flag signal

Flaghoist signalling is one or more flags (or pennants) simultaneously flying from a fixed halyard, and generally any method of signaling by such means. Each of the flags has a distinct shape and color combination. Each flag or combination of flags has a preassigned meaning or "code". The International Code of Signals[1] defines a standard set of flags and associated alphabet suitable for international use, as well as a set of standard codes. Flaghoist is also used in boat racing, to warn of impending severe weather, and other specialized applications. Maritime flag signalling has a long history, especially prior to the advent of radio, and remains the preferred means of signaling in many situations. In naval flag signalling, additional flags and an expanded list of signals are used for identification and commands, as well as the mercantile uses. Many navies have their own proprietary or secret codes, and use additional flags. A designator flag is used to indicate if a flaghoist signal is meant to be inter