proponent of this system is the Entwhistle Manufacturing 

 Corporation of Providence, Rhode Island, This Company 

 manufactures a number of different types of tractor-type 

 capstans under the trade name "Caterpuller , " The Navy 

 some months ago purchased one unit (similar to that shown in 

 Figure 12) andinstalled it on the destroyer USS GLENNON. 

 Tests of this unit have been made by Destroyer Development 

 Division, Group II at Newport, Rhode Island in connection with 

 the installation of a deep-moored buoy system. It is reported 

 that the unit on the GLENNON has successfully handled one- 

 quarter- inch wire rope. Shackles and fittings up to two 

 inches in diameter have been passed through the treads with 

 no apparent difficulty and with no change required in the 

 setting of the machine. 



The use of a "Caterpuller" for the application proposed 

 herein has been discussed with representatives of Entwhistle. 

 The incorporation of a fail-safe system was emphasized, 

 insuring that, if a failure in the equipment should occur, 

 there would be no possibility for release of traction 

 thereby allowing the cable to run free, Entwhistle repre- 

 sentatives are of the opinion that a "Caterpuller" can be 

 designed satisfying all system requirements and incorporating 

 a fail-safe system insuring that any failure will cause 

 sufficient pressure to be applied to the treads to restrain 

 the cable under a load equal to the breaking strength. They 



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