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 spread 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.
[Illustration: 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 hit 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.”
[Illustration: 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 of 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, placing
the target in a quarter. If an eighth of the bracket is less than the
danger space, then the fifth shot must hit.
[Illustration: 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 have 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.
[Illustration: 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 providing 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.
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 to 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 to 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 manœuvring 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 manœuvres 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 manœuvre, 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 manœuvring, it is small
wonder if methods 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 action 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.
“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
to 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 manœuvre to avoid it.
“It looks, then, as if long-range gunnery and gunnery under helm were:
the first, compulsory, and the second, inevitable.”
[Illustration: 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]