The following paper is the substance of a report made last April on a Model with Disappearing Turrets submitted to the Navy- Department by G. W. Van Hoose, Esq.
The idea of the possibility of interest in the publication of the report was first suggested by the bearing that the portion treating of the relative protection of the different elements of efficiency has on the method of estimating naval strength, of estimating the power or value of a vessel of war, as found in the author's paper on the Study of Coming War and in the discussion of the method.
The idea was further suggested by the interest evinced by officers in the subject of the relative exposure of the parts of a vessel, the probability of a particular part being hit in action by the projectiles of different calibers, and the effects of such hits on the efficiency of the vessel.
Some ideas found to be held currently are somewhat at variance with the conclusions arrived at, and some are unformulated, evidently from lack of data, and it was decided that these points, which are of such vital interest both for design, particularly in the distribution of armor, and for directing an engagement, should be further investigated and expanded into a paper which would omit the parts of the report of minor interest. But the pressure of current duties has prevented this investigation and offers little prospect for the near future.
In consequence, it has been decided to offer the paper for publication as it stands. Having been made thus only as incident to, or involved in the investigation of a particular case, the treatment of the broad subject alluded to, while comprehensive in scope, is only suggestive, not exhaustive in its nature.
I.
The model was presented by Mr. Van Hoose in person without any written statement, explanation, or description whatsoever, with the verbal request to the effect that the dispositions embodied and the principles and ideas illustrated be examined as to their utility for adoption on vessels of war.
In order to approximate to the nature of the request and to the extent of the claims, questions were put to and answered by the applicant as to the features, strategical and tactical, of the vessel represented by the model.
These questions and answers are given below. The answers and the explanation of the model demonstrated the fact that the pervading idea is the use of the disappearing principle in such a form that, combined with a flush upper deck, it will permit fire across the above deck positions when the guns are below deck, thus reducing the obstruction and increasing the effective angles of fire.
The method employed by the applicant to realize the ideas of the system is indicated only in outline on the model and was supplemented later by a sketch from patent specifications showing a modified form of barbette and a sectional elevation without dimensions, scantlings, details, or description of any kind. In his verbal description of the method, the applicant explained only the ideas adopted and expressed the desire that the details as found be not entered as part of the examination, as their purpose was only that of illustration. In consequence, a critical examination of the details of the method is not entered into at length, though it is shown that on the practical efficiency of the method and the perfections of the details will depend the entire value of the system.
In order to arrive at conclusions as to the utility of the disappearing principle in the form in which it appears, the features are examined as follows, namely:—
1. The sacrifice of the superstructure, entailed by the system.
2. The extent of the advantage gained in increase of power of the main battery and in increase of protection to guns.
In investigating the increase of protection to guns the question of the advantage to be gained by any increase is first considered, the method adopted being the investigation in usual systems of the relative protection of turret guns and of the other elements of efficiency, adequate protection to each element being the object sought. Then the amount of the increase realized by the system proposed over usual systems is considered.
3. Remarks on certain features inherent in the system and on certain features of the methods proposed by the applicant.
4. A summary comparison of the system in an ameliorated form with systems employed abroad on board ship.
5. Summations, conclusions.
II.
INTERROGATORIES.
GENERAL STRATEGICAL AND TACTICAL FEATURES.
Q. Speed?
A. Not specified.
Q. Endurance at a given speed?
A. Not specified.
Q. Type of vessel?
A. Seagoing battleship.
Q. Designed for engaging in squadron or in duel?
A. For both ; duel preferred.
Q. Main object?
A. To crush enemy by battery power.
Q. Best position for engaging—end on, on quarter, or abeam?
A. Any position ; end on preferred.
Q. Best distance for engaging—long range, moderate range, or close quarters?
A. All three; moderate range preferred.
SUMMARY DESCRIPTION.
Q. Principal dimensions?
A. Not specified.
Q. Displacement?
A. Not specified; supposed to be not less than 12,000 tons.
Q. Condition of stability and steadiness of gun platform?
A. Not specified.
Q. Apportionment of weight?
A. Not specified.
OFFENSIVE POWER.
I. Artillery.
Q. Heavy artillery?
A. Four 10" B. L. R. or larger caliber, in two armored cages, disappearing after firing to loading positions within two barbettes situated in center line of vessel, one forward and one aft.
Eight 8" B. L. R. or larger calibre, in four armored cages, disappearing after firing to loading positions within four barbettes situated two on each beam in waist.
Q. Medium caliber artillery?
A. Not specified; preferred to be developed as much as possible. The pieces—8 on the gun deck, 4 on bridge deck, 1 on each side of the cages of the heavy guns in center line and 1 between the two guns of each waist barbette—are all of undefined caliber.
Q. Light artillery?
A. Not specified other than four Gatling guns in two military tops of two masts that are raised and lowered, the top being housed below the upper deck and the guns firing from a position above the upper deck as well as in the raised position.
Q. Angle of fire.—For successive fire?
A. All heavy guns have an arc of practically 360 degrees.
Q. For volley fire?
A. In two volleys of short interval of separation all guns can bear in all directions. End on, the first volley brings to bear two 10" and four 8"; the second volley the same ; quartering fire, one volley brings whole battery ; beam fire, the first volley brings to bear four 10" and four 8", the second volley brings to bear four 8".
