Topic
Loss of Station Keeping
Unintended departure from required vessel position.
Documents
- 202518 Dec
BSEE: Anchor-handling causes damage to subsea equipment and triggers gas release
An anchor wire snagged a subsea well during recovery by a dive support vessel, subsequently detaching an annulus valve and releasing gas. The flash summarises BSEE findings on inadequate planning, coordination and emergency preparation, with recommendations for consideration covering readiness checks, change management, communication and current-aware anchor-handling plans.
- 20254 Dec
BSEE Safety Alert - 510 - Blackout and Weather-Driven EDS Incidents Underscore the Need for Stronger Operational Discipline
This alert examines two emergency disconnects on a dynamically positioned drillship: a blackout during damper maintenance involving the wrong control panel, and loss of position during severe weather. Both resulted in pollution. Recommendations invite operators to consider clearer controls, competence verification, closed-loop communication and proactive weather-related operational adjustments.
- 202517 Sep
Handling alarms on the bridge – a DP incident
During scrap-metal recovery, a DPO inadvertently selected an adjacent command while trying to silence an alarm, leaving the vessel in manual mode with 10 metres of uncontrolled movement. The flash examines alarm overload, a frozen panel and inconsistent silencing arrangements, emphasising interface design, procedural reinforcement and openness within a no-blame culture.
- 202514 May
Foundering of the yacht Bayesian with loss of 7 lives
This interim investigation examines Bayesian’s capsize and foundering near Porticello, Italy, with seven fatalities. It describes abandonment and rescue, analyses storm conditions, and models stability and windage with the centreboard raised. Findings rely on limited verified evidence and an assumed loss condition, pending examination of the salvaged wreck.
- 202516 Apr
UK HSE: Risk of collision with offshore installations from attendant vessels
This safety flash summarises five vessel collisions with offshore installations and wind turbines reported in an HSE notice. Cases examine distracted watchkeeping, restricted visibility, dynamic positioning limitations and bridge communication. Recommendations address watchkeeping procedures, bridge resource management, alarm operation, attendant-vessel monitoring and consideration of sailing audits.
- 20257 Mar
BSEE Safety Alert 497 - Weather Creates Sudden and Unpredictable Risks
BSEE describes a wave-related femur injury on a deepwater drilling rig and further adverse-weather incidents involving personnel transfers, vessel collision and lost dynamic positioning capability. Recommendations address weather-dependent access restrictions, communication of unusual hazards, suspension of non-critical work and assessment of medical evacuation capabilities during adverse conditions.
- 2025Mar
Risk of collision with offshore installations from attendant vessels
HSE safety notice examines five vessel collisions involving offshore installations and wind turbines. Cases highlight distracted watchkeeping, lost situational awareness, environmental conditions and poor bridge communication. Recommended reviews cover watchkeeping instructions, bridge resource management, navigational alarms and vessel monitoring, with consideration of sailing audits to identify operational bad practice.
- 202520 Feb
Crew transfer vessel (CTV) drifts onto turbine tower
After a successful personnel transfer, a crew transfer vessel drifted into a turbine structure at 0.5 knots while crew completed administrative tasks. No injuries occurred; paintwork damage was noted. The flash examines situational awareness, bridge instrumentation and inappropriate transfer authorisation, emphasising lookout and consideration of vessel position and conditions.
- 202425 Sep
Man overboard during motion compensated gangway transfer
An offshore worker fell overboard from a height of one metre when a manually station-kept vessel drifted off and its motion-compensated gangway disconnected. His life-jacket failed to inflate, but he was recovered within 22 seconds. The flash addresses gangway emergency procedures, drift-off familiarisation, flotation-device checks and safety induction.
- 20244 Sep
MODU mooring line failure
This safety flash describes failure of one of eight mooring lines securing a MODU during drilling. The unit moved approximately 12 m and tilted 2–3 degrees before thrusters and ballasting restored its position. The account refers to Marine Safety Forum Safety Flash 12-31.
- 20243 Sep
Near miss: lift bag released unintentionally from crane hook
A lift bag detached from a crane hook at the splash-zone during a saturation dive and floated near a vessel operating in DP mode. Incorrect folding and attachment allowed buoyancy to defeat the self-locking latch. No harm occurred. The flash recommends risk assessment, rigging checks and a tool basket.
- 202418 Jun
Swinging load after loss of position
During backloading of an empty refrigerated container, a Pipe Supply Vessel lost position and the load swung uncontrollably. Wind gusts, thruster wash and loss of a thruster DP signal contributed. Nobody was harmed and equipment was undamaged. Lessons address vessel-to-vessel operational limits, cargo-lifting procedures and adherence to ASOGs.
