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EQUIPMENT AND INSTRUMENTS 



4111 



Figure 69.— Pilothouse of a , 



A well-designed pilothouse has several doors to provide convenient access to all 

 parts of the bridge and to the radio room if it is adjacent, and an inside passageway to 

 the main part of the ship. It contains chart cases and racks conveniently located foi 

 charts, boat sheets, and tracings. The chart cases have table tops on them on which 

 charts and boat sheets may be spread for use in navigating and plotting. A desk is 

 provided for the use of the recorder during hydrographic surveying and the navigator 

 at other times. The desk is specially constructed to house the chronometers under a 

 glass top, and contains drawers for books, tables, and nautical publications. Numerous 

 lockers or cabinets are provided in which the sextants, binoculars, protractors, flags, 

 etc., are stowed when not in use. To provide a working area for navigation and R.A.R. 

 hydrography at night, the pilothouse is arranged so that the after portion, including 

 the echo-sounding instruments and one chart case, may be blocked off by an opaque 

 curtain. 



In addition to the customary navigation and control equipment, the bridge of a 

 survey ship contains the following special or specially used survey instruments and 

 equipment: 



(a) Two echo-sounding instruments for alternate use in ship hj- drography ; at least one of these 

 should be a Dorsey Fathometer No. 3. 



(6) A gyrocompass and pilot for steering sounding lines in R.A.R. and astronomically conti oiled 

 hydrography. 



(c) Two electric sounding machines, one on each side of the bridge, for vertical casts, water 

 samples, and bottom specimens. 



(d) A gyro repeater on each wing of the bridge for use in taking bearings. 



(e) Electric push-button bell for use in marking fixes or signaling other hydrographic operations. 



