Stachiw 



INTRODUCTION 



The conquest of hydroSpace requires both mobile and fixed under- 

 water structures capable of housing instruments and men for extended 

 periods of time. There is a long history of research on the proper- 

 ties of materials and the design of hulls suitable for submarines; 

 however, the research into materials and designs for static under- 

 water hull structures is just beginning. 



Although many materials developed for submarine or torpedo hulls 

 are also applicable to fixed, ocean-bottom installations, there are 

 materials which have not received careful study because of their 

 manifest inapplicability to high-speed, deep submergence submarines 

 or torpedoes. One such material is concrete. 



The purpose of this paper is to describe several brief explo- 

 ratory investigations into the applicability of concrete to the 

 fabrication of structural hulls for deep submergence structures.* 

 The scope of this series of experiments was limited to models of 

 buoyant spherical hulls of 16 inch external diameter for 3500 feet 

 depth cast from the same concrete mix. Variables were introduced 

 into the study by varying the method of hydrostatic testing, as 

 well as by incorporating into the hull different kinds of penetra- 

 tions and inserts. 



BACKGROUND 



Concrete has been used in harbor installations for many de- 

 cades, but it has not been used for the construction of underwater 

 habitats. There are several reasons for this. Since concrete is 

 not as desirable for submarine hull construction as other materials, 

 no research was done on its properties under seawater hydrostatic 

 pressure prior to the recent interest in fixed, ocean-floor instal- 

 lations. Furthermore, the impetus of research has been directed 

 towards the discovery of new materials that would give buoyancy to 

 a deep submergence hull even at greatest depths in the ocean. The 

 most potent argument used against concrete in the past was that 

 buoyant concrete hulls are limited by concrete's compressive strength 

 to depths less than 5,000 feet and therefore cannot satisfy depth 

 requirements that may arise in the future. Thus the philosophy 

 appears to have been that since buoyant concrete hulls were defin- 

 itely depth limited, there was no need to conduct research on 

 structural characteristics of concrete as a stop-gap solution to 

 the problem of finding suitable materials for deep submergence 

 structures . 



*In this paper, "deep submergence" is used to refer to depths 

 greater than 600 feet. 



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