Signalman 1 & C - Historic Naval Ships Association

CHAPTER 2SIGNAL EQUIPMENTBefore Signalmen can perform their jobs, theymust know the equipment with which they will workand how to operate it. Although equipment may differin size or vary slightly among ships, signal geargenerally is standard throughout the Navy.In this chapter we discuss the principles ofoperation; maintenance procedures where applicable;and safety precautions pertaining to signal lights,infrared (IR) equipment, flags, halyards, and opticalequipment.You will not be permitted to use signal equipmentuntil you have been instructed in the operation of it.The necessary permission must come from thecommunications (or signal) officer or the petty officerin charge of the signal bridge.You must be able to locate, even under conditionsof total darkness, all light switches for electrical visualsignal equipment. Usually this is simply a matter offamiliarization. On the signal bridge most switches areon or within reach of the equipment. When you firstreport aboard ship, explore the bridge to see where thesignal equipment switch panels are located. Do thisbefore your watch. This practice will prove helpfullater when you are scheduled for night watches.SIGNAL SEARCHLIGHTSLEARNING OBJECTIVES: Describe thedifferent types of signaling searchlights.Identify their parts and assemblies and explaintheir functions.repair. That does not, however, relieve the Signalmanof the full responsibility for observing the instructionsfor the proper use and routine maintenance of thesearchlights. The life of a searchlight depends uponthe care given to it. Preventive maintenance and dailycleaning will keep your searchlight ready for instantuse.Searchlights used in the Navy normally use ashutter to interrupt the light beam and permitsignaling. The patterns of light caused by the openingand closing of the shutter are the basis for transmittingmessages by Morse code.12-INCH INCANDESCENTSEARCHLIGHTThe 12-inch incandescent searchlight is usedprimarily for signaling and secondarily for illumination.Figure 2-1 shows a 12-inch incandescentsearchlight, consisting of the mounting bracket,lamp-supporting yoke, and high-power (1,000-watt)incandescent lamp housed in a drum. By use of a braceor extension between the mounting bracket and theyoke, the light can be swung in an arc to clear fixedportions of the ship's structure.Besides holding the lamp, the drum provides amounting for the signaling shutters. On top of thedrum are vane sights, used to aim the light. The backSearchlights are placed aboard naval ships for twopurposes: illumination and communications. The useof a searchlight in visual communications is called thedirectional method, because the light has to be pointedat the receiver. Searchlights are classified according tosize and source. We discuss the 12-inch searchlightsin this chapter. The 12-inch light is either anincandescent or mercury-xenon arc lamp.Searchlights come under the cognizance of theNaval Sea Systems Command (NAVSEASYSCOM),and the ship's engineer officer is responsible for theirFigure 2-1.—12-inch incandescent searchlight.2-1