command functions are put in from the shore end. 
These pass through the necessary cable driving 
circuits and then the cable itself. At the deep 
end, the various commands are sorted out 
according to frequency and polarity. These 
cause the deep unit to go to the desired configu- 
ration. Instrumentation and acoustic data are 
mixed together and amplified by a pair of cable 
driver amplifiers (for redundancy). These sig- 
nals are separated at the shore end of the cable 
by the appropriate filters and then recorded in 
analog form on magnetic tape. The data is then 
sent back and reduced using existing reduction 
facilities at Martin-Baltimore. The deep elec- 
tronics are entirely powered from shore except 
for the stepping switches themselves. These 
operate from a ni-cad battery which is charged 
from the shore supply. 
The deep sea electronics circuitry contains 
over 200 transistors most of which are protected 
from the 6000 psi ambient pressure by a large 
steel sphere. The hydrophone preamplifiers 
are protected by being placed in a small steel 
chamber located inside each hydrophone. The 
tilt indicators and the battery are similarly pro- 
tected by individual steel cylindrical chambers. 
The various components are thus protected 
but necessarily must be electrically connected 
together. This means reliable electrical feed- 
throughs are required which must be able to 
withstand a pressure differential of at least 6000 
psi. The design used is shown in Figure 3. 
This design is an adaptation of that used on 
Piccard's Bathyscaphe and in fact was suggested 
by Mr. Jacques Piccard who was used as a con- 
sultant on the mechanical problems. 
The operation of the feedthrough is as follows: 
The high pressure differential forces the araldite 
(an epoxy) into the tapered hole thus effectively 
sealing the hole. The Bathyceri (a wax like sub- 
stance) is forced into the voids between the aral- 
dite and the polyethylene wires and prevents 
water from causing electrical faults between 
adjacent wires. The PR701 (a sticky putty like 
substance) is used to prevent water from getting 
into the feedthrough when the pressure level is 
too low to ensure sealing due to the above ac- 
tions. Feedthroughs throughout the FAB equip- 
ment are of this design. 
The hydrophone, of necessity, must with- 
stand direct exposure to the 6000 psi pressure 
and this involves some tricky problems also. 
These problems are dealt with in more detail 
in the subsequent paper by Mr. Delaney. 
INSTALLATION 
The installation procedure is shown in 
Figure 4. A two ship operation was necessary 
utilizing a cable laying ship and a smaller aux- 
iliary ship. 
The first step of the installation was to bring 
one end of the shore end cable to Argus Island. 
This was accomplished by use of a work boat in 
conjunction with the cable layer. The cable was 
firmly attached to one of the tower legs by the 
work boat and personnel on the tower. The cable 
ship then laid the 1+ miles of shore cable and 
attached a marker buoy to the end of the cable. 
At this point, the cable ship went to the desired 
implantment location but due to a failure of the 
polyethylene covered array harness in the FAB 
array the operation was postponed while the 
harness was reworked at the factory. 
The array harness had failed at the molded 
splice joint due to improper annealing of the 
molded polyethylene. A second harness was con- 
structed and properly annealed. This was used 
to replace the original harness. 
Prior to the second implantment attempt, the 
completed deep sea unit was lowered into the 
water over the cable layer bow while dockside in 
Bermuda. Final checkout was completed and 
the deep sea unit was attached to the front of the 
bow sheaves. 
The cable layer took it's position as shown 
in Figure 2 and three miles of nylon line were 
paid out to the auxiliary ship. The nylon line 
was attached to the top of the buoyancy tank 
through a corrosive link and the tank was attached 
to the array by 240 feet of grapnel rope. The 
gasoline filled tank was allowed to slide in the 
water from a skid attached to the side of the 
cable layer. 
The corrosive link was not designed to take 
any lateral force but inadvertently was subjected 
to considerable lateral forces during the release 
of the buoyancy tank. Due to this, two links 
were broken during the installation. A three 
foot piece of steel rope was inserted between the 
top of the tank and the link and proved to be a 
satisfactory universal joint preventing any further 
link failures. 
The tank was towed away from the cable ship 
by ship No. 2 and the deep unit was lowered by 
it's coaxial cable to the bottom of the sea, 
14,000 feet down. At this point, the cable layer 
laid the rest of the cable toward Argus Island, 
picked up the marker buoy and the end of the 
shore cable and spliced the two ends of the cable 
together. 
The shore equipment had been installed on 
the cable ship to operate and monitor the deep 
equipment during checkout and installation. The 
installation was completed, except for the re- 
moval of the nylon line, with the transfer of the 
shore equipment to Argus Island and subsequent 
connection with the cable. 
The nylon line was used during the operation 
to prevent fouling of the gasoline tank and the 
coaxial cable. It was also to be used to retrieve 
the deep unit in case of failure during the three 
