Year: 2014-2024 Language: English Author: IMCA Genre: Incident Format: PDF Quality: eBook Pages count: 338 Description: Enhance the safety of your DP operations with IMCA's DP incident and event reports. Our platform delivers crucial insights into DP events, incidents, observations, and drill scenarios, providing the industry a free database from which lessons can be learned and shared. Explore 145 DP events and incidents, shared freely with the industry to ensure lessons are learned, as part of our mission to improve performance in offshore delivery.
Contents
DPE 03/24 - Thorough preparation is key With 4 of 8 diesel generators running and connected to a closed ring bus, and 7 of the 8 thrusters selected to DP, a DP equipment class 3 MODU was set up in Green mode whilst on standby. DPE 03/24 - There – but not really there This DP event occurred on a DP equipment class two supply vessel whilst carrying out cargo operations on the starboard side alongside the asset and working at the lee side in the drift-off position. DPE 03/24 - Equipment Class 3, even if you operate as 'Class 2' This case study examines a DP incident on an equipment class 3 multi-purpose vessel while operating in good conditions. DPE 03/24 - Line of sight This case study covers events onboard a DP equipment class 2 vessel whilst holding position in a turbine field, with three position reference systems selected into DP – DGPS, HPR and Fanbeam. DPE 03/24 - DP Drill Scenario DP emergency drill scenarios are included to assist DP vessel management, DPOs / Engineers, and ETOs in conducting DP drills onboard. DPE 03/24 - News in Brief from the DP Committee The information below is a snapshot of the DP Station Keeping Events to date for 2024. DPE 02/24 - Prepare for 2025 solar activity This case study covers events that occurred on the same vessel, eight months apart. DPE 02/24 - Know your vessel capabilities and when to stop! An incident that occurred on an equipment class 2 MODU, during well intervention operations. DPE 02/24 - Duty/not duty, which is the question? With no steering control of the port azimuth thruster, and no other thrusters operational, the heading of the FPU could not be maintained. DPE 02/24 - You’ve got the ASOG, so now you’ve got to follow it This case study examines an incident that occurred on an equipment class 2 MODU, during well intervention operations. DPE 01/24 - Button trouble A Dynamically Positioned vessel experienced a loss of Dynamic Positioning (DP) control while installing cable within a wind farm. DPE 01/24 - The cascade effect A critical incident aboard a DP vessel, five years post-construction, which experienced a significant power management failure. DPE 01/24 - Push / force off This case study examines an incident involving a vessel during cargo operations adjacent to a fixed platform in the North Sea. DPE 01/24 - Closed Bus – PMS failure leads to thrust limitation of all thrusters A malfunction in the I/O module triggered a series of events leading to a loss of vessel position and an emergency disconnect. DPE 01/24 - Action required during a drive off from position Explore our drill scenario on the action required during a drive off from position. DPE 04/23 - Loss of seawater cooling pump redundancy Explore our drill scenario on the action required following the loss of seawater cooling pump redundancy. DPE 04/23 - Thrust incident due to DP system mode change on vessel A construction vessel experienced an insufficient thrust alarm while holding DP position during offshore installation crew transfer operations. DPE 04/23 - Read the room – Port side azimuth thruster shutdown and subsequent partial blackout on DP vessel A series of incidents involving the unexpected shutdown of a port side azimuth thruster and a subsequent partial blackout on a DP vessel. DPE 04/23 - Follow the ASOG – It’s there for a reason A DP vessel was conducting ROV operations beside an oil platform. One of the generators connected to the port switchboard failed and tripped. DPE 04/23 - Position reference problems again! The dangers of recalibrating The dangers of recalibration. Shallow water environments pose specific challenges for hydroacoustic systems. DPE 03/23 - Distraction – Don’t text and navigate The use of phones and other electronic devices while on duty is a major safety hazard in the offshore industry. DPE 03/23 - What have the alarms ever done for me? A DP vessel with a two-way redundant split was in a blow off situation, even though environmental conditions at the time were marginal. DPE 03/23 - Incorrect entry of DP rotation point offsets A vessel was engaged in Driving and ROV work over a live manifold. Due to rising currents the vessel was required to change heading. DPE 03/23 - Important PRS considerations when operating close to an asset that is not rigidly fixed to the seabed In recent years there have been a number of collisions between DP vessels near to a mobile asset, such as a drilling or heavy lift vessel. DPE 03/23 - Loss of main DP system UPS Explore our drill scenario on the action required following the loss of power. DPE 02/23 - Hybrid failure A malfunction in the battery converter system caused circuit breakers to trip. DPE 02/23 - Common Power Supplies – Don’t have all your eggs in one basket Unexpectedly, all six thrusters stopped functioning and were unavailable to DP Control. DPE 02/23 - Human factors – Training for new vessel essential Using the event’s playback log and crew interviews, it was possible to determine the underlying cause – inadvertent movement of the joystick. DPE 02/23 - Loss of all position references Explore our drill scenario on the action required following the loss of PRS data into the DP Control System. DPE 01/23 - Loss of redundant group (e.g. Port SW/BD) Explore our drill scenario on what actions to take following the loss of any one redundant group. DPE 01/23 - Closed bus – Knowing the risks Unidentified failure modes in this vessel design could cause a blackout and disable both automatic recovery and manual control. DPE 01/23 - Vessel degraded capability Commercial pressures maybe at play... Has the vessel been given enough time within the contract to carry out routine maintenance? DPE 01/23 - Open bus saved the day A blackout was traced back to a short circuit within the drive of the aft azimuth thruster, which propagated the fault up to the port switchboard. DPE 02/22 - Maintenance – Not a good idea during DP operations This event occurred as a result of the decision