Principles of naval engineering - Historic Naval Ships Association

PRINCIPLES OF NAVAL ENGINEERINGAUTOMATIC BYPASSVALVESTEERING WHEELON AFTER DECK HOUSE .TRANSMIHER UNIT,||_SLSTEERING WHEELON BRIDGEELECTRIC CONTROlISYSTEMTRANSMIHER UNITCRANK FOR HAND OPERATIONOF PORT PUMPPORTRUNNING ELEC. MOTORWORM WHEELRECEIVING UNITt>«f>mi!mfl>.TRANSFER SWITCH TRANSMITSCURRENT THROUGH EITHERCABLE OR EITHER TRANSMIHERTO RECEIVER AS SELEOEDf*' TRICK WHEEL FORHAND CONTROLSTBD.CniNDER.AUTOMATIC BYPASS VALVEsuppLyRETURNSTARBOARDIDLE ELEaRICMOTORWORMWHEEL^^WORMSPIRAL GEARSH-HFigure 21-6.— Single-ram electrohydraulic steering gear.27.83Xsteering gear, an additional switch is providedin the steering room for selecting the properreceiver.HYDRAULIC TELEMOTOR SYSTEM. -Atelemotoris a hydraulic device by means of whichthe motion of the steering gear is controlledfrom the pilot house. In general, telemotorsystems are employed for remote steeringcontrol where it is impractical to provide anelectrical synchronous transmission systemand where the length of runs of shafting orwire rope and the paths for such shafting orropes would make the use of these types ofmechanical controls impracticable.The hydraulic telemotor system consists ofone or more transmitters located at remotesteering stations connected by piping to areceiver or receivers located in the steeringengineroom. Each transmitter unit is either aa pair of cylinders or a fixed-delivery pistontypepump connected so that movement of thesteering wheel causes fluid to flow through thesystem, resulting in a corresponding movementof the plungers in the receiver unit. Thereceiver unit is connected by suitable means tothe pump control or valve operating mechanismof the steering engine. The principal componentsof a hydraulic telemotor control system areshown schematically in figure 21-7.WIRE ROPE SYSTEM.-This type of remotecontrol is found in some small ships. Thesteering engine control mechanism is connectedto the wheel by wire ropes. The system has thedisadvantages of requiring long leads involvinglarge friction loads; of the ropes being vulnerableto gunfire above decks; of impairing watertightintegrity by passage of the cables throughbulkheads and decks; and of requiring a526