thumb|Two sailing ships [[Dressing overall|dressed overall with their signal flags.]]
International maritime signal flags are standarized flags used to communicate with ships. 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.
Usage
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.
- Individual flags have specific and standard meanings; for example, diving support vessels raise the "A" (Alfa) flag indicating their inability to move from their current location because they have a diver underwater and to warn other vessels to keep clear to avoid endangering the diver(s) with their propellers.
- 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, flags have other meanings; for example, the P (Papa) flag is used as the "preparatory" flag to indicate an imminent start, and the S (Sierra) flag means "shortened course" (for more details see Race signals).
thumb|Sailor prepares signal flags for operations at sea
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.
During the Allied occupations of Axis countries after World War II, use and display of those nations' national flags was banned. In order to comply with the international legal requirement that a ship identify its registry by displaying the appropriate national ensign, swallow-tailed versions of the C, D, and E signal flags were designated as, respectively, provisional German, Okinawan, and Japanese civil ensigns. Being swallowtails, they are commonly referred to as the "C-pennant" (German: C-Doppelstander), "D-pennant", and "E-pennant".
== Letter flags (with ICS meaning) ==<!-- This section is linked from Flag semaphore -->
{| class="wikitable plainrowheaders"
|+Letter flags and ICS meanings
|-
!scope="col"| Letter /<br>radio<br>name
!scope="col"| Flag
!scope="col"| Blazon
!scope="col"| ICS meaning as single flag
!scope="col"| Meaning when used with numeric complements
|-
!scope="row" id="A"| A<br>Alfa<!-- #### ATTENTION: "ALFA" IS THE CORRECT SPELLING; SEE DISCUSSION ON TALK PAGE BEFORE CHANGING. #### -->
| style="background-color: #c8d0d4; padding-left: 1em; padding-right: 1em;" | frameless|center|upright=0.3
| Swallowtailed, per pale argent and azure
| "I have a diver down; keep well clear at slow speed."
| Azimuth or bearing
|-
!scope="row" id="B"| B<br>Bravo
| style="background-color: #c8d0d4; padding-left: 1em; padding-right: 1em;" | frameless|center|upright=0.3
| Swallowtailed, gules
| "I am taking in or discharging or carrying dangerous goods." (Originally used by the Royal Navy specifically for military explosives.)
|
|-
!scope="row" id="C"| C<br />Charlie
| style="background-color: #c8d0d4; padding-left: 1em; padding-right: 1em;" | frameless|center|upright=0.3
| Azure, a fess gules fimbriated argent
| "Affirmative."
| Magnetic bearing
|-
!scope="row" id="D"| D<br />Delta
| style="background-color: #c8d0d4; padding-left: 1em; padding-right: 1em;" | frameless|center|upright=0.3
| Or, a Spanish fess azure
| "Keep clear of me; I am maneuvering with difficulty."
|
|-
!scope="row" id="G"| G<br />Golf
| style="background-color: #c8d0d4; padding-left: 1em; padding-right: 1em;" | frameless|center|upright=0.3
| Paly of six or and azure
| "I require a pilot."By fishing vessels near fishing grounds: "I am hauling nets."
| Longitude (The first 2 or 3 digits denote degrees; the last 2 denote minutes.)
|-
!scope="row" id="H"| H<br />Hotel
| style="background-color: #c8d0d4; padding-left: 1em; padding-right: 1em;" | frameless|center|upright=0.3
| Per pale argent and gules
| "I have a pilot on board."
|
|-
!scope="row" id="V"| V<br />Victor
| style="background-color: #c8d0d4; padding-left: 1em; padding-right: 1em;" | frameless|center|upright=0.3
| Argent, a saltire gules
| "I require assistance."
| Velocity in kilometres per hour.
|-
!scope="row" id="W"| W<br />Whiskey
| style="background-color: #c8d0d4; padding-left: 1em; padding-right: 1em;" | frameless|center|upright=0.3
| Azure, an inescutcheon gules fimbriated argent
| "I require medical assistance."
