I. a. HYDROGRAPHIC PRECISION SCANNING ECHO SOUNDER 



Primary Use: 



For use on oceanographic survey ships in conducting underway 

 precision developmental (detailed) types of bathymetric surveys in 

 deep oceanic areas. This instrument is needed to obtain a high reso- 

 lution, stabilized, echo- sounding picture, including an automatically 

 plotted contoured chart of the sea floor topography, extending a cer- 

 tain distance (about 2 miles in 4, 000 fathoms of water) perpendicu- 

 lar to and on each side of the ship's track. 



Requirements and Specifications: 



a. To perform reliably at ship's speeds of to 18 knots and in 

 sea states through 5. 



b. Operating Depth Range: 



(1) Automatic contour plotting (sweep width) to 6, 500 fa- 

 thoms. 



(2) Single-ping and regular echo-gram recording operation 

 to 6, 500 fathoms. 



c. Recording Accuracy: 1 fathomi over full range of each scale. 



d. Transducer(s): 



(1) Type: narrow beann, 1° to 3 , at the 10 db point. 



(2) Array: multiple series of transducers faired in to ship's 

 hull, electronically stabilized, and so installed as to scan the sea 

 floor for a specified distance on either side of the ship's track. 



(3) Transducer(s) should be located at a point alpng ship's 

 hull so as to have minimum cavitation interference. 



(4) Should be capable of scanning up to 30 on either side of 

 ship's track. 



(5) Should incorporate a feature for "plug-in" of a portable/ 

 towed transducer. 



e. Stabilizer: 



(1) Maximum stabilization angle of 60 . 



(2) Constant stabilization to 1/2 of arc from the vertical. 



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