Q. Ammunition supply?
A. Nothing specified.
2. Torpedoes.
Q. Number of submarine discharging tubes?
A. Not specified.
Q. Number of over-water discharging tubes?
A. Not specified.
3. Ram.
Q. Ram bow?
A. Affirmative. Nothing further specified.
DEFENSIVE POWER.
Protection by Armor.
Q. For hull and stability by side armor?
A. Nothing specified.
Q. For hull and stability by deck armor?
A. Nothing specified, although it would have an armored bulkhead forward of forward barbette.
Q. For artillery and personnel?
A. For heavy guns, armored cages with heavy armor on their sloping faces and lighter armor on the sides, disappearing for the loading position, guns and cages, into fixed barbettes of heavy armor. Nothing further specified.
Q. Protection by subdivision ?
A. Nothing specified.
Q. Protection by coal ?
A. Nothing specified.
Q. Protection by empty spaces?
A. Nothing specified.
Q. Protection by nets ?
A. Nothing specified.
STRUCTURAL FEATURES.
Construction.
Q. Form of lines?
A. Nothing specified.
Hull.
Q. Internal arrangements, position of boilers, engines, coal bunkers, ammunition rooms, quarters, berthing, etc., etc.?
A. Nothing specified.
Q. Upper works?
A. There are to be no upper works, other than a bridge and boat cradles built on three or more skid beams.
Q. Ventilation, drainage, lighting, etc., etc.?
A. Nothing specified.
Hull Fittings.
Q. Rudder, steering gear, anchor gear, boat gear, torpedo net gear, etc., etc.?
A. Nothing specified.
Q. Masts?
A. Two or more military masts to be raised from housed positions below the upper deck to fighting- positions by appliances, using any sort of power, and to be secured in the fighting positions by stays and guys. Nothing further specified.
Propulsion.
Q. Indicated horse power?
A. Not specified.
Engines.
Q. Number, type, disposition, distinctive features, etc., etc.?
A. Nothing specified.
Boilers.
Q. Number, type, disposition, distinctive features, etc., etc.?
A. Nothing specified.
Screws.
Q. Number, type, disposition, distinctive features, etc., etc.?
A. Nothing specified. The model has three four-bladed screws.
Summing up the answers, the applicant intends the model to represent a seagoing battleship of large displacement. The battery of heavy guns is to be highly developed, their effective power is to be increased by increasing largely the arc of fire, to which end all upper works are sacrificed, and the guns are made to be able to disappear within barbettes below the upper deck after firing so as to leave the field unobstructed for other guns. The military masts are also made to disappear below the upper deck. In this manner, by firing in turn, each gun can be brought to bear over the whole horizon, and the barbettes are so grouped that, for certain points on the bows and quarters, all guns can be brought to bear simultaneously.
While increasing the arc of fire of other guns by disappearing below the upper deck, the heavy guns are intended to increase their own protection by lowering into barbettes, reducing the time of exposure to direct fire to the interval necessary for training and sighting and during this interval protection of the breech against rapid-fire guns is afforded by cage armor, with the increased thickness of armor on the front sloping face.
The general disposition by which these objects are represented to be accomplished is shown in sketches of the model Figs, 1, 2, 3. The ratio of beam to length is 5 to 1; the ratio of beam to draught 2.8 to 1, the ratio of freeboard to draught 1 to 1.485. The same ratios for the Iowa are 5 to 1, 3 to 1, and 1 to 1.354, respectively. The proportions are good ; and as a piece of workmanship the model shows a skill and ingenuity remarkable under the circumstances under which it was made.
The features which render the carrying out of the model as it stands impracticable if not impossible—such as the disposition of rapid-fire guns along with heavy guns—will not be discussed, as it is evident from the answers above, the applicant's object in making and submitting the model was not to offer a model for a design, but to offer simply an illustration, in concrete form, of a method of increasing the effective power and efficiency of the main battery, by increasing the angle of fire and the mean security of the heavy guns.
To this end, two distinct dispositions are employed : First, the disposition of a flush upper deck without any superstructure or upper works of any consequence that would obstruct the angle of fire ; second, the use of disappearing mounts, by which the heavy guns, after firing, can be made to sink into armored barbettes below the level of the upper deck, leaving the field unobstructed for the fire of other guns and realizing an additional security during the period of loading.
Upper works have been sacrificed to arcs of fire in degrees varying from the least to the greatest in war vessels of nearly every maritime power, while disappearing guns have been mounted in five vessels, four Russian and one British. Sketches Figs. 4 and 5 show the disposition on the three recent Russian battleships, the Catharine the Second, the Tchesme, and the Sinope, launched in 1886 and 1887. Fig. 6 shows the disposition on the Russian circular coast-defence vessel, the Vice Admiral Popoff, launched in 1875. Figs. 7 and 8 show the disposition on the British battleship, the Temeraire, completed in 1877. On the Catharine the Second class, the six 12" guns are mounted in a single armored redoubt. On the Temeraire the two barbettes are situated at the extremities with upper works intervening, not shown on the profile sketch but indicated on the plan, which allows the disappearing gun to realize only the moderate angle of fire of 240°. On the Vice Admiral Popoff the two disappearing guns are mounted side by side in one position. In each case the guns are raised only high enough to clear the top of the encircling armor. In none of the cases is the disposition made for firing the heavy guns over the barbettes, redoubt, or pit, into which the guns sink. The only objects sought in adopting the disappearing principle are the increase of protection and the saving of weight.