to replace a critical switchboard component while remaining on DP. DPE 02/22 - Importance of units A mix-up between feet and metres leads to DP systems becoming critically unstable. DPE 02/22 - Consequences of not following ASOG A sudden rejection of the vessel’s starboard azimuth thruster by the vessel’s DP system without any warning... it started to drift astern. DPE 02/22 - Relative PRS – a reflection The laser based relative position reference had switched to another target – the reflective tape on the crane hook. DPE 01/22 - Masking of PRS – SIMOPS As a pipelay vessel’s crane hoisted cargo off the deck of the OSV, it was noted that this was interrupting laser and microwave signals. DPE 01/22 - Force off position Owing to deteriorating weather conditions, the DPO observed a total loss of reference systems and critical alarms for breach of the red watch circle. DPE 01/22 - Closed bus common cause The engines on standby auto started... It was apparent that all running engines were slowing down to the point they stopped. DPE 01/22 - Solitons – Be mindful A number of our Members have submitted DP Event Reports which highlighted the phenomena of a sudden loss of position due to Solitons. DPE 01/22 - Auto/manual – human intervention Explore our drill scenario on the consequences of switching essential DP equipment into local/manual whist in auto DP. DPE 04/21 - Consequences of decisions – Heading change left too late Highlighting the need for good operational planning and a detailed and accurate ASOG/WSOG. DPE 04/21 - Configuration – PRS’ hidden common failure A yellow DP alert was activated on a vessel conducting ROV operations in open waters in the North Sea. DPE 04/21 - Swift action saved stress – Know your vessel Familiarity of Key DP Personnel with the vessels Critical DP systems can lead to a successful outcome following a failure. DPE 04/21 - Action error – Was an ASOG in place? This was a simple case of Key DP personnel not being included in the ASOG process. DPE 03/21 - DP2 supply vessel After ‘daily checks’ on the running engine, engineers accidently activated the emergency stop which resulted in an immediate blackout. DPE 03/21 - Recovery from a full black out Explore our drill scenario on the action required following a full black out. DPE 04/21 - Thruster full failure Explore our drill scenario on the action required to recover a vessel into a controllable condition following a thruster failure to full thrust. DPE 03/21 - Worn components create unwanted thrust A worn key within the coupling of the step motor caused unwanted travel of the thruster pitch. The vessel was forced to return to port. DPE 02/21 - DP2 Service Operations Vessel (SOV) The importance of careful selection and planning in the use of position reference sensors and the potential consequences therein. DPE 02/21 - Action required during a drive off from position Explore our drill scenario on the action required during a drive off from position. DPE 02/21 - Computer error caused a DP incident The vessel engaged the support of the DP system manufacturer for investigation on completion of the operation. DPE 01/21 - DP2 cargo vessel This case study demonstrates the risks of undertaking DP operations with degraded or a complete lack of redundancy. DPE 01/21 - Loss of seawater cooling pump redundancy Explore our drill scenario on the action required following the loss of seawater cooling pump redundancy. DPE 01/21 - Human Factors caused a DP incident Checklists were completed but the minimum number of PRS for a DP class 2 operation were not used. DPE 01/21 - Human Factors caused a DP undesired event Heading changes, particularly in strong current, should be completed at low rates of turn with the vessel position independently monitored. DPE 04/20 - Loss of main DP system UPS Explore our scenario on what to do with the loss of any one redundant group. DPE 04/20 - Lack of experience in dealing with environmental conditions caused loss of position This case study demonstrates the importance of fully understanding the vessel's capability and normal operating limits. DPE 04/20 - Inadequate Position Reference Systems caused incident Inadequate risk assessment was not completed and TAM and ASOG were not thoroughly reviewed prior to their approval. DPE 04/20 - Simultaneous activities on the bridge caused a DP incident The experienced DPO was new to the vessel and misinterpreted a 30 degree heading increment as being a 30 degree/min rate of turn. DPE 03/20 - Loss of gyro input causes loss of position A case study which highlights the importance of conducting daily compass checks and completion of all other operational checklists. DPE 03/20 - Incident caused by human factors Complacency or lack of knowledge with DP redundancy was listed as the cause of this incident. DPE 03/20 - Lack of operational planning leads to DP incident The loss of both DGNSS were due to huge superstructure of the installation interfering with satellite signals. DPE 02/20 - DP2 semi-submersible MODU DP incident A vessel experienced a total loss of all online thrusters, leading to the MODU starting to drift. DPE 02/20 - DP Drill Scenario – Loss of redundant group Explore our scenario on what to do with the loss of any one redundant group. DPE 02/20 - Incident caused by software glitch This and similar incidents highlight the need for extensive testing of the software at all stages. DPE 02/20 - Incident with assisted mooring There appears to be no consideration to the external force being applied to the vessel due to the use of mooring lines when in DP. DPE 01/20 - DP undesired event due to online maintenance work Highlighting the benefit of considering mission equipment in risk assessments and that the results of repairs are not always guaranteed. DPE 01/20 - Change of heading leads to DP incident Further investigation revealed the overspeed settings were too tight and had to be increased in accordance with manufacturer’s recommendation. DPE 01/20 - Unreliable component causes an undesired event Though redundancy is a must in DP 2/3 designs, component quality may impact the likelihood of such DP events occurring. DPE 01/20 - Vessel collision with wind turbine How a DP vessel hit a wind turbine, in an update previously shared by the Marine Safety Forum. DPE 04/19 - Vessel rotation leads to loss of position A DP2 ROV support vessel was working close to a metrological (met) mast within a wind farm. DPE 04/19 - Steering motor failure leads to loss of both aft thrusters