Hard Hat, or the Deep Dive System (MK I 

 and MK II). 



MK V Helium Hard Hat: (Fig. 15.7) 

 This system relies upon a hard hat and 

 umbilical to a surface support ship and uses 

 helium-oxygen breathing gasses. The bottom 

 time is measured in minutes, but under ideal 

 conditions a depth of 450 feet is attainable. 

 Ideal conditions include a calm sea, the sup- 

 port ship in a four-point moor, adequate med- 

 ical facilities and experienced divers. Normal 

 diving with this system is conducted to 300 



feet and the capability exists aboard every 

 U.S. Navy ASK; these are stationed through- 

 out the world and cruise at a speed of 13 

 knots. 



Deep Dive Systems MK I and MK II: (Fig. 

 15.8) 



Also using helium-oxygen breathing gas 

 mixtures, the Navy's Deep Diving Systems 

 are for saturation diving and theoretically 

 provide extended bottom time to 1,000 feet 

 deep. The systems are presently located on 

 the east (Norfolk, Va.) and west (San Diego, 



Fig. 15.7 MK V Helium Hard Hal (U.S. Navy) 



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