More important flag signals.

	N.C.   I am in distress, and require immediate assistance.		A.G.   You should abandon ship as quickly as possible.
	A.N.   I require a doctor.		A.Q.   I have an injured / sick person to be taken off.
	C.G.   Stand by to give me assistance.		C.V.   I am not in a position to give assistance.
	G.N.   Take off the crew.		G.Q.   I cannot help you because of the weather, do all you can.
	G.V.   Try to pass me a line.		G.W.   Man overboard try and recover him.
	N.G.   You are in a dangerous position.

Links to other relevant information.     Morse.      Distress calls.      Sound signals.     
Phonetic Alphabet.      Signal Flags.