The investigation revealed a gradual but significant earth fault within a consumer supplied by the Port 440V general distribution panel. DPE 04/19 - Unreliable position reference systems leads to incident The end-effect was that the deviation from the set point in surge and sway increased with each oscillation. DPE 04/19 - Pipe leak leads to loss of all thrusters Whilst pressurising the fire main for helicopter operations, a gasket failure occurred on the pipework valve under the engine room floor. DPE 03/19 - DP3 drillship switchboard blacked out A DP3 6th generation drillship was set up on automatic DP engaged in plug and abandonment operations in field. DPE 03/19 - Operating outside DP equipment class 2 requirements There were not enough PRSs or sensors online to meet requirements for equipment class 2 DP operations. DPE 03/19 - Failure of DP UPS It was noticed that there was a strong burning smell from the UPS which was still powered up from the ship's supply but was in internal bypass. DPE 03/19 - Accidental breaker trip The watch keeping engineer lost his balance and his hand made contact with the shaft generator breaker push button. DPE 03/19 - Mix of absolute and relative position reference systems Movement towards the drill ship may have been caused by a combination of PRS degradation and interaction from the drill ship’s thrusters. DPE 02/19 - Maintenance during DP operations leads to an undesired event The duty Engineer did not inform Bridge/DPOs of maintenance on the header tank of the stern thruster. DPE 02/19 - Leaking cooling water pump leads to an undesired event The actions taken demonstrate a good example of safe practice during DP operations. DPE 02/19 - Unfamiliarity with DP system leads to an undesired event Vessel specific familiarisation programmes and operation manuals should make allowances for crew members not being familiar with systems. DPE 01/19 - Loss of tunnel thruster Voltage instability was caused by a spike load on an unrelated circuit breaker on the switchboard which tripped the thruster hydraulic pump. DPE 01/19 - Specialised pipe laying DP mode A process is in place to go through all software releases which have this function, and update affected vessels during their next service visit. DPE 01/19 - Planned investigation resulted in DP incident There was a total loss of network communication affecting many field stations together with loss of DP communication to all thrusters. DPE 01/19 - Loss of one redundant group The power management system worked as expected, investigation found a poor connection to the temperature sensor causing fluctuations. DPE 04/18 - Isolation of backup supplies to DP critical equipment A DP 2 vessel was engaged in open water ROV operations with both ROVs and cranes in the water. DPE 04/18 - Position reference systems – A timely reminder The DP committee has identified a trend of DP station keeping events relating to the incorrect use or selection of PRSs. DPE 04/18 - Inadequate shallow water lay-up reactivation procedures The heat exchange system was poorly designed, without redundancy for half the switchboard. This was compounded by turbidity and silt in the cooling... DPE 04/18 - Use of third-party equipment leads to DP undesired event DP equipment should not be repaired and brought online after repair without being suitably tested. DPE 03/18 - Switching to manual mode caused loss of position A DP2 platform supply vessel was set up on auto DP engaged in cargo operations inside the 500m zone of a fixed platform. DPE 03/18 - Switching from auto DP to IJS mode caused loss of control A vessel collided with the working platform on a wind turbine transition piece. The incident occurred during worsening weather conditions. DPE 03/18 - DPO certification deception A DPO was appointed to a vessel via an agent. His experience and certification were not as previously communicated. DPE 03/18 - Load sharing imbalance caused loss of position A DP2 pipelay vessel was set up on auto DP engaged in pipelay operations, inside the 500m zone of a fixed platform. DPE 02/18 - Electrical fault causes loss of thruster One of the three frequency converters on the port azimuth thruster was found to be burnt out. DPE 02/18 - DP controller problems Good practice is to acknowledge and investigate the cause of alarms, even if they are intermittent, otherwise issues can be missed. DPE 02/18 - Routine maintenance leads to loss of thruster When obtaining an oil sample, the valve was opened fully, reducing the pressure to the pressure switch. DPE 02/18 - Good practice following system self-test alarm The decision was made to replace a serial interface module with a new one, dive control was requested to recover the bell whilst this took place. DPE 02/18 - Leak in fuel supply line causes engine to shut down A fuel leak developed in a corroded supply pipe to the port main engine. This caused air to be drawn into the system and the engine to shut down. DPE 01/18 - Unintentional selection of manual mode The incident highlights the importance of vessel operators risk assessing the DP control station and taking appropriate action as necessary. DPE 01/18 - Unintentional deactivation of the DP system Operators are reminded of the importance of DP mode selection buttons, and should assess if the system is susceptible to unintentional deactivation. DPE 01/18 - Lack of maintenance caused a problem involving the bus tie breaker The maintenance requirements of some major DP components were not included in the vessel's computerised Planned Maintenance System. DPE 01/18 - An unassociated failure of one part of a gyro system affected the DP system The systems connected to the DP system need to be fully understood to avoid failures in one connected part affecting the whole DP system. DPE 01/18 - A retrofitted capacitor caused a bow thruster frequency drive to overheat Vessel operators should ensure that a robust management of change procedure is followed. DPE 04/17 - Temporary connection to DP system caused short circuit Connection of any temporary system should be part of a change management plan and risk assessed. DPE 04/17 - Check of the UPS led to loss of power Maintenance needs to be carefully managed during DP operations and avoided whilst the vessel is operating on DP. DPE 04/17 - Lack of planning and situational awareness In such critical subsea operations both DPOs should have been 100% focused on current operations. DPE 04/17 - Thruster command and feedback differences It was concluded