- 20248 Apr
MODU Unlatched from Well
A moored semi-submersible drilling unit without dynamic positioning assist disconnected from its well and moved towards survival draft as storm conditions increased. Over three days, it lost four of eight mooring lines and drifted approximately 800 metres. Non-essential personnel were removed after the fourth line was lost.
- 202314 Aug
MODU mooring systems in cyclonic conditions information paper
This information paper examines cyclonic mooring risks for mobile offshore drilling units. It discusses site-specific design return periods, met-ocean and seabed inputs, component degradation, installation assurance and change management. Operational guidance covers line-tension management, inspection performance standards, emergency preparedness and consideration of position monitoring during cyclone evacuation.
- 202316 May
Close approach of AHTS vessel to offshore rig
During anchor handling, a sliding chaser collar pulled an AHTS vessel towards a rig’s mooring line. A disabled bow thruster initially prevented corrective manoeuvring; restoring all thrusters enabled safe withdrawal. The flash identifies uncommunicated machinery shutdown and missing control-transfer checks, and describes propulsion checks, bridge approval requirements and revised work instructions.
- 20228 Nov
Failure of moorings during heavy weather
A drill ship preparing for lay-up broke its moorings in storm-force winds and drifted until a pre-deployed anchor held. The flash identifies delayed thruster availability, failure to request tug assistance and planning shortcomings. Recommendations address timely thruster starting, improved mooring plans, emergency response and lay-up procedures.
- 202224 Mar
Blackout Condition Results in Loss of Station Keeping Ability and Activates an Emergency Disconnect from the Well
During drillship well completion, an erroneous watermist-release signal caused the fire and gas system to shut down and block all engines, preventing automatic blackout recovery. The emergency generator operated as designed. The vessel drifted off location, and the driller activated emergency disconnection at the red watch circle limit, securing the well.
- 202113 Jun
Report - Error tolerance in dynamic positioning systems - November 2018
NOPSEMA examines inadvertent deactivation of dynamic positioning controls through incident database review, manufacturer consultation and a survey covering 28 Australian facilities. The report assesses double-press vulnerabilities, confirmation dialogues, alarms, protective covers and interface layouts, finding widespread additional safeguards while identifying gaps requiring further risk reduction.
- 20218 Mar
Inadequate Preparations in Advance of Inclement Weather Results in Excessive Rig Damage and Risk to Personnel
A drillship sustained substantial riser and related equipment damage during Hurricane Zeta after delayed evacuation and an emergency disconnect. No personnel casualties were reported. The alert recommends considering improvements to evacuation planning, well-securing procedures, shared emergency authority, weather communication, disconnect criteria and verification of equipment design limits.
- 202028 Apr
Vessel gangway rolled off platform tower and fell to the quayside in high wind
A vessel in port moved away from the quay during gusts exceeding 50 knots, causing its gangway to roll off a tower platform and fall approximately 5.2 m. Nobody was harmed. The flash examines mooring stretch, unrecognised falling-load risk and access design, and recommends reviewing weather reports and access risk assessments.
- 201912 Nov
Grounding of bulk carrier Kuzma Minin at Falmouth
This flash summarises Kuzma Minin’s grounding in Falmouth Bay after its anchor dragged in strong winds. Anchor fouling interrupted attempts to put to sea. Financial constraints influenced the decision to remain anchored, while absent P&I insurance hindered salvage arrangements. Lessons emphasise adequate vessel resources and insurance.
- 201931 Jul
Grounding of bulk carrier Kuzma Minin
Investigation of Kuzma Minin’s grounding in Falmouth Bay after its anchor dragged in strong winds and swell. It examines limited fuel and lubricating oil supplies, distraction from a fouled anchor, and harbour-led refloating. The report also analyses how absent insurance and owner support complicated salvage arrangements and financial responsibility.
- 201831 Oct
Dragging anchor and subsequent collisions by general cargo vessel Celtic Spirit
Investigation of Celtic Spirit dragging anchor in heavy weather on the River Humber and colliding with two anchored vessels. It examines insufficient anchor cable, delayed recognition of movement, engine readiness and warning communications, alongside anchorage allocation. Fleet procedures and port arrangements were revised; no recommendations were made.
- 201820 Jul
USCG: bollard failures at marine facilities
This flash summarises USCG reports of shoreside bollard failures that left moored vessels adrift, sometimes damaging vessels and shore structures without injuries or deaths. Issues included rotted pilings, possible pre-existing fractures and deteriorated bollard bases. USCG strongly recommended routine inspections and advised vessel personnel to report apparent deficiencies.
