SUBMARINE CABLE SYSTEMS
Where Permitted. Use submarine cable only where local conditions
rule out the use of any other system.
Installation Problems. Consider installation problems at the time
of design. These problems (for example, practical length of cables, size of
reels, and transportation to site) will vary for each particular installation.
Location Considerations. When considering locations, consider the
soundings and the restrictions described in paras 4.2.1 through 4.2.4.
Soundings. Obtain soundings along several proposed crossings to
obtain the most convenient profile. Within the United States, soundings can
be obtained from the Department of the Army, Corps of Engineers. For
locations outside the United States, consult local authorities.
18.104.22.168 Turbulences. Do not install submarine cables in waters where bottom
turbulences may occur. Cables exposed to continuous vibration have short
lives due to mechanical fatigue of metallic sheaths.
22.214.171.124 Currents. Provide cables installed across rivers with currents with
a curved upstream concave alinement. Determination of the amount of curved
alinement necessary depends upon the speed of the current.
126.96.36.199 Variable (Changing) Waters. Obtain approval for routes and minimum
depths for crossings under variable waters from the Department of the Army,
Corps of Engineers or by the corresponding authority.
Chemical Composition of Waters. Do not install submarine cable near
sanitary sewers, chemical discharges, dumping areas, or wharves where waste
material has accumulated. Make a provision based on a water analysis for any
chemical reaction with the cable sheaths and coverings. Where feasible,
consider the installation of cable integrally installed in a plastic conduit
or provided with a protective corrosion-resistant jacket.
Marine Traffic. Bury any cables crossing through waters adjacent to
marine traffic to a depth that eliminates any damage from dragging anchors.
Large ships may drop anchors up to 15 feet (4.5 m) in depth on sand bottoms.
Installation. Install cables to lie on the bottom, with ample slack
so that slight shifting will not place excessive strain on them. Because of
the great weights involved when any considerable length of submarine cable is
to be sunk across a waterway, use installation methods to keep tensile
stresses at a minimum. The ideal lay of a submarine cable on a bottom is a
series of horizontal S-curves. This pattern provides the slack necessary to