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Gel batteries (#GEL) are a type of sealed lead-acid battery in which the electrolyte is thickened into a gel by adding silica. They belong to the #VRLA (Valve Regulated Lead Acid) family — maintenance-free, sealed batteries with pressure-relief valves.
Advantages of Gel #Batteries
• Sealed and maintenance-free — no water topping-up, minimal gas emission.
• Long service life — typically 6–12 years in standby applications.
• Deep-cycle capable — handle deep discharges better than AGM batteries.
• Vibration resistant — suitable for marine environments.
• Safe — very low risk of acid leakage.
• Wide operating temperature range — around −20 to +50 °C (model-dependent).
Disadvantages
• More expensive than AGM or flooded lead-acid batteries.
• Lower charge current tolerance — require precise charge control.
• Sensitive to overcharging, especially at high temperatures.
Typical Applications
• Marine systems (emergency power, communication systems).
• #UPS (Uninterruptible Power Supplies).
• Solar and off-grid power systems.
• Electric vehicles and medical equipment.
Charging Parameters
Proper charging is critical for long battery life:
• Bulk/Absorption voltage: 14.0–14.4 V (for a 12 V battery).
• Float #voltage: 13.5–13.8 V.
• Charge current: typically 0.1C (10% of capacity).
• Temperature compensation: about −3 mV/°C per cell.
How to Identify a Faulty Gel Battery
• Significant capacity loss (over 30% drop).
• Strong voltage drop under load.
• #Battery gets unusually warm while charging.
• Swelling of the case (critical sign).
• High internal #resistance during testing.
Advantages of Gel #Batteries
• Sealed and maintenance-free — no water topping-up, minimal gas emission.
• Long service life — typically 6–12 years in standby applications.
• Deep-cycle capable — handle deep discharges better than AGM batteries.
• Vibration resistant — suitable for marine environments.
• Safe — very low risk of acid leakage.
• Wide operating temperature range — around −20 to +50 °C (model-dependent).
Disadvantages
• More expensive than AGM or flooded lead-acid batteries.
• Lower charge current tolerance — require precise charge control.
• Sensitive to overcharging, especially at high temperatures.
Typical Applications
• Marine systems (emergency power, communication systems).
• #UPS (Uninterruptible Power Supplies).
• Solar and off-grid power systems.
• Electric vehicles and medical equipment.
Charging Parameters
Proper charging is critical for long battery life:
• Bulk/Absorption voltage: 14.0–14.4 V (for a 12 V battery).
• Float #voltage: 13.5–13.8 V.
• Charge current: typically 0.1C (10% of capacity).
• Temperature compensation: about −3 mV/°C per cell.
How to Identify a Faulty Gel Battery
• Significant capacity loss (over 30% drop).
• Strong voltage drop under load.
• #Battery gets unusually warm while charging.
• Swelling of the case (critical sign).
• High internal #resistance during testing.
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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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