that the fault had to be in the output control loop, and it was decided to replace items with spares held on board. DPE 04/17 - Common mode failure of DGNSS With both systems suffering issues at the same time, it pointed towards a common factor with the likely cause signal interference. DPE 03/17 - Both DP operating stations stopped communication The report suggests the possibility that the vessel returned to operations without sufficient testing to find the root cause of the problem. DPE 03/17 - High voltage breaker trip One of the wires from a breaker had chaffed on the inside of the box resulting in a short and evidence of arcing to ground. DPE 03/17 - Following a track on DP causes power issues Chosen settings of gain, corridor limits, rate of turn and speed of the vessel could all have contributed. DPE 02/17 - Bow thruster fault compromises redundancy After an event such as this, planned maintenance routines should be checked to ensure they are adequate. DPE 02/17 - Fire in the engine room A fire on any vessel is serious, and in the engine room of a DP vessel engaged in operations it should be considered very serious. DPE 02/17 - Bad connection causes loss of DGNSS There was water ingress at the L-Band connector to the antenna on the vessel's mast. DPE 02/17 - Loss of DGNSS resulted in ROV being recovered When considering redundancy of satellite systems do not just consider the manufacturer, but also correction type and transmission method. DPE 02/17 - Rip tide presents problems A degraded performance was caused by a rip tide. All DP checks were carried out, and the system's performance was monitored for 20 minutes. DPE 01/17 - DP event investigation and testing inside the 500m zone The vessel should have proceeded out of the 500m zone to a safe area prior to investigating the fault and conducting tests. DPE 01/17 - Load sharing imbalance causes loss of position The vessel’s DP operations manual and well specific operating guidelines (WSOG) must be questioned. DPE 01/17 - Inadequate communication and planning causes fouled thruster They did not realise they were isolating the opposite thruster and consequently the thruster closest to the lay chute was still running. DPE 01/17 - UPS failure causes partial blackout The failure of UPS No.1 and subsequent failure of the other equipment should have resulted in a DP yellow alert. DPE 01/17 - Cooling pipe leak threatens main switchboard A failure of a plug on a seawater cooling pipe for the AC compressors resulted in flooding in the incinerator room. DPE 04/16 - Non-routine lift leads to thruster incapacity The lift had not been properly planned for the object being lifted – there was a failure to recognise that the mattress was not a routine lift. DPE 04/16 - Pipelaying equipment short circuit causes thrusters to trip The ROV was restricted to the TMS until the vessel was confident of the cause of the thrusters’ unexpectedly stopping. DPE 04/16 - Alteration of course with COR offset causes loss of power Investigation as to why the emergency generator did not connect to the bus bar, and therefore aid blackout recovery, was ongoing. DPE 04/16 - DP trial leads to partial blackout The 230v supply breaker was open and the two uninterruptible power supply (UPS) batteries completely discharged. DPE 04/16 - Procedures for ploughing using DP discussed The DPO was conducting too many concurrent tasks and they did not sufficiently monitor the vessel's speed. DPE 03/16 - Thruster entanglement during shuttle tanker operations Operations were conducted according to procedure which need to be modified to limit the rope in the water to prevent entanglement. DPE 03/16 - Incorrect wiring causes loss of all propulsion The main cause of the incident was found to be the improper wiring of the main and backup power supplies. DPE 03/16 - Fuel oil filter change leads to generator failure The vessel was five years old, and a design fault was not captured in the FMEA or annual DP trials. DPE 03/16 - Bow thruster tripped due to lack of power The seat for the stop solenoid on the engine was damaged causing a slight air leak causing a reduction in main engine rpm. DPE 03/16 - Separate problem with two thrusters caused loss of DP The seat for the stop solenoid on the engine was damaged causing a slight air leak causing a reduction in main engine rpm. DPE 02/16 - Differences between operator stations Stressing the importance of field arrival and set up tests designed to identify operator station differences. DPE 02/16 - Unintentional deselection of a DP control function Vessel operators should note that this type of event continues to occur and might consider whether additional barriers should be put in place. DPE 02/16 - Thruster failure and unavailability The crew followed good procedures by suspending operations in a controlled manner ready for investigation. DPE 02/16 - Thruster fault 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. DPE 02/16 - Instability of position reference systems Operators need to be aware of shielding and shadowing in similar situations. DPE 01/16 - Thruster unavailability The DP vessel was set up so as to allow for the worst case failure (WCF). DPE 01/16 - Power distribution With only two diesel generators online, the DPO must be fully aware of the consequences of a worst case failure (WCF). DPE 01/16 - Change of a vessel centre of rotation If wind sensors are being shielded, this could have a greater influence on the vessel model when the centre of rotation is changed. DPE 03/15 - Collision with rig A DP2 classed vessel that lost position and made contact with a fixed drilling rig, in an update previously shared by the Marine Safety Forum. DPE 02/15 - DP management – Dealing with the unexpected One thruster within a group was found to be thrusting in a direction 180° opposite to that indicated on the DP display. DPE 01/14 - Loss of three gyros on a DP3 drillship Three DP System connected gyros heading froze within five minutes of time. With all three gyros out of service, drillship’s DP Model took over.
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DP Incidents Collection
Language: English
Author: IMCA
Genre: Incident
Format: PDF
Quality: eBook
Pages count: 338
Description: Enhance the safety of your DP operations with IMCA's DP incident and event reports.
Our platform delivers crucial insights into DP events, incidents, observations, and drill scenarios, providing the industry a free database from which lessons can be learned and shared.
