The Ronan pioneer., 1914-12-11
AUTOMATIC Mines
Menace TO SHIPS

Just what is the mechanism of the
famous submarine mines which, plant
ed broadcast in the North sea by the
Germans, have driven merchant and
fishing ships from that part Of the
ocean after the loss Of score Of YES
sells, mostly belonging to neutral pow.
ers. and probably 100 lives?
Broadly speaking, there are three
kinds of mines-harbor defense mines,
usually connected with the shore and
exploded by electricity; deep sea float
ing mines. which are thrown upon the
surface of the ocean and allowed to
drift at the will of current and tide,
and moored contact mines, which are
anchored to the bottom Of the sea.
The Hague peace conventions forbid
the laying of unanchored mines, except
when they are so arranged usually by
clockworll) that they become harmless
an hour after they are released. In
addition. they can be seen floating on
the water and easily destroyed by gun
or rifle shot. Electrically fred mines
are impracticable except within few
miles Of land. Therefore in all proba-
bility it is the anchored mine which
the Germans are using.
sinker Locks MINDLESS.
When this mine is placed in the sea
it consists Of a spherical shell Of steel
containing from 100 to 500 pounds of
guncotton or other high explosive, to-
gether with air chambers to give it
buoyancy. and it's mooring apparatus.
The chief part Of this last is heavy
sinker, which automatically detaches
itself from the shell as soon as it en-
ters the water. Within the sinker is
a windlass, from which as it descends
a light but strong cable is unwounl.
Below the sinker is second cable,
weighted with a lead plumnet. The
nlummet dives faster than the sinker
and touches the bottom first. The con.
tact of the plummet against the sea
bed instantly actuates ratchet inside
the sinker, which stops the windlass
and locks it. The sinker then contin.
ues to the bottom. dragging the mine
below the surface of the ocean
Whether the mine is two feet or ten
surface may be required is determined
by the length of the cable between the
plumnet and the siuker.
Outside OF the spherical shell con
tanning the explosive is a contact lever.
or trigger When a vessel strikes u
mine the shell, because of it's round
shape, rolls along the hull until the
trigger touches the side. Thereupon
the mine is exploded.
AS this type of mine is anchored be
low the surface it is not visible. and is
hidden peril both to friend and to
foe Unlike the electric mine, which
may be rendered inert by shutting off
the current, the contact mine retains
its deadliness for long periods.
Submarine contact mines are often
placed in tandem formation. Two
mines are anchored few feet below
the surface and are connected by Il
cable. which is held taut by weights
ut either end The mines consist of
an outer case and an inner case which
contains the charge.
Danger In Sweeping.
w hcll IL sup - OONS StIlhe lHc CiDlC
the pressure upon it draws the inner
case from it's sheath, and then as the
pull grows stronger 1t snaps trigger
In the mine which sets off the eXplo.
sive. This type is called the twin mine,
as the area which it imperils is de.
termined not only by the space occu."
pied by the mines themselves, but also |
by the length of the cable connecting
them.
Sweeping for mines is an operation
OF the greatest danger. and several
ships have recently been sunk while
thus engaged. Two ships, steanling in
parallel lines, drag two cables, con
nected at the ends by sweeping
wire. which is weighted with metal
kites to the bottom of the sea. The
wire engages the cables with which
the mines are anchored and drags
them from their places. When a doz.
en- or so mines are collected together
and the ships have withdrawn to safe
distance a shell is fired among them.
If one mine is struck its explosion
causes concussion in the water suf-
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