vertical movement of the eye in the fluke of 1 to 2 feet (0.3 to 0.6 m) . 

 The maximum keying movement (measured as upward line displacement) for 

 developing the ultimate capacity of the 5-1 /2-f oot-long (1.7 m) coral 

 fluke is about 6 feet (1.8 m) in granular materials. Therefore, a 

 movement of only about 18 to 36% of this maximum brought enough fluke 

 area to bear to develop the proof-load. If the same percentages are 

 assumed to indicate proof- load in terms of ultimate capacity, then this 

 rough data agrees reasonably well with the minimum short-term capacity 

 estimated from the piston retrieval loads - the 100,000-pound (445 kN) 

 proof -load is about 33% of the estimated capacity. Long-term loading, 

 including some component of cyclic loading, might reduce the anchor 

 capacity to a level about equal to the long-term strength of the line 

 (approximately 200,000 pounds, or 890 kN) . 



Site Investigation 



The site conditions encountered were described as extremely variable, 

 based on data from diver jetting probes. Anchor penetrations varied 

 somewhat, and piston pullout loads varied by more than a factor of two. 

 Anchor setting distances were small, but also varied by a factor of 

 roughly two. Actual capacities are not known. Based upon these data, 

 it is apparent that a suitable site investigation technique, if available, 

 would have the following characteristics: 



a. Tests that indicate sediment strength 



b. A sufficient number of tests for statistical significance 



c. A known relation between anchor penetration depth and test 

 data, to within a factor of 2 



d. A known relation between anchor holding capacity and test data 

 to within a factor of 1 . 5 or better 



These requirements might be satisfied by static- or impact-driven 

 sounding /samp ling probes or a small test-type propellant anchor. 



At Diego Garcia, it is estimated that an investigation involving 

 one small test anchor at each anchor leg location (a total of eight 

 would be required) would have cost about $3,000 and could have saved 

 about $10,000 in costs of fabricating excess projectiles. It is felt 

 that a suitable site investigation technique for remote locations, such 

 as Diego Garcia, should be used to provide a means to specify a priori 

 the optimum cost-effective type and size for anchor projectiles. In 

 this way, performance can be enhanced and costs can be minimized. 



Operations 



Operational aspects of the anchor system were very good, especially 

 considering that the crew was initially untrained. In fact, UCT-One 

 personnel indicated that the propellant anchors were much easier to 

 install than conventional drag anchors with their required weight clumps 



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