- 201820 Jul
Vessel collision with fixed structure on wind farm
A vessel struck a wind turbine transition-piece platform twice after changing from dynamic positioning to independent joystick control in worsening weather. Thrusters returned to zero pitch during changeover. The flash examines handover awareness and judgement, subsequent system testing, and revisions to procedures, familiarisation and passage planning.
- 20189 May
Grounding of general cargo vessel Islay Trader
Investigation of Islay Trader’s grounding off Margate after dragging anchor and attempting to reposition. It examines insufficient anchor cable for tidal conditions, neglected position monitoring, bridge workload and failure to seek the master’s assistance. Paper-chart navigation, radar monitoring and Schottel controls are discussed, with recommendations addressing anchorage planning and watchkeeping standards.
- 201815 Mar
Collision between general cargo ship Saga Sky and barge Stema Barge II resulting in subsea power cables damage
Investigates the collision of Saga Sky and Stema Barge II off Kent during severe weather, with anchor dragging and severed interconnector cables. Examines outdated anchorage charts, cable burial and condition monitoring, ship handling and emergency towage availability. Recommendations address nautical information, heavy-weather procedures and emergency response capability.
- 201721 Sep
Property damage: Platform supply vessel collided with legs of jack-up rig
A platform supply vessel struck a jack-up rig leg after its starboard engine and thrusters tripped following water transfer, while the hose remained connected. The flash identifies fuel-oil pump seal failure and weather-side working contrary to procedures, and highlights simultaneous-operations risk assessment and planned maintenance.
- 201728 Mar
Vessel activities near platforms – two incidents
Two vessel incidents near fixed platforms illustrate failures in fuel-system restoration and steering control. An AHTS vessel blacked out and drifted away after generators tripped; another vessel struck a flare bridge during personnel transfer following rudder feedback-unit failure. Actions address bunkering procedures, handovers, emergency-generator checks and communications.
- 201619 Dec
Some Ergonomic Issues of DP Vessel Controls
This safety alert examines accidental disengagement of dynamic positioning on a semisubmersible drilling rig and delayed recognition of manual control. It identifies inadequate button protection and unclear mode displays, and calls for operators to review control ergonomics, alert crews to weaknesses and make appropriate improvements.
- 201627 Jun
Vessel loss of position while diving in close proximity to a hydrocarbon facility
A diving vessel drifted over 40 metres after inadvertent deselection of its surge control disabled automatic positioning. A diver noticed his umbilical becoming taut. The alert examines vulnerable console layout, absent confirmation and ineffective excursion feedback, highlighting interface design and safeguards against unintended deactivation.
- 201627 Jan
Crew transfer vessel (CTV) personnel transfers
Two offshore wind crew-transfer incidents illustrate hazards from fall-arrest attachment during vessel movement and thruster wash near a dynamically positioned construction vessel. The flash describes a rogue wave during a dark winter transfer, suspension of transfers pending improved conditions, and revised vessel separation and work sequencing arrangements.
- 201523 Nov
Vessel made contact with installation
During cargo operations alongside a well-head installation, a vessel drifted after its Master switched to manual control and left the controls unattended. Its stern roller struck an installation leg, damaging both assets. The flash highlights complacency, inadequate risk assessment, bridge staffing procedures and failure to exercise stop-work authority.
- 20158 May
Near-miss incidents: Crew transfer vehicles approaching wind turbines
Three crew transfer vessel incidents concern loss of alignment at wind turbine boat landings and steering faults. Two involved near collisions with monopiles; investigations of steering failures identified worn potentiometers. Recommendations address clearing the transfer platform, stopping transfers before repositioning and considering planned maintenance or replacement of control units.
- 201524 Feb
Safety Alert 315 - Dynamic Positioning System Failures on Offshore Supply Vessels Engaged in Oil and Gas Operations
Joint Coast Guard and BSEE alert examines an offshore supply vessel losing position during wireline plug removal, shearing a wellhead tree through connected high-pressure lines and releasing lubricant. It discusses ignored DP failures, emergency disconnect capability, DP equipment classes, activity-specific guidance, personnel competence and leaseholder oversight of contracted vessels.
- 201420 May
Safety Alert 312 - Dynamic Positioning System Failures On Vessels Other Than Mobile Offshore Drilling Units (Vessels)
Joint Coast Guard and BSEE alert examines loss of vessel position during critical well operations. Overdue circuit-breaker maintenance, protection-circuit faults and unsynchronised bus reconnection culminated in total loss of thrust; crew disconnected safely. Recommendations address failure-mode analysis, critical operating modes, maintenance planning, contractor safeguards and demonstrated DP personnel competence.