Explore 145 DP events and incidents, shared freely with the industry to ensure lessons are learned, as part of our mission to improve performance in offshore delivery.
Contents
DPE 03/24 - Thorough preparation is keyWith 4 of 8 diesel generators running and connected to a closed ring bus, and 7 of the 8 thrusters selected to DP, a DP equipment class 3 MODU was set up in Green mode whilst on standby.
DPE 03/24 - There – but not really there
This DP event occurred on a DP equipment class two supply vessel whilst carrying out cargo operations on the starboard side alongside the asset and working at the lee side in the drift-off position.
DPE 03/24 - Equipment Class 3, even if you operate as 'Class 2'
This case study examines a DP incident on an equipment class 3 multi-purpose vessel while operating in good conditions.
DPE 03/24 - Line of sight
This case study covers events onboard a DP equipment class 2 vessel whilst holding position in a turbine field, with three position reference systems selected into DP – DGPS, HPR and Fanbeam.
DPE 03/24 - DP Drill Scenario
DP emergency drill scenarios are included to assist DP vessel management, DPOs / Engineers, and ETOs in conducting DP drills onboard.
DPE 03/24 - News in Brief from the DP Committee
The information below is a snapshot of the DP Station Keeping Events to date for 2024.
DPE 02/24 - Prepare for 2025 solar activity
This case study covers events that occurred on the same vessel, eight months apart.
DPE 02/24 - Know your vessel capabilities and when to stop!
An incident that occurred on an equipment class 2 MODU, during well intervention operations.
DPE 02/24 - Duty/not duty, which is the question?
With no steering control of the port azimuth thruster, and no other thrusters operational, the heading of the FPU could not be maintained.
DPE 02/24 - You’ve got the ASOG, so now you’ve got to follow it
This case study examines an incident that occurred on an equipment class 2 MODU, during well intervention operations.
DPE 01/24 - Button trouble
A Dynamically Positioned vessel experienced a loss of Dynamic Positioning (DP) control while installing cable within a wind farm.
DPE 01/24 - The cascade effect
A critical incident aboard a DP vessel, five years post-construction, which experienced a significant power management failure.
DPE 01/24 - Push / force off
This case study examines an incident involving a vessel during cargo operations adjacent to a fixed platform in the North Sea.
DPE 01/24 - Closed Bus – PMS failure leads to thrust limitation of all thrusters
A malfunction in the I/O module triggered a series of events leading to a loss of vessel position and an emergency disconnect.
DPE 01/24 - Action required during a drive off from position
Explore our drill scenario on the action required during a drive off from position.
DPE 04/23 - Loss of seawater cooling pump redundancy
Explore our drill scenario on the action required following the loss of seawater cooling pump redundancy.
DPE 04/23 - Thrust incident due to DP system mode change on vessel
A construction vessel experienced an insufficient thrust alarm while holding DP position during offshore installation crew transfer operations.
DPE 04/23 - Read the room – Port side azimuth thruster shutdown and subsequent partial blackout on DP vessel
A series of incidents involving the unexpected shutdown of a port side azimuth thruster and a subsequent partial blackout on a DP vessel.
DPE 04/23 - Follow the ASOG – It’s there for a reason
A DP vessel was conducting ROV operations beside an oil platform. One of the generators connected to the port switchboard failed and tripped.
DPE 04/23 - Position reference problems again! The dangers of recalibrating
The dangers of recalibration. Shallow water environments pose specific challenges for hydroacoustic systems.
DPE 03/23 - Distraction – Don’t text and navigate
The use of phones and other electronic devices while on duty is a major safety hazard in the offshore industry.
DPE 03/23 - What have the alarms ever done for me?
A DP vessel with a two-way redundant split was in a blow off situation, even though environmental conditions at the time were marginal.
DPE 03/23 - Incorrect entry of DP rotation point offsets
A vessel was engaged in Driving and ROV work over a live manifold. Due to rising currents the vessel was required to change heading.
DPE 03/23 - Important PRS considerations when operating close to an asset that is not rigidly fixed to the seabed
In recent years there have been a number of collisions between DP vessels near to a mobile asset, such as a drilling or heavy lift vessel.
DPE 03/23 - Loss of main DP system UPS
Explore our drill scenario on the action required following the loss of power.
DPE 02/23 - Hybrid failure
A malfunction in the battery converter system caused circuit breakers to trip.
DPE 02/23 - Common Power Supplies – Don’t have all your eggs in one basket
Unexpectedly, all six thrusters stopped functioning and were unavailable to DP Control.
DPE 02/23 - Human factors – Training for new vessel essential
Using the event’s playback log and crew interviews, it was possible to determine the underlying cause – inadvertent movement of the joystick.
DPE 02/23 - Loss of all position references
Explore our drill scenario on the action required following the loss of PRS data into the DP Control System.
DPE 01/23 - Loss of redundant group (e.g. Port SW/BD)
Explore our drill scenario on what actions to take following the loss of any one redundant group.
DPE 01/23 - Closed bus – Knowing the risks
Unidentified failure modes in this vessel design could cause a blackout and disable both automatic recovery and manual control.
DPE 01/23 - Vessel degraded capability
Commercial pressures maybe at play... Has the vessel been given enough time within the contract to carry out routine maintenance?
DPE 01/23 - Open bus saved the day
A blackout was traced back to a short circuit within the drive of the aft azimuth thruster, which propagated the fault up to the port switchboard.
DPE 02/22 - Maintenance – Not a good idea during DP operations
This event occurred as a result of the decision to replace a critical switchboard component while remaining on DP.
DPE 02/22 - Importance of units
A mix-up between feet and metres leads to DP systems becoming critically unstable.
