Figure A-1. Rock anchor after first test (Test 11) 

 in basalt. 



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(a) Back view. 



(b) Side view. 



Figure A-2. Rock anchor after second test (Test 12) 

 in basalt. 



miles from Port Hueneme) in 67 feet of water. The 

 CEL warping tug was used as the test platform. 



Test 11 (26 Mar 73) 



A 3.75-pound charge was used with the 1-1/2 x 

 3-foot rock projectile. The anchor fired and 

 embedded 30 inches to the point of cable attach- 

 ment. The warping tug was backed off about 50 feet, 

 and load was increased to 100,000 pounds and held 

 for about 10 minutes. The tug was moved directly 

 over the anchor, and 107,000 pounds were required 

 for puliout. Figure A-1 shows the rock fluke after 

 pullout. The fluke nose was bent at its threaded 

 attachment point to the main shaft. Also, the piston 

 receptacle was elongated, which indicates that the 

 fluke tried to move laterally from its fired line of 

 direction. No other damage occurred to the fluke. 



Test 12 (26 Mar 73) 



The anchor was again fired using a 3.75-pound 

 charge. The seas had picked up considerably, and it 

 was becoming difficult to maintain position above the 

 30-foot-diameter basalt plateau that was being used 

 for the tests. When the tug's position was considered 

 to be correct, the anchor was rapidly lowered until 

 touchdown. The plateau was missed, and the anchor 

 fired and embedded into the 45-to-60-degree slope 

 leading to the base of the plateau. Penetration was 

 somewhat in excess of 7 feet; 4 feet of rock slope was 

 shattered before the fluke embedded to the cable 

 connection. Figure A-2 shows the fluke after pullout. 

 The markings on the painted surface and the 

 upturned nose indicate that this fluke also travelled 

 laterally during penetration. The basalt on this slope 

 was obviously weathered, and this resulted in a 

 reduced holding capacity of 20,000 pounds. 



Future rock flukes will be fabricated without the 

 4340 hardened steel nose which is threaded on the 

 central 4140 steel shaft. The 4140 shaft will be 

 machined with a tapered nose to significantly reduce 

 cost. 



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