Test 29 (6 Dec 74) 



Test 32(26 Feb 75) 



The warping tug was moved about 100 yards, 

 because the divers indicated that the seafloor 

 appeared to be more competent but uneven with con- 

 siderably more boulders. The anchor fired and 

 embedded. Load was applied in direct uplift until 

 pullout occurred at 30,000 pounds. The fluke and 

 piston were recovered; the piston receptacle was 

 elongated, indicating that the piston and fluke had 

 tried to separate during penetration. This action 

 should be eliminated with the modifications desig- 

 nated in Test 28. This test was significant in two 

 respects; first, the anchor fired and embedded suc- 

 cessfully in a very uneven rocky seafloor, and second, 

 the anchor held more then expected in direct uplift in 

 this very difficult seafloor. 



TEST OPERATION X 



The purpose of this cruise was to gather more test 

 data in silt and soft clay. Only minimal data had been 

 gathered in these materials in the past. Testing was 

 performed from the CEL warping tug at the CEL 

 600- and 1,200-foot sites in the Santa Barbara 

 Channel. 



To verify that the 2 x 4-foot fluke was optimum 

 for the seafloor conditions at the 600-foot site, one 

 additional test was scheduled. The anchor misfired 

 and was disarmed by Navy EOD divers. The misfire 

 was attributed to a malfunction in the new, reusable 

 safe-and-arm device. This was the sixth use of the new 

 device, and it had functioned satisfactorily to date. 

 The shear disk had not failed, because one solenoid 

 valve malfunctioned, preventing pressure release from 

 the gas bottle. The firing pin was still, however, 

 pushed down. This caused the in-line/out-of-line 

 plunger to be in line — the unsafe position. The 

 anchor should have been safe upon return to the 

 surface, but pressure had leaked by the gold shear 

 disk. Two things will be done to the reusable S/A to 

 further improve its safety characteristics. An O-ring 

 will be placed in the chamber at the shear disk base to 

 guarantee a seal. When properly assembled, the shear 

 disk alone is supposed to prevent pressure bypass; the 

 O-ring will provide a backup seal. Second, a one-way 

 valve will be installed in the S/A housing to reduce 

 chamber pressure, in the event of a misfire, to about 

 2 psi. The available pressure to fire the anchor would 

 then be reduced 1,100 psi to 2 psi. 



Test 30 (25 Feb 75) 



TEST OPERATION XI 



Available soils data (limited to 10 feet) at the 

 600-foot site indicated that the 1-1/2 x 3-foot fluke 

 would be optimum. A peak charge of 3.6 pounds was 

 used. The anchor fired and embedded; however, a 

 link to the fluke fractured during penetration. The 

 fluke possibly hit something on the seafloor, or the 

 link could have been defective; this had not occurred 

 previously. 



Test 31 (25 Feb 75) 



A second anchor, which was also prepared with 

 the 1-1/2 X 3-foot fluke and 3.6-pound charge, was 

 lowered to the seafloor. The anchor fired and 

 embedded 24 to 26 feet. Load was applied slowly 

 until pullout occurred at 28,000 pounds. The soil 

 recovered from the fluke was a nonplastic silt, which 

 was much less stiff than anticipated from the 10 feet 

 of available core data. A greater holding capacity 

 would have been achieved with the 2 x 4-foot clay 

 fluke. 



The purpose of these installations was to install 

 four 20K anchors in a sand seafloor about 1 mile 

 offshore from Coronado, California, to moor a lash 

 barge for helicopter off-loading. All installations were 

 completed from a Navy warping tug. Modifications to 

 the 20K anchor had to be made, because the installa- 

 tions were in less than 60 to 70 feet of water, the 

 practical upper anchor firing limit. The reaction vessel 

 was changed by adding a 36-inch-diameter plate to 

 reduce recoil from 30 feet to about 15 feet. Also, by 

 using the S/A in-line/out-of-line plunger, which was 

 designed to arm at 50 feet, with a U-cup seal to 

 replace the standard O-ring, a consistent arming depth 

 of 27 feet could be achieved. With a 10-foot safety 

 margin, firing in 47 feet of water was possible. The 

 1-1/2 x 3-foot fluke was chosen with a 3.5-pound 

 charge for each installation. 



32 



