Page 627 radio acoustic ranging 6711 



generally reduced visibility, in addition to the usual bow lookout, an additional watch 

 officer is required whose sole duty is to look out for the safety of the vessel. 



Where R.A.R. shore stations are used, a radio technician is required at each 

 station and, if living accommodations are not available near the station, an additional 

 man is needed to serve as cook and helper. 



An officer, stationed at the plotting table, is in direct charge of all operations, 

 under the general supervision of the Commanding Officer. The plotting table should 

 be located on the bridge so that the officer-in-charge may supervise the navigation of 

 the ship, log readings, taking the soundings, etc. Where this is impracticable, the plot- 

 ting is done in a drafting room and an additional watch officer must be stationed on 

 the bridge to supervise the sounding, the observation of supplemental data, and the 

 navigation, making such changes in course as are ordered by the officer-in-charge over 

 the communication system. 



6711. Officer-in-Charge 



The officer-in-charge plots the position of the ship after the time intervals have 

 been obtained and have been relayed to him by the chronograph attendant over the 

 communication system, or by messenger. The data are recorded by the officer-in- 

 charge on Form 722, R.A.R. and Dead Reckoning Abstract (see 8312), on which are 

 also recorded other position data for temporary field use, when the form is used. From 

 the R.A.R. data he plots the position of the ship, using the time or log distances 

 between successive positions as a check. After the position is plotted, a change in 

 course is ordered, if necessary. When time permits, the positions are inked on the 

 sheet, after their accuracy has been verified. A carbon copy of the soundings, includ- 

 ing the position numbers and times, is made by the recorder by inserting a narrow 

 slip of paper and carbon paper beneath that part of the Sounding Record page. The 

 soundings are reduced for predicted tide and the reduced soundings are inked on the 

 boat sheet by the officer-in-charge as the carbon copies become available. An addi- 

 tional man may be required to reduce the soundings and record the data on the R.A.R. 

 abstract if the interval between positions is short, but these duties can usually be 

 performed by the officer-in-charge. 



6712^ Chronograph Attendant 



The chronograph attendant is stationed at the chronograph which must be located 

 in or adjacent to the radio room. The officer-in-charge decides on the interval between 

 positions and usually instructs the chronograph attendant to this effect. The latter 

 then orders the bombs by a system of signal bells (6741) to the bombing station located 

 on the afterdcck of the vessel. On some vessels the signal for the bomb may originate 

 at the plotting station, or on the bridge. At the "bomb over" signal from the bomber,, 

 the chronograph is started and the chronograph attendant attends it while the returns, 

 are being recorded on the tape (see 6851), measures the returns (see 6853), and records 

 them in the Bomb Record (see 8311). He also times the ship's run from the "bomb 

 over" signal to the explosion, unless this is automatically registered on the tape (see 

 6813), and records it. He reports the results over the communication system to the 

 plotting station where they are received by the officer-in-charge, who uses them to plot 

 the position. 



The general operations of bombing and receiving the returns are supervised by the 

 chronograph attendant. He has direct supervision over the radio technician and the 