- 2014May
Dragging anchor and grounding of ro-ro passenger ferry Stena Alegra
Investigation of Stena Alegra’s anchor dragging and grounding off Karlskrona on 28 October 2013. The report examines anchoring equipment limitations, severe yawing, anchorage appraisal, contingency planning and conflicting engine-readiness expectations. Recommendations address anchoring guidance, early preventive action and masters’ handovers concerning vessel capabilities.
- 201329 Nov
Serious DP diving incident
A diving support vessel lost DP control following RBUS communication failure and drifted 240 m. A diver’s snagged umbilical severed, interrupting gas, hot water and communications. The flash describes recovery and medical monitoring, investigation findings without a definitive jamming cause, a firmware remedy and an improvement project for diving and marine operations.
- 201330 Jan
Diver emergency decompression following construction barge anchor loss during tropical storm
A construction barge lost its bow/weather anchors during a severe tropical storm while on standby. Nine saturation divers were transferred to a hyperbaric rescue chamber and began accelerated emergency decompression. After tugs restored station keeping, emergency decompression ceased and the divers surfaced safely using their routine profile.
- 201323 Jan
Warning to offshore industry on blocking of data communications in dynamic positioning systems
This alert examines shared-network vulnerabilities in dynamic positioning systems after a diving support vessel drifted off position with divers subsea. A single fault was identified as a probable cause of blocked communications. Duty holders and suppliers should investigate communications architecture and ensure appropriate protection where functions depend on shared media.
- 2013
Offshore installation moorings
This information sheet explains offshore mooring requirements for permanently moored installations and mobile units. It addresses design standards, weather robustness, thruster assistance, inspection criteria, tension and position monitoring, line-break response and failure reporting. Location-specific analyses and anchor verification are discussed alongside safety-case duties and verification arrangements.
- 2011Sep
Person overboard from landing craft Forth Guardsman during mooring operation with loss of 1 life
MAIB investigates fatal chest injuries to a seaman pulled overboard during mooring south of Jura. It examines the open bight formed when joining a mooring line to a wire, inadequate supervision and risk assessment, flawed DGPS position monitoring, emergency communications and recovery difficulties, and records the operator’s subsequent actions.
- 200821 May
Loss of DP position caused by incorrect gyro heading
A DP Class 2 shuttle tanker lost position during an offtake operation when erroneous GPS signals affected all gyros, corrupting offset calculations and position references. The flash records stricter acceptance criteria for position reference systems and a forthcoming manufacturer software upgrade to reject erroneous latitude and speed compensation data.
- 200612 Dec
DP run-off incident – Class 2 DP vessel
A Class 2 DP vessel alongside a platform experienced a run-off following loss of reference systems and was recovered safely under manual control. The flash examines linked reference failures, incorrect VRS voting configuration, omitted sensor offsets and pitch-compensation wiring errors, highlighting limitations of FMEA trials and the need for current configuration records.
- 20069 Oct
Wire break in wind sensor caused DP drive-off
A vessel suffered a DP drive-off during open-water valve monitoring after water ingress through a failed junction-box seal led to a wind-sensor wire break. Erroneous wind readings affected positioning; the vessel stabilised 17 m from its set-point. Actions included wiring changes, a discrepancy alarm and fleet-wide wire-break tests.
- 20066 Sep
Safety Alert 243 - Unplanned Riser Disconnect Results in Spill
A dynamically positioned semi-submersible lost station during worsening currents and storm conditions, prompting a riser disconnect and release of 710 barrels of synthetic mud into the Gulf of Mexico. The alert identifies unsuitable rig selection and inadequate procedures, recommending site-specific disconnect planning and review of storm-related criteria and T-time estimates.
- 200628 Feb
Recent DP incident onboard a DSV
A diving support vessel lost position during open-water diving when exceptional wave action triggered rejection of all five DP position references. Investigation identified tighter prediction-error limits following a software upgrade and gaps in crew briefing and guidance. Recommendations address settings, reference reselection, operator familiarisation and fleet communication.
- 200531 May
Safety Alert 231 - Human Engineering Factors Result in Increasing Number of Riser Disconnects
This alert reviews accidental and emergency riser disconnects in deepwater operations, highlighting human error, hydraulic connection mistakes and station-keeping failures. It recommends reviewing existing requirements for deliberate sequential disconnection, protected controls and documented subsea function testing. An accompanying table summarises eleven events involving drilling and production risers.
- 20041 Dec
Loss of position of DP DSV
A DP diving support vessel moved some 107 metres off its worksite, leaving a diver unable to return unaided to the bell. He suffered carbon dioxide toxicity from overbreathing. The investigation attributed the movement to a soliton; recommendations address seasonal scheduling, vessel heading, radar watch, quick-release arrangements and diver communication.
