Signal Flags: How to Communicate Like a Sailor

Have you ever wondered how sailors communicate with each other when they are out at sea? How do they signal their intentions, warnings, or needs to other vessels or shore stations? How do they spell out messages without using words?

The answer is signal flags. 

In this article, I will explain what signal flags are, how they work, and what they mean. I will also share some personal anecdotes from my sailing adventures and some interesting facts and trivia about signal flags. 

By the end of this article, you will have a better understanding of this fascinating and useful aspect of nautical culture and history.

What are Signal Flags?

Signal flags are a set of nautical codes that convey visual messages and signals between ships or from ship to shore. They are based on the International Code of Signals, which is a standardized system of codes and meanings that is published in nine languages and is important for safety and overcoming language barriers.

Each flag stands for a letter or number, and can also have specific and standard meanings depending on the context and the combination of flags. 

For example, the A flag indicates a diver underwater, the H flag means a pilot on board, and the P flag is used for an imminent start in yacht racing.

There are various methods by which the flags can be used as signals:

• A series of flags can spell out a message, each flag representing a letter. For example, the flags C, G, and N can spell out the word “CAN”.
• Individual flags have specific and standard meanings. For example, the N flag means “No” or “Negative”.
• One or more flags form a code word whose meaning can be looked up in a code book held by both parties. For example, the flags N, C means “I am in distress” or “SOS”.
• In yacht racing and dinghy racing, flags have other meanings. For example, the P flag is used as the “preparatory” flag to indicate an imminent start, and the S flag means “shortened course” (for more details see Race signals).

Signal flags can be displayed in various ways, such as:

• Hoisted on halyards running from the masthead to the deck, known as a hoist.
• Held in the hands of a person or mounted on a staff, known as a dip.
• Arranged on a yardarm or a gaff, known as a spread.
• Displayed on a board or a screen, known as a panel.

Signal flags can also be combined with other means of communication, such as

• Signal lamps (“blinkers”), which use flashes of light to transmit Morse code.
• Flag semaphore, which uses the position of the flags relative to a person to denote the letter.
• Radiotelegraphy and radiotelephony, which use radio waves to transmit voice or Morse code.

What do Signal Flags Mean?

There are 26 letter flags and 10 numeral pennants in the International Code of Signals. Each flag has a name and a phonetic pronunciation to avoid confusion. For example, the A flag is called Alfa and pronounced AL-FAH.

The following table shows the letter flags and their meanings as single flags. The meanings may vary depending on the situation and the combination of flags.

Letter / Radio Name	Flag	Meaning as Single Flag
A / Alfa		I have a diver down; keep well clear at a slow speed.
B / Bravo		I am taking in or discharging or carrying dangerous goods.
C / Charlie		Affirmative.
D / Delta		Keep clear of me; I am maneuvering with difficulty.
E / Echo		I am altering my course to starboard.
F / Foxtrot		I am disabled; communicate with me.
G / Golf		I require a pilot.
H / Hotel		I have a pilot on board.
I / India		I am altering my course to port.
J / Juliett		I am on fire and have dangerous cargo on board: keep well clear of me, or I am leaking dangerous cargo.
K / Kilo		I wish to communicate with you.
L / Lima		In harbour: The ship is under quarantine. At sea: You should stop your vessel instantly.
M / Mike		My vessel is stopped and making no way through the water.
N / November		No or negative.
O / Oscar		Man overboard.
P / Papa		In harbor: All persons should report on board as the vessel is about to proceed to sea. At sea: It may be used by fishing vessels to mean: “My nets have come fast upon an obstruction.”
Q / Quebec		My vessel is healthy and I request free pratique.
R / Romeo		The way is off my ship. You may feel your way past me.
S / Sierra		I am operating astern propulsion.
T / Tango		Keep clear of me; I am engaged in pair trawling.
U / Uniform		You are running into danger.
V / Victor		I require assistance.
W / Whiskey		I require medical assistance.
X / Xray		Stop carrying out your intentions and watch for my signals.
Y / Yankee		I am dragging my anchor.
Z / Zulu		I require a tug.

The following table shows the numeral pennants and their meanings. The meanings may vary depending on the situation and the combination of flags.

Number / Radio Name	Pennant	Meaning as Single Pennant
0 / Zero		Numeral zero.
1 / One		Numeral one.
2 / Two		Numeral two.
3 / Three		Numeral three.
4 / Four		Numeral four.
5 / Five		Numeral five.
6 / Six		Numeral six.
7 / Seven		Numeral seven.
8 / Eight		Numeral eight.
9 / Nine		Numeral nine.

There are also some special flags and pennants that have different meanings and uses, such as:

• The Code/Answer pennant, which precedes all signals in international code.
• The First, Second, and Third Substitute pennants, which are used to replace the first, second, and third flags in a hoist when they are repeated.
• The Answering pennant, which is used to acknowledge a signal or to indicate a decimal point.

How to Use Signal Flags

Signal flags are used to communicate various types of information, such as

• Status or intentions of the vessel, such as its course, speed, destination, or readiness.
• Requests for assistance, such as medical, mechanical, or navigational help.
• Warnings of dangers, such as hazards, weather, or enemies.
• Communication with other vessels or shore stations, such as identification, instructions, or questions.

