simplified polar closure 



equatorial ring 



acrylic plastic hull 



lifting eyes 



radial pins 



structural framework 

 made up of rods 



bottom of pressure vessel 



Figure D-6. Test arrangement for implosion testing of the 15-inch-diameter capsule 

 with equatorial ring. 



CONCLUSION 



The equatorial ring restraint concept for attaching a spherical 

 acrylic plastic capsule to the structural framework of a submersible system 

 has been found to be feasible, and its application does not compromise in 

 any manner the structural integrity of the acrylic plastic pressure hull under 

 external hydrostatic loading. 



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