Fig. 12.26 Guiding chute. 



intersection of the roll and pitch axes may 

 greatly reduce undesired motion. However, 

 this feature is rarely availably on ships of 

 opportunity. 



Guiding Chute (Fig. 12.26): In this concept, 

 a cage acting as a guiding chute is deployed 

 over the side of the ship. The vehicle is 

 raised and lowered through it using a series 

 of guide shoes attached to the vehicle. Lift is 

 provided by the ship's boom. The probability 

 of dangerous impact loads between vehicle 

 and cage as the vehicle is first drawn into 

 the chute during recovery makes this con- 

 cept unfeasible. 



Balloon Assist (Fig. 12.27): The Balloon As- 

 sist is a variation on the "gradual change to 

 ship-motion" theme. Recovery and deploy- 

 ment take place from a winch riding the 

 tether of a relatively stable balloon towed by 

 the ship. Once the PTC is pulled completely 

 out of the water during recovery, the winch 

 is wound down onto the ship and the PTC is 

 secured. Major drawbacks are the possibili- 

 ties of wind direction change, requirement of 

 at least 315,000 SCF (in the case of the PTC) 

 of helium for the balloon, and the balloon 

 handling, maintenance, and manning prob- 

 lems. 



613 



