The Washington times., 1918-07-28

carried cats or bird cages.
"The submarine would order the boats to get
clear of the ship, often lying only 100 or 200
yards from the deeoy then, when the submarine
was within pointblank range, the concealed guns
were run out and the submarine sunk A num-
Der of submarines have been destroyed in this
wav."
Other forms of decoy ships are constantly
being devised, in order that the Uboat pirates
may not grow too familiar with any one kind
Sometimes an innocent looking tramp steamship
shows a high bow apparently of steel plates
These are really wooden boards which are let
down when U-boat approaches They then
show deadly guns, which open fire on the pirate,
Guns are also concealed under tarpaulin ar
ranged to look like deck cargo and in various
parts of the superstructures.
Probably the most effective work against sub
marines has been done by a weapon that is not
novel. That is the torpedo boat destroyer Its
services are essential to most of the other forms
of protection described here. Making thirty
miles an hour, the destroyer when called on for
help can overtake, a U-boat from almost any
distanee-even a hundred miles. If she takes
U-boat by surprise on the surface she can
wreck her in an instant by ramming her with
a stroke Of her Sharp bow. Long, narrow and
obeying the helm like fash, the destroyer can
nearly always dodge a torpedo, and only one of
our American destroyers has fallen victim to
a submarine.
The power of the destroyer against submarines,
however, has been enormously increased by
new device, and that is the depth bomb. This is
a contrivance arranged to explode at certain
depth under water. The explosion occurs when
the under water pressure reaches certain point,
and can be varied to suit the occasion.
Suppose that destroyer has located U-boat,
either by her own observation or through wire
less call from a ship in distress. She speeds to
the spot. The U-boat has already submerged
and the destroyer cannot use her guns. She
speeds over the course the under water boat is
following and as she does so drops three or four.
depth bombs in a line. Then she circles round
and drops three or more in a circle. The bomb
is thrown into the water by pneumatic pull.
Each bomb will destroy a submarine within
$50 feet of the point of explosion. The missile
contains $50 to 300 pounds of trinitrololuol,
which is about the charge of modern torpedo
Four cubic feet of this explosive produces at
the moment of detonation 10000 cubic feet of
gas Now, when a mine, bomb or torpedo is
detonated the expanding gases seek the line of
least resistance. In the case of tOrpedoed ship
this line leads into the hollow interior of the
Ship the incompressible water forming an OBJ
Stacle in all other directions. The same law with
somewhat changed conditions, applies to the
submarine.
The destroyer seeks to have the bomb explode
below the submarine for a good scientific rea-
son. When the bomb is detonated the line of
least resistance is upwards and the gases cut
their way quickly to the surface, carrying a
fountain-ke mass of water to great height
100 feet or more-in the air. If the explosion
takes place at a considerable depth, however,
the resistance to the upper escape of the gases
is greater, and failing to blow up the surface of
the ocean, the bomb must expend itself entirely
on the submarine.