Loose Wire on Containership Dali Leads to Blackouts and Contact with Baltimore’s Francis Scott Key Bridge
Date: November 18, 2025
Key Points:
• A single loose #wire in the electrical system of the 984-foot long #containership Dali caused an electrical blackout.
• The #blackout led to the vessel losing both propulsion and steering while passing near the Francis Scott Key Bridge (Key Bridge) in Baltimore, and the ship contacted the bridge structure.
• The incident occurred on March 26, 2024; the bridge collapse followed, resulting in the deaths of six highway workers.
• The investigation revealed that the wire-label banding prevented the wire from being fully inserted into a terminal-block spring-clamp, causing an inadequate connection which triggered a #breaker to trip.
• During the series of events: after the first blackout the ship’s heading swung toward Pier 17 of the Key Bridge; despite efforts by pilots and shoreside dispatchers, the loss of #propulsion close to the bridge made avoiding the collision impossible.
• The size of the #ship and the lack of bridge design counter-measures for large ocean-going vessels contributed to the severity of the event. For example, an earlier collision by the ship Blue Nagoya in 1980 (390 ft long) caused only minor damage; the Dali was about ten times the size.
• As a result of the investigation, NTSB issued a series of safety recommendations to multiple parties including the United States Coast Guard, the Federal Highway Administration, bridge-owners nationwide, and electrical-component manufacturers.
• #NTSB emphasised that this incident was preventable, and that implementation of the recommendations is essential to avoid similar tragedies in the future.
🔗 Link to the news ➡️ https://www.ntsb.gov/news/press-releases/Pages/NR20251118.aspx
#news
Date: November 18, 2025
Key Points:
• A single loose #wire in the electrical system of the 984-foot long #containership Dali caused an electrical blackout.
• The #blackout led to the vessel losing both propulsion and steering while passing near the Francis Scott Key Bridge (Key Bridge) in Baltimore, and the ship contacted the bridge structure.
• The incident occurred on March 26, 2024; the bridge collapse followed, resulting in the deaths of six highway workers.
• The investigation revealed that the wire-label banding prevented the wire from being fully inserted into a terminal-block spring-clamp, causing an inadequate connection which triggered a #breaker to trip.
• During the series of events: after the first blackout the ship’s heading swung toward Pier 17 of the Key Bridge; despite efforts by pilots and shoreside dispatchers, the loss of #propulsion close to the bridge made avoiding the collision impossible.
• The size of the #ship and the lack of bridge design counter-measures for large ocean-going vessels contributed to the severity of the event. For example, an earlier collision by the ship Blue Nagoya in 1980 (390 ft long) caused only minor damage; the Dali was about ten times the size.
• As a result of the investigation, NTSB issued a series of safety recommendations to multiple parties including the United States Coast Guard, the Federal Highway Administration, bridge-owners nationwide, and electrical-component manufacturers.
• #NTSB emphasised that this incident was preventable, and that implementation of the recommendations is essential to avoid similar tragedies in the future.
#news
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On 15 March 2025, the gas carrier Gaschem Homer experienced a loss of #propulsion and #steering while manoeuvring in the Port of Brisbane, Queensland. The Australian Transport Safety Bureau (#ATSB) investigated the incident and released its final report on 19 November 2025.
What Happened
• The vessel was departing its berth and performing a turning manoeuvre in the harbour channel.
• During this manoeuvre, the ship suffered a complete electrical #blackout, leading to a loss of propulsion and rudder control for approximately two minutes.
• The blackout occurred when the bow thruster was engaged, causing a sudden increase in electrical load.
Cause of the Blackout
• The ship had three auxiliary diesel generators.
• Before departure, two generators were left in manual mode instead of automatic, contrary to safe operating practice.
• When the #bowthruster load increased, one generator overloaded and tripped.
• The other #generators did not automatically take over the load because they were not configured in the auto mode, resulting in a total loss of electrical power.
• No injuries or damage occurred, but the loss of control inside a confined harbour channel was classified as a serious #incident.
ATSB Findings
• The vessel’s Safety Management System (SMS) used generalized fleet-wide procedures that did not reflect the specific requirements and power system configuration of Gaschem Homer.
• Pre-departure checks were too generic and did not clearly define responsibilities or steps for generator mode verification.
• The crew relied heavily on memory rather than structured, ship-specific procedures — which increased the risk of error.
• The incident occurred due to a combination of inadequate procedures, improper generator configuration, and insufficient adaptation of #SMS to vessel-specific systems.
Actions Taken After the Incident
• The operator updated its risk controls and procedures.
