New-York tribune., 1918-06-24
War Upon U-Boats Described
By Naval Consulting Board
New Subsea Shells Invented Mcrophones Are Developed
to Detect Submarines and at Least One Secret
Base Has Been Destroyed

| nets are those upon which bombs are
strung for the destruction of SUBJ
marines anG also are as light as is
consistent with the weight OF the bombs
attached. The entangling nets are
made Of much heavier material.
"The waters in which nets are used"
II is pointed out, "are under such close
operate on the surface there in the
daytime"
Use of Nets Difficult
Many difficulties are attendant upon
the use Of nets and the Naval Consult
ing Board states in particular: 1.-THE
value of nets with attached bombs is
rroblematical, owing to the great dan
ger from the very rough handling
especially when attempts are made to
lay them in rough water"
On naval patrol boats, it is said, an
alert lookout is the prime necessity,
being far more important than special
optical devices that have been offered
by inventors. 1t was even suggested
and considered-that boats be built
with glass windows in their bottoms.
The board points out that experiments
have shown that in the waters in which
submarines are most active, they would
be invisible to an underwater sentry
unless they were within ten or fifteen
feet of him.
A submarine, it is said, can discharge
its torpedoes when submerged, but it
cannot be sure of it's aim unless the
periscope is above water, and the range
of the most modern German torpedoes
is estimated at only 1000 yards. There
fore, it is pointed out, submarine
employing the torpedo attack is vulner
q fn lI-Q od
pany is on the alert. The only betray
ing sign of the marauder, however, is
the wake of its periscope. The bubbles
| which trail a speeding torpedo are of
little value for observation purposes
as they do not reach the surface until
the missile has passed considerably be-
yond that point.
Few Torpedoes Are Seen
"Only very small percentage of tor
pedoes are seen," says the board.
at has been the general impression
that submarines are not effective
against submarines" the pamphlet con-
tinues. "This belief was also held by
the general naval stats of the various
war; however, Allied submarines have
been succes sfully used in destroying
enemy submarines,
"ln operating against hostile sub
! marines the hunting submarine may
employ one of. two mevhccs-it may
lcmain totally submerged and take OBJ
servations by thrusting ap the peri
scope every few minutes, or 1t may
remain on the surface and only dive
when the enemy submarine is sighted.
In both cases the hunting submarine
tracing the attention of The enemy and
to prevent detection by means of listen
ing devices. The method of total sub
'nergence is used in restricted waters,
such as channels and lanes through
which the enemy submarine must pass.
"T9rpedoes are used when sub
marines fight each other, and If posi-
| BILE the extremely effective ram. All
submarines can ram without specially
designed devices FOR doing So"
Attacks or submarines by surface
vessels are most successful. it is said,
when the submarine is caught recharg-
ing its batteries, an operation which
rust be performed at the surface.
Secret Bases Destroyed
A submerged submarine can be
reached only by "hgh angle" FIRE, un-
less non-ricochet shells are used. The
navy has "cne or more" types Of she'll
that penetrate water satisfactorily, and
the only improvement considered posi-
BILE by the board is in reduction OF
water resistance and straighter sub
surface trajectory Shells designed to
bore their way through the water as
an auger goes through wood do not
work, because the she'll rotates only
once in about twenty-five or thirty
calibres.
Depth bonbs have been found salts
factory within range of about fifty
feet and are being developed and i'm
proved particularly for use by hydro
aeroplanes. Mortars and catapults de-
signed to hurl the bombs from yes
sells deck have been found to be i'm
practicable.
"There are many methods for dealing
with the submarine" the board de-
clares, when it's whereabouts are de-
termincd. The problem lies rather IN
locating the submarine"
Concerning secret bases the pamphlet
says: "It is reported that one or more
German secret bases along coasts under
control of the Allies, have been DIS
covered and destroyed" The pamphlet
is dated May l, although only released
for publication yesterday, sc it is prob
able that these reports concern Euro
rean waters only.
Pigeons Wearing Gas Masks