During 1961 and 1962, approximately 100 sediment cores were taken 

 by the Naval Oceanographic Office (NAVOCEANO). The constituents of the 

 TOTO bottom sediments were predominantly silt size, skeletal and nonskeletal 

 carbonate particles representing both shallow- and deep-water environments 

 (Huddel et al., 1965). Organic carbon content of the sediment ranged from 

 1% to 2%. The general variations of water content, void ratio, density, and 

 undrained strength with depth in the soil profile all indicated a normally 

 consolidated soil profile. Coarse-grained materials, which formed more than 

 50% of some of the cores, were attributed to deposition by turbidity currents. 

 Sediment undrained shear strength (vane shear strength) in the northern area 

 ranged from 1 to 3 psi over the length of the cores. In the southern area, 

 strength averaged less than 1 psi. Sediment sensitivity varied from slightly 

 insensitive to slightly quick. Bottom photographs show an almost feature- 

 less ooze with a few benthic organisms. I n the central northern portion of 

 the channel at a water depth of 6,000 feet, there is a series of cavities and 

 depressions. 



The hydrophone structures are designed with the hydrophone attached 

 to the top of a 1 5-foot-tall conical frame. The 1 2-foot-diameter base is con- 

 structed of 2-inch-diameter polyvinyl chloride (PVC) tubing. Figure 7 shows 

 an almost identical hydrophone structure. Weight of the entire apparatus in 

 water is about 400 pounds. 



Visual performance observations were made 6 months and again 3 

 years after the system was installed. The observations were made from the 

 submersibles Aluminaut and Alvin. No unusual activities or problems (sliding 

 or excessive settlement) were noticed (Austin, 1964). 



BARSTUR. During the spring of 1967, the Navy established a highly 

 instrumented three-dimensional underwater tracking range in Hawaiian waters 

 (Prince, 1968; Okura, 1969). The site is located in the north central Kaulakahi 

 Channel (Kaulakahi Channel separates the Island of Kauai from the Island of 

 Niihau to the west) (Garrison, 1 965) . 



Barking Sands Tactical Underwater Range (BARSTUR), composed of 

 an underwater communications system (UQC) and 37 tracking hydrophones, 

 is located in a 5- by 10-mile area (Figure 8). Water depths within the range 

 vary from 2,200 to 5,500 feet. Each hydrophone is located with respect to 

 a center hydrophone, which, in turn, is referenced (within a 175-foot-diameter 

 circle) to shore facilities. An underwater junction box, located beyond the surf 

 zone in 65 feet of water, forms a terminus for connecting the smaller individual 

 phone cables to a single, multiconductor, heavily armored cable. 



14 



