The Imperial Japanese Navy

by Fred T. Jane

The 12-in. guns are mounted forward and aft on the midship line, as shown in the sketch on the ship. Owing to the powerful nature of the guns, these mountings are necessarily stronger than any hitherto manufactured in this or any other country. The design is arranged with a view to occupying the least possible space in the ship, and, at the same time, to give ample room for working the machinery. The general features of the design are the turn-table proper containing the mountings for the gun, the working chamber underneath into which the ammunition is received from the magazine and shell-rooms in preparation for sending up into the secondary or loading hoist, the trunk connecting the working chamber with the magazines and shell-rooms, and the hoist connecting the working chamber and the gun. This latter hoist is so arranged that a gun can be loaded at any angle of elevation or training. The charge for each gun, consisting of the projectile and the cordite charge, the latter in two halves, is brought up at one time in a loading cage, which is automatically stopped in its proper position in line with the breech opening of the gun. It is then rammed home by means of a chain rammer actuated by a hydraulic motor. The breech-block of the gun is opened or closed by a hydraulic motor, thus enabling this operation to be performed with great rapidity. In the working chamber, by an ingenious arrangement, the projectile and the two halves of the cordite charge are simultaneously transferred from the cage which works in the trunk connecting the shell-rooms and magazines with the working chamber, to the cage working in the hoist connecting the working chamber with the gun position. The ammunition trunk is of a new design, which enables the ammunition cage always to come to the same position in the magazines and shell-rooms; but when it is brought up to the top of the trunk the cage is in its proper position with respect to the ammunition loading hoist, although the turret may be revolving at a quick rate; or, in other words, the ammunition trunk does not revolve at the bottom, but revolves with the turn-table at the top. The guns are protected by 10-in. hard armour in the front, and 8-in. at the sides and back. The feature of the turret is that it is quite balanced, thus enabling it to be readily trained by hand, although the ship may have a heel at the time.

There are three systems for performing the operation of training, primarily by hydraulic power, and should this fail through any of the piping being shot away, electric training gear can be quickly put into operation; and finally, should this be disabled, the turret can be trained by hand. Similarly the operation of elevating and depressing the gun can be performed by working primarily by hydraulic power, and then either by electric or hand. The operations of loading can also be performed by hand should the hydraulic system be disabled. To safeguard against accident by freezing in the intense cold which is found in the China seas during the winter months, heating apparatus is fitted throughout the turret installation. The gun mountings are so arranged as to give the gun 18 deg. elevation and 3 deg. depression, a greater range of elevation than has hitherto been provided for mountings of this description. The training angle is arranged for 270 deg., that is to say, from right ahead or right astern to 45 deg. before or abaft the beam. The turret can be trained at the rate of one complete revolution (viz. 360 deg.) per minute. In the shell-room, suitable overhead hydraulic lifting and traversing arrangements are made for lifting the shell out of the bays and placing them in the cage, but this operation can also be done by hand should necessity require it.

The sighting of the guns is provided for by a central sighting station and two side sighting stations, one on the left and the other on the right. By an ingenious arrangement the captain of the turret is enabled by working one lever to train or elevate the gun or to perform both these motions at the same time. Voice-pipes and other apparatus are fitted to enable the officer in charge of the turret to communicate his orders to the magazines and shell-rooms. A complete system of electric circuits enables the guns to be fired from any one of the eight positions either simultaneously or independently. Percussion firing arrangements are also provided.

10-in. Gun Mountings.

Each 10-in. gun is placed in an armoured revolving gun-house, or turret. The ammunition is sent up in a lifting cage from the magazine and shell-room direct to the gun platform, each cage containing a projectile and cordite charge in two parts. On reaching the gun platform the projectile is quickly transferred to a hinged loading tray fixed on the gun-cradle by means of an intermediate resting tray, the cordite being transferred by hand to the loading tray. By this arrangement three projectiles are always in waiting for loading, ensuring rapidity of fire. The projectile and charges can then be rammed into the gun by a telescopic hydraulic rammer. This rammer is arranged to follow the gun in elevation or depression, so that it always remains in line with the gun axis, enabling the operation of loading to take place at any angle within the usual fighting limits. The training of the gun-house is performed as in the case of the 12-in., primarily by hydraulic power; then by electric, and finally, if necessity occasions it, by hand, and, like the larger mounting, it is balanced so that the operation of training by hand can be readily performed although the ship may have a heel. The breech-block of the gun is arranged to be operated either by hydraulic power or by hand. The gun can be elevated by hydraulic power as in the 12-in. The operations of training and elevating are performed by the single motion of a lever. These guns also have the large range in elevation of 18 deg., with 3 deg. depression. The sighting of the gun is provided for by two positions, placed on the right and the left of the gun respectively. A complete set of electric firing circuits is fitted to enable the gun to be fired from either of these positions. Percussion firing gear is also provided. The guns are protected in front by 9 ins. of hard armour, and on the sides and back 6 ins. The training angle is from right ahead to 30 deg. before or abaft the beam, or a total angle of 120 deg.

6-in. Gun Mountings.

The 6-in. guns are mounted on the well-known central pivot principle. This principle was first introduced by Sir W. G. Armstrong, Whitworth and Co., and has since been adopted for mounting guns of medium calibre by all the Governments and armament constructors in the world. Briefly, to describe this system, it may be said that the gun is mounted in a cradle in which it recoils, the recoil being absorbed by an oil buffer attached to it forming a part of the cradle, the piston of which is attached to the gun. The cradle is mounted by means of trunnions on a Y piece, which revolves on hard steel balls placed on a fixed pedestal. This pedestal is bolted to the ship’s structure, the elevating arrangements are attached to the cradle, thus enabling the elevating gun number to work the gear even during the firing of the gun without injury to himself. Telescopic sights are fitted in a convenient position. Electric circuits are fitted to enable the guns to be fired by the simple operation of pressing the trigger of a pistol. Arrangements for percussion firing are also provided. A circular shield is attached to the revolving Y piece, so as to keep the port opening in the ship’s side blocked up at any angle of training. This port opening allows for the guns to be trained through a range of 120 deg., viz. 60 deg. before the beam and 60 deg. abaft.

12-pounder Gun Mountings.

The 12-pounder mountings are similar in principle to the 6-in. above described, but, of course, arranged to suit the smaller size of the gun. They are protected by revolving shields attached to the Y pieces by elastic stays.