|
|-
!scope="row" id="X"| X<br />Xray
<!-- #### ATTENTION: "XRAY" (WITHOUT A HYPHEN) IS THE CORRECT SPELLING; SEE DISCUSSION ON TALK PAGE BEFORE CHANGING. #### -->
| style="background-color: #c8d0d4; padding-left: 1em; padding-right: 1em;" | frameless|center|upright=0.3
| Argent, a cross azure
| "Stop carrying out your intentions and watch for my signals."
|
|-
!scope="row" id="Y"| Y<br />Yankee
| style="background-color: #c8d0d4; padding-left: 1em; padding-right: 1em;" | frameless|center|upright=0.3
| Bendy sinister of ten or and gules
| "I am dragging my anchor."
|
|-
!scope="row" id="Z"| Z<br />Zulu
| style="background-color: #c8d0d4; padding-left: 1em; padding-right: 1em;" | frameless|center|upright=0.3
| Per saltire or, sable, gules and azure
| "I require a tug."By fishing vessels near fishing grounds: "I am shooting nets."<!-- Removed non-ICS "meanings". See Talk page.-->
| Time (UTC). (The first 2 digits denote hours; the last 2 denote minutes.)
|}
Notes
Number flags
{| class="wikitable plainrowheaders"
|+NATO number flags
|-
!scope="col"| Number
!scope="col"| NATO flag
!scope="col"| ICS flag
!scope="col"| Blazons
|-
!scope="row" style="text-align: center;"| 0<br />Zero
| style="text-align: center; background-color: #c8d0d4; padding-left: 1em; padding-right: 1em;" | frameless|center|upright=0.3
| style="text-align: center; background-color: #c8d0d4; padding-left: 1em; padding-right: 1em;" | frameless|center|upright=0.5
| NATO: Argent, five crosses hummetty azure in saltire<br/>ICS: Or, a pale gules
|-
!scope="row" style="text-align: center;"| 1<br />One
| style="text-align: center; background-color: #c8d0d4; padding-left: 1em; padding-right: 1em;" | frameless|center|upright=0.3
| style="text-align: center; background-color: #c8d0d4; padding-left: 1em; padding-right: 1em;" | frameless|center|upright=0.5
| NATO: Gules, a fess or<br/>ICS: Argent, a torteau
|-
!scope="row" style="text-align: center;"| 2<br />Two
| style="text-align: center; background-color: #c8d0d4; padding-left: 1em; padding-right: 1em;" | frameless|center|upright=0.3
| style="text-align: center; background-color: #c8d0d4; padding-left: 1em; padding-right: 1em;" | frameless|center|upright=0.5
| NATO: Or, a fess gules<br/>ICS: Azure, a plate
|-
!scope="row" style="text-align: center;"| 3<br />Three
| style="text-align: center; background-color: #c8d0d4; padding-left: 1em; padding-right: 1em;" | frameless|center|upright=0.3
| style="text-align: center; background-color: #c8d0d4; padding-left: 1em; padding-right: 1em;" | frameless|center|upright=0.5
| NATO: Azure, a fess gules<br/>ICS: Tierced in pale gules, argent and azure
|-
!scope="row" style="text-align: center;"| 4<br />Four
| style="text-align: center; background-color: #c8d0d4; padding-left: 1em; padding-right: 1em;" | frameless|center|upright=0.3
| style="text-align: center; background-color: #c8d0d4; padding-left: 1em; padding-right: 1em;" | frameless|center|upright=0.5
| NATO: Gules, a saltire argent<br/>ICS: Gules, a cross of Saint Philip argent
|-
!scope="row" style="text-align: center;"| 5<br />Five
| style="text-align: center; background-color: #c8d0d4; padding-left: 1em; padding-right: 1em;" | frameless|center|upright=0.3
| style="text-align: center; background-color: #c8d0d4; padding-left: 1em; padding-right: 1em;" | frameless|center|upright=0.5
| NATO: Or, a saltire azure<br/>ICS: Per pale or and azure
|-
!scope="row" style="text-align: center;"| 6<br />Six
| style="text-align: center; background-color: #c8d0d4; padding-left: 1em; padding-right: 1em;" | frameless|center|upright=0.3
| style="text-align: center; background-color: #c8d0d4; padding-left: 1em; padding-right: 1em;" | frameless|center|upright=0.5
| NATO: Bendy sinister of seven argent and azure<br/>ICS: Per fess sable and argent
