6,000 



4,000 



2,000 



capsule (50-psi/min pressurization rate) 

 I I 



capsule 1 (22-psi/min pressurization rate) 



Notes: 



1. Dimension of capsules — 66-in. OD x 61-in. ID 



2. Ambient temperature — 68 to 72°F 



3. Sustained pressure — 500 psi 



4. Strains measured at the equator on the interior surface 



100 150 



Time (minutes) 



200 



Figure F-5. Comparison of strains on the interior surface of the NEMO 

 capsules under long term 500 psi hydrostatic loading. 



RECOMMENDATIONS 



The specifications and drawings used in the production of three 

 capsules by the contractor were generally satisfactory; however, as result 

 of the experience gained in the fabrication of the three capsules, the follow- 

 ing specification changes should be introduced: 



1. Decrease the tolerance on the diameter to 65.875<D<66.125 inches. 



2. Increase the tolerance on the thickness of the finished hull to 

 2.300<t< 2.700 inches. 



3. Increase the tolerance on the chord length between nonadjacent pentagon 

 tips to 32.970< K< 33.030 inches. 



4. Increase the minimum tensile strength requirement of the joint from 

 4,000 psi to 5,000 psi. 



5. Increase the tolerance on the thickness of the acrylic plastic discs prior 

 to forming to 2.350<t< 2.650 inches. 



214 



