SUMMARY AND CONCLUSIONS 



1. On the basis of measured deviations from sphericity, hull thickness 

 measurements made by the fabricators and material stress-strain curves 

 available at this time, collapse depths of the ALVIN Pressure Hulls No. 1, 



2, and 3 were calcialated as 15,800, 16,100, and 15,100 ft, respectively. 



2. The maximum local radius of curvature for the three hulls was only 5 

 percent greater than the nominal radius. 



3. Local geometry and not nominal geometry must be used to determine the 

 collapse strength of a spherical shell. The collapse strength of a 

 spherical shell with the same geometry as ALVIN, fabricated to boiler code 

 tolerances may be as low as 40 percent of the strength which was predicted 

 for the ALVIN spheres. 



ACKNOWLEDGMENTS 



The author is indebted to CDR Lasley of the Office of Naval Re- 

 search for his interest in this project. The cooperation of Mr. H. E. Froelich 

 of Litton Industries, Messrs. J. W. Mavor and J. B. Walsh of the Woods Hole 

 Oceanographic Institution and representatives of Hahn and Clay is 

 appreciated. Thanks are also due to Mr. M. A. Krenzke who directed this 

 project and contributed to the work described in this report and to 

 Mr. R. M. Charles who designed the measuring instrument and obtained the 

 measurements on the ALVIN pressure hulls. 



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