MESOTECH Model 971 Scanning Sonar 



41. The MESOTECH Model 971 does not fit the description of the SSS 

 given at the beginning of this report. A Model 971 system consists of a 

 motorized scanning transducer head, a "black box" processing unit, and a CRT 

 color video display unit (this can be connected to a video recorder by means 

 of an optional adapter) . Experience with this system consists of a demonstra- 

 tion performed at Crescent City, CA, where there was an 8-ft swell with 2- ft 

 waves. Features of the Model 971 system include: 



a. Flexible mounting configuration and scanning scheme. 



b. A 675 -kHz frequency transducer with a beamwidth of 1.7 by 



60 deg; other beam patterns available include 1.7 by 30 deg and 

 1.7 deg (conical). 



c. Lightweight, compact transducer head. 



d. High-resolution display. 



e. Various processing/display modes. 



42. In the conditions tested, the system was found to be of no use for 

 the purposes of coastal engineering structure inspection; however, there may 

 be useful applications in sheltered environments or when mounted on an ROV. 

 Also, the contrast and gain were not adjustable for easy viewing. The system 

 may be helpful for profiling applications (where the bottom profile for a sec- 

 tor under the transducer is scanned in a sweep, a configuration appropriate 

 for channel dredging-related surveys). 



ULVERTECH Dual Scanning Sonar Profiler 



43. The ULVERTECH system also should not be classified as a conven- 

 tional SSS. This system consists of two separate motorized scanning heads, an 

 electronics box to be mounted underwater, a control unit, and a display/ 

 recorder unit. The configuration was tested in a demonstration at the Colum- 

 bus Lock and Dam on the Tenn-Tom Inland Waterway. Principal features of the 

 system are: 



a. Flexible mounting and scanning. 



b. A 1-MHz frequency transducer with a 1-deg conical beam. 



c. Automatic combination of the data of two scanners to display 

 continuous bottom profile. 



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