The Elk Mountain pilot., 1917-03-08
HOW SUBMARINE DOES ITS
WORK OF DESTRUCTION

can descend to depth greater than
100 feet. Consequently there is very
little resting on the bottom once they
start on cruise far out to sea.
A submarine that wishes to dodge
vessels afloat may sink and remain
beneath the water until 1t figures that
all danger is past. Her commander
will know when he has descended
about eighty feet and he will remain
there. He has delicate instruments
notwithstanding bells some call them
that convey to him the throb of
propeller. He can then cruise by COM
pass to some other portion of the sea
und there take his chances of being
discovered when coming up.
| When rising to the surface for air
and observation those on submarines
In. war time take chances. They have
no way of learning the presence of
some drifting trawler armed with
light gun that can destroy them. Nor
can they know torpedO-boat destroyer
Is waiting, ready with her sharp PROV
| to ram them.
| Aviation has proved OF great assist
ance In the hunt for submerged sub
marines. Observers In hydrOplanes
can "spot" the submarine even when
submerged and warn torpedo boats of
its presence.
| When the submarine has poked her
periscOpe above water and those on
board have noted the. sea is clear she
can rise. She remains at the cruising
| u =,
watching for the appearance of fight
ing ships, from which she will flee.
She is defenseless and must be careful
lest she be destroyed while trying to
launch her torpedo. Therefore she is
used principally as commerce raider.
| If ut the cruising depth the look
out sights the smoke of some vessel
the course Is changed, and when ut
the proper distance the submarine is
sunk beneath the surface, only the
periscope sticking up.
"Noiselessly we slip closer and
closer in our exciting chase" the
commander of one of the U-boats has
related. "The main thing was that
our periscOpe should not be observed
so that the steamer would not change
her course at the last moment and
escape u.s.. Very cautiously l stick
just the tip of the periscope above
the surface Mt intervals of few
minutes, take the position of the
steamer in a second. and, like flash,
pull it down again.
"This second was sufficient for me
to see what l wanted to see. The
steamer was to starboard and was
heading Mt good speed across our
bows. To judge from the foamIng
waves which were thrown Off from
the bows 1 calculated that her speed
must be about sixteen knots.
Estimating Speed.
.'The hunter knows how important
1t is to have knowledge of the
speed at which his prey is moving.
He can calculate the speed closer
when it is wounded hare than
when 1t is one which in flight at high
speed rushes past. 1t was only neces-
sary for me, therefore, to calculate
the speed of the ship. for which n
sailor has an experienced eye. l then
plotted the exact angle we needed.
measured this by scale which had
been placed above the sights of the
periscope. Now only had to let the
steamer come along until 1t had
reached the zero point on the peri
scope and fire the torpedo, which
then must strike Its mark.
"You see, 1t is very simple. esti-
mate the speed Of the boat, aim with
the periscOpe, and fire at the right
moment"
Submarine commanders must cal
culate well the speed of the vessel at
which they intend firing and figure
exactly where 1t Will be when the tor
pedo shall hit 1t. They have instru-
ments for measuring the speed of the
vessel. The commander who will be
successful in surprise attack must
prove correct in his presumption that
he has not been observed. The yes
sci must continue ut its usual speed.
Then 1t Is merely a mathematical
problem. worked out with a $4,UUO