the technology is deficient, explicit statements of the research and 
development necessary will be found at the end of each section; these 
are intended as technical work statements for specific efforts, no matter 
where the research and developmental efforts are conducted. 
The research and development is to be conducted on two Navy Deep 
Ocean Technology (DOT) work units authorized by the Chief of Naval Mate- 
rial (1969) and described as Subprojects WBS 3.1420 of Project 46-36X, which 
is in turn described in the Technical Development Plan of the same number. 
The titles of the respective Subprojects are respectively: ‘Excavators and 
Dredgers’’* and “Drilling and Tunneling.” 
The first of these subprojects is concerned with shallow excavation 
and drilling preparatory to making emplacements on or in the soil surface at 
the bottom of the ocean. Technological development is complicated by the 
fact that the soil may vary from a gelatinous, almost nonviscous water-filled 
clay with little shear strength to solid, strong rock. 
The second project involves (1) penetrating and shoring against a 
soil or silt overburden to solid rock; (2) penetrating competent rock with 
a large diameter hole, probably cylindrical; (3) sealing the opening with a 
prepared access hatch; and (4) dewatering and excavating large lateral and 
vertical cavities in a one-atmosphere environment. An alternative and prob- 
ably more difficult method would be to tunnel from adjacent land and make 
functional site openings to the sea through the seafloor. 
The operational ocean depths considered in this study are all beyond 
diver depths. It is anticipated that most of the mechanical systems developed 
will be made essentially depth-independent by having the pressure-sensitive 
components in pressure equilibrium with the surrounding ocean. For those 
pressure-sensitive components such as buoyancy pontoons, which must func- 
tion at full ocean pressure, 6,000 feet is the initial target, with eventual 
capability to 20,000 feet. 
Two major work systems fulfill the aims of the DOT tasks, with 
several minor systems in support: 
1. For the Seafloor Excavator the major piece of equipment foreseen 
is a mobile chassis, probably with rubber tires for firm bottoms and an inter- 
changeable low-ground-pressure track system for low-shear-strength materials. 
A track system will be needed for the worst cases and probably will be func- 
tional for most bottoms. The unit will receive power through an umbilical, 
either as electrical power or high-pressure seawater. The vehicle will have a 
cutter system capable of leveling, trenching, and drilling shallow foundation 
holes to a prepared plan, under computer and/or numerical control. Several 
* In FY 70 designated ‘’Seafloor Excavator.” 
