Operation V - San Clemente Island, sand . The goal of this operation 

 was to evaluate the anchor under long term constant loading conditions 

 similar to those that would be experienced in service. Operations were 

 performed in Wilson's Cove at San Clemente Island in 30-50 feet of 

 water aboard a Naval Underwater Center (NUC) barge. 



An attempt to embed the anchor in a sand bottom was unsuccessful. 

 Two causes were identified. The linkage between the fluke and shaft 

 was not tight, therefore, the shaft and fluke were not vibrating as a 

 unit resulting in a drastic reduction of driving energy being transmitted 

 to the soil. Rather, the energy was being used to drive the fluke in a 

 hammer action, which in sands is not as efficient as vibration for 

 achieving penetration. In addition, the electrical cable transmitting 

 power became overloaded and failed. 



Operation VI - Seneca Lake, clay . The primary objective was to 

 determine the functionality and holding capacity of the vibratory 

 anchor for its possible application in a long-term mooring for the 

 Naval Underwater Sound Laboratory (NUSL) . Operations were conducted 

 aboard an NUSL barge on Seneca Lake, New York at a location where the 

 water was 500 feet deep. The bottom consisted of a very weak clayey 

 bottom ooze. 



The anchor was lowered to the bottom with a crane aboard the barge 

 under carefully controlled conditions. The barge was firmly anchored 

 in a four-point moor. Power to the vibrator was supplied by a generator 

 on the barge through an electrical cable. 



The anchor easily penetrated the weak sediments to the limit 

 permitted by the support guidance frame, in this instance 15 feet. 

 Penetration was determined with the newly developed displacement 

 monitoring system. Loading was applied and breakout occurred at a peak 

 load of 5000 pounds. On retrieval, it was established that the fluke 

 tripping mechanism had functioned satisfactorily and the fluke had "keyed" 

 to the maximum resistance to pull out position. 



The Seneca Lake operation demonstrated that the anchor was 

 functional for use in the lake even though the holding capacity was less 

 than desired. Also, it confirmed the functionality of the anchor in 

 soft sediments. Seneca Lake presented a unique problem, not likely to 

 be duplicated in the deep sea. However, the data obtained was valuable 

 because it indicated that the present anchor is not able to provide 

 acceptable holding capacities in weak sediments. The weak sediment 

 problem was studied theoretically, and the results of the study are 

 being incorporated in the future program. 



43 



