The International Code of Signals (ICS) is a system by which vessels are able to communicate effectively about safety or navigation. Signals can be sent by flaghoist, signal lamp (“blinker”), flag semaphore, radiotelegraphy, and radiotelephony. Prior to 1969 the Code was much more extensive, covering a wider range of messages, and included a list of five letter codes for every prominent maritime location in the world. Since 1969 it has been reduced to focus on navigation and safety, including a medical section. Signals can be sorted into three groups:
- Single-letter signals which are very urgent, important, or common.
- Two-letter signals for other messages, sometimes followed with a numeric “complement” that supplements or modifies the message.
- Three-letter signals beginning with “M” – these are the Medical Signal Codes.
In some cases additional characters are added to indicate quantities, bearing, course, distance, date, time, latitude, or longitude. There is also provision for spelling words, and for indicating use of other codes. Several of the more common single-letter signals are shown at the right. Two-letter signals cover a broad gamut of situations; the interested reader is urged to download a copy of the Code from the link below.
Repeated characters can be a problem in flaghoist. To avoid having to carry multiple sets of signal flags, the Code uses three “substitute” (or “repeater”) flags. These repeat the flag at the indicated position. For instance, to signal MAA (“I request urgent medical advice”, see diagram below) the Mike, Alfa, and 2nd substitute flags would be flown, the substitute indicating a repeat of the second character. source:
wikipedia
| A
. _
|
ALFA |
 |
I have a diver down – keep well clear at slow speed |
| B
_ . . .
|
BRAVO |
 |
I am taking in or discharging or carrying dangerous goods |
| C
_ . _ .
|
CHARLIE |
 |
Yes (affirmative) OR The significance of the previous group should be read in the affirmative |
| D
_ . .
|
DELTA |
 |
Keep clear of me – I am manoeuvring with difficulty |
| E
.
|
ECHO |
 |
I am altering my course to starboard |
| F
. . _ .
|
FOXTROT |
 |
I am disabled – communicate with me |
| G
_ _ .
|
GOLF |
 |
I require a pilot (or by fishing vessels – I am hauling in nets) |
| H
. . . .
|
HOTEL |
 |
I have a pilot on board |
| I
. .
|
INDIA |
 |
I am altering my course to port |
| J
. _ _ _
|
JULIET |
 |
I am on fire and have dangerous cargo on board – keep well clear of me |
| K
_ . _
|
KILO |
 |
I wish to communicate with you |
| L
. _ . .
|
LIMA |
 |
You should stop your vessel instantly |
| M
_ _
|
MIKE |
 |
My vessel is stopped and making no headway through the water |
| N
_ .
|
NOVEMBER |
 |
NO (negative) OR the significance of the previous group should be read in the negative |
| O
_ _ _
|
OSCAR |
 |
Man overboard |
| P
. _ _ .
|
PAPA |
 |
IN HARBOUR – All persons should report on boardAT SEA – My fishing nets have become fast on some obstruction |
| Q
_ _ . _
|
QUEBEC |
 |
My vessel is healthy and I request free pratique |
| R
. _ .
|
ROMEO |
 |
|
| S
. . .
|
SIERRA |
 |
My engines are going astern |
| T
_
|
TANGO |
 |
Keep clear of me, I am engaged in pair trawling |
| U
. . _
|
UNIFORM |
 |
You are running into danger |
| V
. . . _
|
VICTOR |
 |
I require assistance |
| W
. _ _
|
WHISKEY |
 |
I require medical assistance |
| X
_ . . _
|
X-RAY |
 |
Stop carrying out your intentions and watch for my signals |
| Y
_ . _ _
|
YANKEE |
 |
I am dragging my anchor |
| Z
_ _ . .
|
ZULU |
 |
I require a tug
When made by fishing vessels – I am shooting my nets
|
| ONE
. _ _ _ _
|
UNAONE |
 |
|
| TWO
. . _ _ _
|
BISSOTWO |
 |
|
| THREE
. . . _ _
|
TERRATHREE |
 |
|
| FOUR
. . . . _
|
KARTEFOUR |
 |
|
| FIVE
. . . . .
|
PANTAFIVE |
 |
|
| SIX
_ . . . .
|
SOXSIX |
 |
|
| SEVEN
_ _ . . .
|
SETTESEVEN |
 |
|
| EIGHT
_ _ _ . .
|
OKTOEIGHT |
 |
|
| NINE
_ _ _ _ .
|
NOVENINE |
 |
|
| ZERO
_ _ _ _ _
|
NADAZERO |
 |
|
| 1ST SUBSTITUTE |
 |
Used to repeat the first flag or pendant in the same hoist |
| 2ND SUBSTITUTE |
 |
Used to repeat the second flag or pendant in the same hoist |
| 3RD SUBSTITUTE |
 |
Used to repeat the third flag or pendant in the same hoist |
| CODE & ANSWER |
 |
Used to acknowledge a signal |
