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Vol. 45, No. 5
Whole No. 195
THE BATTLE CRUISER
A great desideratum in building up a fighting fleet is economy in the expenditure of money and men. It is hardly to be expected that all such expenditures could be so made that all are represented in a general action, and one measure of the efficiency of a fleet is the percentage of the total expenditures that are then available.
There will always be special classes of vessels used for special purposes, which cannot be used for fighting, in a fleet action, and they will require men that are therefore not used in battle. There are, on the other hand, vessels that will always be valuable in a general action, such as the battleship, the destroyer, and the submarine-real fighting ships—and we might say that their crews are fighting men. How many of the others though are non-combatants?
Are cruisers fighting ships? To be sure, a cruiser will fight a cruiser or a vessel inferior to herself, but she is wasted capital in a general action, as she cannot inflict damage on a capital ship. The same may be said, to a large extent, of the battle cruiser; indeed it might be asked, is the battle cruiser intended to fight in a general action?
This is usually answered in the affirmative, and it is probable that the first intent was that the battle cruiser should be employed in a general action as a battleship, though of course in a special organization, such as a fast wing. That this is, however, the
present idea, is to be doubted, and that such ships, in action, can be considered as anything more than inferior battleships is open to question,
Cruisers have always been required for purposes other than use in a fleet action, and even in the days of wooden ships, when the only essential difference between the type used for fighting and the type used for cruising was a matter of size of ship and numbers of guns, the cruiser type was used strictly for the special work of its type, and was rarely employed in a general battle. It is likely, however, that this was due more to the fact that sufficient numbers of the type were never available, rather than to an idea that the type was unsuitable for fighting.
Modern cruisers, even the battle cruiser, differ in a much greater degree from the type that has been accepted as the most suitable for fighting in a general action, and it can hardly be denied that in an engagement of battleships the cruiser type, as exemplified by the modern scout, and to a less degree by the battle cruiser, could not be used for heavy work.
It becomes then a question how much money we can afford to spend for a type of ship that should be on hand in considerable numbers, and yet is not available to be drawn into the line of battle for work against the main body of the enemy fleet. In the long run, it always means that money expended on such ships means less money available for fighting ships.
It seems hardly necessary to argue that if all the ships used for scouting and screen purposes could also be effectively used in action against capital ships, their value would be greatly enhanced, and money expended to build them would be not only more wisely expended, but also more easily obtained.
Let us therefore examine into the reasons why the present ships of these classes are not fit for fighting capital ships, and see if some method cannot be suggested to overcome the handicap under which they fight.
The scout cruiser need hardly be investigated at all, since its weaknesses in action are well known. With no protection at all against the battery of a battleship, this vessel also lacks offensive power suitable for use against a capital ship. Its 6-inch battery need not be expected to make any impression on a capital ship, even at short range, and at long range it could not even reach.
With the battle cruiser the question is not so easily answered, although demonstration is not difficult. This vessel cannot be pitted against a battleship of her own date at close range, since she has insufficient protection against a battleship battery at short distances. Even under the most favorable circumstances the 5-inch belt will fail to keep out a 14-inch projectile, and the ship might, therefore, at short ranges, say up to 10,000 yards, be considered entirely unarmored, as far as a battleship battery is concerned.
It is also to be considered that the battle cruiser lacks a sufficient number of guns to fight on equal terms a battleship of her own date, and it will hardly be argued that she will nevertheless be useful against older ships. That is not the aim of naval design.
When we consider fighting at long range, the battle cruiser is not so hopelessly outclassed, though still, on account of the less numerous battery, at a disadvantage. Before going farther, it will be well to define the term long range. It might well be that at, say, 15,000 yards the armor of a battle cruiser will be relatively more effective; that is, the 5-inch belt will keep out a greater proportion of 14-inch projectiles at that 'range than it would at short range. On the other hand, the battleship armor also gains in effectiveness at such a range, and it can still be said that as compared to the battleship the battle cruiser is unarmored.