DPE 02/22 - Consequences of not following ASOG
A sudden rejection of the vessel’s starboard azimuth thruster by the vessel’s DP system without any warning... it started to drift astern.
DPE 02/22 - Relative PRS – a reflection
The laser based relative position reference had switched to another target – the reflective tape on the crane hook.
DPE 01/22 - Masking of PRS – SIMOPS
As a pipelay vessel’s crane hoisted cargo off the deck of the OSV, it was noted that this was interrupting laser and microwave signals.
DPE 01/22 - Force off position
Owing to deteriorating weather conditions, the DPO observed a total loss of reference systems and critical alarms for breach of the red watch circle.
DPE 01/22 - Closed bus common cause
The engines on standby auto started... It was apparent that all running engines were slowing down to the point they stopped.
DPE 01/22 - Solitons – Be mindful
A number of our Members have submitted DP Event Reports which highlighted the phenomena of a sudden loss of position due to Solitons.
DPE 01/22 - Auto/manual – human intervention
Explore our drill scenario on the consequences of switching essential DP equipment into local/manual whist in auto DP.
DPE 04/21 - Consequences of decisions – Heading change left too late
Highlighting the need for good operational planning and a detailed and accurate ASOG/WSOG.
DPE 04/21 - Configuration – PRS’ hidden common failure
A yellow DP alert was activated on a vessel conducting ROV operations in open waters in the North Sea.
DPE 04/21 - Swift action saved stress – Know your vessel
Familiarity of Key DP Personnel with the vessels Critical DP systems can lead to a successful outcome following a failure.
DPE 04/21 - Action error – Was an ASOG in place?
This was a simple case of Key DP personnel not being included in the ASOG process.
DPE 03/21 - DP2 supply vessel
After ‘daily checks’ on the running engine, engineers accidently activated the emergency stop which resulted in an immediate blackout.
DPE 03/21 - Recovery from a full black out
Explore our drill scenario on the action required following a full black out.
DPE 04/21 - Thruster full failure
Explore our drill scenario on the action required to recover a vessel into a controllable condition following a thruster failure to full thrust.
DPE 03/21 - Worn components create unwanted thrust
A worn key within the coupling of the step motor caused unwanted travel of the thruster pitch. The vessel was forced to return to port.
DPE 02/21 - DP2 Service Operations Vessel (SOV)
The importance of careful selection and planning in the use of position reference sensors and the potential consequences therein.
DPE 02/21 - Action required during a drive off from position
Explore our drill scenario on the action required during a drive off from position.
DPE 02/21 - Computer error caused a DP incident
The vessel engaged the support of the DP system manufacturer for investigation on completion of the operation.
DPE 01/21 - DP2 cargo vessel
This case study demonstrates the risks of undertaking DP operations with degraded or a complete lack of redundancy.
DPE 01/21 - Loss of seawater cooling pump redundancy
Explore our drill scenario on the action required following the loss of seawater cooling pump redundancy.
DPE 01/21 - Human Factors caused a DP incident
Checklists were completed but the minimum number of PRS for a DP class 2 operation were not used.
DPE 01/21 - Human Factors caused a DP undesired event
Heading changes, particularly in strong current, should be completed at low rates of turn with the vessel position independently monitored.
DPE 04/20 - Loss of main DP system UPS
Explore our scenario on what to do with the loss of any one redundant group.
DPE 04/20 - Lack of experience in dealing with environmental conditions caused loss of position
This case study demonstrates the importance of fully understanding the vessel's capability and normal operating limits.
DPE 04/20 - Inadequate Position Reference Systems caused incident
Inadequate risk assessment was not completed and TAM and ASOG were not thoroughly reviewed prior to their approval.
DPE 04/20 - Simultaneous activities on the bridge caused a DP incident
The experienced DPO was new to the vessel and misinterpreted a 30 degree heading increment as being a 30 degree/min rate of turn.
DPE 03/20 - Loss of gyro input causes loss of position
A case study which highlights the importance of conducting daily compass checks and completion of all other operational checklists.
DPE 03/20 - Incident caused by human factors
Complacency or lack of knowledge with DP redundancy was listed as the cause of this incident.
DPE 03/20 - Lack of operational planning leads to DP incident
The loss of both DGNSS were due to huge superstructure of the installation interfering with satellite signals.
DPE 02/20 - DP2 semi-submersible MODU DP incident
A vessel experienced a total loss of all online thrusters, leading to the MODU starting to drift.
DPE 02/20 - DP Drill Scenario – Loss of redundant group
Explore our scenario on what to do with the loss of any one redundant group.
DPE 02/20 - Incident caused by software glitch
This and similar incidents highlight the need for extensive testing of the software at all stages.
DPE 02/20 - Incident with assisted mooring
There appears to be no consideration to the external force being applied to the vessel due to the use of mooring lines when in DP.
DPE 01/20 - DP undesired event due to online maintenance work
Highlighting the benefit of considering mission equipment in risk assessments and that the results of repairs are not always guaranteed.
DPE 01/20 - Change of heading leads to DP incident
Further investigation revealed the overspeed settings were too tight and had to be increased in accordance with manufacturer’s recommendation.
DPE 01/20 - Unreliable component causes an undesired event
Though redundancy is a must in DP 2/3 designs, component quality may impact the likelihood of such DP events occurring.
DPE 01/20 - Vessel collision with wind turbine
How a DP vessel hit a wind turbine, in an update previously shared by the Marine Safety Forum.
DPE 04/19 - Vessel rotation leads to loss of position
A DP2 ROV support vessel was working close to a metrological (met) mast within a wind farm.
