RETRACTABLE 

 GUIDE SHEAVE 



DRAWWINCH 



FLOATS 



BALL-IN-SOCKET 

 JOINT 



^n 



RAMP 



(TWO SECTIONS FOR 

 VEHICLE SLED RETRACTION AND STOWAGE 



Fig. 12.22 Hinged ramp concept. (Proposed by R. Gaul and R. Bradley, Westinghouse) 



^ 



Fig 12.23 Spar buoy wilh trolley. 



and the accompanying discussion of their 

 pros and cons are taken from Doerschuk et 

 al. (5) who, as mentioned previously, per- 

 formed analyses of many different systems 

 for the U.S. Navy's Personnel Transfer Cap- 

 sule (PTC). 



Spar Buoy With Trolley (Fig. 12.23): This 

 system provides a gradual transition from 

 the underwater motion of the vehicle to the 

 motion of the ship. The spar-buoy end of the 

 trolley is stable, while the pinned end is fixed 

 relative to the ship. Deployment and recov- 

 ery of the vehicle takes place far out on the 

 arm next to the buoy. The vehicle travels to 

 and from this point above water by virtue of 

 an electric or hydraulic trolley. Using a 5- 

 foot-diameter spar buoy, recovery of a vehi- 

 cle from the water would cause a 20-foot drop 

 in the spar-buoy's vertical position (total 

 weight of vehicle, buoy and arm equals 12.5 



tons). A major drawback with this concept is 

 sheer magnitude. Transportability, stowage, 

 and deployment of a buoy at least 5 feet in 

 diameter and long enough to attenuate the 

 maximum waveheight would pose severe 

 problems. 



Inflatable Ramp (Fig. 12.24): In this con- 

 cept an inflatable rubber ramp is suspended 

 over the side of the ship. The vehicle is 

 lowered and raised using the ramp as a guide 

 and the ship's boom as support. Stowage and 

 weight problems would be practically nonex- 

 istent. However, the idea may be too simplis- 

 tic in that the configuration of the vehicle 

 may not lend itself to be easily guided by a 

 simple ramp. Vertical orientation may be 

 difficult to maintain, and fragile exterior 

 equipment would be prone to damage. 



Centerwell (Fig. 12.25): Deployment and re- 

 covery through a hole in the ship near the 



611 



