Evening star. [volume] (Washington, D.C.) 1854-1972, 1895-09-05
THE IoWA's ARMoR|
It VIII Keep Out Projectiles of the Best
Rifle of Modern Timea
Important and Satisfactory Tests
Made at the Indian Head Prov.
ing Ground Yesterday.

The test at Indian Head yesterday demon
strated that the armor of the big battle
ship Iowa will keep out the projectiles Of
the best Pinch rife of modern times. It
was the first time Stree the use of modern
guns and modern armor that the govern
ment has made practical experiments to
determine the actual strain and injury to
which a battle ship would be subjected II
struck by projectile. For that purpose
side armor plate of the battle ship Iowa,
now building at the Cramps yards In Phila-
delphia, was fitted upon an actual repro
duction of section of the ship. 1t con-
sisted of the inner and outer bottoms OF
fve-eighths inch steel forming compart-
ments, with lateral steel bulkheads four
feet apart. Above was the projection deck
and below tn main deck, the whole being
backed abo,, and below by oak Of the
estimated strength Of the protection and
main decks The plate itself was sixteen
feet nv seven and one-half fourteen inches
thick at the top, and sloping toward the
bottom to a thickness of seven inches.
1t was what is known as the carnegie
double-forged plate-that Is. 1t was forged
before and after carbonization-and was
the FIRST service plate subjected to the
ballistic test
The Shots Fired.
The shots were fired at $50 yards. at right
angles to the plate, to secure the normal
impact. The first was a 5OO-pound Car
penter projectile from ten-inch gun. 1t
struck the plate with a velocity of 1872
feet per second, or with an enerf{ OF 74l,-
COO foot-pounds The projectile WIS driven
into the plate about six inches, and not
single injury to the backing was discovered
after a careful examination. The bolts
were examined and found to be intact. The
second shot vas also from the ten-inch
gun, the same sized projectile being used,
but the powder charge was increased TO PIG
pounds. which increased the velocity to
1862 feet per second, so that it struck with
an energy of 931. 600 foot-pounds. This shot
also spent itself on the plate without Great
ing a sign of crack or injury, or strain
ing the frame work. There was not a bulge
in the plate or frame Of the vessel. A
bolt was within six inches of the place
where the projectile struck. Having thus
tested the plate, it was decided to subject
the frame work to 4 still Severer test, and
an S5O-pound Misunderstanding SHE'LL driven
by 400 pounds of powder, was fired at it
from a twelve-inch gun. The projectile
struck with velocity of 1880, or an en-
ergy of 1,530000 foot-pounds. This shot
should, according to the estimates, have
penetrated a sixteen-inch HarveyiZed plate.
Although it cracked the plate, already
weakened by the two previous shots, and
penetrated to the wood backing it did not
get through the backing. It struck close to
a bolt, and sent it with tremendous force
across the compartment against the inner
bottom, which was bulged, but not pene-
trated. the outer bottom was slightly
bulged also, and the bulkhead, where the
shot struck buckled.
The Result Remarkable.
On the whole the result of the test with
the plate and frame work was considered
remarkable. The plate withstood the gov
eminent test for a. fourteen-inch plate
splendidly. and constructively the test of a
seventeen-inch plate. The bolts proved sat
isfactory, and the resistance of the frame
work really astonished all. Secretary Her
bert was pleased at the result, and Capt.
Sampson, chief of the ordnance bureau,
said the injury, both to the plate and
frame, was the very minimum.