• Checklists were rewritten to require generators to be in AUTO mode before manoeuvring.
• A power consumption matrix was introduced to manage electrical loads during port operations.
• Training for engineers was enhanced, focusing on generator management and load-sharing principles.
Why This Matters
• The event highlights how even short power losses during #manoeuvring can create significant risks.
• Safety procedures must be updated, ship-specific, and easy to use.
• Proper load management and #generator mode selection are essential for safe navigation, especially in restricted waters.
Official Sources
• ATSB news release:
https://www.atsb.gov.au/media/news-items/2025/gas-carrier-loss-propulsion-highlights-importance-date-and-usable-procedures
• Full ATSB report (PDF):
https://safety4sea.com/wp-content/uploads/2025/11/ATSB-Loss-of-propulsion-Gaschem-Homer-2025_11.pdf
#news
What Happened
• The vessel was departing its berth and performing a turning manoeuvre in the harbour channel.
• During this manoeuvre, the ship suffered a complete electrical #blackout, leading to a loss of propulsion and rudder control for approximately two minutes.
• The blackout occurred when the bow thruster was engaged, causing a sudden increase in electrical load.
Cause of the Blackout
• The ship had three auxiliary diesel generators.
• Before departure, two generators were left in manual mode instead of automatic, contrary to safe operating practice.
• When the #bowthruster load increased, one generator overloaded and tripped.
• The other #generators did not automatically take over the load because they were not configured in the auto mode, resulting in a total loss of electrical power.
• No injuries or damage occurred, but the loss of control inside a confined harbour channel was classified as a serious #incident.
ATSB Findings
• The vessel’s Safety Management System (SMS) used generalized fleet-wide procedures that did not reflect the specific requirements and power system configuration of Gaschem Homer.
• Pre-departure checks were too generic and did not clearly define responsibilities or steps for generator mode verification.
• The crew relied heavily on memory rather than structured, ship-specific procedures — which increased the risk of error.
• The incident occurred due to a combination of inadequate procedures, improper generator configuration, and insufficient adaptation of #SMS to vessel-specific systems.
Actions Taken After the Incident
• The operator updated its risk controls and procedures.
• Checklists were rewritten to require generators to be in AUTO mode before manoeuvring.
• A power consumption matrix was introduced to manage electrical loads during port operations.
• Training for engineers was enhanced, focusing on generator management and load-sharing principles.
Why This Matters
• The event highlights how even short power losses during #manoeuvring can create significant risks.
• Safety procedures must be updated, ship-specific, and easy to use.
• Proper load management and #generator mode selection are essential for safe navigation, especially in restricted waters.
Official Sources
• ATSB news release:
https://www.atsb.gov.au/media/news-items/2025/gas-carrier-loss-propulsion-highlights-importance-date-and-usable-procedures
• Full ATSB report (PDF):
https://safety4sea.com/wp-content/uploads/2025/11/ATSB-Loss-of-propulsion-Gaschem-Homer-2025_11.pdf
#news
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What R-S-T Means in Three-Phase Electrical Systems
R, S, and T are traditional names for the three #phases of an #AC three-phase power system.
They are commonly used in Europe, Asia, and especially in industrial and marine electrical installations.
1. What the letters mean
The letters do not have special meanings.
They simply represent:
• R = Phase 1 (L1)
• S = Phase 2 (L2)
• T = Phase 3 (L3)
This naming system was adopted in older European standards and is still widely used.
2. Why R-S-T is used
R-S-T helps identify:
• the three power lines in a three-phase system,
• the phase rotation (R → S → T),
• correct connection of motors, generators, switchboards, and #MCCs.
Maintaining the correct order (R-S-T) is important for equipment that depends on rotation direction, such as motors and pumps.
3. Relation to modern designations
Today, international standards (#IEC) prefer:
• L1, L2, L3
But R-S-T is still common in:
• marine systems,
• generator panels,
• industrial switchgear,
• old European installations.
#RST
R, S, and T are traditional names for the three #phases of an #AC three-phase power system.
They are commonly used in Europe, Asia, and especially in industrial and marine electrical installations.
1. What the letters mean
The letters do not have special meanings.
They simply represent:
• R = Phase 1 (L1)
• S = Phase 2 (L2)
• T = Phase 3 (L3)
This naming system was adopted in older European standards and is still widely used.
2. Why R-S-T is used
R-S-T helps identify:
• the three power lines in a three-phase system,
• the phase rotation (R → S → T),
• correct connection of motors, generators, switchboards, and #MCCs.
Maintaining the correct order (R-S-T) is important for equipment that depends on rotation direction, such as motors and pumps.
