General Information on the 16in. guns
(page 2)
The gun house is in the armored portion of the rotating structure extending above the
barbette. The individual gun and slide assemblies, the two sight stations and the
rangefinders station are each located in separate flameprofed compartments in the gun
house.  The gun pit and the machinery flat extend below the shelf plate of the gun
house and the upper roller track is attached to the underside of the gun pit pan plate.
A central column extends from the machinery flat down to the base of the turret
foundation and supports the rotating upper and lower projectile handling flats or shell
decks. Each handling flat level has its own machinery for moving projectiles.
This machinery is located inside the circular bulkhead attached to the central column.
The fixed circular foundation bulkhead, or stool, supports the rotating elements of the
gun house from the roller bearings on the lower roller track. Each gun house rests
on seventy-two coned roller bearings. Twin pinions in the gun house machinery flat,
located inside the training circle, engage the rack to train the turret. The fixed
upper and lower handling flats, or shell decks, are supported from the stool sides.
Each turret can be trained at the rate of 4 degrees per second, and the guns can be
elevated at the rate of 1-2 degrees per second. The guns can be depressed 5 degrees.
Most of the projectiles are stored on the fixed and rotating rings of the
upper and lower shell flats in the turrets. Each storage flat is sub-divided into
three concentric rings. The outer, or fixed, ring is attached to the stool.
The center ring, or shell-handling platform, is part of the rotating structure and
contains the three projectile hoists in its after portion. It also mounts the
parbuckling gear for moving the projectiles and no projectiles are stored on this
ring. The inner, or rotating ring is a power driven platform resting on rollers which can be
rotated in either direction. It is also supported by the rotating
structure. The machinery for operating the shell flats and parbuckling gear, as
previously mentioned, is located within the circular bulkhead around the central column.
All projectiles are stowed erect on their base and each is separately lashed to the
adjacent fixed or rotating bulkhead. The projectiles are moved from the and rotating
rings onto the handling platform by a parbuckling system of power driven capstans.
In this arrangement, all three projectile hoists can be served simultaneously.
 Nominal storage per turret is:
Turret I, 390 rounds; Turret II, 460 rounds; Turret
III, 370 rounds. Allowance is made for nine drill projectiles per turret.
There are presently twenty 16in powder magazines serving the three turrets: six for
Turret I, eight for Turret II; and six for Turret III. These are powder scuttles in
the magazines for feeding the powder flats. Turret I has four scuttles and Turrets
II and III each have six scuttles. Each turret has three dumbwaiter powder hoists which
move the powder bags from the first platform to the second platform magazines.
The 16in guns are termed 'bag guns', meaning that the propellant charge is contained in
bags which are loaded separately from the projectiles. The guns require a
large amount of powder for the projectile to attain its required initial velocity.
If the powder was placed in a single container, the size and weight would make loading
difficult and slow and would greatly complicate the powder-handling machinery.
By
breaking up the charge into sections and packing the powder grains in fabric bags, the
sections can be easily handled by the turret crew.
The powder bag is usually made of silk so that it will completely burn away leaving no
smoldering embers when the charge is ignited.
Rayon will
shortly be introduced for use with reduced charges and later with full charges.
As
mentioned above, the gas ejection system automatically clears the bore after firing as a
safety precaution. The powder can be loaded by either stacking or dumping the
grains into the bag. In a stacked charge the powder grains are arranged in layers
with their axis parallel to that of the bag. In an unstacked charge the powder
grains are dumped into the bag randomly without regard for positioning of the individual
grains. The bags are cylindrical and are provided with handling straps and laciness
to take up any slack in the bag. An ignition pad containing black powder is fitted
to the bag to spread the black powder evenly insuring instant ignition between bags, and
is usually painted red to ensure proper alignment of the charge.
The protective coating deposited on the liner surface from the wear reducing jackets,
as powder burns, protects against erosion caused by hot gasses. The effects of
friction from the rotating band of the projectile, however, causes the liner to stretch
and it distends from the end of the muzzle as shown in the picture taken on IOWA in 1987.
CLICK HERE to return to the first page of the
General Information on the 16in. guns Section
CLICK HERE to return to the 16in. gun loading
menu
All of the information in these pages is from the two sources below:
Reference #1
*Muir, Malcolm, THE IOWA CLASS BATTLESHIPS, 1987, Sterling Publishing, New
York. ISBN 0-7137-17327
Reference#2
*Sumrall, Robert, F., IOWA CLASS BATTLESHIPS, 1988, Naval Institute Press,
Annapolis. ISBN 0-87021-298-2
|
