The Fargo forum and daily republican. [volume] (Fargo, N.D.) 1894-1957, 1918-08-23
"Sea Tanks" Raid Naval Base

In the September issue OF the Electrical Expert
menter, H Winfield secor gives the following
account Of the recent raid on Pola:
The very latest wartime animal is the electric
sea tank used by the Italians in a recent
naval raid on Pola, Austria's famous naval base
From the information available on this latest
hybrid among wartime offensive devices, it is
learned that the sea tanks measure about 40 feet
in length and six feet in width and that they are
propelled by electricity. Further, these tanks
are provided with an endless rotary chain, run
ming 1engthwise around the vessel, these rapidly
moving chains being fitted with sharp steel barhs
or knives which cut their way through nets
and other obstacles just like their prototypes the
land tanks, first used so effectively by the Brit
ish This underwater demon Is provided with
several torpedo tubes at the bow, and from all
accounts it seems that the device was crewless,
and operated by means Of electrical control cur
rents sent through a flexible insulated cable con-
Meeting with war vessel which latter nosed its
way up to within a few miles of the steel nets
guarding the harbor Of Pola.
The account Of the attack on Pola by the Ital-
ian sea tanks states that they bored their way
through the heavy steel nets spanning the navi-
gable approaches to the port, within which there
lay at anchor Austria's fighting fleet, and that
a mighty Austrian battleship Of the Viribus
Units type Of about 10000 tons displacement
was torpedoed.
Steel nets carrying net-cutting knives or barbs
are driven by powerful electric motors, which OBJ
tain current from a storage battery carried in
the undersea craft, or from electric energy sup
piled through the cable connected with it. They
enable the craft to penetrate protective sea bar
riers
The electrical control cable in such devices as
this, and where 1t is Of any considerable length,
is invariably coied up and stored in the tank
or torpedo, as otherwise the device would have
to be extremely powerful in order to pull the
constantly increasing length Of cable through the
water If 1t were stored in a magazine on the ten
der ship.
It is entirely feasible for device of this kind
to be controlled by warship of the destroyer
class at distance of seven miles, even eight
to ten miles more With ingenuity and the
proper design OF the device Of the type here I'M
der discussion, and also in consideration Of the
neers, there is no doubt but what such a device
could be sent out and steered SO as to be SUBJ
merged when 1t neared the steel nets and to bore
its way through Them and then to rise again;
also at this juncture the observation officer on
the war vessel looking through his night glasses
could press the proper electric control button and
cause one or more torpedoes to be discharged at
an enemy war vessel in the manner described in
the report from Rbme and which now forms
part Of italian naval history.
It is most probable, however that the Italian
sea tank as now used is fitted with powerful
propellers the same as the submarine and also
that 1t has suitable rudder for the purpose Of
steering it. To prevent the cable from becom-
ing fouled in the propeller blades, the latter
encased in substantial steel cages. The pilot
light or lights are provided with shields at the
front, so as to throw intermittent signal flashes
sternward, and by arranging this on telescope
mast the officer in charge can by simply press
ing the proper button cause them to rise 10 to Is
feet above the back Of the tank while 1t is
progressing through the water near its objective
When the tank has progressed sufficiently near
the net other obstruction it Is to burrow
through the proper electrical impulses are sent
over the electrical control cable which starts up
the water ballast tank motor, and by filling the
tanks the craft Is caused to submerges 1t is a
simple matter and one which has been used here
tofore to provide suitable electrical position in
dicating arrangement, whereby 1t becomes posi-
bic to know at any instant the direction and
location OF the sea tank while 1T lis submerged
BY means of a sensitive microphone installed i'm
the vessel it would be possible to ascertain when
the tank had cheWed its way through the enemy
nets and 1t could then be caused to approach the
surface again If so desired. It is not, however,
imperative that the vessel be made to come to
the surface so as to show the signal Tight for by
means Of the position indicating apparatus Just
described its exact position at any moment could
be known and torpedoes discharged from 1t at
any enemy war vessel swinging at anchor within
the melted area