at some of the systems and equipment the Navy
The gun is the Navys oldest and most fre-
quently used piece of ordnance equipment.
Modern improvements in the construction of guns
and ammunition have revolutionized gunnery by
increasing the destructive power and maximum
range of this weapon. During the revolutionary
war, American ships fought at ranges of only
several hundred yards. Using inaccurate cast-iron
guns without sights, they threw solid shots that
usually failed to penetrate. Modern guns hurl
explosive shells that may weigh up to 2,700
pounds. The range of the largest (16-inch) gun
now in service exceeds 24 miles. This gun can
destroy a ship or some other target with only one
of its projectiles.
Naval guns, exclusive of small arms, are
classified according to size, type of ammunition
used, and method of fire.
Large guns are usually mounted in turrets,
boxlike structures of armor enclosing the breech
end of two or three guns. The turret rotates within
and on top of a barbette, a fixed circular tube of
armor extending down to the armored decks. The
barbette encloses the ammunition-handling rooms,
hoists, and gun-laying machinery of the turret.
Smaller guns are housed in two types of gun
mounts: open and closed. The latter type
resembles a turret but does not have an armored
The mounts or turrets of all naval guns except
the smallest are trained (rotated in the deck
plane), and the guns are elevated by electric or
electric-hydraulic power drives. The power drives,
which are usually automatic, move the gun to a
position designated by a fire control system.
The following sections briefly describe some of
the gunnery systems used by the Navy.
The 16"/50 turret-mounted gun is the only
major-caliber weapon in the fleet today. Installed
only on battleships, it can fire a 2,700-pound
projectile a distance of 24 miles.
Although it has a low firing rate (2 rounds per
minute), the 16" projectile is quite destructive.
The 5"/54 Mk 42 is an automatic dual-purpose
(DP) gun carried by most frigates (FFs), destroyers
(DDs), and guided-missile cruisers (CGs) built in
the 1950s and 1960s. Depending on the class of
ship, the weapons maybe located on one, two, or
three single mounts. The gun has an effective
range of 24,500 yards and fires 70-pound shells at
a rate of 32 rounds per minute.
The Mk 45 (fig. 20-1) provides destroyers and
large ships with an all-weather capability for
support of amphibious operations. It also provides
them with an all-weather capability for delivery of
rapid and accurate naval gunfire against surface
craft, aircraft, and shore targets. It is a shielded,
single-barrel, fully automatic gun that fires 5"/54
semifixed ammunition. Total installation weight
varies from 49,000 to 54,000 pounds, depending on
the installation configuration. The DD-963, DDG-
993, LHA-1, CGN-36,
Figure 20-1.-Mk 45 5"/54.