is highly important because it provides confirmation of satisfactory 

 implantment of the anchor plus reasonable data on which to base 

 calculations to predict holding capacity. Still another consideration 

 is that the cost of the vibratory anchor is low compared to explosive 

 anchors of comparable capacity if the normally reusable gun-reaction 

 component of the explosive anchor is considered to be expendable in 

 deep water. 



There are evident detrimental features to the vibratory anchor. 

 The present nature of the concept dictates that it be of a long slender 

 configuration. This factor makes it awkward to handle on shipboard 

 and presents difficulties in stabilizing and orienting it while on the 

 seafloor prior to embedment. The size, power, and weight limitations 

 from a practical handling and control standpoint seem to limit the 

 vibratory anchor's holding ability to moderate capacities. Nevertheless, 

 a workable direct embedment anchor with the reliable and predictable 

 capacity anticipated of the vibratory anchor would be of immense 

 immediate value for many current ocean constructions. 



The initial design and fabrication of vibratory anchor prototypes 

 were accomplished under contract to Ocean Science and Engineering 

 Corporation. The Contractor conducted demonstration tests. The 

 Laboratory subsequently received the prototype hardware and initiated 

 a program that involved testing and modifying the initial design. Also, 

 an analytical investigation was begun to optimize the vibratory anchor 

 system for different seafloor conditions. 



Description 



The first generation vibrator anchor design is a long slender 

 metal construction comprised of four basic subsystems; a vibrator, a 

 fluke-shaft assembly, a support guidance frame, and a storage battery 

 power pack. Figure 19. 



The vibrator consists of two eccentrics enclosed in a pressure 

 resistant rectangular aluminum block and two motors, each of 4 hp and 

 housed in a pressure resistant aluminum cylinder attached to the block. 

 The eccentrics generate a peak driving force of 10,000 pounds. The 

 vibrator and housings are bolted to the top of the fluke-shaft assembly. 



The fluke-shaft assembly with the vibrator attached is about 24 feet 

 long. The fluke is a special rotating design (developed during the 

 free-fall anchor program) that provides minimum resistance to penetration, 

 then keys with little vertical displacement to a position presenting a 

 maximum resistance to breakout. Figure 20. It is made of 1/2- inch 

 thick T-1 steel plate cut in two half-circles and one 1/4-circle that 

 are welded together along their diameters to form a "Y"-shape with 

 three 120° angles. When in the penetrating position, the fluke is 

 firmly fixed to the shaft by a locking/tripping mechanism. This 

 attachment must be maintained very rigidly to ensure that the vibration 

 is transmitted to the fluke. The shaft is a 21-foot long, 3-inch, 

 Schedule 80 pipe with special weldments at each end for attachment of 

 the fluke and the vibrator. 



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