|-
!scope="row" style="text-align: center;"| 7<br />Seven
| style="text-align: center; background-color: #c8d0d4; padding-left: 1em; padding-right: 1em;" | frameless|center|upright=0.3
| style="text-align: center; background-color: #c8d0d4; padding-left: 1em; padding-right: 1em;" | frameless|center|upright=0.5
| NATO: Gules, a pale argent<br/>ICS: Per fess or and gules
|-
!scope="row" style="text-align: center;"| 8<br />Eight
| style="text-align: center; background-color: #c8d0d4; padding-left: 1em; padding-right: 1em;" | frameless|center|upright=0.3
| style="text-align: center; background-color: #c8d0d4; padding-left: 1em; padding-right: 1em;" | frameless|center|upright=0.5
| NATO: Or, a pale azure<br/>ICS: Argent, a cross of Saint Philip gules
|-
!scope="row" style="text-align: center;"| 9<br />Nine
| style="text-align: center; background-color: #c8d0d4; padding-left: 1em; padding-right: 1em;" | frameless|center|upright=0.3
| style="text-align: center; background-color: #c8d0d4; padding-left: 1em; padding-right: 1em;" | frameless|center|upright=0.5
| NATO: Azure, a pale argent<br/>ICS: Quarterly argent, sable, gules and or
|-
!scope="row" style="text-align: center;"| ./½<br />Point/One Half
| style="text-align: center; background-color: #c8d0d4; padding-left: 1em; padding-right: 1em;" |
| style="text-align: center; background-color: #c8d0d4; padding-left: 1em; padding-right: 1em;" |frameless|130x130px
|ICS: Paleways of five pieces, gules and argent
|}
Substitute
Substitute or repeater flags allow messages with duplicate characters to be signaled without the need for multiple sets of flags.
The four NATO substitute flags are as follows:
{| class="wikitable"
|-
|
| frameless|center|upright=0.5 || frameless|center|upright=0.5 || frameless|center|upright=0.5 || frameless|center|upright=0.5
|-
|
| First substitute || Second substitute || Third substitute || Fourth substitute
|-
|Blazon
|Triangular, or, a bordure azure which does not touch the dexter end
|Triangular, per pale azure and argent
|Triangular, argent, a fess sable
|Triangular, gules, a square or in the fess position touching the dexter end
|}
The International Code of Signals includes only the first three of these substitute flags. To illustrate their use, here are some messages and the way they would be encoded:
{| class="wikitable"
|-
| "N" || frameless|center|upright=0.3
|-
| "O" || frameless|center|upright=0.3
|-
| "NO" || frameless|center|upright=0.3 || frameless|center|upright=0.3
|-
| "NON" || frameless|center|upright=0.3 || frameless|center|upright=0.3 || frameless|center|upright=0.5
|-
| "NOO" || frameless|center|upright=0.3 || frameless|center|upright=0.3 || frameless|center|upright=0.5
|-
| "NOON" || frameless|center|upright=0.3 || frameless|center|upright=0.3 || frameless|center|upright=0.5 || frameless|center|upright=0.5
|-
| "NONO" || frameless|center|upright=0.3 || frameless|center|upright=0.3 || frameless|center|upright=0.5 || frameless|center|upright=0.5
|-
| "NONON" || frameless|center|upright=0.3 || frameless|center|upright=0.3 || frameless|center|upright=0.5 || frameless|center|upright=0.5 || frameless|center|upright=0.5
|-
| "NONNN" || frameless|center|upright=0.3 || frameless|center|upright=0.3 || frameless|center|upright=0.5 || frameless|center|upright=0.5 || frameless|center|upright=0.5
|}
See also
References
External links
- "How Ships Talk With Flags", October 1944, Popular Science
- John Savard's flag page. Collection of different flag systems.
- Freeware to aid memorizing the flags
- La flag-alfabeto - signal flags used for the Esperanto language - the flags for the Esperanto letters with diacritical marks have the lighter color in the normal flag replaced with light green, which is not used in any normal flag.