The model represents, as far as extensive research has disclosed, the first disposition where the disappearing principle is designed to clear the field of guns during the process of loading in such a way as to permit unobstructed fire across the space occupied by them in the firing position, the deck being cleared of other obstructions, to realize thus the double purpose of increasing the effective angles of fire of the heavy guns, and, at the same time, of increasing their protection.
III.
In order to realize the advantage of this novel feature, it is first necessary to clear the deck of obstructions. The superstructure must be abandoned with the mounts it furnishes within and on top for pieces of the secondary battery and housed space available for quarters, berthing, etc. Incident to this measure there would be a gain of weight and an increase of stability, depending in amount on the weight and position of the objects removed. It would further reduce the area of the target offered by an amount depending on the dimensions of the superstructure.
On the other hand, it would increase the period of roll and consequent steadiness of gun platform by an amount depending on the weight and position of the objects removed. It would reduce the secondary battery by an amount depending on the number and importance of the pieces whose mounts were swept away. In many cases, the loss of power of secondary battery would be so great as to be altogether inadmissible, not only because of the heavy reduction in power of offense against unarmored and lightly armored vessels and parts of armored vessels, but also because of the serious reduction of power of defense against the attack of torpedoes, now so widely carried by unprotected but swift vessels.
In the case of the Indiana, the loss would comprise all four of the 6", and fourteen out of eighteen of the 6-pdrs., practically an annihilation of the secondary battery, which would reduce the role of the battleship to that of a coast-defense vessel unfitted to approach within radius of a hostile torpedo flotilla.
The secondary battery, being indispensable and being swept from the level of the heavy guns, must find mounts below this level, or else above it on objects not swept away, which can carry mounts for only light calibers. This would lead naturally to a developed gun deck battery which would necessitate a deck more of freeboard, increasing thereby the hull weight and the size of target offered and necessitating higher barbettes which must extend from the upper deck to the armor deck, increasing thus the weight of armor. The result would either be a serious decrease of weight and consequent reduction of efficiency of other important elements, or else a considerable increase in displacement with consequent increase of cost. It would change the Indiana into an Iowa with her upper deck extended to the stern, permitting an increase of power of secondary battery and necessitating an increase of her displacement and cost.
There might be a condition in which the necessity of a gun deck and the incident advantages just cited could be avoided. The guns of the secondary battery, instead of being lowered to the distance of the gun deck, could be left still to fire over the upper deck, if they were within light turrets similar to those adopted on .recent French battleships, the platforms of the turrets being below the level of the deck and the gun a short distance above this level. The rise of the heavy guns above the deck would have to be somewhat increased so that they could fire over these turrets without danger of injuring them from the blasts, measures being taken to prevent depression when firing in the line of the small turrets sufficient to hit them. Guns of lighter caliber swept away could be mounted higher on the bridge, which could be supported in a developed form with chart-house by smokestacks and masts. The boats whose cradles would be swept away with superstructure, could be carried on skid beams assembled and secured by bolts which, before action, would be unrigged and sent below, the boats being put overboard. The conning-tower would have to remain the sole obstruction, offering a conspicuous and exposed target, or else it would have to descend to the level of the small turrets just described, with the necessity of having a portion of the horizon cut off by the heavy guns while in the firing position. With the conning-tower placed well forward of the forward turret, with perhaps a second one aft, abaft the after turret, this disposition would incur but slight objection on this score, offering a better view than the usual disposition within the horizon of an engagement, a view obstructed only in the rear and then only intermittently by the heavy guns. A conning-tower consistent with this condition would be one that could rise and fall like the turrets ; or, if not the conning-tower proper, an armored tube large enough to contain one or more men with an apparatus for communicating to the conning-tower proper.
Thus, for battleships, the disadvantages incident to the sacrifice of the superstructure and the removal of the objects of obstruction above the upper deck in order to have the deck flush and clear for the disappearing guns, though serious, are not, on the whole, without the possibility of partial remedy. In many cases they are not of serious consequence. This first measure, necessary to the realization of the advantages sought in increasing the effective angle of fire of the heavy guns, does not present insuperable obstacles.
For coast defense vessels, which have less need of a developed secondary battery, the disadvantages and difficulties are less serious than for battleships.
IV.
With a flush unobstructed deck, the minimum total angle of fire gained for each gun by the disappearing system proposed is the sum of the angles subtended by the turrets of other guns. As a matter of fact, a shot would never be allowed to be fired so that the circumference would pass tangent to a turret.
The absolute minimum of a gain would be the sum of the angles subtended by the turrets plus the angles subtended in each case by the caliber of the gun firing placed at a distance equal to the distance of the point of tangency from the gun.
Where the guns of the two turrets are on the same level it would not be safe to allow the projectiles to pass within the circle swept by the muzzles of the guns of the turrets in question. Assuming that the gain is only the sum of the angles subtended by the turrets in the case of guns on different levels, the least favorable assumption, and that it is the sum of the angles subtended by the circles swept by the muzzles when the guns are on the same level, the total gain in usual cases would be large even with the best disposition of the turrets. On the Iowa, the sum of the angles subtended by turrets for the guns of a 12" turret is about 35 degrees; the dead angle as now provided being about 90 degrees. The sum for the guns of an 8" turret is about 95 degrees, the dead angle being 195 degrees. When the circles swept by the muzzles are taken instead of the turrets for the cases of guns on the same level, the sum becomes 90 degrees, the total dead angle, for the forward 12" guns, and 165 degrees, of the dead angle, for all of the 8" guns, the forward 12" and all of the 8" guns being on the same level, which indicates that in reality the presence of a superstructure would add but little to the dead angle.
