International maritime signal code flags of the sea

 

International maritime signal flags refers to various flags used to communicate with ships, yachts and people on or near the sea.

The principal system of flags and associated codes is the International Code of Signals. 

Various navies have flag systems with additional flags and codes, and other flags are used in special uses, or have historical significance.

  • There are various methods by which the flags can be used as signals
  • Each flag spells an alphabetic message, letter by letter
  • One or more flags form a code word whose meaning can be looked up in a code book held by both parties
  • In yacht racing and dinghy racing, flags have other meanings

 

marine flags code signals coastal safety sea school

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

The NATO usage generally differs from the international meanings, and therefore warships will fly the Code/answer flag above the signal to indicate it should be read using the international meaning.

Letter flags and their meaning

A
Alfa
ICS Alpha.svg “I have a diver down; keep well clear at slow speed.”
B
Bravo
ICS Bravo.svg “I am taking in or discharging or carrying dangerous goods.” 
C
Charlie
ICS Charlie.svg “Affirmative.”
D
Delta
ICS Delta.svg “Keep clear of me; I am maneuvering with difficulty.”
E
Echo
ICS Echo.svg “I am altering my course to starboard.”
F
Foxtrot
ICS Foxtrot.svg “I am disabled; communicate with me.”
G
Golf
ICS Golf.svg “I require a pilot.”

 

By fishing vessels near fishing grounds: “I am hauling nets.”

H
Hotel
ICS Hotel.svg “I have a pilot on board.”
I
India
ICS India.svg “I am altering my course to port.”[
J
Juliet
ICS Juliet.svg “I am on fire and have dangerous cargo on board: keep well clear of me.”
K
Kilo
ICS Kilo.svg “I wish to communicate with you.”
L
Lima
ICS Lima.svg In harbour: “The ship is quarantined.”

 

At sea: “You should stop your vessel instantly.”

M
Mike
ICS Mike.svg “My vessel is stopped and making no way through the water.”
N
November
ICS November.svg “Negative.”
O
Oscar
ICS Oscar.svg Man overboard.”[b] (often attached to the man overboard pole on boats).
P
Papa
ICS Papa.svg
In harbour: 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
ICS Quebec.svg “My vessel is ‘healthy’ and I request free pratique.”
R
Romeo
ICS Romeo.svg (No ICS meaning as single flag)
S
Sierra
ICS Sierra.svg “I am operating astern propulsion.”
T
Tango
ICS Tango.svg Fishing boats: “Keep clear of me; I am engaged in pair trawling.”
U
Uniform
ICS Uniform.svg “You are running into danger.”
V
Victor
ICS Victor.svg “I require assistance.”
W
Whiskey
ICS Whiskey.svg “I require medical assistance.”
X
Xray
ICS X-ray.svg “Stop carrying out your intentions and watch for my signals.”
Y
Yankee
ICS Yankee.svg “I am dragging my anchor.”
Z
Zulu
ICS Zulu.svg “I require a tug.”
By fishing vessels near fishing grounds: “I am shooting nets.”[d]
Note – N and C together (“no” and “yes”) is used as a distress signal.

 

Number flags

Number NATO flag International flag
0
Zero
ICS Zero.svg ICS Pennant Zero.svg
1
One
ICS One.svg ICS Pennant One.svg
2
Two
ICS Two.svg ICS Pennant Two.svg
3
Three
ICS Three.svg ICS Pennant Three.svg
4
Four
ICS Four.svg ICS Pennant Four.svg
5
Five
ICS Five.svg ICS Pennant Five.svg
6
Six
ICS Six.svg ICS Pennant Six.svg
7
Seven
ICS Seven.svg ICS Pennant Seven.svg
8
Eight
ICS Eight.svg ICS Pennant Eight.svg
9
Nine
ICS Niner.svg ICS Pennant Niner.svg

Substitute

Substitute or repeater flags allow messages with duplicate characters to be signaled without the need for multiple sets of flags. IE the second substitute flag repeats the second flag in the hoist or signal.

The substitute flags are as follows:

ICS Repeat One.svg ICS Repeat Two.svg ICS Repeat Three.svg ICS Repeat Four.svg
First substitute Second substitute Third substitute Fourth substitute

 

Examples of multiple-flag signals

Sample International Code of Signals Messages
Flag Hoist Code Meaning Flag Hoist Code Meaning Flag Hoist Code Meaning
Alpha flag.svg
Charlie flag.svg
AC I am abandoning my vessel. Alpha flag.svg
Delta flag.svg
AD I am abandoning my vessel which has suffered a nuclear accident and is a possible source of radiation danger. Alpha flag.svg
November flag.svg
AN I need a doctor.
Alpha flag.svg
November flag.svg
1-Unaone.svg
AN 1 I need a doctor; I have severe burns. Alpha flag.svg
November flag.svg
2-Bissotwo.svg
AN 2 I need a doctor; I have radiation casualties. Echo flag.svg
Lima flag.svg
EL Repeat the distress position.
Echo flag.svg
Lima flag.svg
1-Unaone.svg
EL 1 What is the position of vessel in distress? Golf flag.svg
Mike flag.svg
GM I cannot save my vessel. Golf flag.svg
November flag.svg
GN You should take off persons.
Golf flag.svg
November flag.svg
1-Unaone.svg
GN 1 I wish some persons taken off. Skeleton crew will remain on board. Golf flag.svg
November flag.svg
2-Bissotwo.svg
GN 2 I will take off persons. Golf flag.svg
November flag.svg
3-Terrathree.svg
GN 3 Can you take off persons?
India flag.svg
Tango flag.svg
IT I am on fire. Mike flag.svg
Alpha flag.svg
Alpha flag.svg
MAA I request urgent medical advice. Mike flag.svg
Alpha flag.svg
Bravo flag.svg
MAB I request you to make rendezvous in position indicated.
Mike flag.svg
Alpha flag.svg
Charlie flag.svg
MAC I request you to arrange hospital admission. Mike flag.svg
Alpha flag.svg
Delta flag.svg
MAD I am . . . (indicate number) hours from the nearest port. Mike flag.svg
Sierra flag.svg
1-Unaone.svg
MS 1 My vessel is a dangerous source of radiation; you may approach from my starboard side.
Victor flag.svg
Golf flag.svg
VG The coverage of low clouds is… (number of octants or eighths of sky covered). Uniform flag.svg
Sierra flag.svg
4-Kartefour.svg
US 4 Nothing can be done until weather moderates.
November flag.svg
Charlie flag.svg
NC Distress signal