- 20023 Jul
Power management system dynamic positioning (DP) incident
A power management fault interrupted stern thruster operation during saturation diving, causing a DP vessel to leave its intended position. Divers returned to the bell and were recovered. The flash examines inadequate control-card segregation and an unidentified single-point failure, recommending reconfiguration, electrical protection, independent review and FMEA validation trials.
- 20022 Jul
Dynamic positioning (DP) vessel blackout
A saturation-diving vessel suffered a complete blackout and moved some 190 m before control was regained. Divers were recovered without injury. Investigation identified degraded power-management electronics and management-system weaknesses. Recommendations address replacement of the ageing system, UPS maintenance and testing, broader redundancy analyses and revised diving emergency arrangements.
- 20011 Nov
Electrical fire in engine room
A vessel’s step-down transformer overheated and emitted smoke following a power fluctuation. The chief engineer switched off the main breaker, leaving the vessel adrift, used extinguishers and subsequently bypassed the transformer. The cause remained under investigation. Personnel were advised to assess situations calmly, check protective devices periodically and report defects.
- 2001May
Dragging anchor and grounding of liquid petroleum gas carrier Happy Lady
Investigates Happy Lady’s grounding in the Thames estuary during anchor recovery in strong winds. The cable jammed around the bulbous bow and raked stem while the vessel dragged towards shoal water. Analysis addresses the master’s decisions, forecastle supervision, anchoring procedures and preservation of safety history when ownership changes.
- 20001 Jan
Thruster feedback incident
A vessel operating in Class 2 alongside a platform experienced a drive-off after severe gear wear in a thruster’s azimuth feedback unit. Incorrect thrust direction appeared normal to the operator, and the mismatch alarm did not activate. No damage or injury occurred; the company advised assessment and preventative measures for affected arrangements.
- Undated
Emergency Disconnect During Completion Operations Releases Zinc Bromide
BSEE investigates a weather-related emergency disconnect during completion operations aboard Noble Stanley Lafosse in the Gulf of Mexico. A misaligned thruster compromised station keeping, while the well suspension procedure remained incomplete. Zinc bromide discharge was revised to approximately 420 barrels. The report examines failed barrier tests and subsequent thruster correction.
- Undated
Vessel Struck Drilling Rig During Synthetic-Based Mud Transfer
An investigation describes C-Rover striking Diamond Ocean Valiant during synthetic-based mud transfer after losing bow-thruster hydraulic power. Wind, current and seas contributed to drifting; a tight stern line was cut and a hull breach was subsequently reported. The report records revised mooring arrangements and a prospective DP2 upgrade.
- Undated
Vessel Collision with Unmanned Platform Following Anchor Dragging
Investigation of MAERSK KENTUCKY’s collision with the shut-in, unmanned High Island 154 B platform. The report identifies inadequate anchor watch, failure to respond to changing weather, dragging anchor and unavailable propulsion following engine shutdown. It also documents platform damage and well isolation arrangements that prevented pollution.
- Undated
Vessel Allision During Pipeline Riser Decommissioning
Investigation of a vessel allision during pipeline-riser decommissioning at Ewing Banks 921 A. The account examines unexpected winch payout, a wedged shackle and severed hold-back cable. Vessel bollard pull was insufficient and had not been checked against lift calculations. Damage affected the platform and vessel crane.
- Undated
Crane Damage During Produced Sand Transfer to Vessel
Investigation of crane damage during transfer of produced sand to Miss Darlene. Vessel drift while the load remained connected caused shock loading, side loading and overload. Communication failure may have contributed. Inspector recommendations address captain and rigger certification and vessel-crew involvement in the pre-lift job safety analysis.
- Undated
Drillship Excursion During Drilling Prompts Emergency Disconnection and Mud Release
BSEE investigates a weather-driven excursion of the Deepwater Poseidon drillship during drilling in Mississippi Canyon Block 391. The report describes emergency disconnection, synthetic-based mud release and ROV verification of well security. It also documents a falling drill-pipe and bearing assembly, recovery operations and failures to disclose the resulting damage.
- Undated
Emergency Riser Disconnect and Drilling Mud Release During Drilling
Investigation of an emergency riser disconnect during drilling on Diamond Ocean Confidence. High winds, currents and engine unavailability increased dynamic-positioning power demand. Approximately 218 barrels of synthetic-based mud entered the Gulf of Mexico. Subsequent engine trips caused blackout and drifting; manual restarts restored station keeping. No injuries or fatalities occurred.
