International Code of Signals (ICS).
Letter flags with ICS meaning.
|Flag||ICS Meaning as Single Flag||Meaning when used with Numeric Complements|
|“I have a diver down; keep well clear at slow speed.”||Azimuth or bearing|
|“I am taking in or discharging or carrying dangerous goods.” (Originally used by the Royal Navy specifically for military explosives.)|
|“Affirmative.”||Course in degrees magnetic|
|“Keep clear of me; I am maneuvering with difficulty.”||Date|
|“I am altering my course to starboard.”|
|“I am disabled; communicate with me.”|
|“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.)|
|“I have a pilot on board.”|
|“I am altering my course to port.”|
|“I am on fire and have dangerous cargo on board: keep well clear of me.”
“I am leaking dangerous cargo.”
|“I wish to communicate with you.”||“I wish to communicate with you by…”:
1) Morse signaling by hand-flags or arms;
2) Loud hailer (megaphone);
3) Morse signaling lamp;
4) Sound signals.
|In harbour: “The ship is quarantined.”
At sea: “You should stop your vessel instantly.”
|Latitude (The first 2 digits denote degrees; the last 2 denote minutes.)|
|“My vessel is stopped and making no way through the water.”|
|“Man overboard.” (often attached to the man overboard pole on boats).
With a sinister hoist, the semaphore flag.
|The Blue Peter.
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.”
|“My vessel is ‘healthy’ and I request free pratique.”|
|(No ICS meaning as single flag)||Distance (range) in nautical miles.|
|“I am operating astern propulsion.”||Speed (velocity) in knots|
|“Keep clear of me.”
Fishing boats: “Keep clear of me; I am engaged in pair trawling.”
|Local time. (The first 2 digits denote hours; the last 2 denote minutes.)|
|“You are running into danger.”|
|“I require assistance.”||Speed in kilometres per hour.|
|“I require medical assistance.”|
|“Stop carrying out your intentions and watch for my signals.”|
|“I am dragging my anchor.”|
|“I require a tug.”
By fishing vessels near fishing grounds: “I am shooting nets.”
|Time (UTC). (The first 2 digits denote hours; the last 2 denote minutes.)|