The effective gain would practically be in each case the dead angles, 90 degrees for the 12" guns and 195 degrees for the 8" guns. Assuming that the angles gained are of equal value with angles of the other bearings, that angle of fire is of uniform importance around the horizon, an assumption that will not be discussed, being of sufficient accuracy for the purpose of the present comparison, the proposed system would add practically 1/3 to the effective angle of the 12" guns and practically double the angle of the 8" guns. Take muzzle energy as the comparison between the two calibers. The four 12" guns in a single round aggregate 4 X 26,000 ft. tons, equals 104,000 ft. tons, and the eight 8" guns in a single round aggregate about 8 X 8000 ft. tons, equals 64,000 ft. tons. The relative amount of energy in a single discharge is as 13 to 8. Taking one minute and a half as the interval between the rounds for the 8", and 3 minutes as the interval for 12" guns, then, in a given length of time, sufficiently long, the total muzzle energy generated by the two batteries would be in the proportion or 13 for the 12" battery and 16 for the 8" battery. This is the relation of the quantities of offensive energy generated. To make the comparison more complete, a factor representing the relative qualities of the two energies should be introduced. This factor would vary in each engagement with the nature of the target, depending upon its relative vulnerability to hostile energy in the form of 12" projectiles and 8" projectiles in movement. It will be sufficiently accurate for the present purpose to assume that the average target with which the vessel is designed to engage is equally vulnerable to the two kinds of energies, that the quality of unit quantity of energy is the same for both batteries.
V.
Increase in protection and not increase in angle of fire was the object that gave birth to the disappearing mount. The birth took place on shore about a century ago and was produced by the increase in accuracy of fire which necessitated improvement in the methods of gun protection, for the guns, being the main elements in the infliction of injury, the immediate object of battle, and being mounted usually in commanding positions, form the most important target for the concentration of hostile fire. These improvements took the form of minimum embrasures and disappearing mounts. On a disappearing mount, the gun is in view of the enemy only in the firing position. After firing, it disappears into a position more or less secure, where it remains during the process of loading and now usually during the process of pointing, the object sought and partially realized being the reduction to a minimum of the time of direct exposure. The security of the housed position is realized by the use of earth, masonry or armor, or a combination of these means, with or without the additional security of invisibility. The security is practically perfect where the gun disappears behind or under unbroken covering that gives no indication of the spot. Where such conditions can be realized, the advantage of the disposition is overwhelming ; the enemy has no target, he may not have the range, and he cannot accurately keep the bearing. A few years ago, a dummy 10" gun was mounted on a disappearing carriage off the coast of England and was made to rise and fall at regular intervals giving out a puff of smoke like a gun in action, while it was fired on by all the battery that the battleship Sultan could bring to bear and it was found that absolutely no effect could be produced, though the conditions were most favorable for the attack.
Thus ashore the disappearing principle has decided military advantages, and the inherent practical difficulties of the mount are not of great importance. In many cases, like the one just cited, in particular those of batteries covering sea approaches, where the guns can be scattered and where no objects would indicate the positions of the gun pits, where the enemy as a rule, will lack guns adapted to oblique fire, the only fire to which pits are seriously exposed, even in the case of the enemy possessing accurate knowledge of the range and bearing, in these cases, the advantage of the disappearing principle is so pronounced as to insure practically a perfect defense, without the expense of armor, having a sea-borne enemy at a hopeless disadvantage, exposed to injury and powerless to inflict it in return. When, however, the position remains visible, forming a permanent target, the conditions change, and the methods of defense common to other mounts, earth, masonry and armor, must be resorted to. When the position is vulnerable and its welfare is essential to the gun, conditions can be imagined where it might be more advantageous for the gun offering a small target to remain in sight and invite fire, much of which would pass over, which, if aimed at the position, would strike it. The value of a vessel of war, as measured by her power to inflict injury, depends on the power of her weapons and on her power or ability to use them. Moreover, it results from a product of these two interdependent elements, which is greatest when both elements are large together. It would be needless to have powerful weapons, if use could not be made of them. The power to use the guns of a vessel in action will depend on the power to maintain alike their own integrity and the integrity of the platform that carries them; will depend alike on the protection afforded to guns and their crews, and the protection afforded the hull. It would be useless to have well protected guns if the vessel sank or turned over, or changed trim, or heeled to such an extent as to render their use impossible. It would be unwise to overprotect the guns and underprotect the hull, or vice versa.
With turret guns as usually mounted on battleships, the breech, including about ½ the length, is protected by heavy armor. When pointing at right angles to the angle of fire, the breech may be said, in the comparative sense adopted, to be perfectly protected. When pointing in the direction of the line of fire it is exposed to projectiles that may enter the gun ports and explode.
If the breech plug were closed at the time of explosion, the breech proper being cylindrical in form and fitted and held to the platform by straps, not trunnions, could stand heavy impact from fragments of projectiles without being seriously injured. If the breech were open and a shot or fragment struck the breech plug it would be disabled without doubt. On the whole, the breech of the gun is but slightly vulnerable. At the Yalu, a fragment, entering under the hood and deflected downward, killed the whole crew, but did not affect the guns.
