The Kansas City sun. (Kansas City, Mo.) 1908-1924, 1917-06-16

u 1 IL I l 1 III ~-~
that no unanchor- ~
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 are not controlled from any shore or
observing station and are well-nigh instantly men
acing when cast overheard.
Just before the war the Germans, with their
usual technical cummings, developed a naval Of
tense and defense mine which could be used either
in a fixed position or 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 an electric battery placed
inside of the mine, this battery being inactive I'M
til the mine has been submerged and then struck
by a passing craft.
A development of the contact mine which the
Germans have at times employed successfully Is
one surmounted by a dummy or decoy periscope.
The object of this ruse Is to invite ramming on
the part of a patrolling vessel or even a mer-
chairman when the deceived navigator believes
that the chance is good for sending n U-boat to
the bottom. OF course a vessel attempting to ram
that dummy periscope is sure to strike the con-
tact mine and cause it TO explode, the result being
disastrous to the ramming craft.
This lure has not worked so we'll latterly be-
cause the observer is able in a few moments to
establish the fact that the periscope is stationary,
and the work of getting the underlying mine out
of the way is left to the fairly safe process of
sweeping-trawler linked together by q loop of
wire rope doing the work.
In order to deal with both the submarine tor
pedo boat and the submarine mine planter the
British Admiralty has had recourse to defense
nets Of a novel character. These have been very
we'll described by Rear Admiral William S. Sims.
According to this authority:
1--WE did not find out for a long time what those
nets are like and I think 1t Is necessary that It
should be understood in order to realize the great
danger submarines run in the presence of light
surface craft.
1.-THE net is a very light one, made of little wire
rope, probably not as big as a lead pencil. prob
ably not more than a quarter of an inch in dame
ter. The meshes of the net are 10 to II feet
square. On top of this net are floats and on the
bottom are little weights.
1.-THE moment this Observation-Disclosures 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 if he runs into it his bow goes into one of
the meshes and the net falls back around him,
and 1t may foul his propeller or may not.
1.-THE net is 300 or 400 yards long, and MS the
submarine proceeds the floats will trail on the
surface, so that even if he dives deeper he leaves
these on the surface and his trail is plain and there
is no difficulty then in capturing him. He knows
when he runs into a net that his capture is prac-
tically certain. If 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 is n
fact that even though a submarine be running
totally submerged 20 or 80 feet down, it still
causes a disturbance at the surface, not u wake
in the usual sense of the term, but a 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 a
hydroplane.
To return to the submarine mine. We have so
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
now let us take up that kind which can be dropped
overheard in much deeper water. This sort is
capable of being planted from a 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 is the
least vital section. A craft may have her bow
blown off and yet be able to make a 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 a 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 Is well.
nigh certain to be fatal-New York Sun,