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A GUIDE TO SHIP ALARMS: WHAT YOU SHOULD KNOW

Emergencies at sea are unpredictable. While no one can foresee when a crisis might occur, ships are equipped with a range of alarms designed to warn the crew and help them respond effectively. These signals, both audible and visual, are critical to maintaining safety onboard and ensuring the right action is taken, no matter the situation.


Across the maritime industry, emergency alarms follow a standardized system so that seafarers can recognize and respond to them quickly, regardless of the vessel or company they sail with.


1. General Alarm


The general alarm is the main signal used to alert the crew that an emergency has occurred, such as a fire, collision, grounding, or any other event that could lead to abandoning ship.


It is recognized by seven short rings followed by one long ring on the ship’s bell, or seven short blasts followed by one long blast on the horn.


Once sounded, all crew members must proceed to their designated muster stations, listen for announcements on the public address (PA) system, and follow instructions according to the muster list.


2. Fire Alarm


If a fire is detected onboard, the nearest fire alarm switch should be activated immediately, or the emergency raised verbally by shouting “FIRE, FIRE, FIRE.”


The ship’s fire alarm consists of a continuous ringing of the electrical bell or a continuous blast on the whistle for at least 10 seconds.

When the master dismisses the crew from fire stations, the signal changes to three short rings or blasts to indicate the end of the drill or emergency.


Actions to take:

  • Go to your assigned fire station
  • Confirm the location of the fire
  • Perform your duties as listed in the muster list


3. Man Overboard Alarm


A man overboard (MOB) situation requires immediate response. The alarm is identified by three long rings on the internal bell system and three long blasts on the ship’s whistle.


Lifebuoys fitted with light and smoke signals are also deployed to mark the person’s location in the water and assist in search efforts.


Actions to take:

  • Raise the alarm and alert the bridge immediately
  • Keep sight of the person in the water
  • Deploy the MOB buoy and prepare rescue equipment


4. Abandon Ship Alarm


When conditions onboard become too dangerous to remain, the abandon ship signal is given by the master, usually through the PA system.

It consists of more than six short blasts followed by one long blast on the whistle and general alarm bells, similar to the general alarm but followed by verbal confirmation to abandon ship.


Actions to take:

  • Take your lifejacket or immersion suit and muster as assigned
  • Bring essential items listed in the muster list (water, rations, blankets, etc.)
  • Avoid using interior routes if possible
  • Wait for the master’s final order to abandon ship


5. Navigational Alarms


On the bridge, all navigational systems, such as radar, gyro compass, and lights, are fitted with failure alarms.

If a fault occurs, an alarm will sound, and the affected system or equipment will be displayed on the navigation panel.


Actions to take:

  • Identify which equipment triggered the alarm
  • Locate the cause of the malfunction
  • Rectify the fault or switch to backup equipment


6. Machinery Space Alarm


The engine room houses multiple pieces of critical machinery that are continuously monitored. Each system is fitted with safety alarms to indicate malfunctions.


When a machinery alarm is activated, it appears on the control room panel, showing which equipment or system is affected.


Actions to take:

  • Identify the equipment related to the alarm
  • Investigate the cause
  • Rectify the issue or switch to standby machinery


7. Machinery Space CO₂ Alarm


Engine rooms are equipped with a CO₂ fixed firefighting system that releases carbon dioxide to extinguish fires.

This alarm differs from all other signals to avoid confusion. When the CO₂ release cabinet door is opened, both audible and visual alarms are triggered to warn all personnel to evacuate immediately.


8. Cargo Space CO₂ Alarm


Cargo holds on certain vessels also have fixed CO₂ systems with distinct alarms.


These signals are designed to be clearly recognizable, alerting the crew that CO₂ has been or will be released in a cargo space.


Actions to take:

  • Conduct a headcount to ensure all crew are safe
  • Confirm that the cargo hold is sealed and unmanned
  • Shut down all ventilation systems in the affected area


9. Ship Security Alarm System (SSAS)


In compliance with SOLAS Chapter XI-2/5, all ships must have a Ship Security Alert System (SSAS).


Unlike other alarms, the SSAS is silent - activated in the event of piracy or security threats. When triggered, it sends a signal to designated coastal or flag-state authorities via satellite, without alerting anyone onboard or nearby vessels.


Every alarm on board a ship serves one purpose - to protect lives and assets at sea. Understanding what each alarm means, how it sounds, and what actions to take is essential for every seafarer. Familiarity saves time, and at sea, time can save lives.