The Hawaiian star. [volume] (Honolulu [Oahu]) 1893-1912, 1902-10-18
HOW THE PACIFIC
CABLE WILL. Be LAID
SPECIAL MACHINERY FOR CON-
TROLLING SPEED OF CABLE AS
IT LEAVES THE SHIP.

The manner in which the cable to
Honolulu will be stretched across the
ocean bed by the cable ship is an inter-
esting operation. Obviously it would
not be possible to steam along and let
the cable pay itself out over a pulley, as
often many miles of unnecessary strand
would be laid, and the whole twisted
about in a zigzag line, while the cable
itself would often be overstrained in the
process of submersiOn. To obviate this
special machinery for measuring and
controlling the speed at which it leaves
the ship and for measuring the pull on
the cable has been introduced. Similar
machinery would have prevented the
breaks which occurred during the earl
Ter attempts at cable laying in the At
| lantic.
An intricate system of wheels and
| rollers, with tanks where continual
| tests for electrical condition can be
made constitute the paying out APP
paratus on the Silverton. The wheels
are so arranged that they can be raised
or lowered to give the cable less or
more bend" as it passes between them.
| Powerful brakes are also supplied by
which the speed can be regulated. The
length paid out and the rate of paying
out are obtained approximately from
the number of turns made by the drum
/
checked by the mile marks, the known
position of the points, etc, as they pass.
The difference between the speed of the
ship and the rate of paying out gives
/ the amount of slack.
| Another point which has to be con-
! sidered is the probability of steep hills
being encountered on certain parts of
the route. Should one of these hills be
/ at any part sleeper than the incline of
! r1 a
sinks to the bottom, it is evident that
| either the friction between the cable
| and the ground would cause the former
| to break or the cable would be left in
| a long span ready to break at some
| future time. SO the speed of the ship
/ has to be regulated to the inclination of
! the cable and the probable angle Of
| incline of the steepest hill likely to be
| encountered. -
| One of the principal differences in the
| composition of the cable itself which
! will be laid across the Pacific from
! the early cables under the Atlantic is in
! the increased weight of copper in the
/ strand. Where the copper wires used
| to weigh 200 pounds to the knot, the
same length now has 500 pounds of
/ copper.
! This increases the efficiency of the ca
| bic and insures it much greater perma-
nenCe. The central conductor is cover
ed with several coatings of gutta percha
the weight of which sometimes exceeds
that of the copper.
Manufacturing a cable requires an eX-
| tensive plant and is an involved process
| The copper strand has to be successive
ly passed through several vessels of
melted gutta percha, resin and tar
purified by repeated operations, and
then wound on bobbins to be electrical
/ ly tested. 1t is then placed in a tank
| of water and kept at a certain fixed
! temperature until it assumes approx
| mately a constant electrical state.
! After several more elaborate tests,
/ the core is sered with jute yarn, coiled
! in water-ti tight tanks and surrounded by
| salt water. The insulation is again
tested and the core next passed through
| O sheathing machine and the iron
sheath and outer covering laid on.
AS the cable is sheathed it is once
more stored in large water tight tanks
! and kept at a nearly uniform tempera-
ture by means of water. 1t is then
transferred to the cable ship.
/ Accurate observations of latitude and
longitude are made on board the cable
ship as it steams along, and in this
manner the exact location of the cable
can always be known. When breaks
occur, which with the big Atlantic ca
| BILE companies happen on an average OF
once or twice year, the approximate
location of the break is established
and then a repair ship sent to raise the
! cable and fix it.
The determination of the location Of
the break is another interesting fea-
ture of submarine telegraphy. A sort
| of electrical balance or scale is set up
at the land terminus of the line and
with coils of fine wires on one side OF
the scales and the cable on the other
the experimenter plugs and unplugs an
til he gets a balance between the cleo
trical energy consumed by the coils in
the office and the broken cable. Then
he works out an equation of distances
and finds about how many miles away
the cable has been interrupted. The e-
pair ship is communicated with, the