Fig- 14.16 Inflatable modules increase MAKAKAI's freeboard to about 4 feet for safe exit when surfaced- (NUC) 



mersibles (NEMO, MAKAKAI, JOHNSON 

 SEA LINK), only MAKAKAI provides a 

 means of minimizing the potential for 

 swamping. Unless flat calm conditions pre- 

 vail, the occupants may safely open the 

 hatch only when the submersible is aboard 

 its support craft. 



Snorkel: 



Several of the shallow-diving vehicles and 

 the early FNRS-2 and 3 bathyscaphs incor- 

 porate a simple snorkel device which allows 

 fresh air to enter the hull by merely opening 

 a valve. 



DEVICES TO ASSIST 

 UNDERWATER RESCUE 



In the event that a submersible cannot 

 surface and egress is impossible, there are 

 instruments or devices available to the occu- 

 pants to assist their rescuers (Table 14.5). 

 From the rescuers' point of view the ques- 



tions calling for immediate answer are: 

 Where are they? How deep? What is the 

 nature of the casualty? and What is the 

 remaining life support? At this point, not 

 only are the design and capabilities of the 

 vehicle critical, but the ocean environment 

 surrounding it is another salient factor. 



A critical instrument in all rescue opera- 

 tions is the underwater telephone. If there is 

 no means of communication between rescuer 

 and rescuees, recovery of the submersible 

 within its life support endurance would be 

 fraught with uncertainty and difficulty. 



In addition to the need for communications 

 is the ability to locate the submersible. There 

 are several underwater three-dimensional 

 navigational systems commercially available 

 through which a submersible may determine 

 its own position or a surface craft may locate 

 the submersible relative to itself with ex- 

 treme accuracy (see Chap. 10). But such sys- 

 tems are quite expensive and beyond the 

 operating budget of most private and many 

 government owners. 



675 