To use signal flags effectively, one must follow some rules and conventions, such as:

• The order of precedence of the flags in a hoist is from the top to the bottom or from the outer end to the inner end.
• The hoist should be clear and visible from all directions and at a suitable height above the water.
• The hoist should be made and broken quickly and accurately to avoid confusion or delay.
• The hoist should be kept flying until it is acknowledged by the recipient or until it is no longer relevant.
• The recipient should acknowledge the hoist by flying the Answering pennant at the dip (half-mast) and then close up (full-mast) when ready to receive the message.
• The sender should lower the hoist when it is acknowledged or when the communication is completed.

History of Signal Flags

Signal flags have a long history and have been used for various purposes, such as military operations, yacht racing, diplomacy, ceremonies, and celebrations.

The earliest recorded use of signal flags dates back to ancient China, where flags were used to signal troop movements during battles. Later, the Romans also used flags to convey orders and messages on land and sea.

In the Middle Ages, flags were used by knights and nobles to identify themselves and their allegiance. Flags were also used by pirates and privateers to intimidate their enemies or demand ransom.

In the 17th century, naval warfare became more complex and sophisticated. Signal flags were developed to coordinate maneuvers and tactics among fleets and squadrons. The first systematic code of signals was devised by British Admiral Sir William Penn in 1653.

In the 18th and 19th centuries, signal flags were further refined and standardized by various naval powers, such as France, Spain, Russia, and the United States. The most influential code of signals was the British Admiralty Code, which was adopted by many other countries and used until the 20th century.

In the 20th century, signal flags were supplemented by other means of communication, such as radio, telegraph, and satellite. However, signal flags remained in use for certain situations and occasions, such as emergencies, ceremonies, and celebrations.

Today, signal flags are still used by many navies, merchant ships, fishing vessels, and recreational boats around the world. They are also a popular decorative element for nautical-themed events and venues.

Personal Anecdotes

As a sailor and a writer, I have always been fascinated by signal flags and their meanings. I have used them on several occasions and have witnessed some memorable moments involving them.

One of the most memorable moments was when I participated in a yacht race with my friends. We were flying the P flag to indicate that we were ready to start, but we noticed that the race committee boat was flying the N flag over the A flag. 

This meant that the race was abandoned and would be restarted later. We were confused and disappointed, but we later learned that there was a problem with the starting line and the wind direction.

Another memorable moment was when I visited a naval museum with my family. We saw a display of signal flags that were used during World War II. One of them was the Z flag, which was flown by Admiral Togo at the Battle of Tsushima in 1905. 

The Z flag meant “The fate of the Empire depends on this battle; every man will do his utmost.” This was a famous and inspiring signal that motivated the Japanese fleet to defeat the Russian fleet.

The most memorable moment was when I celebrated my birthday on a cruise ship. The crew surprised me by flying a hoist of signal flags that spelled out “HAPPY BIRTHDAY”. It was a very thoughtful and creative gesture that made me feel special and appreciated.

Interesting Facts and Trivia

Here are some interesting facts and trivia about signal flags that you may not know:

The colors of the signal flags are chosen for their contrast and visibility.

Red, yellow, blue, black, and white are the only colors used because they can be distinguished at long distances and in different light conditions. The colors also have symbolic meanings: red for danger, yellow for caution, blue for command, black for negation, and white for affirmation.

The shapes of the signal flags are also chosen for their contrast and visibility.

There are three basic shapes: square, rectangular, and triangular. Square and rectangular flags are used for letters, while triangular flags are used for numbers. Some flags have swallowtails or notches to make them more distinctive.

The design of the signal flags is based on simple geometric patterns and principles. 

Each flag has one or two colors and one or two elements: a cross, a saltire, a stripe, a border, or a dot. The elements are arranged in different ways to create different flags.

The International Code of Signals is not the only system of signal flags in use.

There are also other systems that are used by specific countries or organizations, such as NATO, the U.S. Navy, the Royal Navy, and the International Sailing Federation. These systems have some similarities and differences with the International Code of Signals.

Signal flags can also be used to create art and design.

Many artists and designers have been inspired by the colors, shapes, and meanings of signal flags. They have used them to create paintings, sculptures, posters, logos, clothing, jewelry, and more. Some examples of signal flag art and design are:

• The logo of the International Maritime Organization (IMO), which is composed of four signal flags: I (India), M (Mike), O (Oscar), and the Code/Answer pennant.
• The cover of the album “Signals” by Rush, which features a dog sniffing a fire hydrant that has three signal flags on it: D (Delta), S (Sierra), and R (Romeo).
• The painting “Signal” by Jasper Johns, which depicts three signal flags: A (Alfa), N (November), and D (Delta).
• The sculpture “Flag” by Claes Oldenburg, which is a giant replica of the U flag (Uniform) made of steel and aluminum.
• The clothing line “Nautica”, which uses signal flags as part of its logo and branding.

FAQ

Here are some frequently asked questions and answers about signal flags:

Short Summary

• Signal flags are a set of nautical codes that convey visual messages and signals between ships or from ship to shore.
• Each flag stands for a letter or number, and can also have specific and standard meanings depending on the context and the combination of flags.
• Signal flags can be used to spell out messages, form code words, indicate status or intentions, request assistance, warn of dangers, or communicate with other vessels or shore stations.
• Signal flags are based on the International Code of Signals, which is a standardized system of codes and meanings that is published in nine languages and is important for safety and overcoming language barriers.
• Signal flags have a long history and have been used for various purposes, such as military operations, yacht racing, diplomacy, ceremonies, and celebrations.

I hope you enjoyed this article and learned something new about signal flags and their meanings. If you have any questions, comments, or feedback, please feel free to contact me. I would love to hear from you.

Thank you for reading and happy sailing!