The Durham daily globe. (Durham, N.C.) 1889-1894, 1892-05-24
HARBOR DEFENSES.
PLANTING DEADLY EXPLOSIVES TO
PROTECT THE COAST.

plete q Thorough System of Coast De-
fense-Advantages of the Torpedo.
There is a very widely difused idea
among people who have not made a
special study of the subject that torpe-
does, and torpedoes alone, a defend
any harbor against a hostile attack.
The destructive effects Of a few tor
pedo explosions under the most favor
able circumstances have caused this
branch Of warfare to assume an undue
Importance, an importance wholly un-
warranted by the results and created by
congratulations from isolated instances,
entirely without regard to the natural
limitations of the efficiency of any tor
pedo system, however perfect.
1t is the object Of this article to en-
deavor to show the actual capabilities of
torpedoes, the results attainable by their
use, and the restrictions inevitably at
tending their indefinite expansion into a
complete system Of defense.
Great guns must play an important
part in all harbor defense, but for the
proper and adequate defending of navi-
gable chennels bouyant mines, exploded
by contact, are the mainstays.
With their use, however, a host of per-
picking conditions arise, the twisting
and wearing of the cables and m~oorings,
the depression due to the currents, the
danger of sympathetic explosions, the
leaking Of the cases, the obstruction Of
the channel for friendly navigation-all
these have to be overcome as best they
may be.
Where a port has several navigable
channels, and it is practicable to sacri-
fee one or more, their closure by means
of self acting torpedoes is easy.
Where a channel, however, cannot be
entirely abandoned, self acting mines
are useless, for in order to be thorough
ly reliable they must be as dangerous to
a friend as to an enemy. Furthermore,
their planting, and much more, their re-
moval upon the cessation of hostilities
is to be accomplished only at great risk.
The limited, applicability of ground
mines is well known. Torpedo science
furnishes two other types for harbor de-
Tense; the buoyant mine and the dirig-
IDLE torpedo, although the latter proper
ly forms a distinct class.
Great nicely in planting torpedoes
cannot be expected, and this fact, cou-
pied with the inevitable shifting of the
mines from various causes, leads direct
Iy to the conclusion that a great num-
Der of mines must be relied upon rather
than precision In their manipulation.
Despite the number Of mines, a vessel
attempting to pass the lines may still
fail to strike a mine hard enough to
work the circuit closer. To meet this
contingency a perfect torpedo system
must provide means for firing the mines
at will in groups Of three or four. 1t
will always be possible to accurately To-
cate a vessel within a dangerous space
of this number Of mines, and their stimuli
taneous explosion will have the desired
effect.
To furnish a passage for the electric
current many cables are needed, and to
avoid confusion some regular method Of
planting must be adopted. 1t is on
v~enient to plant the torpedoes in groups
capable Of being fired by judgment,
these groups constituting the units,
which are combined into the larger unit
whose limit is generally the number Of
mines that al be operated through a
single seven core cable.
The grand groups thus formed are ar
ranged in lines, the latter radiating in
such a from the operating case
ments that the separate units can be
easily located by triangulation. The
intervals between the lines are filled with
skirmish lines-single mines strung On a
single conductor cable and exploding by
contact only.
Many forms Of movable torpedOes for
harbor defense have been tried in differ
ent countries with varying degrees Of
success. For accuracy Of direction and
range of destructive power the Sims-Ed-
ison fish torpedo is perhaps une1celled
Extended trials at Willet's point have
satisfactorily demonstrated its ability to
carry 200 pounds Of dynamite to a dis
lance of two miles at a speed of about
twenty miles per hour. The charge is
exploded upon contact with the vessel
or by the action of the operator on shore.
The dirigibility of the torpedo is per-
feet. 1t follows its prey as though
endowed with life, %swerving to the right
or left as necessary, diving under boOms
or other Instructions, cutting through
nets, and never s~lackening its great
speed until the end Of it's cable is
reached. At present a two mile radius
is deemed sufficient, although this could
be increased if necessary by enlarging
the fish" tself.-Cosmopolitan.
Confederate Camp Flags.
The Confederate stars and bars We're
in 1868 supplemented by the camp flag.
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