Shelf Diver. (Perry Submarine Builders photo) 
Electrical cable failures have resulted from 
tearing by bubbles forming and expanding inter- 
nally upon ascent. Connectors with adequate 
insulation and reliable disconnect properties are 
not available. Essentially no switches, relays, or 
fuses have been designed for ambient operation. 
Usually standard equipment designed for use in air 
at atmospheric pressure has been modified for 
undersea use by emersing it in oil, which has led to 
some failures attributed to carbon deposits. Per- 
formance of AC and DC electric motors generally 
has been poor because of bearing and insulation 
failures. 
Small submersibles have been severely limited 
by heavy, bulky, inadequate battery power sources 
which require time-consuming recharging. Manipu- 
iators have proved unreliable primarily because 
of electrical distribution and motor difficulties, 
water intrusion, and poor control systems. 
Hydraulic systems operated at very high differ- 
ential pressures have failed becasue of water 
intrusion and incompatibility with certain mate- 
rials. Lubricants operating in high pressure have 
caused bearing failures and efficiency losses due to 
increased viscosity. Pressure compensating oil and 
gasoline used for buoyancy have serious drawbacks 
of combustibility and bulk modulus. 
Underwater communications, navigation, and 
positioning systems and equipments for nonmili- 
tary submersibles are too limited in range and 
accuracy. Materials are deficient in strength-to- 
weight ratios, toughness, corrosion resistance, and 
V1-86 
Star III. (General Dynamics photo) 
fatigue strength. Critical limitations exist in ad- 
vanced materials fabrication techniques and testing 
methods. 
b. Future Needs Vigorous pursuit of ocean activ- 
ities will require continuing development, not only 
of fundamental technology but also of submersible 
systems. Submersible use can be forseen in many 
ocean activities: 
—Fish behavior and location studies and undersea 
fish harvesting. 
—Undersea core drilling, site surveying for pipe- 
lines and structures, and operations to complete, 
inspect, maintain, and repair botic:a petroleum 
production installations. 
—Mineral surveys, evaluations, and observation of 
seafloor mining operations. 
—Search, identification, and recovery of lost ob- 
jects. 
—Cargo and personnel transfer to undersea installa- 
tions. Saturated diver delivery to work sites. 
—Support of scientific studies of coastal and 
oceanic processes including observation, measure- 
ment, and sampling. 
—Ocean surveillance and mapping. 
—Support of underwater equipment. 
