Fig. 12,27 Ballcxin assist. 



•-X;0 



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Fig. 12 28 Quick snatch. 



Quick Snatch (Fig. 12.28): This concept 

 employs a shock-absorbing collar such that 

 the vehicle can be quickly removed from the 

 sea. As the vehicle passes thru the air-sea 

 interface it contacts the absorbing collar 

 which is attached to an arm that moves 

 upwards to a restraint. The pivot of the arm 

 is set on a rotating table that allows the 

 entire package to rotate the vehicle over a 

 stowage point. 



Telescoping Cylinder (Fig. 12.29): This con- 

 cept employs a hydraulic cylinder with two 

 modes of operation — normal push-pull power 

 and damping, controlled by variable orifices. 

 The lift cable leads through an attachment 

 at the end of the cylinder that provides auto- 

 matic latching. The cylinder is powered 

 about its horizontal axis by a rotary actuator 

 or gears, with the entire unit on a turntable. 



Deployment commences by positioning the 

 attachment on the cylinder end over the 

 vehicle which is in a stowage position. 

 Hookup is made and the vehicle is moved 

 overboard and into the water. At some point 

 below the surface the hookup is released and 

 the vehicle is lowered. Recovery commences 

 by pulling the lift-cable in until the vehicle 

 latches onto the attachment device, at which 

 time the cylinder is in its damping mode, 

 preventing undesired ship motion from re- 

 sulting in damaging dynamic loads. Once the 

 vehicle is attached the cylinder is switched 



to power mode and the vehicle is raised from 

 the sea and set on deck. 



The major problem with the dual-mode 

 telescoping cylinder, in the case of the 10-ton 

 PTC, is the bending stress induced when it is 

 extended and carrying the weight of the 



Fig. 12.29 Telescoping cylinder. 



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