Evening star., 1898-05-14
SPANS TORPEDO DEFENsEs.
| They Are n Copy of French and Eng
1fsh Systems.
From COlliers WeeLlv

Aohn Soihers weekly.
In the torpedo defense of her coast Spain
has simply copied the English and French
systems, with 4 few changes to suit her
geographic features. She depends princi-
pally upon strong land defenses, supple
| mented by distractions and submarine
mines In the more important harbors a
! regular system of defensive torpedoes is
| employed Hfgh-power rapld-fre guns pro-
| tect the observer and firing stations and
| sweep the lines of approach to the sub
marine mines; while powerful searchlights
! reveal the presence of an enemy's vessel
at night. The submarine mines are planted
| III grand groups of forty-nine each, occu-
pylns three parallel lines at a distance of
1oo yards apart. Several large mines in
the rear form a reserve, which covers the
| opeE spaces in the lines ahead and can
be fired at the will Of the operator
The total length of 'front.' protected br
each grand group is LOO yards. Auto
matte. mines, without circuit closer buoys
are IN the first line. These contain from
eisnty 10 100 pounds OF guncotton or eX-
ploslVe gelatin and are fired in contact with
the sides or bottom of a vessel. The sec
ond and third lines consist of automa tic
mines with circuit closer puoys They cor
tain from 40 TO 800 pounds of guncotton.
Inc service of the three lines and reserve
| IS unnecessarily complex, owing to the
! TACT that both ground and buoyant mines
are found in the same group.
It requires five officers and lO4 enlisted
men TO operate single grand group. In
the larger harbors several groups are
planted. pa A peculiar feature of the Span
lsh system is the reliance that is placed
upon mechanical mines. A great quantity
OF these are always kept on hand, and as
they can be planted quickly and easily
all OF the unimportant narbors can be rem
deied safe from attack in a comparatively
short time. These mines contain a heavy
charge OF eunpowder, which, Burning slow
~, instead OF decorating, acts in immediate
w ha hot
mechanical mine is so called from the fact
that the explosion is produced by purely
mechanical means. rhe mechanism, con-
Sfstfng of buoyant case containing the
charge, is fitted with a self acting primer
Tor 1gniting the explosive when the tor
pedo is struck by passing vessel. Abers
chemical fuse is the one fitted to all of
the Spanish mechanical mines. Mathieson's
model has been adopted as the regulation
case, though in emergency any suitable
vessel MAJ be used.
The spaniards employ steel lined with
cork ror their mine cases. Though this
combination gives great strength and light
ness, the use of cork diminshes the de-
structfve effect. This is counterbalanced,
however, by lessening the danger from
sympathetic action. thus rendering it more
dificult for a hostile vessel to clear a pass
age by countermining. The form of case
Is rather international in character, and
consists of the conical, the hemispherical
and the cylindrical. In the ground mine
they have adopted two French types; one
is a cylindrical body with truncated conf
cal ends, and the other hemispherical
The buoyant mine case is of the Dutch
type, and conical in form. 1t is of triple
steel with intermediate layers of cork.
The Understanding device is of English
design.
The explosive used in Spanish mines IS
wet guncotton, explosive gelatin and gun
powder. Decorating primers are fitted to
each. The size OF charge varies accordinS
to the character of the mine. The cylin-
drlcal ground mine contains from O~O to
LOO pounds of gunpowder, or an equiva-
lent amount of high explosives, guncotton
being considered four times as effective as
powder and explosive gelatin six times
The hemispherical ground mines often have
as great a charge as 5000 pounds of gum
powder, while the conical buoyant mines
acting at a less distance, contain only 500
pounds of guncotton.