- Undated
Blackout and Drift-Off During Accommodation Fire Damper Testing
BSEE investigates a blackout and drift-off aboard Noble Stanley Lafosse during accommodation fire-damper testing. Inadvertent operation of emergency fuel shut-off valves preceded loss of station keeping, emergency disconnection and brine discharge. Findings address missing task risk assessment, unused stop-work authority, inadequate assistance and unprotected valve controls.
- Undated
Electrical Failure Disabled Thrusters and Caused Vessel Drift
Investigation of an electrical failure aboard Discoverer Clear Leader that disabled thrusters and allowed a five-foot drift off station. Power returned to five thrusters after approximately 50 seconds. The crew closed middle pipe rams following a yellow alert. A circuit card was suspected, with investigation still pending; no agency recommendations were made.
- Undated
Basket Struck Vessel Deck During Diver Transfer
An MMS investigation examines a diver’s injury during a basket lift between a motor vessel and a lift boat. Vessel drift left the basket off-centre; it struck the deck after the diver boarded. The report identifies rough seas and boarding the basket as probable causes and records a hairline fracture and restricted duties.
- Undated
Drift-Off and Emergency Disconnection During Well Completion
This investigation examines the Discoverer Spirit’s drift-off during well completion operations in the Gulf of Mexico. Rapid changes in thunderstorm winds exceeded the thrusters’ ability to maintain position, prompting emergency disconnection. Subsequent investigation confirmed a release of 938 barrels of zinc bromide/calcium bromide fluid. An ROV surveyed the well’s security.
- Undated
Supply Boat Collided with Rig During Drilling Mud Transfer
Investigation of Cape Hope’s collision with the Arctic I during synthetic oil-based mud transfer. Vessel-wide fuel shutdown removed propulsion power, allowing the supply boat to drift into and beneath the rig. The report describes emergency actions, lifeboat and structural damage, checks confirming no flooding, and estimated repair and well costs.
- Undated
Drillship Drift and Emergency Disconnection Released Calcium Bromide
An investigation examines the Discoverer Inspiration drillship’s drift during well abandonment in strong frontal weather. Emergency disconnection released a reported 513 barrels of calcium bromide from the riser. Reduced thruster output remained unexplained; the disconnect system performed as intended, with no injuries or equipment damage. BSEE made no recommendations.
- Undated
Vessel Collided with Platform While Preparing to Offload
Investigation of the Triple Play’s collision with Matterhorn Platform while preparing to offload. Both GPS systems failed, resulting in loss of dynamic positioning before the captain regained control. Two caissons were damaged; no injuries, spills or vessel damage were reported. The probable cause was loss of dynamic positioning system power.
- Undated
Emergency Disconnect and Calcium Chloride Release Following Loss of Station Keeping
BSEE investigates weather-driven loss of station keeping aboard the Noble Stanley Lafosse drillship during preparations for cementing. The crew initiated an emergency disconnect, closing blind shear rams and releasing an estimated 417 barrels of calcium chloride to sea. The report examines forecast limitations, vessel excursions and the decision to disconnect; no injuries were reported.
- Undated
Derrick Barge Struck Compressor Platform After Anchor Recovery
Investigation of the William Kallop derrick barge striking Chevron’s ST 130D compressor platform after anchor recovery. The report identifies loss of tugboat control, poor communication and strong current as probable causes, describes structural damage, and records failure to follow Arena Offshore’s emergency evacuation plan.
- Undated
Transformer Failure Causes Total Power Loss During Well Completion
Investigation of a transformer failure aboard Deepwater Pontus during well completion operations. Total power loss led to vessel drift, emergency disconnection and seabed damage to the lower marine riser package. The well remained secure, with no injuries or pollution. Findings identify unmonitored breaker position and planned monitoring improvements.
- Undated
Electrical Fire in Dynamic Positioning Controls Disabled Thrusters
An investigation documents an electrical fire in the Discoverer Clear Leader’s dynamic positioning controls. Cooling-system cracks allowed water into electrical cabinets, disabling six thrusters and causing the rig to drift 15½ ft off location. Personnel mustered, power and position were restored, and control logic was subsequently modified to respond better to power demands.
- Undated
Vessel Lost Station Keeping and Severed Production Tree During Wireline Operations
Investigation of Endurance’s loss of station keeping during wireline operations at Eugene Island 355A. Vessel movement severed the production tree through connected rigid pipework, causing an oil spill and deck damage without reported injuries. Suspected communications-tower interference and absent emergency disconnection are examined, alongside equipment-separation measures and proposed vessel evaluation procedures.