DPE 04/19 - Steering motor failure leads to loss of both aft thrusters
The investigation revealed a gradual but significant earth fault within a consumer supplied by the Port 440V general distribution panel.
DPE 04/19 - Unreliable position reference systems leads to incident
The end-effect was that the deviation from the set point in surge and sway increased with each oscillation.
DPE 04/19 - Pipe leak leads to loss of all thrusters
Whilst pressurising the fire main for helicopter operations, a gasket failure occurred on the pipework valve under the engine room floor.
DPE 03/19 - DP3 drillship switchboard blacked out
A DP3 6th generation drillship was set up on automatic DP engaged in plug and abandonment operations in field.
DPE 03/19 - Operating outside DP equipment class 2 requirements
There were not enough PRSs or sensors online to meet requirements for equipment class 2 DP operations.
DPE 03/19 - Failure of DP UPS
It was noticed that there was a strong burning smell from the UPS which was still powered up from the ship's supply but was in internal bypass.
DPE 03/19 - Accidental breaker trip
The watch keeping engineer lost his balance and his hand made contact with the shaft generator breaker push button.
DPE 03/19 - Mix of absolute and relative position reference systems
Movement towards the drill ship may have been caused by a combination of PRS degradation and interaction from the drill ship’s thrusters.
DPE 02/19 - Maintenance during DP operations leads to an undesired event
The duty Engineer did not inform Bridge/DPOs of maintenance on the header tank of the stern thruster.
DPE 02/19 - Leaking cooling water pump leads to an undesired event
The actions taken demonstrate a good example of safe practice during DP operations.
DPE 02/19 - Unfamiliarity with DP system leads to an undesired event
Vessel specific familiarisation programmes and operation manuals should make allowances for crew members not being familiar with systems.
DPE 01/19 - Loss of tunnel thruster
Voltage instability was caused by a spike load on an unrelated circuit breaker on the switchboard which tripped the thruster hydraulic pump.
DPE 01/19 - Specialised pipe laying DP mode
A process is in place to go through all software releases which have this function, and update affected vessels during their next service visit.
DPE 01/19 - Planned investigation resulted in DP incident
There was a total loss of network communication affecting many field stations together with loss of DP communication to all thrusters.
DPE 01/19 - Loss of one redundant group
The power management system worked as expected, investigation found a poor connection to the temperature sensor causing fluctuations.
DPE 04/18 - Isolation of backup supplies to DP critical equipment
A DP 2 vessel was engaged in open water ROV operations with both ROVs and cranes in the water.
DPE 04/18 - Position reference systems – A timely reminder
The DP committee has identified a trend of DP station keeping events relating to the incorrect use or selection of PRSs.
DPE 04/18 - Inadequate shallow water lay-up reactivation procedures
The heat exchange system was poorly designed, without redundancy for half the switchboard. This was compounded by turbidity and silt in the cooling...
DPE 04/18 - Use of third-party equipment leads to DP undesired event
DP equipment should not be repaired and brought online after repair without being suitably tested.
DPE 03/18 - Switching to manual mode caused loss of position
A DP2 platform supply vessel was set up on auto DP engaged in cargo operations inside the 500m zone of a fixed platform.
DPE 03/18 - Switching from auto DP to IJS mode caused loss of control
A vessel collided with the working platform on a wind turbine transition piece. The incident occurred during worsening weather conditions.
DPE 03/18 - DPO certification deception
A DPO was appointed to a vessel via an agent. His experience and certification were not as previously communicated.
DPE 03/18 - Load sharing imbalance caused loss of position
A DP2 pipelay vessel was set up on auto DP engaged in pipelay operations, inside the 500m zone of a fixed platform.
DPE 02/18 - Electrical fault causes loss of thruster
One of the three frequency converters on the port azimuth thruster was found to be burnt out.
DPE 02/18 - DP controller problems
Good practice is to acknowledge and investigate the cause of alarms, even if they are intermittent, otherwise issues can be missed.
DPE 02/18 - Routine maintenance leads to loss of thruster
When obtaining an oil sample, the valve was opened fully, reducing the pressure to the pressure switch.
DPE 02/18 - Good practice following system self-test alarm
The decision was made to replace a serial interface module with a new one, dive control was requested to recover the bell whilst this took place.
DPE 02/18 - Leak in fuel supply line causes engine to shut down
A fuel leak developed in a corroded supply pipe to the port main engine. This caused air to be drawn into the system and the engine to shut down.
DPE 01/18 - Unintentional selection of manual mode
The incident highlights the importance of vessel operators risk assessing the DP control station and taking appropriate action as necessary.
DPE 01/18 - Unintentional deactivation of the DP system
Operators are reminded of the importance of DP mode selection buttons, and should assess if the system is susceptible to unintentional deactivation.
DPE 01/18 - Lack of maintenance caused a problem involving the bus tie breaker
The maintenance requirements of some major DP components were not included in the vessel's computerised Planned Maintenance System.
DPE 01/18 - An unassociated failure of one part of a gyro system affected the DP system
The systems connected to the DP system need to be fully understood to avoid failures in one connected part affecting the whole DP system.
DPE 01/18 - A retrofitted capacitor caused a bow thruster frequency drive to overheat
Vessel operators should ensure that a robust management of change procedure is followed.
DPE 04/17 - Temporary connection to DP system caused short circuit
Connection of any temporary system should be part of a change management plan and risk assessed.
DPE 04/17 - Check of the UPS led to loss of power
Maintenance needs to be carefully managed during DP operations and avoided whilst the vessel is operating on DP.
