DEEPLY -TOWED ECHO-SOUNDER RECONNAISSANCE 

 OF A FLEET TACTICAL RANGE SITE 



by 



Michael S. Loughridge and F. N. Spiess 



University of California, San Diego 



Marine Physical Laboratory of the 



Scripps Institution of Oceanography 



San Diego, California 92152 



INTRODUCTION 



At the request of the Applied Physics Laboratory, University of Washington, Seattle, 

 personnel and a ship, the R/V OCONOSTOTA, from the Marine Physical Laboratory , 

 University of California, San Diego, participated in precision bath3rmetric studies west 

 of the island of Kauai in late October and early November 1964. This work was part 

 of the oceanographic site studies for a proposed Fleet Tactical Range west of the island 

 of Kauai and was intended to supplement precision narrow-beam bathymetric work done 

 from ships of the U. S. Naval Oceanographic Office. Figure 1 is an index chart of the 

 area studied which shows the location of the probable range area and the Pacific Mis - 

 sile Range FPS-16 Radar Facility. 



The Marine Physical Laboratory effort consisted of two parts. The first part made 

 use of MPL's deeply -towed echo-sounder system and it is this data with which we are 

 concerned in this paper. The second part of our effort was a conventional echo- 

 sounder survey with Raydist navigation in a shallow water area to the Jiorthwest of 

 Nohili Point. The data from this work were given directly to the Applied Physics Lab- 

 oratory for their use in planning cable runs. 



It has been demonstrated in previous MPL work that the MPL deeply-towed system 

 has a capability for delineating small features on the ocean floor that are rarely de- 

 tected by conventional surfece echo sounders and could provide valuable topographic 

 information necessary for the successful installation of underwater devices and in 

 planning cable runs to these underwater installations. 



To achieve the desired end, six deeply -towed echo-sounder profiles were made in 

 the area of interest. The locations of these profiles are shown in Figure 2. 



The data obtained are readily adaptable to an analysis of bottom slopes and it was 

 quickly recognized that such an analysis could he of importance in estimating fire 

 control performance of bottom bounce sonars. This point is a particularly important 

 one in that our newer bottom bounce sonars will probably be used extensively in the 

 new Fleet Tactical Range. 



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