Fig. 13.4 In moderate seas the close quarters t)etween LULU's pontoons make line-liandling and control of ALVIN an exacting task (NAVOCEANO) 



vious and may cause damage to the vehicle, 

 the occupants and the support ship as well. 



Hydraulics: The most Vulnerable moment 

 during launch/retrieval is when the submers- 

 ible is free of the deck or water and sus- 

 pended between the two. If, for example, the 

 hydraulically-powered lift system were to ex- 

 perience a failure which made it incapable of 

 lateral or vertical movement, and the sea 

 were running high, the pendulum motion of 

 the vehicle could be sufficient to cause great 

 damage to participants and components. 



Collision: Present submersibles come within 

 a few feet of the support ship for attachment 

 of the lift device; at this point the danger of 

 collision, with its attendant damage, is cru- 

 cial. 



Line-Entanglement In addition to the main 

 lifting cable, from two to six lighter restrain- 

 ing lines may be used to steady the submers- 

 ible. Personnel entanglement with such lines 

 is a possibility which may cause injury from 

 the line itself, or temporarily immobilize the 

 crew member, thereby putting him in a posi- 

 tion of considerable jeopardy if the vehicle is 

 plunging or swinging. 



Divers Virtually all submersibles use divers 

 or swimmers to attach or detach lift and 

 steadying lines. Working between the sub- 

 mersible and ship, which may at times be 

 separated by only a few feet, the swimmer is 

 exposed to getting caught and crushed be- 

 tween both (Fig. 13.5). In addition, he is 



629 