3. Relation to modern designations
Today, international standards (#IEC) prefer:
• L1, L2, L3
But R-S-T is still common in:
• marine systems,
• generator panels,
• industrial switchgear,
• old European installations.
#RST
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⭐ #Star (Y) Connection
What it is
The three #windings of the motor are connected so that one end of each #winding is joined together at a common point (neutral).
The other ends connect to the three-phase supply.
Characteristics
• Phase voltage = Line voltage / √3
(≈ 58% of full voltage)
• Starting current is lower (about 1/3 of delta)
• Starting torque is lower (about 1/3 of delta)
Where it is used
• During #motor starting to reduce inrush #current
• On light-load start motors
• For star–delta starters
🔺 #Delta (Δ) Connection
What it is
The windings are connected end-to-end in a triangle.
Each winding receives the full line #voltage.
Characteristics
• Phase voltage = Line voltage
• Full rated current
• Full rated torque
• Higher starting current
Where it is used
• For normal running of the motor
• When full torque is required
• For motors designed for Δ run
⚡ Star–Delta Starting (Y–Δ)
This is a common method to start large motors smoothly.
Why it’s used
• Reduces starting current to about 30–35% of direct-on-line (#DOL)
• Reduces mechanical shock
• Protects the electrical network from voltage dips
How it works
1. Start in Star → lower voltage on each winding → low current, low torque
2. After a few seconds (motor reaches 70–80% speed)…
3. Switch to Delta → full voltage → full torque for normal running
What it is
The three #windings of the motor are connected so that one end of each #winding is joined together at a common point (neutral).
The other ends connect to the three-phase supply.
Characteristics
• Phase voltage = Line voltage / √3
(≈ 58% of full voltage)
• Starting current is lower (about 1/3 of delta)
• Starting torque is lower (about 1/3 of delta)
Where it is used
• During #motor starting to reduce inrush #current
• On light-load start motors
• For star–delta starters
🔺 #Delta (Δ) Connection
What it is
The windings are connected end-to-end in a triangle.
Each winding receives the full line #voltage.
Characteristics
• Phase voltage = Line voltage
• Full rated current
• Full rated torque
• Higher starting current
Where it is used
• For normal running of the motor
• When full torque is required
• For motors designed for Δ run
⚡ Star–Delta Starting (Y–Δ)
This is a common method to start large motors smoothly.
Why it’s used
• Reduces starting current to about 30–35% of direct-on-line (#DOL)
• Reduces mechanical shock
• Protects the electrical network from voltage dips
How it works
1. Start in Star → lower voltage on each winding → low current, low torque
2. After a few seconds (motor reaches 70–80% speed)…
3. Switch to Delta → full voltage → full torque for normal running
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Below is a clear and practical explanation of the #Wärtsilä #WECS 9520 control system used on many Wärtsilä main engines (usually medium-speed engines like W-32 / W-38 series). I’ll keep it understandable but still technical so it’s useful for ETOs and engineers onboard.
What is WECS 9520?
WECS = Wärtsilä Engine Control System
9520 = model/version of the electronic automation and control platform.
It is the electronic control system that manages all main functions of the engine:
• Fuel injection
• Start/stop sequences
• Speed and load control
• Safety protections
• Alarms & shutdowns
• Monitoring of critical sensors
• Cylinder balancing and performance control
WECS 9520 is similar in philosophy to #MAN’s EDC / Volvo’s EMS but designed for Wärtsilä engines.
Main Components of WECS 9520
1. #ECU (Engine Control Unit)
The “brain” of the system.
Located on the engine, often one ECU per engine (sometimes redundant).
Functions:
• Processes sensor data (speed, temperature, pressure)
• Calculates injection timing & quantity
• Controls actuators (fuel injection valves, start-up valves)
• Manages safety logic—overspeed, low oil pressure, etc.
Runs on a real-time processor and has dedicated I/O boards.
Cylinder Control Units (#CCU) / Injection Control
On electronically-controlled engines, each cylinder has a solenoid-controlled fuel injection valve.
The ECU controls these solenoid valves with precise timing.
WECS 9520 determines:
• #Injection timing (start of injection)
• Injection duration (fuel quantity)
• Cylinder balancing
3. #Sensor Modules
WECS 9520 uses many digital and analog inputs:
• Speed #pickup / crankshaft encoder
• Scavenge temperature sensors
• Charge air pressure and temp
• Lubricating oil pressure & temp
• Fuel pressure
• Knock sensors (on some models)
All these signals go through WECS I/O boards.