The chase of the gun is exposed in the open, including about one-half of the total length. A shot from a gun of the calibre, striking normally, would probably disable the gun, but the form is cylindrical, and when struck in a line deviating from the radius of a section, offers an oblique surface of large resistance, the obliquity increasing rapidly as the direction of the impact varies from the radius. Further, a considerable indenture could be cut in the wall of a gun without disabling it, the strain in a longitudinal direction on a cross section being small.
Guns being now mounted in beds and strapped to the platforms, not as formerly on trunnions, a shot would strike the chase with considerable force and leverage without springing the securings of the gun. On the whole, the chase of the gun, though more vulnerable than the breech, could receive large punishment without disabling the gun.
In the Yalu the chase of a gun of moderate caliber was struck near the muzzle by a projectile from the secondary battery without disabling the gun or interfering with its fire.
Figure No. 9 represents the results of target practice with the 6" guns in the U. S. Navy at ranges from 1000 to 1500 yards on the following vessels : Atlanta, Baltimore, Bennington, Boston, Charleston, Chicago, Concord, Newark, Petrel, San Francisco and Yorktown. The total number of shots fired was 340.
If a gunport of a 13" turret had been the target, twelve shots would have struck it. The probability of a single shot striking was thus 12/340 = 1/18.
If the center of the chase of a 12" gun as protruding from the turret had been the target, twelve shots would have struck it. Of these twelve, four striking obliquely at an angle of less than 30 degrees may be considered as ineffective ; eight may be considered as effective, and the probability of a single shot being effective is 1/42.
If the center of the turret had been the point aimed at with the guns at right angles, the chase of the gun, if pointing to the left, would have received four shots, if pointing to the right, one shot, of which total two would have been ineffective, giving a mean probability of the chase being hit effectively of 3/340 = 1/113.
Thus the gun as a whole, with the chase exposed to fire from direction perpendicular to the line of fire and the gun ports exposed in the direction of the line of fire, offers a target of small dimension, and, in the case of the chase, disposed horizontally in the most advantageous manner. Thus the gun proper is only moderately vulnerable, and has small probability of being struck effectively.
The carriage and platform and their gear, including the elevating gear and loading gear, and mechanism for controlling the training gear and ammunition hoist, below, are exposed in the same manner as the breech to fragments of projectiles entering the gun ports and exploding, and their vulnerability is greater than that of the breech of the gun, though in the case occurring at the Yalu, cited above, none of their gear was disabled.
The gun's crew assembled around the breech is exposed in the same way, and is more vulnerable. All its members were killed in the case cited. On the other hand, the number of the crew is small and if the precaution has been taken beforehand of training other men in the duties, the crew or part of it can be replaced.
This assemblage of objects near the breech of the gun presents by far the most vulnerable feature, though they can be reached only by projectiles entering the gun ports. These projectiles are not limited in size ; the smallest R. F. projectile entering and exploding could inflict irreparable injury, while, if it struck the chase of the gun, it would be without effect. It might be pointed out at this point that the gun ports as now fitted, for the reason just mentioned, are most dangerous targets, but shields carried externally could be devised, which, while moving with the gun, would effectually close the openings.
The fixed part of the turret extending to the armor deck, properly covered above by a platform of sufficient thickness to catch fragments, and without connection with the objects inside, so that bulging or displacing slightly will not affect the objects inside, offers a perfect protection (speaking in the comparative sense) for the supports of the movable parts of the turret and for the ammunition tubes, while the training gear if properly placed below the armor deck would enjoy a similar protection.
Thus 12" turret guns on a seagoing battleship, considered as a whole, from the point of view of protection, present a vertical cylinder extending from the armor deck to the top of the movable turret, a vertical target of a total area of 750 to 800 sq. ft, in usual cases, which is completely protected over its whole surface except at the gun ports which present two elliptical areas of about 12 sq. ft. each, with a vertical diameter of 4' 3", together an area of about 1/32 of the total area of the vertical target. This area is of a most vulnerable nature, though the vulnerability could be reduced if not entirely annulled by the fitting of port shields. This cylinder carries in addition, when the guns are trained perpendicularly to the line of fire, a horizontal area about 20' long, 20" high at the outer and 40" at the inner end, making a target of about 30 sq. ft., about 1/25 of the whole area, of partial or moderate vulnerability and small probability of being struck effectively.
Thus on the whole, assuming that the gun ports are protected by shields, the system composing the heavy turret guns, their fittings, and accessories, is well protected, offering but very small vulnerable areas, with slight probability of being struck effectively.
VI.
To serve her function the vessel must float, must maintain her floatability against the intrusion of water. This can be done by protection against the opening of breaches through which water might enter and by the reduction of the quantity of water that would enter a breach, or a number of breaches if made.
Water can enter by steady flow only through breaches that are made below the water level. It can enter by swash through breaches above the water line, but near it, the nearness varying with the condition of sea.
Since projectiles cannot reach the vessel below the water, protection against them, as far as floatability is concerned, could be secured if armor of sufficient thickness could be worked on the sides over the region liable both to attack by being emerged and to intrusion of water by being immersed.
A vessel of 70' beam, rolling 20°, a roll common in seas where engagements would be entered into, assuming for simplicity that she is wall sided in the region in question, would emerge on one side points that were 12.7' below the surface of the water when on an even keel and would immerse on the other side points that were 12.7' above the water line. With a 20° roll, the region thus exposed to injury at one time and to submersion at another on the vessel in question would extend over a height of 25.5' from end to end. On vessels whose side armor is best disposed for protection of floatability, extending in complete heavy and light belts, the region protected by heavy armor extends from about 4.90' below the L. W. L., to about 1.65' above, and the region protected by the light armor, from the top of the heavy belt to a mean height of about 3.9'. Of the total height exposed on the above supposition, .255 is protected by heavy armor and .153 is protected by light armor, .592 being unprotected.
