4112 



HYDROGRAPHIC MANUAL 



Page 316 



(/) A loud-speaker system for two-way communication between the pilothouse and various parts 

 of the ship; this is especially useful during taut-wire measurements, R.A.R., and other survey opera- 

 tions, and when hoisting and lowering survey launches and small boats. 



{g) A rangefinder and a gyro repeater on the flying bridge. 



Other equipment located on the bridge or in the pilothouse, which is only indirectly connected 

 with hydrographic operations but deserves mention, includes a manually and electrically operated 

 whistle and siren, radio direction finder (unless located in the radio room), clear-view screen, propeller- 

 shaft revolution indicator, rudder-angle indicator, indicator for electric logs, telephone system, light- 

 control switchboard, fire-control system with automatic smoke indicators, automatic alarm howlers, 

 and control for operating the CO2 fire-control system and for closing the watertight doors. 



4112. The Radio Room 



The radio room of a well-designed survey ship is located directly aft of the pilot- 

 house, from which it can be entered by an interior door, and with which it is connected 

 by telephone and speaking tubes. In addition to the usual ship radio communications, 

 many operations connected with R.A.R. are conducted in the radio room. A 

 chronograph installed here is used in R.A.R. 



Figure 70. — Radio room of a survey shi|i. 



The radio room should be of sufficient size to accommodate without congestion the 

 necessary radio equipment for survey use and ordinary communications. The commu- 

 nications equipment for code should consist of two transmitters and two receivers. 

 One of the transmitters should be for intermediate-frequency communications, rated 

 at 1,000 watts, and crystal-controlled to operate on 375, 400, 425, 454, and 500 kilo- 

 cycles. The power to operate this transmitter should come from the ship's power 



