As a boater, it's important to understand nautical flags and their meaning. Some flags may alert you to a weather warning, while others may help you communicate with other ships on the water.
Nautical flags are made with a sequence of 26 square flags. Each flag represents a letter of the alphabet. There are also ten numbered flags, one answering pendant, and three substitutes or repeaters.
You will only find nautical flags in a few specific colors because they are easily recognizable. These colors are:
- Blue 
- Yellow 
- White 
- Black 
- Red 
There are different signals and messages specific flags or combinations of nautical flags communicate. Let's look at a few of the different types of flag signals and what they mean.
Weather Warning Signals
Four signals are created from nautical flags to signal different weather warnings. All-weather warning signals are communicated with red and/or black flags.
A small craft warning is simply a single red pendant flag, while a small craft advisory (gale warning) is two red pendant flags.
A storm warning is signaled by a single square red flag with a second black square in the center. If two square red flags with black squares are present, it's meant to communicate a hurricane warning.
Signals Broken Down By Number Of Flags
The number of flags present has a meaning. Here's the breakdown
- One-Flag Signals - Urgent or Common 
- Two-flag Signals - Distress or Maneuvering 
- Three-Flag Signals - Points of the Compass, Standard-Times, Verbs, Punctuation, Code and Decode Signals 
- Four-Flag Signals - Geographic, Names of Ships, and Bearings 
- Five-Flag Signals - To Relate Position and Time 
- Six-Flag Signals - Indicate West, East, South, or North in Longitude or Latitude Signals 
- Seven-Flag Signals - Longitude with more than one-hundred degrees 
Nautical flags are also used in racing to communicate messages to competitors.
International Nautical Flag Meanings
Each flag representing a letter of the alphabet has a meaning. The meanings are as follows:
- A or Alpha - keep clear, diver down 
- B or Bravo - carrying dangerous cargo 
- C or Charlie - yes 
- D or Delta - keep clear 
- E or Echo - altering course to starboard 
- F or Foxtrot - I am disabled 
- G or Golf - I want a pilot 
- H or Hotel - a pilot on board 
- I or India - altering course to port 
- J or Juliet - vessel on fire, keep clear 
- K or Kilo - I want to communicate with you 
- L or Lima - stop your vessel instantly 
- M or Mike - my vessel is stopped 
- N or November - no 
- O or Oscar - man overboard 
- P or Papa - vessel is about to sail 
- Q or Quebec - I request free pratique 
- R or Romeo - reverse course 
- S or Sierra - engines are going astern 
- T or Tango - keep clear 
- U or Uniform - you are heading into danger 
- V or Victor - require assistance 
- W or Whiskey - require medical assistance 
- X or X-ray - stop your intention 
- Y or Yankee - I am dragging anchor 
- Z or Zulu - I require a tug 
Understanding the meaning of nautical flags can help you communicate and receive messages on the water.