4. Actuators and Valves
Controlled by WECS:
• Fuel injection solenoids
• Start air valves
• Fuel rack (if mechanical-electronic hybrid)
• #Wastegate / turbo control
• Shutdown solenoids
5. #HMI / Engine Control Panel (#ECP)
This is the user interface on the engine or on the bridge/ERS:
• Start/Stop buttons
• Operating modes (Local / Remote)
• Alarm display
• Parameter viewing (temperatures, pressures, speed)
• Trend pages
• Fault diagnostic
How the System Works — Simple Overview
1. Start Sequence
WECS automatically performs:
• Pre-lubrication check
• Turning gear check
• Start air sequence
• Fuel injection enable
• Ramp-up to idle speed
All logic is internal; operator only presses Start.
2. Running Operation
During operation WECS continuously:
• Monitors all sensors
• Controls injection quantity based on load command
• Adjusts turbocharger control
• Balances cylinders
• Prevents overload or knocking
• Logs alarms
3. Stop Sequence
WECS safely:
• Cuts off fuel
• Closes start valves
• Executes post-lubrication
• Performs run-down checks
• Logs “Engine Stopped” status
WECS 9520 Protections & Alarms
Typical shutdowns controlled by WECS:
• Overspeed
• Low lube oil pressure
• High temperature
• Crankcase mist / oil mist detector
• Emergency stop
• Fuel leakage detection
• Start failure
Alarms are prioritized (High, Medium, Low).
Communication
WECS 9520 communicates via:
• CAN bus (for cylinder units)
• RS-485 or Ethernet to the main ship automation system
• Modbus (on some engines)
This sends parameters to the alarm monitoring system, #PMS, and remote control.
What is WECS 9520?
WECS = Wärtsilä Engine Control System
9520 = model/version of the electronic automation and control platform.
It is the electronic control system that manages all main functions of the engine:
• Fuel injection
• Start/stop sequences
• Speed and load control
• Safety protections
• Alarms & shutdowns
• Monitoring of critical sensors
• Cylinder balancing and performance control
WECS 9520 is similar in philosophy to #MAN’s EDC / Volvo’s EMS but designed for Wärtsilä engines.
Main Components of WECS 9520
1. #ECU (Engine Control Unit)
The “brain” of the system.
Located on the engine, often one ECU per engine (sometimes redundant).
Functions:
• Processes sensor data (speed, temperature, pressure)
• Calculates injection timing & quantity
• Controls actuators (fuel injection valves, start-up valves)
• Manages safety logic—overspeed, low oil pressure, etc.
Runs on a real-time processor and has dedicated I/O boards.
Cylinder Control Units (#CCU) / Injection Control
On electronically-controlled engines, each cylinder has a solenoid-controlled fuel injection valve.
The ECU controls these solenoid valves with precise timing.
WECS 9520 determines:
• #Injection timing (start of injection)
• Injection duration (fuel quantity)
• Cylinder balancing
3. #Sensor Modules
WECS 9520 uses many digital and analog inputs:
• Speed #pickup / crankshaft encoder
• Scavenge temperature sensors
• Charge air pressure and temp
• Lubricating oil pressure & temp
• Fuel pressure
• Knock sensors (on some models)
All these signals go through WECS I/O boards.
4. Actuators and Valves
Controlled by WECS:
• Fuel injection solenoids
• Start air valves
• Fuel rack (if mechanical-electronic hybrid)
• #Wastegate / turbo control
• Shutdown solenoids
5. #HMI / Engine Control Panel (#ECP)
This is the user interface on the engine or on the bridge/ERS:
• Start/Stop buttons
• Operating modes (Local / Remote)
• Alarm display
• Parameter viewing (temperatures, pressures, speed)
• Trend pages
• Fault diagnostic
How the System Works — Simple Overview
1. Start Sequence
WECS automatically performs:
• Pre-lubrication check
• Turning gear check
• Start air sequence
• Fuel injection enable
• Ramp-up to idle speed
All logic is internal; operator only presses Start.
2. Running Operation
During operation WECS continuously:
• Monitors all sensors
• Controls injection quantity based on load command
• Adjusts turbocharger control
• Balances cylinders
• Prevents overload or knocking
• Logs alarms
3. Stop Sequence
WECS safely:
• Cuts off fuel
• Closes start valves
• Executes post-lubrication
• Performs run-down checks
• Logs “Engine Stopped” status
WECS 9520 Protections & Alarms
Typical shutdowns controlled by WECS:
• Overspeed
• Low lube oil pressure
• High temperature
• Crankcase mist / oil mist detector
• Emergency stop
• Fuel leakage detection
• Start failure
Alarms are prioritized (High, Medium, Low).
