cable found, and how is access gained to the cable to effect a repair. 

 Also, once the cable is repaired, how is it buried again. The first two 

 items, location and repair, are not intrinsically part of a cable burial 

 system, and would unnecessarily complicate the hardware and threaten the 

 success of the development program. Therefore, location and repair of 

 a buried cable are not imposed as requirements of the cable burial system. 

 Also, the telecommunication industry is currently developing a system 

 to locate and repair buried cables. Since failure of buried cables will 

 be an unlikely event, the repair system will be rarely used, and, there- 

 fore, should be available to the Navy on a contractual basis as needed. 

 Burying the cable after a repair is made will be within the capabilities 

 of the cable burial system, as it is foreseen that cables which must be 

 buried may already have been repaired one or more times. Burial of a repair 

 section is also within the capabilities of the cable repair system being 

 developed. 



CABLE BURIAL SYSTEM REQUIREMENTS 



To develop a cable burial system that will provide adequate protection 

 to Naval cable installations, a set of operational requirements must be 

 identified and ranked in their order of importance. The requirements iden- 

 tified below are divided into general operational requirements and specific 

 requirements. The general requirements are the more important ones, and 

 impact heavily on the selection of a good concept. Specific requirements 

 affect subsystem capabilities which must be part of any of the concepts. 



General Operational Requirements 



a. Bury cable no less than 3 feet in the seafloor without damaging 

 the cable. 



This requirement, the most important, is the basic objective of the 

 entire program. A cable burial mission analysis [1] determined that damage 

 due to fishing activities will be eliminated if the cable is buried 3 

 feet deep in water depths greater than 20 fathoms. Obviously this must 

 be accomplished without damaging the cable. The mission analysis also 

 determined that a 6-foot burial depth is required in water depths from 

 5 to 20 fathoms, principally due to the anchor drag threat. Although it 

 is important to meet this shallow-water requirement, it is felt that the 

 increased burial depth has little impact on concept selection. Also, it 

 may be more effective to use nearshore cable burial techniques that are 

 being developed separately to depths of 20 fathoms. 



b. The cable burial operation must be supported from a ship of 

 opportunity. 



The Bell Sea Plow buries cable during a cable-laying operation, 

 weighs 23 tons, and requires a nominal tow force of 50,000 pounds at a 

 speed of 1 knot. Use of a ship of opportunity, although ranked second 



