RECOMMENDATIONS 



It is recommended that preliminary investigation, including model 

 studies, in the following areas be initiated in order to validate the 

 conclusions drawn in this report. 



1 . Determine the drawbar force reduction resulting from an upward 

 cutting vibratory plow in typical seafloor soils. Determine the optimum 

 frequency and amplitude as a function of soil type and speed of advance. 



2. Investigate the effect of water lubricating skids and feed shoes 

 as a function of water pressure, nominal unit ground pressure, and 



flow rate. 



3. Validate the pressure and flow required for jetting a 36-inch- 

 deep trench in seafloor soils. 



Track/wheel propulsion scored highly in most categories, and might be 

 expected to result in a more efficient, more easily controlled, and more 

 versatile cable burial system than the propulsion subsystem selected. 

 However, supportive information, tests, or experience with tracked systems 

 are not available, and, as such, these candidates were downgraded princi- 

 pally because their probability of success is questionable. It is recom- 

 mended that research, development, and testing be performed to determine 

 whether track/wheel vehicles are capable of meeting the needs of a cable 

 burial system. Specifically, the drawbar force that such a system can 

 generate, its slope -climbing ability, and its obstacle-handling capabil- 

 ities in typical seafloor soils should be determined. 



REFERENCES 



1. ''Cable Burial Mission Analysis (U) , " Chesapeake Division of NAVFAC, 

 Washington, DC, 2 Apr 1975. 



2. J. B. McBeth. "The Use of Manned Submersibles for the Burial of 

 Submarine Telecommunication Cable,'' IEEE Conference, Ocean 74, vol 1, 

 Published 74, CH08973-OCC, pp 209-214. 



3. Personal communication with Bill Sherwood, FPO-1 . 



4. Personal communication with Bill Gardner, FPO-1. 



5. Anon. ''Excavators Dig in 40 Feet of Water on Both Sides of the 

 Atlantic," Construction Methods, Dec 1967, pp 68-70. 



6. J. G. Hendrick and W. F. Buchele. "Tillage Energy of a Vibrating 

 Tillage Tool," Transactions of the ASAE, 1963, pp 213-216. 



7. D. MacQueen. ''Some Aspects of the Design and Use of Cable Ploughs - 

 Part II," The Telecommunication Journal of Australia, Jun 1963, pp 52-62. 



8. M. Senator. ''Penetration Rates and Stability of Motions of a 

 Harmonically Forced Fore-Aft Vibrating Plow," ASME 73-DET-125, Sep 9-12, 

 1973, Cincinnati, OH. 



46 



I 



