Signalman 1 & C - Historic Naval Ships Association

PRECEDENCE—The relative order in which navalmessages are to be handled and delivered.PYROTECHNICS —Ammunition containingchemicals that produce smoke or a brilliant lightin burning; used for signaling and illumination.QUICK-FLASHING LIGHT—A navigationallight, such as a lighthouse, that flashes continuallyat least once a second.RADIOTELEPHONE (R/T)—Used by ships andaircraft as the primary method for voice tacticaland administrative communications.RELATIVE BEARING—Bearing relative toheading or to the ship.SAILING DIRECTIONS—A book issued by theNavy Department to supplement charts of theworld. Sailing Directions contains descriptions ofcoastlines, harbors, dangers, aids to navigation,and other data that cannot conveniently be shownon a chart.SECURITY CLEARANCE—An administrativedetermination by competent authority that anindividual is eligible, from a security standpoint,for access to classified material.SEMAPHORE—May be considered directional ornondirectional; however, nondirectionalprocedures are used during transmission. Thismethod uses small hand flags during daylighthours and wands fitted with red lenses duringhours of darkness. The position or movement ofthe flags represents letters.SIDELIGHT —A running light showing green tostarboard and red to port, showing an unbrokenlight over an arc of the horizon of 112.5°, fixed toshow the light from right ahead to 22.5° abaft thebeam on the respective sides.SOUND SIGNALING—The use of sirens, whistles,bells, and similar devices used to transmit shortmessages normally consisting of prearrangedsignals. Such methods are slow and satisfactoryfor short messages only; they are usually confinedto warning or alert signals.STANDARD OPERATING PROCEDURES(SOP)—Guidelines tailored to the uniquerequirements of a signal bridge. These orders aredrafted by the leading Signalman and approved bythe communications officer.VISUAL SIGNALING—The means of passingtactical and administrative traffic between shipswithin visual signaling range, and between shipsand shore stations.AI-3