patterns of the concrete are presented. In general, the 

 concrete was made from a high-quality mix design 

 where the cement factor was 7.8 sacks per cu yd and 

 water-cement ratio was 0.40; the compressive 

 strength at 28 days was an average 7,660 psi. 



Disposition of the control cylinders and blocks 

 is as follows: of the six control cylinders placed in the 

 fog room, three were tested at 28 days; their com- 

 pressive strengths are given in Appendix A, Table A-2. 

 The remaining three control cylinders will stay in the 

 fog room and will be tested when the spheres are 

 retrieved from the ocean. Three of the six control 

 cylinders cured with the hemisphere were tested at 

 age 28 days and the remaining three were tested 

 approximately one month prior to emplacing the 

 spheres in the ocean (Table A-2); these later tests gave 

 the compressive strength used in calculating the 

 short-term implosion pressure, Pi^. There were two 

 control blocks per sphere; one block went with the 

 sphere into the ocean and the other block stayed on 

 land, located within 50 yards of the ocean. Both 

 blocks will be cored and tested when the sphere is 

 retrieved. 



EMPLACEMENT 



The spheres were emplaced in the ocean 4 miles 

 south of Santa Cruz Island, California (Figure 6), on 

 23 September 1971. The method of emplacing the 

 spheres was as follows: a barge loaded with the 

 spheres (Figure 7) was towed by a surface vessel 

 (USNS Gear) which maintained a constant course 

 over a location where the seafloor increased in depth 

 at a fairly uniform rate. At predetermined depths, the 

 appropriate sphere was pushed overboard to free-fall 

 to the seafloor. The method worked well with most 

 of the spheres landing within a few hundred yards of 

 the target location. Final location of the spheres is 

 given in Table 3. Figure 8 shows a plan view and 

 Figure 9 a profile view of the sphere locations. 



Water samples were obtained from the depth of 

 2,5 30 feet and gave the following data: temperature 

 of 5.33°C, salinity of 34.41 ppt, pH of 7.2, oxygen 

 content of 0.06 ml/1, and velocity of sound of 

 1,483.9 m/sec. A water sample from 4,740 feet gave a 

 temperature of 5.16°C and a pH of 7.0. 



Figure 4. Final assembly of sphere. 