Communication
WECS 9520 communicates via:
• CAN bus (for cylinder units)
• RS-485 or Ethernet to the main ship automation system
• Modbus (on some engines)
This sends parameters to the alarm monitoring system, #PMS, and remote control.
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#Maintenance & #Troubleshooting (Quick Guide)
1. #ECU Status LEDs
Check power supply, CAN bus, I/O board health.
2. #Sensor Calibration
WECS 9520 is sensitive to:
• Faulty speed pickup
• Wrong T/C pressure signals
• Bad L.O. pressure sensors
Bad sensors cause derate or “Emergency Mode”.
3. Logs / Error Codes
#ECP display allows viewing:
• Active alarms
• Stored historical alarms
• Injection faults
• CAN communication faults
4. Backup & Configuration
WECS uses configuration files with engine parameters.
Normally stored by #Wärtsilä — copying or modifying requires service software.
Common Problems Engineers Face
1. Speed signal error
Cause: Dirty or faulty speed encoder.
Result: The engine may trip due to incorrect RPM feedback.
2. CAN bus fault
Cause: Loose cable connections or improper shield grounding.
Result: Cylinder control units stop responding or communication becomes unstable.
3. Injection solenoid failure
Cause: Burned coil or stuck solenoid valve.
Result: One cylinder produces low power or misfires.
4. Sensor drift
Cause: Aging sensors, heat, or vibration.
Result: Incorrect readings lead to wrong load control or emergency mode activation.
#WECS #Wartsila
1. #ECU Status LEDs
Check power supply, CAN bus, I/O board health.
2. #Sensor Calibration
WECS 9520 is sensitive to:
• Faulty speed pickup
• Wrong T/C pressure signals
• Bad L.O. pressure sensors
Bad sensors cause derate or “Emergency Mode”.
3. Logs / Error Codes
#ECP display allows viewing:
• Active alarms
• Stored historical alarms
• Injection faults
• CAN communication faults
4. Backup & Configuration
WECS uses configuration files with engine parameters.
Normally stored by #Wärtsilä — copying or modifying requires service software.
Common Problems Engineers Face
1. Speed signal error
Cause: Dirty or faulty speed encoder.
Result: The engine may trip due to incorrect RPM feedback.
2. CAN bus fault
Cause: Loose cable connections or improper shield grounding.
Result: Cylinder control units stop responding or communication becomes unstable.
3. Injection solenoid failure
Cause: Burned coil or stuck solenoid valve.
Result: One cylinder produces low power or misfires.
4. Sensor drift
Cause: Aging sensors, heat, or vibration.
Result: Incorrect readings lead to wrong load control or emergency mode activation.
#WECS #Wartsila
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Articles about Automatic Voltage Regulator on the eto-engineer.com
1. Automatic Voltage Regulators. What is a generator AVR or Automatic Voltage Regulator?
2. Automatic Voltage Regulator and Parallel Operation of generators. Voltage droop
3. Automatic Voltage Regulator. Real power, Reactive power, Apparent power. KW, KVAR, KVA
4. Function of Voltage Regulator and Parallel Generator Operation
5. The Current Transformer Unit - Parallel Switch. Paralleling Different Size Generators
6. Checking and Troubleshooting a Reactive Compensation Circuit for the AVR in an Isolated AC Bus
7. ACB Trouble. The generator does not connect to the main busbars. Troubleshooting
✅ All articles in one place➡️ https://www.eto-engineer.com/p/automatic-voltage-regulator.html
#automaticvoltageregulator #AVR #circulatingcurrent #CurrentTransformer #droop #generator #generators #paralleloperation #powerfactor #troubleshooting #voltage #voltagedroop #voltageregulator
1. Automatic Voltage Regulators. What is a generator AVR or Automatic Voltage Regulator?
2. Automatic Voltage Regulator and Parallel Operation of generators. Voltage droop
3. Automatic Voltage Regulator. Real power, Reactive power, Apparent power. KW, KVAR, KVA
4. Function of Voltage Regulator and Parallel Generator Operation
5. The Current Transformer Unit - Parallel Switch. Paralleling Different Size Generators
6. Checking and Troubleshooting a Reactive Compensation Circuit for the AVR in an Isolated AC Bus
7. ACB Trouble. The generator does not connect to the main busbars. Troubleshooting
✅ All articles in one place
#automaticvoltageregulator #AVR #circulatingcurrent #CurrentTransformer #droop #generator #generators #paralleloperation #powerfactor #troubleshooting #voltage #voltagedroop #voltageregulator
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