FOREWORD 



History records evidence of insatiable human curiosity about our 

 world. But it was a more urgent need than curiosity which tempted 

 early man to look beneath the surface of the sea and test his limits of 

 endurance. He went in search of natural treasure to augment his hard- 

 won food supply and for naturally occurring materials that were useful 

 in a primitive, comfortless routine of living. Limits were quickly 

 reached in his invasion of the ocean depths, and all that lay beyond was 

 called mysterious, remaining unapproachable without some form of 

 protection against hostilities destructive to the fragile vehicle of hu- 

 man life. 



Twentieth century technology has cleared the pathway for safe 

 passage through those deep sea hostilities for an invasion of the 

 marine environment unparalleled in history. A growing host of varied 

 undersea vehicles is entering the ocean's depths in missions of science, 

 engineering and exploration for industrial opportunity, as well as for 

 the satisfaction of simple curiosity. 



The U.S. Navy is required, by the responsibilities of its mission, to 

 operate throughout the entire ocean environment. Those responsibili- 

 ties, in turn, impose requirements for knowledge about our operational 

 environment and technology that will operate there, effectively. In 

 order to gain knowledge of the deep ocean and its influences upon 

 naval operations, we have to go there. One way to go there is to send 

 tools which function as extensions of man's senses and work capabili- 

 ties. But, even though modern technology is helping us to develop 

 increasingly refined instrumentation and methods for perceiving the 

 nature of the ocean depths, there are observations and conclusions 

 which cannot be achieved without the benefit of man's highly devel- 

 oped sensory capabilities operating in the immediate vicinity of investi- 

 gation and work areas. 



It is the manned submersible which offers us the opportunity to be 

 on the scene and perform tasks in a relatively comfortable and secure 

 environment at ocean depths or locations which would otherwise be 

 destructive to human life. The Navy has developed a small family of 

 manned submersibles to investigate the deep ocean and to perform 

 various kinds of work included in the Navy's mission. We are also 

 interested to know what others have done in the development of 

 manned submersibles, because each effort in the field is helpful in 

 solving problems of how to work most effectively in the deep ocean 

 environment. 



Our Nation . . . indeed, the whole world . . . has demonstrated 

 renewed interest in developing the technology and the methods neces- 

 sary to begin harvesting natural resources from the sea, in quantity. 

 Amateurs as well as professionals are at work to design and build 

 vehicles of one kind or another which will permit useful work in the 

 ocean. Progress toward those goals is assisted by sharing both suc- 

 cesses and failures in development efforts. The problems of reaching 

 those goals are based on the difficulties of creating technology that 

 works in the deep ocean. But the problems are basically the same no 

 matter what kind of work is contemplated so a sharing of them and 

 their solutions works to speed progress for all. 



HI 



