CHAPTER VII 1. Naval Gunnery, Weapons, and Technique

Before passing to the actions, it is important to have a clear idea of two things which these actions illustrate. The first is the nature of the advantage which heavy guns have over lighter pieces. In each of these actions the side which had the largest number of heavier guns, or generally heavier guns, was successful. A heavy shell obviously has far greater effect than a light shell when it hits. Its advantages in this respect do not need demonstration. It is as well, however, to make it quite clear why it is more probable that a heavy shell will hit.

And next, these actions illustrate the great advance in fire control which has been made in the last ten years, and they also show, and I think convincingly, the limitations of the systems in use. As my comments on these actions will be particularly directed towards showing the tactical developments that have followed on the advance of gunnery and towards what further tactical developments must follow from a greater advance, it is essential that the nature of the fire-control problem should be understood.

The principle of heavy guns being superior at long range is exemplified by the Sketches 1 and 2. Sketch 1 represents the manner in which a salvo of guns may be expected to spread if all the sights are set to the same range. All guns lose in range accuracy as the range increases, but light guns more than heavy. If six 6-inch guns are fired at a target at 12,000 yards the shell will be apt to be spread94 out as shown in the top line. Six 9.2’s will fall in a closer pattern, as shown in the second line, six 12-inch in a still smaller space, and the 13.5 in one still smaller. Regarded simply as instruments for obtaining a pattern at a given range, heavy guns are, therefore, far more effective than light ones.
Big guns more accurate at long range, because more regular

But this is far from being the heavy guns’ only advantage, as will be seen from Sketch 2. The heavier the projectile is, the longer it retains its velocity. The angle at which a shot falls from any height depends solely upon its forward velocity while it is falling. Sketch 2 shows the outline of a ship broadside on to the enemy’s fire, the shell being fired from the right-hand of the sketch. A is the point where the ship’s side meets the water. If the gun were shooting perfectly accurately and was set to 10,000 yards, all the shots would hit at this point. And clearly any shot set at a range greater than this, but one which did not carry the shot over the target, would hit95 the ship somewhere between the points A and X. Now if a 6-inch shot grazes the point X and falls into the water, it falls at the point B beyond the ship. But the angle at which it is falling is so steep that the difference in range between the point A and the point B is only forty yards. To hit, then, with a 6-inch gun the range must be known within forty yards. This interval is called the “Danger Space.”
Big guns need less accurate range-finding, because the danger space is greater

The 9.2 will fall at a more gradual angle, and the shot grazing on X will fall at C, which is twenty yards beyond B; and a 12-inch shell, falling still more gradually, will fall at D, which is 100 yards from A; and similarly the 13.5 at E, which is 150 yards beyond it. Hence, at any given range, far more accurate knowledge of range is necessary for hitting with a 6-inch gun than with a 9.2, with a 9.2 than with a 12-inch, and with a 12-inch than with a 13.5.

But we have seen from Sketch 1 that, in proportion as the range gets long, so does the range accuracy of the gun decrease, and that this loss of accuracy is greater in small guns than in bigger. To hit with it at all a more perfect fire control is necessary, and for any given number of96 rounds a much smaller proportion of hits will be made. The advantage of the big gun over the small, merely as a hitting weapon, is twofold. It does not require such accuracy in setting the sight, and more shots fired within these limits will hit.
FIRE CONTROL

If ships only engaged when they were stationary the range would not change, and it could be found by observation without rangefinders. And even with rangefinders it can never be found at great distances without observation. But ships do not stand still, and when they move the distance between them alters from second to second. If these movements could be (1) ascertained, (2) integrated, and (3) the results impressed upon the sight, change of range would be eliminated, and we should have come back to the conditions in which ships were stationary. Fire control is successful in so far as it succeeds in doing these three things. Sketches 3 and 4 show the process by which hits are secured, when the conditions are not complicated by changes in the range, that is, if these complications have been eliminated by fire control. The second two illustrate what these complications are. The ships turn away from each other and then turn towards each other.

The rate graph (6) shows the effect of these movements on the range and the rate at which it is changing from moment to moment.