- Undated
Electrical Failure During Drilling Leads to Drift and Emergency Disconnection
BSEE investigated an electrical failure aboard Ensco 8502 during drilling in Green Canyon 237. Loss of four thrusters led to vessel drift and emergency disconnection. The disconnect system operated as designed, but approximately 150 barrels of SBM escaped from drill pipe and hoses. No injuries occurred; the well remained secure and undamaged.
- Undated
Transformer Short Circuits Caused Vessel Power Loss and Drift
An investigation examines transformer short circuits during re-energisation following maintenance aboard Discover Deep Seas. Power loss disabled thrusters and steering, allowing drift of up to 83 feet and prompting crew muster. Moisture accumulation was identified as the most probable cause. Inspection recommendations address condensation heating, drying and insulation-resistance checks before re-energisation.
- Undated
Loss of Position and Riser Damage During Hurricane
Investigation of Deepwater Asgard’s loss of position during Hurricane Zeta while connected to a well. Emergency disconnection succeeded, but the marine riser and lower marine riser package sustained damage, including seabed impacts. Findings address inaccurate forecasts, the decision to remain connected, delayed well securing and subsequent storm-preparation changes.
- Undated
Electrical Disruption and Emergency Riser Disconnection with Drilling Fluid Loss
An investigation records harmonic-filter failure, a small fire and electrical supply disruption aboard a drilling vessel. Thrusters went offline, prompting emergency riser disconnection and loss of synthetic-base drilling fluid. Power and position were subsequently restored. The cause of essential-services circuit-breaker tripping remained under investigation.
- Undated
Platform Damage Involving Liftboat Subsequently Found Adrift
This investigation describes platform damage involving the jacked-up liftboat Hercules Tiger Shark, subsequently found upright and adrift approximately 40 miles away. Personnel had been removed before the overnight event. Weather and sea conditions were identified as probable causes, with improper air gap contributing; the district offered no recommendations.
- Undated
Emergency Buoy Disconnect Failed Following Loss of Station
BSEE investigates a failed emergency buoy disconnect on Helix Producer 1 following weather-related loss of station. Subsea production shut in successfully, but a hydraulic piston failed to open. The report details disconnect-system testing, piston replacement and subsequent maintenance measures; teardown inspection found no cylinder failure, and no injuries or infrastructure damage were reported.
- Undated
Dynamic Positioning Malfunction with Riser Disconnection and Brine Release During Well Completion
Investigation of a dynamic positioning malfunction during well completion and console maintenance. Corrupted control data and subsequent troubleshooting caused the rig to leave its watch circle, triggering riser disconnection and releasing approximately 550 barrels of sodium bromide brine. Planned changes address alarms, command timing, console verification and simulator training.
- Undated
Dragging anchor and grounding by general cargo vessel Baltic Champ
MAIB examines Baltic Champ’s anchor dragging and grounding off Kirkwall in winds gusting between 60 and 70 knots. The synopsis identifies inadequate anchor cable length and position monitoring among contributory causes. It discusses delays in agreeing towage arrangements and recommends reviewing dedicated UK emergency towage cover.
- Undated
Dragging anchor and grounding of general cargo vessel Harvest Caroline
Investigation synopsis of Harvest Caroline dragging anchor and grounding at Tanera More in strong northerly winds. Findings address unsuitable anchorage selection, insufficient anchor cable, an absent anchor watch and deficient safety management. It describes passenger evacuation, refloating and towage, revised bridge manning instructions, a watch alarm and recommendations concerning ISM verification.
- Undated
Dragging anchor and grounding of general cargo vessel Thunder
Thunder dragged anchor and grounded near Mostyn after navigating without an appropriate chart. The synopsis examines agent-supplied waypoints, anchorage arrangements, watchkeeping and delayed recognition of the grounding. Recommendations address pilotage, passage planning, chart updates, emergency procedures and anchoring guidance. No vessel damage, crew injuries or pollution were reported.
- Undated
Dragging anchor and grounding of oil/chemical tanker Astral
Investigation synopsis of Astral dragging anchor and grounding on Princessa Shoal during severe weather. It describes engine readiness, the bridge response and subsequent tow. Hull, rudder and steering gear damage occurred without pollution or loss of watertightness. Actions address anchoring procedures, officer assessment and harbour safety communications.
- Undated
Dragging anchor and grounding of tanker Willy
Investigation synopsis of Willy’s grounding after dragging anchor in Cawsand Bay. Contributing factors included insufficient cable for the conditions, delayed detection of movement, delayed notification of the master and insufficient time to make the engine available. The GPS guard zone exceeded the swinging-circle radius by almost three times.
