INTRODUCTION 
This report presents information on the problems involved in ocean 
subbottom drilling and excavating. This study is the first step in the develop- 
ment of equipment and techniques for extensive construction site preparation 
on, in, and beneath the ocean floor. Because so much of the ocean’s bottom 
is at depths where divers cannot function safely and efficiently—if at all— 
emphasis is on programmed or highly controlled equipment which can function 
automatically or with a minimum of semiremote supervision from a nearby 
operator in a One-atmosphere vessel. 
While the deep ocean provides a remote, formidable, and hostile 
environment for doing the simplest of tasks, there are some aspects of this 
environment which may lead to accomplishing the planned work in a more 
straightforward fashion than for similar tasks on land. Because the density 
of seawater is high compared with air, the handling of very large weights by 
buoyancy techniques is technically feasible at the present time. With increas- 
ing depths, the cost of pressure-resistant buoyancy materials increases, and 
usually their density also increases to achieve the necessary pressure-resistance 
capability. Thus when suitable materials and control systems are developed, 
weight handling promises to be simpler and more effective, though more 
costly in the ocean than on land. Although it might be possible to mechan- 
ically subdivide, blow and disperse soil in the earth’s atmosphere, the practice 
would not generally be tolerated in any but the most deserted areas. In the 
deep ocean, on the other hand, the superiority of seawater in comparison 
with air for conveying particulate matter as a slurry should provide a unique 
capability for earthmoving equipment to machine a site to a preplanned con- 
tour and eject the resulting slurry into a current or to deposit it some distance 
from the work site, if the current is inadequate. For many one-time simple 
assembly tasks, high-pressure seawater will be usable as a hydraulic fluid for 
locking subassemblies together, etc., if a small receiver is furnished to provide 
the necessary pressure drop across the working piston. 
It is the purpose of this report to define the problems foreseen, assess 
the state-of-the-art in the relevant equipment technologies, and to define the 
development work which is believed necessary to accomplish the goals. Where 