The process shown in Sketches 3 and 4 is called “bracketing.” Two shots are fired at a difference of, say, 800 yards. Observation shows the first to be too short, the second to be too far. The difference is bisected by the third shot. This places the target in one of the halves of the bracket. This half is bisected by the fourth shot,97 placing the target in a quarter. If an eighth of the bracket is less than the danger space, then the fifth shot must hit.
Range-finding by bracket

In Sketch 5 the ships keep parallel courses for two minutes. The range does not change. The line in the graph (6) is, for these two minutes, horizontal. It is as if both were stationary. When the ships turn the range increases and the graph rises. But the graph is not a straight line but a curve. This shows that the rate also is changing. Each movement of the two ships, whether they keep steady courses or turn, alters the range and the rate. As projectiles take an interval of time to travel from the gun to the target, the range must be forecasted. B, then, cannot engage A unless he knows where A is going to be. He cannot know this until A has settled on a steady course. While A is turning, then he is safe from gunfire except by a chance shot. B cannot engage while he is himself turning unless he can integrate his own movements with A’s. It is this latter difficulty which largely explains the duration of modern actions. At the mean range of each engagement, with ships standing still, Sydney could have98 sunk Emden in ten minutes; Inflexible and Invincible could have sunk Scharnhorst and Gneisenau in fifteen. But it was ninety minutes before Emden was driven on the rocks, 180 before Scharnhorst sank, and 300 before Gneisenau went under.
The crux of sea fighting, changes of course and speed produce an irregularly changing range

In the ten years preceding the war, Admiralty policy, as shown by the official apology for the Dreadnought design and by the course of naval ordnance administration, had been governed by the purely defensive idea of providing99 ships fast enough to keep outside of the zone of the enemy’s fire, armed with guns that outranged him. The professed object was to have a chance of hitting your enemy when he had no chance of hitting you. At the Falkland Islands there was given a classic example of the tactics that follow from this conception. On the assumption that twenty-five 12-inch gun hits would suffice to sink each of the enemy’s armoured cruisers, it appeared that in this engagement the 12-inch gun had attained the rate of one hit per gun per 75 minutes. This figure may be contrasted with the one hit per gun per 72 seconds attained by the Severn in her second engagement with the Koenigsberg at the Rufigi. The contrast seems to show that it was only the obsession of the defensive theory that explained contentment with methods of gunnery so extraordinarily ineffective in battle conditions. For the difference in the rate of hitting was almost completely explained by the range being constant at the Rufigi, and inconstant at the Falklands. And the methods of fire control in use were proved at the Falklands to be unequal to finding, and continuously keeping, accurate knowledge of an inconstant range.

Again at the affair of the Dogger Bank, Lion, Tiger, Princess Royal, New Zealand, and Indomitable were in action for many hours against three battle-cruisers and an armoured cruiser, and for perhaps half the time at ranges at which good hitting is made at battle practice; and although two of the enemy battle-cruisers were hit and seen to be in flames they were able, after two and a half hours’ engagement, to continue their retreat at undiminished speed, and only the armoured cruiser, whose resisting power to 13.5 projectiles must have been very feeble, was sunk.

