The destructive effect of gun-fire depends upon the character of the projectile and of the ship. Against unarmored ships shells with compara tively thin walls, but containing a large bursting charge, are used. Against armored ships armor piercing projectiles are used, if the armor is too thick to he perforated by heavy common shell. To secure greater penetration in hard-faced ar mor, soft steel caps are placed on shell which are to be used against armor. (See ARMOR PLATE; also PROJECTILES.) At close range it is possible to select a particular part of a ship for attack; but close ranges are likely to be the exception in naval battles, and many will doubt less be decided before close range is reached. At long range the probability of hitting at all is not large; therefore it is not advisable to reduce this probability by attempting to strike par ticular parts of the enemy's vessel; all pro jectiles should therefore be fired to hit the centre of the target it presents. The unavoidable er rors will cause the projectiles to deviate more or less from this point, but many will hit in places where they will do much damage. Large armor-piercing shells usually have no bursting charges, because gunpowder is not strong enough to burst their thick walls, and very few high power explosives will stand the shock and heat engendered by passing through armor. There are a few powerful explosives that can be fired through armor; but they are so insensitive that they will not explode of themselves when beyond the armor, and it is difficult to construct a fuze which will explode them that will not be ignited too soon. The most promising explosives for leading 'armor-piercing shells are perhaps jovite and maximite; shells filled with each of these compositions have been fired through armor and satisfactorily exploded beyond. For common shell and armor-piercers not exceeding 6 inches in calibre, fine black gunpowder is used as the bursting charge. It is safer than any high-power explosive, and can be satisfactorily exploded. Moreover, it breaks the shell into a sufficient number of pieces, and its incendiary effect is be lieved to be greater than that of any high-power explosive. The latter breaks the shell up into very small pieces, which are less destructive than larger ones. The damage caused by the explosion of a shell containing a bursting charge made up of a high-power explosive is very great in the immediate vicinity of the explosioin, but the area of destruCtion is generally less than from shells filled with gunpowder.
In former days, if a ship could cross the bow or stern of an enemy and deliver a raking fire, it often caused sufficient destruction of life and material to decide the fight. while the vessel raked could bring few or no guns to hear in re turn. The value of a raking position has much decreased, and is likely to be further lessened. Recent armored ships are well protected against raking fire, and a very large proportion of their batteries is available against an enemy crossing bow or stern. The different plans upon which the batteries of modern ships are arranged will cause them to try to select such positions with reference to the enemy as will enable them to use their gun power to the best effect. while that of the enemy is less favorably situated; but if the enemy is sufficiently alert. not even the posses sion of superior speed will insure that this can be done. The direction of the enemy from a ship is called the angle of presentment, and it is usu ally measured from the beam; but as regards the striking of shell, the angle of presentment is the angle between the path of the projectile and a normal line or perpendicular to the surface hit. In both old and modern ships the broadside fire is greater than the how or stern fire; but in modern shins the bow and stern fire is usually strong. With the exception of
one or two guns, the broadside battery is generally available in any direction from 45 or 50 degrees forward of the beam to a point at an equal angle abaft it. The advantage of giving the widest practicable arcs of fire (the angle through which the gun can be trained or fired) is easily seen, for it may result in giving a deci sive advantage, and it is carefully sought when the plans of a ship are made. It was formerly the custom to fire at the enemy's water-line, be cause hits there were most serious, and if the shell fell short it would usually strike the ship after making a 'ricochet' (i.e. glancing from the surface) ; while if it went too high it might cause no damage whatever. The ricochet of spherical projectiles was usually in the line of fire; but elongated rifled projectiles do not con tinue on the course after striking the water; they usually turn to the right, often at a considerable angle, and sometimes shoot sharply upward to a considerable height. The present practice is therefore to aim at the middle of the target the enemy presents, both as regards length and height. In defense against torpedo boats, the smaller guns of ships are chiefly relied upon; but as a result of experiment and experience in war it is found that the very small pieces are of little use. They are inaccurate, owing to the curved path of the projectile, which loses its velocity more rapidly than a large one, while it is too small to disable a modern torpedo boat. Guns using projectiles weighing from 6 to 14 pounds are the ones chiefly relied upon; but it is doubt-. ful if even these are quite adequate, and it is certain that shrapnel from 5-inch, 6-inch, 7-inch, and 8-inch would be very useful.
The last point to consider about a gun is speed of fire. As has already been said, speed is last to be considered, not because of lack of impor tance, but because a gun must be safe, and its fire accurate and destructive, or speed is useless. A high rate of fire can be attained only by means of a properly designed mount and breech mech anism, adequate ammunition supply, a reason ably steady gun-platform, and a well-trained crew. The mount must be strong, and admit of rapid and easy training and elevation. The breech mechanism must be simple, effective, strong, and quick working. No delay must occur through inadequacy of the ammunition supply, and there must be sufficient room for the crew to carry on the operations of loading in the most expeditious manner. The speed of fire from tur rets is generally much reduced for lack of room, particularly in turrets mounting guns of 8-inch calibre or less. More, perhaps, depends upon a suitable form of drill than upon anything else. Exact adherence to prescribed forms should not be required; a drill manual should be a general guide, and not a plan to which exact compliance is required, if it can be shown that greater speed can be obtained by a variation of it. In prepar ing a plan of drill, the fact must be kept in view that the greatest effective speed is attained when the work is so divided that every man is working all the time in a manner which will not interfere with, but facilitate, the work of others; and no man should be called upon to do what another can do better, if that can be avoided. Such a division of duty is usually impossible; but it is the end to be sought and approximated to. Or ders and all talking should be done away with, and the different operations going on at the same time made to fit in with each other in a way to make orders superfluous.