GUNNERY 



375O 



GUNNERY 



range. That was the reason for the 

 introduction of the " all-big-gun " 

 Dreadnought. Range has been in- 

 creased mainly by adding to the 

 propelling energy within the gun, 

 and elevating the angle of fire. It is 

 exceedingly difficult to master even 

 the elements involved in the hitting 

 of an enemy's shipatextreme range. 

 The utmost accuracy is required in 

 scientific gunnery, and it must be 

 continuous accuracy. The oppos- 

 ing ships are moving at high speed, 

 and the range is constantly chang- 

 ing it may vaiy as much as 900 

 yards in a minute and it is chang- 

 ing at a rate that is not constant. 

 Fleets rarely move upon parallel 

 courses. Difficulties arise also from 

 mist and the condition of the atmo- 

 sphere, wind, temperature, and 

 other factors. At great ranges the 

 trajectory, that is the curve of 

 flight of the projectile, is neces- 

 sarily very high, its fall very steep, 

 and the danger zone therefore 

 narrow. 



Moving Targets 



But there is another important 

 factor always presented to the 

 gunnery officer. The ships are 

 moving swiftly, and the position of 

 the target, relatively to the firing 

 ship, changes during the flight of 

 the projectile, which may cover a 

 period of 8, 10, 12, or even more 

 seconds, according to the range. 

 Therefore the gun must be aimed, 

 not at the ship in the position she 

 occupies at the instant of firing, but 

 at the position she will occupy at 

 the moment when the projectile 

 arrives. 



At first sight it may seem that 

 the problem of aiming at a place 

 where a swiftly moving enemy will 

 arrive a few seconds later is in- 

 soluble. But there is a guide to her 

 future position in a knowledge of 

 the course she has previously pur- 

 sued, whether a direct course or a 

 curved course under helm. In 

 order that this may be ascertained 

 and the range found and retained, 

 observing and reckoning instru- 

 ments of the finest and most in- 

 genious character have been de- 

 vised. It is necessary first to ascer- 

 tain the range, bearing, and speed 

 of the enemy, next to integrate 

 these factors with the speed and 

 changing curve of the firing ship, 

 and then to transmit them instan- 

 taneously to the guns. 



The system of training in range- 

 finding, and retaining and keeping 

 the sights on the target, employed 

 at the British naval gunnery estab- 

 lishment at Whale Island, Ports-, 

 mouth, and in the tenders, and at 

 the Gunnery School, Devonport, 

 is quite wonderful. Single and 

 double " dotter " apparatus for 

 teaching men to fire with accuracy 



without expending ammunition, 

 deflection-teachers, and sub-calibre 

 arrangements are employed. 



At Devonport is a rocking plat- 

 form, actuated by mechanism 

 which has about 200 movements, 

 and whose speed can be adapted to 

 represent the rolling and pitching 

 movements of a battleship or light 

 cruiser. Thus gunlayers are trained 

 in keeping their sights on the target, 

 and attain remarkable accuracy of 

 observation and shooting. 



Range-finders up to a 15-ft. base 

 line have been installed in British 

 ships in elevated armoured posi- 

 tions. Sometimes they are placed 

 in low armoured towers, and are 

 often installed within the ar- 

 moured structure of the gun turret, 

 with large-angle prismatic sighting 

 telescopes. It was no uncommon 

 thing before the war for the service 

 target to be hit, even at a long 

 range, by the first shot. In asso- 

 ciation with the range-finder, elec- 

 tro-mechanical devices are in- 

 stalled to establish fire-control, by 

 determining the rate of change of 

 range and bearing of the enemy, 

 and then of transmitting the infor- 

 mation to the gunner. An indicator 

 on a graduated dial affixed to the 

 gun sights, being electrically con- 

 trolled, gives the range from the 

 control station. The sight-setter 

 then moves a pointer round to the 

 required place, and by his control 

 wheel keeps this pointer always 

 opposite to the index mark. The 

 same system is applied to the de- 

 flection gear. The men are very 

 highly skilled, and have all gone 

 through the gunnery schools. 

 Modern Fire Control 



There are recent modifications 

 and improvements in this system, 

 the electro-mechanical arrange- 

 ments having been reduced to a 

 very simple form of transmitting 

 switch and gear at the dial operat- 

 ing the pointer. The whole ten- 

 dency, seen in the actions of the 

 Great War, has been to establish 

 more firmly the system of fire con- 

 trol and direction. Advantage can 

 be taken in director firing of the 

 roll of the ship, which elevates the 

 guns and increases the range, and 

 salvo firing proved highly effective 

 in the sea fighting. 



Director firing was greatly re- 

 vived before the war. The advan- 

 tage was conspicuous of being able 

 to direct a vessel's guns from a cen- 

 tral station, where range and suc- 

 cessive corrections could be calmly 

 and quietly worked out apart from 

 the confusing noises which must 

 prevail in the vicinity of the guns. 

 When sighting and laying mechan- 

 ism became more accurate, Sir 

 Percy Scott, director of target 

 practice, developed the system of 



controlling fire from a central sta- 

 tion. Much is due to the experi- 

 mental department at the Whale 

 Island Gunnery School, and to Ad- 

 mirals Peirse and Browning, suc- 

 cessively directors of target prac- 

 tice, under whom the establish- 

 ment became the focus of the best 

 gunnery brains in the British navy. 

 For several years practically every 

 gunnery advance emanated from 

 it. In the system of control it was 

 feared there might arise a disposi- 

 tion to trust too much to the con- 

 trol officer and his instruments to 

 the neglect of individual training 

 and practice with the gun, but no 

 such defect was discovered during 

 the naval fighting in the Great War. 

 German Range-finding 



The Germans employed a very 

 efficient system of range-finding 

 and fire direction and control, per- 

 fected during recent years, which 

 has never been fully described, and 

 from the ships surrendered the 

 scientific appliances had been re- 

 moved. It differed in no important 

 degree from the British and Ameri- 

 can systems. Lord Jellicoe's dis- 

 patch spoke of the high standard 

 of the German gunnery, resulting 

 from the use of some such system 

 of fire as the Petravic. In one 

 British appliance the speed of the 

 observing ship and the estimated 

 direction and speed of the target 

 were so combined that rate of 

 change of the range and the 

 deflection could be read off on 

 a graduated map surface. In 

 others a rate-of-change clock de- 

 vice was employed, with a pointer 

 moving over a dial at a rate 

 variable at will, so that from the 

 initial range given changes of range 

 could be transmitted corresponding 

 as nearly as possible to the ranges 

 given by the range-taker. 



In the finest apparatus, the 

 speed and course are almost auto- 

 matically ascertained from ob- 

 servation. The change-of -range in- 

 strument gives a forecast of the 

 ranges based on this knowledge, as 

 well as the bearing of the enemy 

 relatively to the firing ship, and 

 the plotting can be corrected for 

 any change of course of the latter. 



It will be realized that great ex- 

 perience, high powers of observa- 

 tion, and much skill are required 

 to use these elaborate appliances 

 successfully. The gunnery officers 

 of the British navy are men of the 

 very highest training. They go 

 through long and exhaustive 

 courses in the theory and practical 

 work of internal and external bal- 

 listics the gun and its effective 

 working. They are also in a true 

 sense engineers, every gun turret 

 being a mass of machinery of the 

 most complicated character. 



