF). Therefore, if it had been deemed necessary, the vessel would have been capable of remaining on automatic DP following the failure of No 2 shaft generator.

Alerts iconPower distribution

Considerations from the above event: With only two diesel generators on line the DPO must be fully aware of the consequences of a worst case failure (WCF).