The portion behind heavy armor cannot like objects behind turret armor be considered as perfectly protected, for the armor tapers to less than half the maximum thickness, which is about the same as the uniform thickness of the turret armor, from the upper to the lower edge, and from amidships to both extremities, while the mean surface of impact will on the whole be much less oblique than that of the turrets. The region covered by light armor is not protected against breaches from guns of medium caliber.
The parts covered by neither heavy nor light armor, .59 of the total, are exposed to breaches being made by projectiles of all calibers and may be expected to be riddled by those of small caliber in an engagement of any length with an enemy of creditable marksmanship.
Thus, on the whole, on the supposition of a 20° roll, the vessel's floatability is exposed to breaches which would allow the intrusion of water over an enormous area along the total length, of which only ¼ is protected by heavy armor and less than 1/6 by light armor, the protection from which is only partial. The Iowa on the supposition of a 20° roll offers a total surface of 8925 sq. ft, of which 1946 sq. ft. are protected by heavy armor, 555 sq. ft. above and 1391 sq. ft. below the L. W. L., 779 sq. ft. are protected by light armor, and 6200 sq. ft. are without protection.
This supposition of a 20° roll is but moderate. A battleship is expected to give battle in conditions of sea where water mounts much higher on the sides than in a roll of 20° and where actual rolling may occur exceeding this angle.
The conditions are of course less severe where the sea is more moderate, and could be assumed much less severe for coast defence vessels.
The quantity of water that will enter a breach or number of breaches can be reduced by causing the breach to close wholly or in part, by subdivision, and by the presence of water excluding materials.
The use of mats and plugs to close breaches in metal vessels can be considered, at best, but slightly practicable.
The use of materials which, swelling from the effect of water, tend to close the breach is of questionable efficiency, and is limited in its application to a small region covering from | to | of the height of light armor in the case above cited.
Subdivision is the most effective way. It reduces the quantity of water by diminishing the space to which a breach in the side may give access.
The total space may be considered as divided horizontally into two distinct parts. Water entering on one side of the armor deck is accepted as limited to that side only if so desired. After an engagement of consequence has lasted some time this subdivision must be considered as incomplete, particularly now that the armor deck is subject to contact explosion of projectiles carrying high explosives or large charges of powder entering at an angle above the side armor. The horizontal subdivision by other decks and platforms can be considered at best as only partial.
The vertical subdivision by transverse and longitudinal bulkheads is highly developed below the armor deck. Above this deck it is but slightly developed (the case in question being a battleship as above) and includes the cofferdam above the heavy armor, which is used with or without the obturating material for closing breaches.
The effect of a breach in the side from a projectile above or a torpedo below water on the subdivision in that region will vary, but in each instance the resistance of the thin plating of bulkheads even to fragments of small dimensions is very slight. Access will be made not only to the compartments in which the breach is made, but also to other compartments in the line of the trajectory of a projectile not exploding, and to all compartments in the neighborhood in the case of a projectile exploding, except where the explosion occurs in coal, which, when well placed, covers in varying thickness part of the top and the whole of both sides of the space devoted to motive power.
The floatability of a well planned battleship will not be destroyed by the filling of the two largest compartments, but her efficiency would be greatly reduced, the plane of floatation being considerably altered, reducing the reserve buoyancy, the stability and the efficiency of the battery and the motive power. It would cause a sinkage sufficient to submerge the top of heavy armor belt.
Further, the efficiency of subdivision will always have a coefficient of reduction depending on the efficiency of the personnel and the fittings for guaranteeing the bulkheads against the openings that are made in them.
A third cause reducing the quantity of water that may enter flooded compartments is the presence of other materials which exclude their own volume from the volume accessible to water. On battleships, light materials for this special purpose are carried only on the unarmored ends, above the armor deck. The obturating materials of the cofferdams also serve this purpose, and the coal as usually stowed preserves about 7/10 of the volume it occupies. In all three of these cases the subdivision of the space is more or less minute. Whereas, the large compartments whose flooding would be most serious cannot be stowed with water excluding materials.
Against the ram and torpedo, armor protection is not practicable. Destruction or avoidance of the agent is the only method. As the range is zero for the ram and as the guns to which the agent is vulnerable at short ranges are not likely to be found out of action, the probability of being rammed under normal circumstances is small. The probability of being torpedoed on the other hand is greater as the range of the torpedo may be considered at the extreme as 1000 yards. Though the accuracy of fire is small, the agents may be numerous.
These agents as a steady target would be most vulnerable to the fire of the smallest caliber of R. F. guns, but their diminutive size and swiftness may afford comparative protection under certain conditions of attack notwithstanding the development of the secondary batteries and the use of the search lights, and the use of torpedo nets.
Experiments in Italy go to prove that three thicknesses of plating spaced apart, are insufficient to overcome the effects of torpedo explosion. The outer and inner bottom and the wing longitudinal bulkhead will be inadequate, notwithstanding the fact that the wing passage is left empty so as to transmit as little as possible of the force of explosion, and the probability is that the large compartments in wake of the explosion, unless fitted with two wing longitudinal bulkheads, would be flooded and endanger the floatability.
