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The system of international maritime signal flags is a way of representing individual letters of the alphabet in signals to or from ships. It is a component of the International Code of Signals. Nautical signal flags can be used in various methods:

  • Each flag spells out a letter of an alphabetic message.
  • Individual signal flags have specific and standard meanings; for example, diving support vessels raise the "A flag" indicating their inability to move from their current location because they have a diver underwater.
  • One or more flags form a code word whose meaning can be looked up in a code book held by both parties. An example is the Popham numeric code used at the Battle of Trafalgar.
  • In yacht racing and dinghy racing, nautical signal 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".
  • Note: NATO uses an extra set of flags to communicate specific types of messages.

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International Code Signal Letters

Letter

Flag

Meaning

 Buy Flags

A

Alfa

 Alfa

I have a diver down; keep well clear at slow speed.

With three numerals, azimuth or bearing.

B

Bravo

 Bravo I am taking in, or discharging, or carrying dangerous goods. (Originally used by the Royal Navy specifically for military explosives.)

C

Charlie

Charlie

Affirmative.

With three numerals, course.

D

Delta

Delta

Keep clear of me; I am maneuvering with difficulty.

With two, four, or six numerals, date.

E

Echo

Echo I am altering my course to starboard.

F

Foxtrot

Foxtrot I am disabled; communicate with me.

G

Golf

Golf

I require a pilot. When made by fishing vessels operating in close proximity on the fishing grounds it means: "I am hauling nets".

With four or five numerals, longitude. (The last two numerals denote minutes and the rest degrees.)

H

Hotel

Hotel I have a pilot on board.

India

India I am altering my course to port.

J

Juliet

Juliet I am on fire and have dangerous cargo on board: keep well clear of me, or I am leaking dangerous cargo.

K

Kilo

Kilo

I wish to communicate with you.

With one numeral, I wish to communicate with you by; 1) Morse signalling by hand-flags or arms; 2) Loud hailer (megaphone); 3) Morse signalling lamp; 4) Sound signals.

L

Lima

Lima

In harbor: The ship is under Quarantine. At sea: You should stop your vessel instantly.

With four numerals, latitude. (The first two denote degrees and the rest minutes.)

M

Mike

Mike My vessel is stopped and making no way through the water.

N

November

November Negative.

O

Oscar

Oscar Man overboard (often attached to the man overboard pole on boats).

P

Papa

Papa The Blue Peter. 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

Quebec My vessel is "healthy" and I request free pratique.

R

Romeo

Romeo

The way is off my ship.

With one or more numerals, distance in nautical miles.

S

Sierra

Sierra I am operating astern propulsion. With one or more numerals, speed in knots.

T

Tango

Tango

Keep clear of me; I am engaged in pair trawling.

With four numerals, local time. (The first two denote hours and the rest minutes.)

U

Uniform

Uniform You are running into danger.

V

Victor

 Victor

I require assistance.

With one or more numerals, speed in kilometers per hour.

W

Whiskey

Whiskey I require medical assistance.

X

Xray

Xray Stop carrying out your intentions and watch for my signals.

Y

Yankee

Yankee I am dragging my anchor.

Z

Zulu

Zulu

I require a tug. When made by fishing vessels operating in close proximity on the fishing grounds it means: "I am shooting nets".

With one or more numerals, time (UTC). (The first two denote hours and the rest minutes.) (Origin of the phrase 'Zulu Time'.)

* N and C together (No and Yes) is used as a distress signal.

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International Code Numbers

Number

International Code Signal

Buy International Code Signal Pennant with:

NATO

(Custom Order)

Russian

(Custom Order)

0

Zero

 ICS_Zero  NATO_Zero  Russian_Zero

1

One

 ICS_One  NATO_One  Russian_One

2

Two

 ICS_Two  NATO_Two  Russian_Two

3

Three

 ICS_Three  NATO_Three  Russian_Three

4

Four

 ICS_Four  NATO_Four  Russian_Four

5

Five

 ICS_Five  NATO_Five  Russian_Five

6

Six

 ICS_Six  NATO_Six  Russian_Six

7

Seven

 ICS_Seven  NATO_Seven  Russian_Seven

8

Eight

 ICS_Eight  NATO_Eight  Russian_Eight

9

Nine

 ICS_Nine  NATO_Nine  Russian_Nine

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NATO Signal Flags

Signal

Flag

Meaning

 Buy Flag:

First Substitute

 ICS_Repeat_One

Repeat of the first flag in the hoist

Second Substitute

 ICS_Repeat_Two

Repeat of the second flag in the hoist

Third Substitute

 ICS_Repeat_Three

Repeat of the third flag in the hoist

Fourth Substitute

 ICS_Repeat_Four

Repeat of the fourth flag in the hoist

Custom Order

ANS

 ICS_Answer

Code/Answer

CORPEN

 ICS_Corpen

Course Pennant

Custom Order

DESIG

 ICS_Designation

Designation

Custom Order

DIV

 ICS_Division

Division

Custom Order

EMERG

 ICS_Emergency

Emergency

Custom Order

FORM

 ICS_Formation

Formation

Custom Order

FLOT

 ICS_Group

Group

Custom Order

NEGAT

 ICS_Negation

Negation

Custom Order

PORT

 ICS_Port

Port

Custom Order

PREP

 ICS_Prepare

Preparatory

Custom Order

INT

 ICS_Question

Question

Custom Order

SCREEN

 ICS_Screen

Screen

Custom Order

SPEED

 ICS_Speed

Speed

Custom Order

SQUAD

 ICS_Squadron

Squadron

Custom Order

STBD

 ICS_Starboard

Starboard

Custom Order

STATION

 ICS_Station

Station

Custom Order

SUBDIV

 ICS_Subdivision

Subdivision

Custom Order

TURN

 ICS_Turn

Turn

Custom Order

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Storm Warning Flags

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Flag

Meaning

 Buy Flag:

 storm warning

Storm Warning / Tropical Storm Warning

Buy with Grommets
 hurricane warning

Hurricane Warning / Hurricane Force Wind Warning

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 small craft

Small Craft Advisory

Buy with Grommets
 gale warning

Gale Warning / Gale Force Wind Warning

Buy with Grommets

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This article is licensed under the GNU Free Documentation License.

It uses material from the Wikipedia article "International Maritime Signal Flags".