100 The lesson of Jutland is still more striking, and it is possible to draw the moral with a little greater precision since it has been officially admitted in Germany that Lutzow, Admiral von Hipper’s flagship, the most modern of Germany’s battle-cruisers, was destroyed after being hit by only fifteen projectiles from great guns. It is not clear from the German statement whether this means fifteen 13.5’s and omits to reckon 12-inch shells, or whether there were fifteen hits in all, some of the one nature and some of the other. The latter is probably the case; for we know from Sir David Beatty’s and the German despatches that it was Invincible’s salvos that finally incapacitated the ship and compelled Von Hipper to shift his flag. Lutzow was always at the head of the German line and so was exposed to the fire of our battle-cruisers for nearly three hours. If we assume that she was hit by ten 13.5’s and five 12-inch; if we further assume that the effect of shells is proportionate to their weight; if we take the resisting power of British battle-cruisers, German battle-cruisers (which are more heavily armoured than the British), and all battleships to compare as the figures 2, 3, and 4 respectively; if we further assume that the Fifth Battle Squadron did not come into effective action till the second phase began, and went out of action at 6:30, and that the battle cruisers were in action for three hours, and omit Hood’s squadron altogether, we get the following results: Five German battle cruisers were exposed to seventy-two hours of 13.5 gun fire and to twenty-four hours of 12-inch gun fire, and five German battleships were exposed to forty-eight 15-inch gun hours. Similarly—omitting Queen Mary, Indefatigable, and Invincible, seemingly destroyed by chance shots and not overwhelmed by gunfire—four British battle-cruisers were exposed to101 thirty-seven 12-inch and sixty 11-inch gun hours, and the Fifth Battle Squadron was exposed to one hundred and eighty 12-inch gun hours. Had both sides been able to hit at the rate of one hit per hour per gun, the Germans, roughly speaking, should have sunk six British battle-cruisers, and the four ships of the Fifth Battle Squadron nearly twice over; the Fifth Battle Squadron should have sunk four German battleships; and the British battle-cruisers seven German battle-cruisers! The number of hits received by the British Fleet has not been published, but it is probably safe to say that the Germans could not have made a quarter of this number of hits, nor the British ships more than a third. It would seem, then, that at most we made one hit per gun per three hours and the Germans one hit per gun per four hours.

At no time, throughout such parts of the action as we are considering, did the range exceed 14,000 yards, and at some periods it was at 12,000 and at others at 8,000. In battle practice not only on the British Fleet but in all fleets, hits at the rate of one hit per gun per four minutes at 14,000 yards have constantly been made. How, then, are we to explain the extraordinary difference between battle practice and battle results? In the former certain difficulties are artificially created, and methods of fire control are employed that can overcome these difficulties successfully. But these methods evidently break down when it comes to the quite different difficulties that battle presents. So far we are on indisputable ground. Whether fire control can be so improved that the difficulties of battle can be overcome, just as the difficulties of battle practice have been overcome is another matter.

The difference between action and battle practice is, broadly speaking, twofold. First, you may have to102 fight in atmospheric conditions in which you would not attempt battle practice. All long-range gunnery, whether on sea or on land, depends for success upon range-finding and the observation of fire, and as at sea the observations must be made from a point at which the gun is fired, the correction of fire becomes impossible if bad light or mist prevents the employment of observing glasses and range-finders. In the Jutland despatch particular attention was directed to the disadvantages we were under in the matter of range-finding from these causes. It would appear, then, that those who, for many years, had maintained that the standard service rangefinder would be useless in a North Sea battle, have been proved to be right.

The second great difference lies in the totally different problems which movement creates in battle. In battle practice the only movement of the target is that which the towing ship can give to it. Its speed and man?uvring power are strictly limited, whereas a 30-knot battle-cruiser can change speed and direction at will. The smallest change of course must alter the range, and the smallest miscalculation of speed or course must make accurate forecast of range impossible. But the movements of the target are only a part of the difficulty. Those that arise from the man?uvres of the firing ship may be still greater and more confusing. And so obvious is this that, in peace time, it used to be almost an axiom that to put on helm during an engagement—even for the sake of keeping station—should be regarded almost as a crime. But the long-range torpedo has long since made it clear that a firing squadron may have to put on helm. It must man?uvre, that is to say, in self-defence—a thing it would never have to do in battle practice. And when both target ship and firing ship are man?uvring, it is small wonder if methods103 of fire control, designed primarily for steady courses by one ship and low speed and small turns by the other, break down altogether. It is undoubtedly true that the mainspring of all defensive naval ideas is doubt as to the success of offensive action, and as the only offensive action that a battleship can take is by its guns, it would seem as if those who disbelieve in the offensive have had far too much reason for their scepticism.
THE TORPEDO IN BATTLE

It was the invention of the hot-air engine round about 1907 that converted the torpedo from a short- to a long-range weapon, and when, a year or two later, the feasibility of running one of these with almost perfect accuracy and regularity to a distance of five miles was demonstrated, it became quite obvious that a new and, as many thought, a decisive element had been introduced into naval war, the effect of which would be especially marked in any future fleet actions. Just what form its intervention would take was much discussed in three years, and the following quotation from a confidential contribution of my own on this discussion, written in December 1912, is perhaps not without interest as indicating the points then in debate:

“The tactical employment of fleets has, of course, recently been complicated, in the opinions of many, by the facts that the range of torpedoes is more than doubled; that their speed is very greatly increased; and that their efficiency (that is, the extent to which they can be relied upon to run well) has increased almost as much as their range and speed. This advance of the torpedo has followed very rapidly on the development of the submarine, and has led, quite naturally, to the suggestion that it should be employed on a considerable scale in a fleet action104 either from under-water craft or by squadrons of fast destroyers.

