International maritime signal flags

[2] There are various methods by which the flags can be used as signals: 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.

[citation needed] 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".

[citation needed] Prior to 1969: "The way is off my ship; you may feel your way past me."