The watchman and southron. [volume] (Sumter, S.C.) 1881-1930, 1917-08-08
Facts Abut Our Navy.
(By Lieut.. Fitzhugh Green of the
VigilanteS.)

(By Lieut.. Fitzhugh Green of the
Vigilantes.)
dieut. Fitzhugh Green of the u.
S. s. Texas is one of our naval officers
who is not content to do merely his
duy as such. That is why he writes
articles to inspire interest in the
work Of the navy and to keep warm
our patriotism. A true Vigilante, he
is turning out poems, sketches, and
cXhortations in his spare time. His
naval service includes two years with
the farthest north Crocker Land ex.
pedition. in which he acquitted him
self with distinction.)
A 14-inch gun is built up from eight
or ten hoops or steel tubes. Each IS
turned to an exact fit less several thou
sandths of an inch, then heated red
until expansion permits it to be drawn
on. 1t cools and adds strength not
only by it's thickness but by the grip
of it's shrinking.
The first inner tube has helical
grooves to give rotation to the shell
just as in any sporting rifle. Tremend-
Gus firing pressures between fifteen
and twenty tons per square inch COM
bined with acid gases and other pro-
ducts of explosion cause erosion or
wearing away and pitting of the
grooves. Inner tubes must be renew /.
ed periodically. The life of the gun,
so-called, is about $50 shots. Since
frequent target practices are held few
years elapse before guns must be TAX
en- ashore and retubed. The total cost
Of retubing a 14-inch guns is in the
|neighborhood of $4,000.
Besides the inner erosion constant
shocks Of explosion crystalize the
whole steel structure. Crystalization
of metal may be likened to the drying
of cheese. At first the mass is rela-
lively tough and elastic. After the
heavy punishment of protracted firing
gun tubes weaken and become brittle.
Microscopic examination reveals con-
traction and disntegration of metal
particles just as cracks and crumbly
sections occur in a cheese. Further
use of the gun is dangerous Some
times the crystallzed state is reached
sooner than was expected. The guns
crack or burst. On the Michigan
fifteen feet of a 12-inch gun broke off
and fell on deck. On the next load
the Gun Captain, having opened the
breech to report "bore clear" shout
ed There amt no Eoren Fortunate.
ly no one was killed.
The charge of a 14-inch gun is 385
pounds of smokeless powder put UP in
four silk-linen bags. The back end of
each bag is painted red and contains
about four ounces Of black powder
called the ignition charge. A brass
primer similar to a rifle cartridge ex-
ccpt it has no bullet. ignites the
black powder which in turn sets fire
to the smokeless powder. Contrary 70
popular belief there is no real explo-
sion but progressive burning of
enormous rapidity. Vast volumes of
gas at high temperature and pressure
are produced, forcing the projectile
out.
A 14-inch shell weighs 400 pounGs,
is five feet long, and contains a burst
ing charge. Twelve strong men lift
one with difficulty. Yet from the gun
it can sink battleship IL miles away.
1t travels at the rate of $500 feet o
second or n mile every two seconds.
On striking it eXpends an energy of
G5,6S7 foot-tOns, or enough to trans
port a load of two tons tot vice the
height Of Mt. Everest.