The mechanical and electrical system can be used at all depths with 
high efficiency, but it is desirable for each system to convert its power to 
hydraulic power at the ocean floor site for reasons presented in the next 
section. The linear-motion cable system appears relatively simple, inexpen- 
sive, and rugged; it will require a minimum of development. It produces the 
desirable hydraulic power directly. 
Future Plans 
Depending upon the state-of-the-art in electrical power cables at the 
time that decisions must be made on selecting a power transmission system, 
some effort may be needed to develop an alternate system. No immediate 
effort is planned, except in the development of seawater hydraulic motors 
which could utilize a high-pressure hose for power transmission in an open 
seawater system (NCEL, 1969). There is some possibility of a simple exper- 
iment with reciprocating and rotating cable power transmission systems 
(Figure 26) as part of SEACON experiments in early 1971. 
POWER TRANSFER AND CONVERSION SYSTEMS 
Power Transfer 
In the absence of fully developed self-contained generating systems 
capable of operating on the ocean bottom, it will be necessary to conduct 
bottom operations with power supplied from the surface or on a bottom- 
laid conductor from the shore. The three known potential systems of 
possible merit transmit energy as electricity, hydraulic pressure, and as a 
force in a rigid system, as discussed in detail in the previous section. The 
means of conducting power in the three cases are insulated electrical cables, 
hydraulic hoses, and reciprocating or rotating steel wire cables, respectively. 
Because the optimum system (best from a cost-effectiveness standpoint) for 
transmission may not be the best for supplying power to a specific piece of 
equipment, an additional trade-off study is needed to establish the best com- 
bination and the most effective method for converting from one form of 
power to another at the bottom. An additional complicating factor may 
arise if it proves necessary or desirable to transmit power from the surface 
to a stationary unit and then locally through distribution channels. The 
distribution lines or hoses necessary to supply power to a mobile or semi- 
mobile platform (Figure 27) could easily become fouled by crawler tracks 
Or moving machine parts. Therefore, the connecting system would undoubt- 
edly require buoying to keep it off the ocean bottom—a simple solution 
because of the high density of seawater. 
25 
