Maritime flag signalling

Maritime flag signalling, generally flaghoist signalling, is the principal means other than radio by which ships communicate to each other or to shore (distinguished from flags showing nationality, ownership, or (for naval vessels) organizational status). Virtually all signalling by non-naval vessels is now organized under the International Code of Signals (whether by flaghoist, semaphore, signal lamp, or other means), which specifies a standard set of flags and codes. Naval vessels generally use an extended set of flags and their own codes. This article will touch on the historical development of maritime flag signalling.