“The torpedo menace has undoubtedly confused the problem of fleet action in a most bewildering manner; but, with great respect to those who attach the most importance to this menace, there are, it seems to me, certain principles that should be borne in mind in estimating its probable influence.

“There is a world of difference between a weapon that can be evaded and one that cannot. You can, by vigilance, circumvent the submarine and dodge the torpedo—at any rate, in some cases. You can never double to avoid a 12-inch shell. It may yet be proved that not the least interesting aspect of modern naval warfare will be that the torpedo will thus put seamanship back to its pride of place.

“In any circumstances the torpedo, however highly developed, is not a weapon of the same kind as the gun. It seems to belong to the same order of military ideas as the cutting-out expeditions and use of fire-ships in olden days and the employment of mines of more recent date. It is, of course, an element in fighting, and a most serious element; a means of offence far handier, and with a power of striking at a far greater distance than has been seen in any parallel mode of war hitherto. And yet I should be inclined to maintain that it and its employment remain more in the nature of a ‘stratagem’ than of a tactical weapon, truly so called.

“Mines, torpedoes, a bomb dropped from an airship or aeroplane—these are all new perils of war. In the hands of a Cochrane their employment might conceivably be decisive. But it would need the conjunction of an extraordinary man with extraordinary fortune.

105 “Both Japanese and Russians lost ships by mines and torpedoes in 1906, and ships will be lost in future wars in the same way, but I find it hard to believe that the essential character of fleet actions or of naval war generally can be affected by them. It seems indisputable that the future must be with the means of offence that has the longest reach, can deliver its blow with the greatest rapidity, and, above all, that is capable of being employed with the most exact precision. In these respects the gun is, and in the nature of things must remain, unrivalled.

“The two directions in which fleet-fighting seems likely to be most noticeably affected by the new weapon are in the formation of fleets and the maintenance of steady courses, and in making longer ranges compulsory.

“I think there are other reasons why the tactical ideal set out above—viz., that of using long lines of ships on approximately parallel courses at equal speed in the same direction—will be questioned; but even if there were not, that a mobile mine-field can be made to traverse the line of an on-coming squadron, and do so at a range of 10,000 yards, and that ships formed in line ahead offer between five and six times more favourable a target to perpendicular submarine attack than a line of ships abreast, will make it certain that sooner or later there will be a tendency in favour of smaller squadrons and, even with these, of large and frequent changes of course, and possibly of formation, so as to lessen the torpedo menace.

“In other words, we must recognize that in the long-range torpedo we have a new element in naval battle, that of the defensive offensive. It is defensive because, if the range of the torpedo is 10,000 yards of absolute run, its range is greater if fired on the bow of an advancing squadron by the distance that squadron may travel—3,000 to106 4,000 yards—while the torpedo is doing its 10,000. A very fast battle-cruiser, for instance, may have a speed only a few knots less than that of the under-water weapon. This means either keeping out of gun range of an enemy that is retreating, or taking the risk of torpedo attack. If you face the risk, you must be ready to man?uvre to avoid it.

“It looks, then, as if long-range gunnery and gunnery under helm were: the first, compulsory, and the second, inevitable.”

107
(LARGER)

THEORY OF DEFENSIVE USE OF TORPEDO IN RETREAT.

In the above sketch the black silhouette shows the position at the moment the torpedo is fired; the white silhouette the position the ship has reached when the torpedo meets it. In the upper sketch the ship is running away from the torpedo, in the lower one coming to meet it. The distance run by the torpedo is the same in each case, but the range at the moment of firing is 6,000 yards in the upper case and 13,300 in the lower