Though, under normal circumstances, the probability of being torpedoed is small, and the probability of being rammed is much smaller, the consequences in each case are most serious.
In sum, the first requisite, floatability, is at best but partially protected. It is in greater danger than the heavy turret guns. The probability is, that the most efficient type of battleship yet afloat while engaging under the conditions for which designed, if stability is not destroyed previously, will sink before all her heavy turret guns are disabled, the turrets having been supplied with port shields.
If additional cost and weight are available for protection they would be more efficiently expended in increasing the protection of floatability by increasing the area above the water line protected by light armor and by increasing the power of the secondary battery against torpedoes, than by adding to the protection of the heavy turret guns.
VII.
To serve her function a vessel must not only float but must float right side up. Integrity of battery and floatability would be maintained in vain if the vessel turned over.
Stability like floatability is overthrown by the intrusion of water.
Water entering in any part will cause sinkage and reduce the freeboard and the range of stability particularly when it causes an initial heel causing capsizing at a smaller angle of heel, but entering in particular parts under certain conditions its effects are serious and pronounced in another way by influencing the quantity or amount of stability within the reduced range, affecting the righting arm, the magnitude of the upsetting moment required to cause a given heel.
This result is produced by the effect on the position of the center of buoyancy, on the length of the metacentric radius, on the vertical position of the center of gravity of the vessel, and on the shifting character of the weight added, the first two affecting the position of the metacenter, the last two the position of the center of gravity, the sum of all effects being the influence on the metacentric height.
The position of the center of buoyancy will probably not vary greatly. The compartments liable to be opened up to the sea will probably not be found, on the whole, to vary far in vertical position from the center of buoyancy found at about f the mean draught below the load water line. On battleships with unarmored ends, the riddling of these ends will cause the center of buoyancy to be lowered, but on the other hand the gain of buoyancy by sinking to balance the loss of buoyancy by the filling of low compartments will raise the center. On the whole, the change in position of the center of buoyancy is but a small element in the probable reduction of metacentric height. The means of safe-guard are the same as part of those for floatability; an increase in the protection of the upper compartments by increase in extent of light side armor.
The reduction in length of metacentric radius will be in direct proportion to the reduction of the moment of inertia of the water plane and to the increase in the volume of displacement.
The accumulation of water in the course of an extended engagement may materially increase the volume of displacement, but the effect is not so serious on this score as it is in diminishing the reserve buoyancy and reducing the range of stability.
The effect depends as for floatability on the amount of water that enters ; the inadequacy of the protection is best remedied as in the case of floatability by increasing the extent of light side armor.
The probable reduction to the moment of inertia of the water plane in an engagement is most serious. This is the largest factor that enters to determine the range of stability and the amount of stability in this range ; it is the great reduction in the moment of inertia of the water plane caused by the edge of the deck going under or otherwise, that causes capsizing in the usual cases.
If the vessel floated on an even keel in a smooth sea, the danger would be very small except in the cases of battleships whose belt armor is of limited extent leaving large portions of the water plane on the full ends exposed or only partially protected by the presence of water excluding materials.
But when the vessel rolls even slightly, about 3°, her heavy belt is submerged and the actual water plane has only the protection of the light belt, which in English types extends in the form of box armor but a limited distance amidships. The light belt is submerged in vessels with complete belts at the moderate roll of 9°, and above its top the water planes have no protection. Here the vessel's sides will have breaches made by projectiles of all calibres, the effect being most pronounced on the side opposite the side struck, where fragments tear off great lengths of plating.
Thus after a prolonged engagement the vessel on rolling will reach at moderate angles points where the moment of inertia of her water plane will be seriously compromised.
Thus the length of the metacentric radius is but partially protected for angles of roll caused by an ordinary sea swell, and is but slightly protected if not altogether unprotected for angles liable to occur in moderate seas in which battleships are expected to engage.
Amelioration lies along the line of increase of extent of light side armor.
The vertical position of the center of gravity of the vessel will be affected by the quantity of water that enters and its vertical position after entering.
Remarks on quantity of water liable to enter are given above in the consideration of the subject of floatability.
The vertical position of the water will depend on the position of the opening through which it enters and the disposition made of it after entering.
Openings are liable to be made below the armor deck by torpedoes and can be made as above mentioned, by projectiles piercing the heavy belt or entering below the heavy belt when the lower edge is emerged in rolling, which occurs ordinarily at about 8 ½°, and by fragments projected downward in the blast of projectiles containing high explosives or large charges of powder, exploding in contact with armor deck. It is not likely that such openings below the water line will be stopped in action and in consequence the compartments flooded may be considered as permanently flooded, it not being practicable in most cases to drain to other compartments or pump out while the openings are unstopped.
The position of the water entering below the armor deck may thus be considered as fixed and its effect on the center of gravity of the vessel, which is usually in the vicinity of the load water line, is to lower it.
Openings above the armor deck made through light armor and in the unarmored sides are liable to only intermittent flooding due to immersion from the rising of waves on the side and from rolling. Water is thus able to collect on the armor deck and on the berth deck and gun deck.
The quantity that enters will depend almost wholly on the condition of the sea and the rolling properties of the vessel. For water entering and collecting on the armor deck near the water line, the breaches will be less pronounced, less numerous and more easily closed or partially closed than water entering above a higher deck, but on the other hand they will be more frequently and for longer periods under water ; but being a shorter distance above the center of gravity, this water will have a less marked effect in raising the center. In both cases the quantity can be rapidly reduced by an efficient system for clearing the decks, from the gun deck through scuppers or special ports overboard, from the armor deck through special non-return valves overboard or else through a special system of pipes leading to special compartments in the bottom of the vessel, in communication with the pumps, which latter arrangement causes the water entering above the center of gravity to pass below it.
