This paper discusses the ramifications, particularly in terms of hardware, of the current trend in deep-diving submarine vehicles towards increased capability for accomplishing “real life” work tasks. The configuration of small deep-diving submarines for this purpose, as opposed to observation missions, is a significant step in man’s drive to achieve effective utilization of the resources of the oceans of the world. The Beaver Mark IV, a typical example of an underseas “work boat,” is specifically configured to perform a number of work and research tasks that are oriented to the requirements of the present state of ocean engineering and the expected developments in the immediate future.A short summary is provided of the historical backgrounds of early submarines. Brief comments are made for purpose of orientation on the trends which have occurred in the last 40 years in submarine design, principally as a consequence of naval submarine design and construction with which the author has had extended experience. Specific discussion is provided regarding the component and hardware features which are significant in developing deep-diving work vehicles. Essential characteristics, such as viewing, illumination, manipulators, interchangeable tools, the capability of transferring men to underseas habitats at normal atmospheric pressures, and the support of diver operations are included in the comments.