The types of structures for which deep water moors are needed 

 include oceanographic data buoy stations, surface and subsurface 

 instrument arrays, ships, submarines beneath the surface, and manned 

 or unmanned sea platforms. As yet, it is not valid to label any deep 

 sea moor as a typical design. Some significant deep sea moors have 

 been accomplished that illustrate both the requirements and the 

 problems. Among these are the Tongue of the Ocean II (TOTO II) moor 

 for large surface vessels. Figure 1, Naval Oceanographic Meteorological 

 Automatic Device (NOMAD) anchor system. Figure 2, and the U. S. Coast 

 and Geodetic Survey, Undersea Stabilized Platform, Figure 3, (Smith, 

 1965). Several underwater instrument array anchoring methods are 

 depicted in Figures 4 and 5. It is noteworthy with respect to problems 

 of deep sea moors that a moor system similar to the undersea stabilized 

 platform design that was installed in 4,000 feet was attempted in water 

 18,000 feet deep. It was unsuccessful and a major difficulty pertained 

 to lack of adequate anchors specially adapted for use in the deep sea 

 (Interstate Electronics Corporation, 1970). 



Modified Anchor Criteria 



Conventional anchors have evolved through the ages into efficient 

 implements to meet holding requirements under many operational conditions. 

 There is much diversification in sizes, shapes, and arrangement of 

 components of conventional anchors. However, all conventional anchors 

 share certain characteristics that can serve to good advantage in meeting 

 conditions for which they are designed but which are detrimental in 

 deep ocean applications. They must be dragged in order to embed and 

 develop rated holding capacity. The dragging force must be applied 

 parallel or near parallel to the seafloor. They then are able to 

 resist maximum forces only from the direction in which they were dragged. 

 Forces from other directions and/or uplift forces greatly reduce their 

 holding capability. One other limitation is that the performance of 

 conventional anchors in hard seafloors is erratic and unreliable. In 

 such conditions, they do not embed but depend on holding by falling 

 into a crevice or by snagging on a protrusion or outcropping. 



These characteristics demonstrate the unsatisfactory nature of 

 conventional anchors for deep water applications. Large scopes of line 

 and other connective gear are required first to apply the forces 

 parallel to the seafloor to effect embedment and second to maintain 

 the parallel force direction during use. Attendant surface operational 

 and coordination problems in handling the immense amounts of line and 

 in maintaining correct position and course of work platforms during 

 placement are acute. 