DPE 04/17 - Lack of planning and situational awareness
In such critical subsea operations both DPOs should have been 100% focused on current operations.
DPE 04/17 - Thruster command and feedback differences
It was concluded that the fault had to be in the output control loop, and it was decided to replace items with spares held on board.
DPE 04/17 - Common mode failure of DGNSS
With both systems suffering issues at the same time, it pointed towards a common factor with the likely cause signal interference.
DPE 03/17 - Both DP operating stations stopped communication
The report suggests the possibility that the vessel returned to operations without sufficient testing to find the root cause of the problem.
DPE 03/17 - High voltage breaker trip
One of the wires from a breaker had chaffed on the inside of the box resulting in a short and evidence of arcing to ground.
DPE 03/17 - Following a track on DP causes power issues
Chosen settings of gain, corridor limits, rate of turn and speed of the vessel could all have contributed.
DPE 02/17 - Bow thruster fault compromises redundancy
After an event such as this, planned maintenance routines should be checked to ensure they are adequate.
DPE 02/17 - Fire in the engine room
A fire on any vessel is serious, and in the engine room of a DP vessel engaged in operations it should be considered very serious.
DPE 02/17 - Bad connection causes loss of DGNSS
There was water ingress at the L-Band connector to the antenna on the vessel's mast.
DPE 02/17 - Loss of DGNSS resulted in ROV being recovered
When considering redundancy of satellite systems do not just consider the manufacturer, but also correction type and transmission method.
DPE 02/17 - Rip tide presents problems
A degraded performance was caused by a rip tide. All DP checks were carried out, and the system's performance was monitored for 20 minutes.
DPE 01/17 - DP event investigation and testing inside the 500m zone
The vessel should have proceeded out of the 500m zone to a safe area prior to investigating the fault and conducting tests.
DPE 01/17 - Load sharing imbalance causes loss of position
The vessel’s DP operations manual and well specific operating guidelines (WSOG) must be questioned.
DPE 01/17 - Inadequate communication and planning causes fouled thruster
They did not realise they were isolating the opposite thruster and consequently the thruster closest to the lay chute was still running.
DPE 01/17 - UPS failure causes partial blackout
The failure of UPS No.1 and subsequent failure of the other equipment should have resulted in a DP yellow alert.
DPE 01/17 - Cooling pipe leak threatens main switchboard
A failure of a plug on a seawater cooling pipe for the AC compressors resulted in flooding in the incinerator room.
DPE 04/16 - Non-routine lift leads to thruster incapacity
The lift had not been properly planned for the object being lifted – there was a failure to recognise that the mattress was not a routine lift.
DPE 04/16 - Pipelaying equipment short circuit causes thrusters to trip
The ROV was restricted to the TMS until the vessel was confident of the cause of the thrusters’ unexpectedly stopping.
DPE 04/16 - Alteration of course with COR offset causes loss of power
Investigation as to why the emergency generator did not connect to the bus bar, and therefore aid blackout recovery, was ongoing.
DPE 04/16 - DP trial leads to partial blackout
The 230v supply breaker was open and the two uninterruptible power supply (UPS) batteries completely discharged.
DPE 04/16 - Procedures for ploughing using DP discussed
The DPO was conducting too many concurrent tasks and they did not sufficiently monitor the vessel's speed.
DPE 03/16 - Thruster entanglement during shuttle tanker operations
Operations were conducted according to procedure which need to be modified to limit the rope in the water to prevent entanglement.
DPE 03/16 - Incorrect wiring causes loss of all propulsion
The main cause of the incident was found to be the improper wiring of the main and backup power supplies.
DPE 03/16 - Fuel oil filter change leads to generator failure
The vessel was five years old, and a design fault was not captured in the FMEA or annual DP trials.
DPE 03/16 - Bow thruster tripped due to lack of power
The seat for the stop solenoid on the engine was damaged causing a slight air leak causing a reduction in main engine rpm.
DPE 03/16 - Separate problem with two thrusters caused loss of DP
The seat for the stop solenoid on the engine was damaged causing a slight air leak causing a reduction in main engine rpm.
DPE 02/16 - Differences between operator stations
Stressing the importance of field arrival and set up tests designed to identify operator station differences.
DPE 02/16 - Unintentional deselection of a DP control function
Vessel operators should note that this type of event continues to occur and might consider whether additional barriers should be put in place.
DPE 02/16 - Thruster failure and unavailability
The crew followed good procedures by suspending operations in a controlled manner ready for investigation.
DPE 02/16 - Thruster fault
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.
DPE 02/16 - Instability of position reference systems
Operators need to be aware of shielding and shadowing in similar situations.
DPE 01/16 - Thruster unavailability
The DP vessel was set up so as to allow for the worst case failure (WCF).
DPE 01/16 - Power distribution
With only two diesel generators online, the DPO must be fully aware of the consequences of a worst case failure (WCF).
DPE 01/16 - Change of a vessel centre of rotation
If wind sensors are being shielded, this could have a greater influence on the vessel model when the centre of rotation is changed.
DPE 03/15 - Collision with rig
A DP2 classed vessel that lost position and made contact with a fixed drilling rig, in an update previously shared by the Marine Safety Forum.
DPE 02/15 - DP management – Dealing with the unexpected
One thruster within a group was found to be thrusting in a direction 180° opposite to that indicated on the DP display.
DPE 01/14 - Loss of three gyros on a DP3 drillship
Three DP System connected gyros heading froze within five minutes of time. With all three gyros out of service, drillship’s DP Model took over.
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DP Incidents Collection - IMCA [2014-2024]
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