There is, for any kind of gun, a range at or beyond which the angle of fall is so large as to make a glancing blow on an armored deck practically impossible. This angle may be 30°, or it may have to be as great as 45°.. Then, if the gun has a sufficiently large caliber, penetration of the armored deck becomes possible upon a hit being obtained. It might be stated as a general proposition that for the calibers used nowadays and for the decks as at present fitted such penetration is practically sure with angles of fall of 30° or more. With angles of fall between 15° and 30°, penetration is more or less uncertain, and below 15° practically impossible.
If, then, we consider as long ranges those at which penetration through the armored decks becomes easily possible, when a hit is obtained, such ranges, with guns now used, must be more than, say, 16,000 yards, and in most cases must be well over 20,000 yards.
At such long ranges, the battleship is reduced to equal terms with the battle cruiser, as far as the decks are concerned, assuming that considerations of weight have made it impossible to give the cruiser the same weight of decks as is usual with battleships. This, by the way, is the weakest feature of the battleship, and with the present type it is most difficult, and one might almost say impossible, to fit decks strong enough to withstand plunging
It does not need to be pointed out that at such ranges the side armor of either type of ship is practically a negligible quantity, since the width of the target, in the line of fire, is, in the case of the deck, several times as great as in the case of the side belt. Thus, with an angle of fall of 30°, the target offered by the deck is about 100 feet in range, while that due to a belt 8 feet above water is but 14 feet. This is with the ship broadside on, and with any other presentation the difference is greater.
It has often been claimed for the battle cruiser that on account of her speed she can choose her range. That is quite true, but it is of advantage to her, leaving out of consideration a fight with an inferior ship, only to obtain and retain long range, and this seems to have been what was really meant, since the effort was made to give her guns supposedly able to outrange those of her possible opponents. It might here be stated that such outranging is not possible, except as we compare her with older ships, since, aside from the fact that in a contemporary design similar guns might be used, there is, in guns of about the same size, no great difference between their possible ranges at any given elevation, and there need be no limit to the elevation up to the point of maximum possible range, which is much beyond present necessities.
The speed of the battle cruiser, then, in a ship to ship action, is of advantage to her only to avoid close action, which must usually be disastrous to her, and to place her, as far as her protection is concerned, on a par with the battleship. It does not, however, overcome the handicap of smaller battery, so that, other things being equal, a ship to ship action between a battle cruiser and a battleship, both of the present type, must of necessity end in disadvantage to the former. Of course, speed gives the advantage of possible combination of forces against detached enemy units, but this would probably be against an already beaten enemy.
Long range, therefore, offers the only means by which the lightly armored battle cruiser can hope, in action, to give as much as she must take. It will then be in order to investigate the prospects such a vessel would have in such an engagement.
Although assuming equal skill on both sides, long range firing really requires less skill, except in spotting, than in the case of short ranges.
This is because the error in range due to a given error in elevation is much less at longer ranges, so much so that at extreme ranges, with high elevations, there might be several degrees error in elevation with no great error in range. It all comes down to a matter of skill in spotting and keeping the range. With equal skill, hitting at long range is entirely a question of chances, and is practically in accordance with the law of probability.
This being so, the question is at once seen to be one of the number of shots that can be fired on either side, in equal times. This also, since equal rates of fire per gun must be assumed, is reduced at once to the simple matter of the number of guns on the two sides, so that, where the battle cruiser has eight guns to the battleship's 12, it is readily seen that it will require at least three of the former to be on even terms with two of the latter, neglecting any superiority in fire control that is inherent in the superior fire concentration of the two battleships. Since battle cruisers cost twice as much as battleships, and require the same numbers of men per ship, it can hardly be said that building battle cruisers to fight battleships is an economical proposition.
Since the battle cruiser must fight a capital ship at long range, and since, at such ranges, vertical armor becomes so small a target as to have a very small chance of being hit, the idea seems to suggest itself to save money and displacement by omitting such side and other vertical armor, and indeed this seems quite logical. In action with a battleship at any range, it would seem that such armor' as can be carried would probably be penetrated if hit, and the only reason that might be assigned for carrying it at all is to prevent damage from the lighter guns of small craft, if the vessel were unexpectedly to find herself in close contact with such small craft.
This could not be called a logical reason, as the weight of armor to be carried would be a severe penalty to pay for the chance of accidentally or carelessly running into such an en