Nautical flags aim to provide ways and means of communication in situations related to safety of navigation and persons, being an international code system used for a boat to signal to shore or for two boats to signal to each other.

Individual flags have specific and standard meanings. These ones can be used in combination with another flag or alone. Using different nautical colored flags have a different meaning.

Nautical flags are made up of 26 square flags, which represent the letters of the alphabet. There are also 10 numbered pendants, one answering pendant and three substitutes.

You will see nautical flags in a few colors because only a few flag colors are easily recognized:

  • Blue
  • Yellow
  • Red
  • Black
  • White

Nautical Flags and their meanings

It’s important to understand nautical flags and their meaning because they are valuable at sea in case of breakdowns in other communications systems (eg. radio) or in case of danger.

  • One-flag signals are urgent or common signals.
  • Two-flag signals are used for distress and maneuvering.
  • Three-flag signals are for points of the compass, relative bearings, standard times, verbs, punctuation and also general code and decode signals.
  • Four-flags are used mostly for geographical signals, names of ships, bearings, etc.
  • Five-flag signals are used to relate time and position.
  • Six-flag signals are used to indicate the main cardinal directions (N, S, E or W) in latitude and longitude signals.
  • Seven-flags are for longitude signals containing more than one hundred degrees.

Nautical flags are also used in nautical racing which signal to the competitors what they are supposed to do.

nautical flags
International Nautical Flags and Pennants1st , 2nd & 3rd Repeaters are called substitutes. 0-9 – numeral pennants.

The Nautical Flag Alphabet 

It is important to know each flag representing a letter has a meaning.
International meanings for nautical flags:

  • A: Alpha – diver down; I am undergoing a speed trial
  • B: Bravo – carrying dangerous cargo
  • C: Charlie – yes (affirmative)
  • D: Delta – keep clear of me, I am manoevering with difficulty
  • E: Echo – altering course to starboard
  • F: Foxtrot – I am disabled, communicate with me
  • G: Golf – I want a pilot
  • H: Hotel – a pilot on board
  • I: India – I am altering my course to port
  • J: Juliet – vessel on fire keep clear
  • K: Kilo – I want to communicate with you
  • L: Lima – stop your vessel instantly, I have something important to communicate; Come Within Hail or Follow Me (Sailing Regatta)
  • M: Mike – my vessel is stopped and making no way through the water; Mark Missing (Sailing Regatta)
  • N: November – no (negative); Abandonment and Re-sail (Sailing Regatta)
  • O: Oscar – Man overboard
  • P: Papa – In port: All personnel return to ship; vessel is about to sail; At sea: It may be used by fishing vessels to mean: “My nets have come fast upon an obstruction”
  • Q: Quebec – I request free pratique
  • R: Romeo – reverse course
  • S: Sierra – engines are going astern
  • T: Tango – Keep clear; engaged in trawling. (International); Do not pass ahead of me. (Navy)
  • U: Uniform – you are heading into danger
  • V: Victor – require assistance
  • W: Whiskey – require medical assistance
  • X: X-ray – stop your intention
  • Y: Yankee – am dragging anchor
  • Z: Zulu – I require a tug

Solo or combined nautical flags have different meanings

Depending on the type of message, boats fly between 1 and 7 nautical flags. The combination of the O (Oscar) and W (Whiskey) flags, meanwhile, means “Man overboard. I require medical assistance”.

Signals with two nautical flags usually mean a certain problem of danger or maneuver. Three or more flags may include pendants and may indicate things such as compass points, time and position, geographic signals, geographic coordinates, and boat names.

Nautical Flags, sometimes the secret language of ships

While sailors around the world use nautical flags to communicate different scenarios, certain situations use secret language.

For example, the US Navy groups signals together in ways known only to its staff to communicate with its fellow ships.

NATO uses also the same nautical flags, with a few additional ones to warships, alone or in short sets to communicate various unclassified messages.

In yacht racing, the nautical flags have other meanings. These ones are solo or combined. For example, the P flag is used as the “preparatory” flag to indicate an imminent start while the S flag indicates that a course has been shortened.