Search, survey, and recovery systems to ex- 
amine the bottom, much as one views land from a 
helicopter, are needed. Desirable capabilities in- 
clude hovering, close station keeping, precise 
navigation, and the ability to return to a given 
spot. The system should be able to take biological, 
geological, and chemical samples (including cores) 
and to map, make bathymetric charts, photograph, 
listen, and touch. The floor must be explored to 
discover exploitable resources, to find hiding 
places, and to study seamounts, volcanoes, and 
mud slides. A 20,000-foot depth capability will 
permit these operations in almost 99 per cent of 
the world’s ocean volume, covering 98 per cent of 
the ocean’s floor, excepting only the deep tren- 
ches. 
New vehicles and equipment will be needed to 
support and maintain more fixed, portable, and 
mobile undersea systems. As Dr. John P. Craven, 
Chief Scientist of the Navy’s Deep Submergence 
Systems Project has said, “In the long run, 
underwater transfer is the key to effective use of 
the ocean depths.” Therefore, a key secondary 
mission for rescue vehicles will be underwater 
transfer to supply habitats, stations, and sub- 
marines not in distress. Such vehicles would 
provide deployed underwater installations freedom 
from surface support. 
Inherent to practicability of these vehicles is 
substantial payload capacity. For example, the 
Navy’s Deep Submergence Rescue Vehicle will be 
able to carry internally only 4,300 pounds of 
personnel or cargo. Ambient pressure, wet cargo 
carriers will be necessary to transport thousands of 
tons, especially for mining, construction, salvage, 
and the deployment of instruments and equip- 
ment. 
The Navy has been pursuing actively its Deep 
Submergence Rescue Vehicle (DSRV) and Deep 
Submergence Search Vehicle (DSSV) projects and 
is conducting preliminary studies on a Deep Ocean 
Survey Vehicle (DOSV) and a Deep Ocean Tech- 
nology (DOT) test bed vehicle. These projects are 
of the utmost importance to extend U.S. capa- 
bility and knowledge of the undersea frontier. 
Search and rescue projects certainly should receive 
high priority, since the world has lost an average of 
two submarines per year in peacetime. Recently a 
one-half million dollar isotope power source was 
recovered off the Pacific Missile Range after a 
long, extensive search. 
VI-84 
Submersible vehicles of all types—tethered and 
untethered, manned and unmanned—will be useful 
in ocean activities. Once each is developed to its 
full capability, normal comparative studies will 
establish the range of conditions and operations 
for which each is most effective. 
1. Submersible Vehicles 
Submersibles have many operational advan- 
tages. They function in an environment free of 
wave forces and the potential damage and limita- 
tions imposed by adverse weather. They provide 
an ultraquiet platform for acoustic studies. They 
can take advantage of the force of buoyancy to 
emplace or recover objects and, perhaps most 
important, they can bring man into the oceans for 
observation and work. 
a. Current Situation Operational submersibles 
have demonstrated limited usefulness in several 
exploration and inspection tasks. Many special 
purpose oceanographic submersibles exist in a 
wide variety of configurations, hull materials, and 
depth capabilities. Of the 82 proposed or existing 
vehicles for which operating depths are known, 24 
(29 per cent) are planned for operations to at least 
6,000 feet and only 12 (15 per cent) for opera- 
tions to 20,000 feet. The operating 20,000-foot 
submersibles can be classified as unmaneuverable 
bathyscaphs. Additional technological advances 
are necessary to develop capability for work at 
great depths. 
Typical submersibles (Figure 30) now in opera- 
tion have pressure hulls generally of ring-stiffened 
cylinders or spheres made of high strength steel. 
Maximum speeds vary from two to five knots, 
mission endurance from 4 to 30 hours, and range 
from several miles to about 100 miles. 
Submersibles usually are powered from bat- 
teries located external to the pressure hull, and 
have external propulsion motors. Ballast systems 
typically involve both soft or free-flooding tanks 
blown for additional freeboard and surface stabil- 
ity and tanks or dropable weights to change 
buoyancy at great depths. 
A number of technological deficiencies have 
reduced the efficiency and potential usefulness of 
submersibles. Most are highlighted here; more de- 
tailed discussions may be found in the appropriate 
subsections of this chapter, pages 29-77. 
