INTRODUCTION 

 Background 



Anchors and anchorage systems are an important but neglected area 

 of development in the greatly expanding field of ocean exploration and 

 exploitation. There are requirements for sophisticated structures and 

 instrument arrays plus other constructions to be positively and reliably 

 secured in position on and under the sea in depths and locations not 

 normally associated with anchoring. Yet, while intense effort is 

 being expended on design and development of the constructions, attempts 

 are made to hold them in position with dead weights and/or with 

 conventional anchors ill-suited to the unusual demands put upon them. 



The U. S. Naval Facilities Engineering Command is sponsoring a 

 program at the U. S. Naval Civil Engineering Laboratory, Port Hueneme, 

 California, concerned with improving anchoring capability for mooring 

 Navy equipment in the deep sea. Early objectives are to obtain a 

 functional anchor design with a working holding capacity in the range 

 of 25,000 to 50,000 pounds and operational in depths to 6,000 feet in 

 seafloor sediments. An anchor with this capacity would provide a 

 practical advantage over use of dead weights and conventional anchors. 

 The 6,000-foot depth affords a practical anchoring capability throughout 

 all continental shelf areas plus many strategic ocean areas beyond 

 the continental shelves, e.g., sea mounts. Later objectives include 

 anchoring capacities in the 100,000 to 300,000 pound range and an 

 operational depth capability to 20,000 feet. 



At this stage in the program, a vibratory anchor design that appears 

 to approach the early objectives of anchoring in soft sediments has been 

 achieved. Also, valuable knowledge on other anchor designs and techniques 

 has been gained. This report traces the history of the program and 

 describes the present status of the vibratory anchor. 



Requirements 



There is a wide variety of structures and constructions for which 

 deep ocean anchorage requirements exist. Mooring configurations to 

 meet these requirements may be placed in four major categories: surface- 

 single leg; surf ace-multi- leg; subsurface-single leg; subsurface- 

 multi-leg. In addition, new areas of construction effort involve bottom 

 rest structures for which the term anchorage may properly be applied 

 to refer to the means of supporting and restraining the structures. 



