do. Skids are the least complicated running gear for a bottom-traversing 

 machine and have been used successfully in the past. The force required 

 to move unlubricated skids is near 4,000 pounds, but it is expected that 

 this force can be reduced by water lubricating the contact surface. 



11. Rolling elements, such as tracks or wheels, reduce resistance to 

 motion and can provide some steering control by differential braking. 

 They must be large to reduce the nominal unit ground pressure. Since 

 they are rotating, they are somewhat complicated and are susceptible 

 to jamming from sediment. 



12. The water cushion vehicle is an unproven concept, requires large 

 amounts of power, and the skirt flow may wash away the soil and cause 

 the system to jet itself into the seafloor. Vertical stability may cause 

 burial depth variations, and the small skirt clearance makes it difficult 

 to operate in non-level terrain. 



CONCLUSIONS 



1 . It is concluded that the deep -ocean burial system concept with the 

 best chance of success, which will provide positive burial depth and 

 which meets power, weight, size, ship support, and speed requirements, 

 is comprised of the following major subsystems. 



Excavation subsystem - vibratory plowshare or water jet 



Propulsion subsystem - self propelled by thrusters 



Running gear subsystem - lubricated skids 



2. The primary operating mode should be the burial of previously 

 laid cables so that (1) the support ship need not be a cable layer, 

 (2) problems with the cable -burying operation will not threaten the 

 cable-laying operation, and (3) repair sections or existing cables can 

 be buried. Towing may be used as an alternate propulsion means. 



3. The auxiliary systems required include: 



(a) Cable guide mechanism, hydraulically controlled to attach to 

 and lift cable into feed shoe. 



(b) Cable following sensors which feed data to machine control 

 system to steer the burying machine along the cable route . 



(c) If vibratory plowing is the final excavation subsystem, a jet 

 pump system capable of burying repeaters, hockles, kinks or cable 

 anomalies which cannot be fed through the feed shoe. 



(d) Fail-safe means to allow disengaging the cable should the burial 

 machine fail. 



(e) Magnetometer or other device for locating previously laid cable. 



(f) Obstacle avoidance sonar system. 



(g) Television and hydrophones. 



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