Maritime Signal Flags

These flags are used at sea for communication between ships. They can spell out short messages and individual flags and various combinations of flags also have special meanings. On ceremonial and festive occasions the signal flags are used to 'dress' (decorate) ships.

This signalling system was drafted in 1855 and published in 1857, and was gradually adopted by most seafaring countries. It was revised in 1932.

Usage

One-flag signals are urgent or very common signals (see meanings below)
Two-flag signals are mostly distress and maneuvering signals
Three-flag signals are for points of the compass, relative bearings, standard times, verbs, punctuation, also general code and decode signals
Four-flags are used for geographical signals, names of ships, bearings, etc
Five-flag signals are those relating to time and position
Six-flag signals are used when necessary to indicate north or south or east or west in latitude and longitude signals
Seven-flags are for longitude signals containing more than one hundred degrees.

International Maritime Signal Flags

Special meanings of individual flags

a (alpha) = Diver Down; Keep Clear
b (bravo) = Dangerous Cargo
c (charlie) = Yes
d (delta) = Keep Clear
e (echo) = Altering Course to Starboard
f (foxtrot) = Disabled
g (golf) = Want a Pilot
h (hotel) = Pilot on Board
i (india) = Altering Course to Port
j (juliet) = On Fire; Keep Clear
k (kilo) = Desire to Communicate
l (lima) = Stop Instantly
m (mike) = I Am Stopped
n (november) = No
o (oscar) = Man Overboard
p (papa) = About to Sail
q (quebec) = I Request
r (romeo) = (The way is off my ship. You may feel you way past me)
s (sierra) = Engines Going Astern
t (tango) = Keep Clear of Me
u (uniform) = You are Standing into Danger
v (victor) = Require Assistance
w (whiskey) = Require Medical Assistance
x (x-ray) = Stop Your Intention
y (yankee) = Am Dragging Anchor
z (zulu) = Require a Tug

Links

Further details of Martime Signal Flags
http://www.boatsafe.com/nauticalknowhow/flags.htm

Other signal flag systems
http://www.pem.org/archives/guides/signals.htm

Signalling at sea
http://home.earthlink.net/~mcmillanj/signals/Signals.html

Other communication/notation systems

Braille, Maritime Signal Flags, Moon, Morse code, Semaphore