The St. Charles herald. [volume] (Hahnville, La.) 1873-1993, 1917-03-31
HOW SUBMARINE DOES ITS
WORK OF DESTRUCTION

can descend to a depth greater than
$50 feet. Consequently there is very
little resting on the bottom once they
start on q 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
and 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 tofpedo-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
depth while searching for her prey or
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
| II at the cruising depth the look
out sights the smoke Of some vesse
| the course is changed, and when al
the proper distance the submarine Ii
sunk beneath the surface, only thu
periscope sticking up.
1 sNoiselessly we slip closer ant
closer in our exciting chase" thu
commander of one Of the U-boats ha
related. 1.-THE main thing was tina
our periscope should not be observed
so that the steamer would not chang
, her course at the last moment ant
. escape us. Very cautiously / sticl
. Just the tip Of the periscope abov
the surface at intervals Of a fev
, minutes, take the position Of tn
steamer In a second, and, like flasf
lpull 1t down again.
, "This second was sufficient for m
{ to see what wanted to see. Th
! steamer was to starboard and wa
!. heading at a good speed across GU
!. bows. To Judge from the foamin
: waves which were thrown off frol
: the bows I calculated that her spec
i must be about sixteen knots.
= Estimating Speed.
r "The hunter knows how importaI
J. 1t is to have a knowledge of Il
II speed at which his prey is movin
J. He can calculate the speed clos
when 1t Is wounded hare this
II WnGu IL Is Ouc WuiGA 1A might dt Ae
n speed rushes past. 1t was only nece
n sary for me, therefore, to calcula
r. the speed Of the ship. for which
Re sailor has an experienced eye. thu
,e plotted the exact angle we needed.
re measured this by scale which hi
st been placed above the sights of t
RS periscope. Now / only had to let t
steamer come along until it h;
err reached the zero point on the pc
re scope and fire the torpedo, viii
n then must strike its mark.
or aYou see, it Is very simple. es
lr- mate the speed of the boat, aim wi
az the periscope, and fire at the rig
st moment"
L. Submarine commanders must c
is culate well the speed of the vessel
en- which they intend firing and fg,
Ist exactly where 1t will be when the t
by pedo shall hit 1t. They have inst
ne tments for measuring the speed of
an vessel. The commander who win
ut successful In surprise attack nj
Ia proye correct In his presumption Il
nv he has not been observed. The Y
inf sci must continue at its usual spe
Then Ii is merely q mathemati
at lDroblem. worked ont with 81