To effect operations, submersibles must be 
designed to fulfill performance criteria for depth, 
endurance, speed, payload, instrumentation, and 
working tools. The vehicles themselves are only 
one part of a total system which includes shore 
bases, support platforms, transportation to work 
sites, maintenance equipment, supply logistics, 
supporting instrumentation and tools, and person- 
nel. Integrated design of the entire system is 
necessary for optimum performance. 
Exploration submersibles will be needed to 
support studies directed toward utilizing and 
exploiting the oceans. The functions of personnel 
and light cargo transfer and of search and rescue 
should be included in their capabilities wherever 
practicable. Based on the state-of-the-art of man- 
ned and unmanned deep submergence vehicles and 
an examination of anticipated requirements, sub- 
mersible characteristics can be determined for 
many anticipated technological development tasks 
with a minimum number of vehicle configurations. 
Characteristics should not be constrained by the 
current technology; rather, they should anticipate 
subsystems and components compatible with fu- 
ture scientific, government, and industrial require- 
ments in the deep ocean. 
Submersible requirements for both shelf (to 
2,000 feet) and deep ocean (to 20,000 feet) 
depths include: 
—Power sources. 
—Propulsion machinery and control, variable bal- 
last, and electrical distribution. 
—Pressure hull, outer hull, and buoyancy mate- 
rials. 
—Navigation and positioning equipment, obstacle 
avoidance and search sonar. 
—Improved manipulators and controls. 
—Magnetic and seafloor anchoring. 
—Underwater communications and viewing. 
—Emergency escape. 
2. Unmanned and Tethered Vehicles 
a. Current Situation Tethered submersibles his- 
torically were typified by diving bells or chambers. 
One of the best known one-atmosphere diving 
chambers is the bathysphere in which William 
Beebe descended to a record depth of 3,028 feet 
in 1934. Submersible work chambers used in diver 
operations are another type of manned, tethered 
system. Some have dual compartments, one at 
one-atmosphere pressure and the other at ambient 
sea pressure with provision for diver entry and 
exits 
Probably the best known unmanned tethered 
submersible is the Navy’s Cable-Controlled Under- 
water Recovery Vehicle (CURV), operated from a 
surface ship and carrying equipment for photo- 
graphy, television observation, limited search, and 
retrieval of small objects (Figure 31). Such a 
vehicle has unlimited endurance, low initial cost, 
and a capability for round-the-clock operation. 
The Navy has under construction a CURV type 
vehicle capable of operation to 7,000 feet. 
Figure 31. Navy's cable-controlled underwater 
recovery vehicle, CURV II. (Navy photo) 
Bottom crawling or rolling submersibles may be 
tethered or untethered, manned or unmanned. 
Several have been built for special purposes. In 
many cases, obscured vision from disturbed sedi- 
ments limited mission effectiveness. However, a 
bottom crawler would be suitable on hard sedi- 
ments or when turbid water viewing systems (like 
acoustic imaging) become available. Recently a 
research submersible operated very successfully 
along the bottom by ballasting slightly heavy and 
riding on wheels. 
In recent years, several successful tethered 
unmanned vehicles equipped with special instru- 
ment suits have been built. Cable controlled or 
