American Falls press. [volume] (American Falls, Idaho) 1907-1937, 1919-05-02

Brought Into Play, While Convoy
x,sHaUosd
Few Americans knew. during the
months of lodging submarines, the
navy's method of guarding against
enemy submarines. Only now can they
be enlightened. The accompanying
diagrams explain 1t.
Because Of the d~estroyer's speed.
sharp bow and depth bombs, the sub
marines were in constant dread Of
these sea cats. To hit q U-boat square
would mean TO drive through her.
The most effective weapon against
the submarine proved TO be the depth
charge, invented before America en-
tered the war. A submarines greatest
reliance for defense is submerslon.
When 1t did submerge the destroyer
dropped depth bombs as near the tnr'
get ms could be calculated.
An lash can" depth bomb) Ia n
steel cylinder 10 inches In diameter
and % inches long, and containing 300
pounds of INT. II has a device for
automatically exploding the -horge nj
predetermined depth.
Guns and Depth Bombs.
When n destroyer reached n posi-
ton where the submarine was esti-
mated to be, the "Y" guns would be
brought into play to fire depth charges.
The FIRST charge would be dropped
from the stern. Then the destroyer
sped nhead nifty yards, firing from
the "Y" guns and thus throwing II
charge on each side for about 30 yards,
-Four charges were usually dropped in
n few seconds in this manner around
the submarines supposed position, as
shown in the lower diagram. If the
estimate OF position wns correct the
submarine was at least badly dam
aged. II she was In the center OF the
pattern Of depth charges she was sent
down for good.
After the initial four charges the
destroyer put her rudder over and
started turning In n spiral curve, drop
ping charges now and then, ms also
shown In the lower diagram. n other
destrOyers were seen coming mp, the
first destroyer dropped a marker buoy
to guide the others. Always the craft
were prOdigul with their charges. But
the result was seldom certain, Sub
mnrines could eject oil TO lead the at
tnckers into believing the U-boat had
been sunk,
The upper diagram shows the diff
Guilty fmhd by n submarine that de-
sired to nttack n ship In convoy. The
speed ~ u submerged submarIne-that
X the torpedo firing position-was I'M
ll'rlv - cqunl the speed OF the convoy,
81 thni The submarine could not hope
10 nV'rhnul II convoy or fire success
fully from aStrrn. II had 20 approach
Submerged mud nearly ahead.
The U-boat's most successful firing
position was 300 yards on the bow Of
the tnrget. Reaching that position.
however. she was likely TO find near by
one OF more d~estroyers. making II nee
eSsary 10 poke her periscope up often,
with attendant peril.
The upper diagram shows a de
str0yer FIVE miles ahead Of the convoy
with an observation balloon in tow
Every group of destroyers escortlni
u N FhbiVD bVHhs
There were numerous other methods
by which destroyers cordoned around
\ conveys, forming practically impreg
I nnble barriers.
\ FzIaxaogina on Signal
\ There were several standard meth
i DDS n slipping away from submarines
by zigzng. Theoretically. and almos
always in actual practice, the troop
ships proceeded in a straight fronta
line. by doing this the transports al
i forded n minimum Of target. A tor
pedo missing one Of the line. probabl,
would miss them all. whereas II tn
vessels wA<e in row, one behind ar
other. not only might a torpedo cate
III one after missing a preceding ship, bu
Ri from the same position the submarin
III could launch successive missiles at tn
III phrading t%roopships, taking a crac
perhaps at the leader. another at IN
third or fourth member. and a I'm,
q blow Mt the last in the row..
Zigzagging was in accordance wit
81 rode diagrams and with code instru,
III lions. At given signals the comman
Isl lHk utriipefff kolHb hDfnu Nj 10y rpr'
III and leaving the destroyers TO fight
out with the submarines. would swir
into varying degrees Of zigzag.
The fleet commander would sign
by wireless and by ught-fash the plf
OF zigzag to be pursued. The tran
ports in unison would swing a certa
number Of degrees and then. at a CIV
interval. as prearranged. swing in
another slant Of a predetermined d
gree. A number Of these swim
would follow. all troopships acting I
gether. Sometimes In the course Of
attack the fleet commander would
der two or three systems Of zigzag
quick succession. The tr~oopships col
piled Instantly and tremendously. B
cause each held a code chart indic'
b ing the degrees n directions 10