Carderock, Maryland, successfully tested the hull in a pressurized 

 oil bath to the equivalent of 13,000 feet in depth. Alvin's new hull will 

 be tested at sea in mid-1973. 



A continuing program to improve methods of providing buoyancy 

 for submerged systems has resulted in the use of solid, lightweight 

 syntactic foams. The foams are long-lived and neither flammable nor 

 subject to permeation by seawater. Currently, a great deal of effort is 

 being made to improve the foams by reducing their density and by 

 developing techniques by which large quantities can be produced 

 relatively inexpensively. 



The Sea Construction (SEACON I] experiment, conducted off 

 Santa Barbara, California, is designed to evaluate concrete for 

 seafloor construction and to provide a facility for testing hatch and 

 viewport designs as well as antifouling techniques. One cylinder and 

 18 spheres of precast concrete are used in the experiment. In January 

 1972, after eleven months' submergence, the experimental cylinder 

 was raised from a depth of 600 feet. Monitoring sensors within the 

 cylinder provided information on stress, strain, seawater 

 permeability, and internal atmosphere (dust, humidity, oxygen, 

 etc.). The concrete spheres are still anchored near the bottom at 

 graduated depths from 2,000 to 5,000 feet. SEACON II, an eighteen- 

 month sea-construction demonstration, will begin in October 1973 

 with the installation of a seafloor platform, cable structures, and 

 otherequipment, much of which is in the final stages of development. 



A new type of deep-ocean corer is being fabricated to take 50-foot 

 bottom cores at depths of 6,000 feet. Unlike other corers, this device 

 will not disturb or rearrange the bottom sample. Engineering 

 analysis of the samples will be correlated with less direct electronic 

 analysis of the seafloor to determine its weight-supporting ability 

 and other engineering properties, knowledge of which is necessary 

 for the installation of bottom structures. 



Anchors and cables are being developed to hold subsurface and 

 bottom structures in place. A vibratory embedment anchor, which 

 uses an electric motor to drive the anchor into the sea floor, has been 

 demonstrated. The anchor can hold 50 times its own weight at 6,000 

 foot depths. An explosive embedment anchor, which is driven into 

 the sea floor by an explosive charge, is also under development. At a 

 20,000 foot depth, it will hold against a 20,000 pound pull. 



Cables are being developed to moor platforms to these anchors and 

 to control unmanned underwater work systems. New resin materials 

 are being investigated for use in durable, light-weight cables that are 

 neutrally buoyant and of high strength. These cables will be used to 

 support the Remote Unmanned Work System, RUWS-20, at 20,000 

 foot depths. The vehicle and other system components have been 

 completed and will be assembled next year. Four miles of cable will 

 be used in RUWS operations. Because of the cable's neutral 

 buoyancy, the RUWS vehicle will be able to move without the use of 

 additional power or flotation. 



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