62 THE NAVY OCEAN SCIENCE PROGRAM 



Another buoy system, Sea Spider, has been developed to 

 provide a stable support system for underwater instruments 

 placed in very deep water. It consists of a submerged float moored 

 by three wires whose buoyancy is adjusted to zero by external 

 floats. An experimental model installed in 2600 feet of water 

 exhibited movements essentially equal to or better than the 

 accuracy of measurement of its position— less than three feet. 

 Design of a system for installation in 17,000 feet of water is 

 currently underway. 



For some types of measurement, a platform is required which 

 will exhibit a very high degree of stability in high sea states. 

 A unique spar buoy, some 350 feet long, was designed and 

 constructed. It moves vertically less than one foot in waves 15 

 feet high. It can be towed from place to place while lying hori- 

 zontally on the water and can be erected (flipped) to a maximum 

 draft of 300 feet at will. This technique allows transport at 

 moderate speeds and permits equipment installation at dockside. 

 Accommodations for six to eight men are provided for 30 days 

 at sea. 



The need for long-term investigations with fixed equipment 

 has led to the construction and installation of fixed towers in 

 moderate depths of water. Four such towers are actively used 

 in the Navy Ocean Science Program, 



Argus Island— K tower atop a 15,000-foot underwater moun- 

 tain some 30 miles southwest of Bermuda. The mountain top is 

 a flat plateau, about five miles in diameter, 200 feet under 

 the ocean surface. Argus is near the southern edge of the 

 plateau, for ease of installation of sensors on the steep slope 

 of the sea mount. About 30 persons can be accommodated in 

 comfort. 



NEL Tower— k platform in 60 feet of water near San Diego, 

 equipped for long-term measurement of physical, chemical, 

 meteorological, and acoustic measurements. 



MDL Towers— Two towers, one in 60 feet of water and a very 

 large structure in 100 feet of water near Panama City, Florida. 

 These towers are used in specialized studies of Gulf of Mexico 

 phenomena. 



