MOTIVE SYSTEMS 



Most concepts for positioning and guidance require both motive and 

 alignment systems. In the discussion that follows, a distinction is drawn 

 between the mechanical devices responsible for final emplacement of bottom 

 loads and the subsystems, whether acoustic or photo-optical, which provide 

 necessary feedback to guide emplacement. Some of the candidate motive 

 systems are limited most by the availability of power at 6,000 feet. First to 

 be discussed, then, are the motive systems for positioning suspended loads. 



Winches 



J-Star. A system utilizing the winch-anchor approach, for use in 

 underwater search and recovery, has been successfully developed and 

 employed by Jacobson Brothers, Inc., of Seattle, Washington. ^^ Called the 

 J-Star, the system uses four anchors and a remotely controlled camera- 

 manipulator array. The system is illustrated in Figure 9. 



The method of operation is relatively rapid and simple. The recovery 

 vessel is first anchored in a three-point moor or a single-point moor using 

 bow thrusters for positioning. Four camera anchors are then installed and 

 the camera-manipulator is deployed. The array is supported by a single cable 

 from the surface. Lateral movement of the array is achieved by paying out 

 or winding (under tension) the four lines to each camera anchor by means of 

 a four-spool hydraulic winch mounted on the recovery vessel. It is claimed 

 that precise positioning within a fraction of an inch, uninfluenced by tides, is 

 possible. The system is used, primarily, in water more than 600 feet deep, 

 and long duration explorations in depths of around 3,500 feet are possible. 

 The unit is extremely steady and has been used to locate, grasp, and raise a 

 large number of torpedoes, arrays, and aircraft. 



It is conceivable that this system could be modified to the point where 

 it could be utilized for the placing of heavy modular units. However, the 

 inherent need for cables, particularly for support of the array, would probably 

 place a limit on the weight of the unit suspended. Nevertheless, it does 

 appear that given moderate weight and depth requirements, only minor 

 design problems must be solved to utilize this successful system for extremely 

 accurate positioning of underwater loads. 



Submersible Winches. Submersible winches have been used to depths 

 greater than 1 ,000 feet, mostly in a vertical attitude to move loads up or 

 down. SeaLab III will use a winch to ferry the personnel transfer capsule 

 (PTC) from the surface to the habitat at a depth of 600 feet. The winch was 



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