The Idaho Springs siftings-news., 1917-06-15


ed mines should
be used which would be dangerous more than an
hour after they had been dropped into the sea.
The mines In question are self-contained contact
mines that not controlled from any shore or
observing station and are wenigh instantly men
acng when cast overheard.
Just before the war the Germans, with their
usual technical cummings. developed a naval Of
fense and defense mine which could be used either
In a fxed position be planted hastily In water
traversed by enemy shipping This mine Is the
type which has done such destructive work and is
designed to be fired by electric battery placed
inside Of the mine, this battery being inactive
til the mine has been submerged and then struck
by a passing craft.
development Of the contact mine which the
Germans have at times employed successfully is
one surmounted by dummy decoy periscope
The object OF this Is to invite ramming on
the part Of a patrolling vessel a
chantman when the deceived navigator believes
that the chance is good for sending a U-boat to
the bottom OF course a vessel attempting to ram
that dummy periscope Is sure to strike the con-
tact mine and 1t to explode the result being
disastrous to the ramming craft
This lure has not worked well latterly be-
the observer is able in few moments to
establish the fact that the perscope is stationary
and the work of getting the underlying mine out
of the way is left to the fairly safe process Of
sweeping-tvawlers linked together by loop of
wire rope doing the work.
In order to deal with both the submarine tor
pedO boat ana the submarine mine planter the
British admiralty has had recourse to defense
nets of a novel character. These have been very
well described by Rear Admiral William 8. Sims
According to this authority:
ave did not find out for a long time what those
nets are like and think 1t Is necessary that It
should understood in order to realize the great
danger submarines run in the presence Of light
surface craft.
.The net is a very light one. made Of little wire
rope, probably not as big as lead pencil, prob
ably not more than quarter of an inch In diane
ter. The meshes Of the net are IL to Is feet
square. On top OF this net are floats and on the
bottom are little weights.
1.-The moment this net-unbeknownst to the
submarine commander, Of course-is In the water
In front Of him, the floats keep the net on the
surface and the weights keep the bottom down.
and II he runs into 1t his bow goes into one Of
the meshes and the net falls back around him,
and 1t may foul his propeller or may not.
THE net is 300 400 yards long, and as the
submarine proceeds the floats will trail on the
surface so that even II he dives deeper he leaves
these on the surface and his trail Is plain and there
Is difficulty then in capturing him. He knows
when he runs into a net that his capture Is prac-
tcally certain. II he goes down 200 feet the
floats Of the net are still on the surface"
These nets are used in two ways either passive
ly at chosen points In guarded waters or they are
dropped overheard by patrolling vessels that dis
cover a submerged submarine in motion. 1t IL q
fact that even though a submarine be running
totally submerged 20 80 feet down, it still
causes disturbance at the surface, not a wake
in the usual sense Of the term, but q type Of
wave which is easily distinguished from the regu-
lar surface waves, and this phenomenon is readily
discernible from the bridge Of a ship or from q
hydropane.
To return to the submarine mine. We have 80
far considered only that so-called offensive type
which can be anchored in fairly smooth waters,
such as prevail extensively in the North sea- but
let us take up that kind which can be dropped
overheard in much deeper water. This sort Is
capable Of being planted from speedy ship
seemingly bent upon escaping from her pursuers,
and her strategy consists In inviting chase while
dropping these stumblingblocks right in the path
Of her oncoming enemies.
Generally the ship hitting weapons of this sort
does so bow on, and that part Of a vessel IL the
least vital section. craft may have her bow
blown off and yet be able to make haven. and
besides the damage may be susceptible of speedy
repair Our mines. on the other hand have a de-
layed action, and after being hit by the stem
Of craft roll sternward in contact with her bot
tom for some distance before they explode In
this way the blow. when the mine does burst
strikes some vital area and the damage 10 we'll
nigh certain to be fatal.-New York Sun