- Undated
Dragging anchor by product carrier Young Lady resulting in snagging and damaging of gas pipeline
Young Lady dragged anchor in heavy weather in Tees Bay. A windlass hydraulic motor failure occurred while weighing anchor, and the anchor subsequently snagged and damaged the CATS gas pipeline. The investigation identified an inappropriate anchoring decision and incomplete assessment of vessel–pipeline risks; recommendations addressed information, notification and pipeline protection.
- Undated
Entanglement in moorings of smaller vessels by ro-ro cargo ferry Claymore during attempt to berth
Claymore lost manoeuvring control while berthing at St Margaret’s Hope in gale-force winds, and its starboard propeller fouled smaller vessels’ moorings. The investigation identifies unavailable propulsion assistance, a seized anchor, inadequate weather planning, bridge communication failures and insufficient preparation after lay-up. Passengers were evacuated without injury.
- Undated
Equinor – Statfjord A – investigation of collision by vessel
The PSA investigates Sjoborg’s collision with Statfjord A during cargo discharge. Reduced thruster power led to loss of position, damage to lifeboat arrangements and personnel evacuation. The report examines technical faults, alarm interpretation, compliance with activity-specific operating guidelines and bulk hose handling, using interviews, inspections and supplied documentation rather than independent technical testing.
- Undated
Equinor/Floatel International - Floatel Endurance - investigation of unintentional gangway disconnection
Investigates Floatel Endurance’s loss of position and automatic gangway lift at Martin Linge on 29 February 2020. One person returned safely without physical injury. The report examines wave loading, dynamic positioning limitations, deficient operating limits, conflicting safety instructions and delayed personnel accounting, alongside helicopter transfers following disconnection.
- Undated
Jack-up Drilling Rig Fitness Requirements
MMS guidance sets out information required with drilling and modification permit applications for jack-up operations during Gulf of Mexico hurricane seasons. It uses API RP 95J for evaluation and requires an assessment checksheet, proposed preloading procedures and holding times, alongside information on rig fitness and securing wells before evacuation.
- Undated
Loss of Stability and Positioning
Inspection guidance examines maritime integrity management on floating installations, including stability calculations, ballast operation, watertight boundaries, mooring integrity and dynamic positioning. It addresses competence, emergency arrangements, failure analysis and FPSO cargo operations. Illustrative inspection questions contrast good and poor practice, supporting assessment of dutyholder arrangements and risk ranking.
- Undated
Moored Drilling Rig Fitness Requirements
This MMS notice specifies evidence required in drilling and modification permit applications for moored rigs operating during Gulf of Mexico hurricane seasons. It addresses site hazards, metocean criteria, anchor holding capacities, mooring inspections and risk assessments, using API RP 2SK Appendix K to guide regulatory review.
- Undated
Parting of mooring line between shuttle tanker Randgrid and monobuoy resulting in discharge of 12 tonnes of crude oil
Investigation of Randgrid’s mooring release at the Tetney monobuoy during cargo discharge. Accidental operation of chain stopper controls released the chafing chain; the pickup-rope lashing subsequently failed and discharge hoses broke away. An estimated spill of about 12 tonnes occurred without injury. Recommendations address control design, alarms and bridge procedures.
- Undated
Parting of mooring lines from liquid petroleum gas tanker Havkong while loading butane
Joint investigation of Havkong’s breakaway during butane loading at Braefoot Bay. It examines ineffective mooring geometry, overloaded winch brakes, severe-weather procedures and emergency coordination. Loading arms disconnected without cargo spillage. Vessel-specific mooring analysis, tug arrangements and emergency planning are considered alongside modelling of potential release consequences.
- Undated
Safety warning after dragging anchor and grounding of vessel
MAIB safety bulletin following Willy’s anchor dragging and grounding in Cawsand Bay. It examines delayed detection using a GPS guard zone and radar, and engine availability. Recommendations address anchor watchkeeping, cable scope, weather reassessment, second-anchor readiness and moving from unsafe anchorages.
- Undated
Seadrill – West Mira – investigation of unintentional disconnection of LMRP
Investigation of West Mira’s unintended LMRP disconnection during drilling on the Maria field. Weather-related loss of position triggered automatic string cutting and well shut-in, with drilling fluid discharged to sea. The report examines thruster-assisted mooring, power-sharing constraints, draught changes, procedural deficiencies, alarm limits and inadequate assessment of operating assumptions.
- Undated
Unintended movement of ro-ro passenger ferry Ben-My-Chree resulting in collapse of access structure trapping 8 people
Ben-My-Chree moved approximately 8 m during boarding and vehicle loading at Heysham, damaging passenger access structures and trapping eight passengers without injury. The synopsis examines propulsion-control handover, autotension mooring winches and structural weaknesses, alongside post-maintenance testing arrangements and recommendations for port risk reviews and access-structure inspections.