21 Distress Signals That Indicate a Ship is Asking for Help

by | Last updated May 9, 2024 | Lifesaving | 0 comments

Distress signals are among the most important communication tools on board every vessel.

Because these emergency calls for help are universal, any seafarer should be able to tell that someone is in dire need of assistance.

Over the years, the maritime industry has developed various types of distress messages from ships.

If you receive any of these signals, act swiftly to provide assistance if you can do so.

What are distress signals?

Distress signals are a universal call for help at sea by mariners on merchant ships and other vessels.

These emergency signals tell everyone they are in imminent danger and require immediate assistance.

The most famous distress signal is the Morse Code SOS, which is internationally recognized and used by many distressed vessels, including the Titanic.

You can send a distress signal in many ways, such as visually, audibly, and electronically, like today’s DSC, EPIRB, SART, and Inmarsat terminals.

Visual Distress Signals

Visual distress signals are methods of communicating an emergency situation or a call for immediate assistance through highly visible visual indicators.

Like flares and high-intensity flashing lights, visual signals can be seen during the day, night, or even both.

They have specific colors and arrangements designed to attract attention.

1. Rocket Parachute Flare

A Rocket Parachute Flare is a type of pyrotechnic distress signal that shoots a glowing projectile into the sky and attracts the attention of nearby vessels, aircraft, or search and rescue teams.

2. Hand flares

Hand Flares are handheld pyrotechnic devices that produce a bright, red, or orange flame when activated.

A person riding a liferaft and holding a hand flare as his distress signal.

3. Orange smoke signal

The orange smoke signal is useful for instantly locating the exact position of the distressed mariners when rescuers are nearby.

The orange smoke signal is part of your liferaft equipment, along with the rocket parachute flares and hand flares.

4. Visible smoke and fire on a ship

If the nature of the distress is fire, you should be able to see visible smoke or fire, indicating the vessel is in grave danger.

5. Raising and lowering of hands repeatedly

Crew on deck visibly raising and lowering their extended hands is also a call for help. 

6. Ball Over Square (and vice versa)

Anything resembling a ball and a square (can be a flag) is a distress signal usually used by boaters.

7. Black ball and square on orange background

A black ball or circle beside a square on an orange background is a distress signal. This is an enhancement of the above signal.

8. Flag November-Charlie (N.C.)

Displaying the November flag above the Charlie flag indicates a cry for help.

This flag signal literally translates to “Yes-No,” which means the person displaying it is confused, doesn’t know what to do, and needs immediate assistance.

9. Visible SOS Mark

In some cases, seafarers paint their deck and ship’s hull with SOS letters if they are looking for rescue. At night, you can broadcast an SOS signal using an Aldis Lamp to nearby vessels.

The meaning of SOS is “Save Our Souls” or “Save Our Ship.”

10. Inverted and knotted national flag

For smaller ships, you may only have your national flag with you.

To inform nearby ships about your distress, you can tie your national flag in an overhand fashion and raise it upside-down.

11. Heliograph (Daylight Signalling Mirror)

A heliograph is a tool used that uses the sun’s light energy to attract attention over long distances.

The heliograph can be any object capable of reflecting sunlight toward the intended recipient, such as planes or other ships.

A daylight signaling mirror or heliograph.

12. Dye Marker

In some countries, like Canada and the U.S., marking the sea with a dye is used as a distress call. Dye markers function similarly to orange smoke signals, except that they are used on the water.

13. High-intensity white light flashing 60 times per minute

A flashing white light with high intensity can attract attention especially during night time. Some countries employ this as a form of distress signal.

Auditory Distress Signals

Auditory distress signals are sounds or alerts that indicate a person or vessel is in distress and requires immediate assistance.

As sound-based methods, Auditory signals are loud and unmistakable, even in poor visibility conditions.

14. Continuous sounding of emergency alarm signals

The vessel’s emergency alarm signals could be an immediate indicator of a distress signal, especially in heavy traffic.

Because of our safety drills, the loud and continuous alarms with the ship’s horn and bells unmistakably convey a vessel’s emergency.

15. Gunshot (or any explosive) fired every one minute

The internationally community recognizes the pattern of firing a gunshot every one minute as a distress call.

However, we should not use guns or other explosives sparingly, but instead, use other emergency signals if possible.

16. MAYDAY Call over the radio

Seafarers use the voice call “MAYDAY!” repeated three times over the radio as a form of emergency signal.

Broadcasting the MAYDAY call on Channel 16 takes precedence over any other calls.

17. SOS (- – – – – – – – -) Morse code in sound

Until the 1990s, seafarers use the telegraph key to transmit SOS over long distances.

Today, the invention of the Global Maritime Distress and Safety Systems (GMDSS) has made this tool obsolete.

An old telegraph key.

Electronic Distress Signals

Electronic distress signals are modern communication methods that utilize advanced technology to broadcast distress messages quickly and accurately.

These electronic signals send distress alerts by utilizing satellite technology and modern navigational tools such as radar, ECDIS, and GPS.

18. EPIRB (Emergency Position-Indicating Radio Beacon)

An Emergency Position-Indicating Radio Beacon or EPIRB is a distress beacon that transmits emergency signals on the 406MHz frequency to search and rescue authorities ashore via satellite technology.

EPIRB can be activated manually or automatically when the device is submerged underwater.

19. SART (Search and Rescue Transponder)

A Search and Rescue Transponder, or SART, is another form of homing beacon that specifically interrogates the 3 cm, 9 GHz X-band radar.

20. DSC (Digital Selective Calling) Alerting

A Digital Selective Calling (DSC) is a feature of the Global Maritime Distress and Safety System (GMDSS) that enables vessels to send distress alerts and pre-formatted distress messages over radio frequencies like VHF, M.F., and H.F.

21. Inmarsat C Terminal (via satellite communication)

An Inmarsat C Terminal is another satellite-based signal where the emergency signal is directly relayed to the nearest Maritime Rescue Coordination Centre (MRCC).

Pressing the red distress button on the Inmarsat terminal can send a distress signal in as little as 5 seconds.

An Inmarsat C Terminal with a red distress button.

When your vessel is in distress, you must use all available means to quickly attract the attention of the Rescue Coordination Center (RCC) and the nearest vessels.

These 21 distress signals will help you achieve just that. You only have to use the most efficient method appropriate to your situation.

May the winds be in your favor.



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