On the whole, the water entering the vessel, even when the engagement is in a seaway, when the arrangements for clearing the armor and gun decks are efficient, will tend to lower the center of gravity.
Water on board is liable to affect the horizontal as well as the vertical position of the center of gravity. Under the influence of gravity it tends to flow toward the side of the roll or heel and increase their amplitude and danger.
It may be looked on as causing the center of gravity under heel to move out toward the center of the buoyancy, reducing the righting arm, or as an upsetting moment that sets in. The effect is proportional to the quantity of water multiplied by the horizontal distance through which it shifts.
The quantity of water liable to enter is considered above.
The longitudinal subdivision below the armor deck will prevent extensive shifting of water except in the case of large compartments partially filled.
On the armor deck partial and complete longitudinal bulkheads or simple "barrages" are or can be fitted to reduce the shifting. On the gun deck usually no means are provided, and accumulation of water on the deck endangers the stability.
In an ordinary case of a battleship of moderate size, water accumulating to a depth of 6" on the gun deck by running over to the side of the roll will deduct about 10" from the righting arm, or 2/3 to ¾ of the maximum righting arm.
In the intact condition this reduction would cause the righting arm to disappear and the vessel to capsize at lo or 15 degrees less angle of heel or roll.
In an engagement in anything like a heavy sea, this element becomes serious ; large quantities of water are liable to collect on the berth and gun decks, and, flowing from side to side without obstruction, to endanger the righting arm at large angles, particularly in the rolls to leeward, where the wind would superpose an additional upsetting moment.
The entering of water on one side below the armor deck, though not shifting, would materially affect this element of stability by causing an additional upsetting moment, an initial heel to the side bilged, reducing thus the range of stability and the effective righting arm during the roll to this side.
This effect could be partially remedied by the admission of water on the other side, but it would be at the expense of reserve buoyancy and the other elements affected by the admission of water in the region in question.
In sum, the protection to stability is partial at best, the two elements, loss of inertia of water plane and the accumulation of water on the armor deck and decks above the armor deck, becoming of increasing consequence as the sea rises.
Taken altogether, for all seas in which a battleship is expected to engage, the protection to stability is less than the protection to turret guns. In an engagement in a moderate sea, under ordinary conditions, the vessel would capsize before all the heavy turret guns are disabled, and where the vessel is of somewhat low freeboard, and efficient means are not provided, and used for clearing water from decks above the water line, and transferring it from one side to the other, where practicable, or flooding other compartments to counteract the heeling effect, under these conditions particularly when the sea is running at all high, the probability is that the vessel would capsize before foundering.
If additional cost and weight are available for protection, they would be more efficiently devoted to increasing the protection to stability, by increasing the extent of light side armor than to increasing the protection to heavy guns.
VIII.
The admission of water will almost invariably be unsymmetrical, and will cause heel and change of trim, affecting thereby various elements of efficiency. The extreme elevation of turret guns as usually mounted being 15° and the extreme depression 5°, a heel to one side of 5° would render it impossible for guns training toward the opposite side to attain a point blank range.; a heel of 10° would cause these guns at extreme depression to fire over any vessel engaging at moderate ranges ; a 15° heel would make these guns wholly unserviceable, while the gun on the side of the heel could then only attain an elevation for point blank range.
A heel of 3° would submerge the top of the heavy belt, and a heel of 9° will submerge the top of the light belt. A heel of about 8 ½° will emerge the lower edge of armor.
Thus only moderate angles of heel will materially reduce the efficiency of the battery, and will reduce the protection to floatability and stability, and even expose permanently or periodically all the vitals.
Change of trim will reduce the efficiency of protection to both ends and will affect, in a less marked degree than for heel, the efficiency of the battery. Both heel and change of trim will reduce the speed by increasing the resistance and reducing the efficiency of the screws. They will ordinarily occur together and the total result when pronounced becomes particularly serious in the reduction of stability.
IX.
The protection of what may be called the vitals, the parts containing the elements of mobility, of governability, and the substances of explosive character, situated below the armor deck, has been involved in the consideration of protection to floatability, stability and uprightness.
The weakest point in this protection in all battleships except those recently designed in France, is the lack or insufficiency of provision for catching fragments caused by the explosion in contact with the armor deck of projectiles containing high explosives, or large charges of powder. Experiments in Italy have shown that the armor deck is shattered in the region, and that the fragments of the deck are projected downward with high velocities, which simple plating cannot check.
To protect the objects below, a heavy splinter deck or second armor deck is necessary at some distance below the armor deck, unless the side armor is fitted, as m the English battleships of the Majestic class, to prevent a projectile, carrying high explosives or a large charge of powder, from reaching and exploding in contact with the armor deck.
With the existing dispositions, excepting in the instances named, the protection to the vitals is not equal to the protection to the heavy turret guns. Under the probable conditions of coming engagements, the probability points to the destruction of motive power, or steering power, or boiler explosion before the disabling of all the heavy turret guns.
Additional weight and cost would be more efficient, devoted to a splinter deck or second armor deck, partial if not complete, than to increase of protection of heavy guns.
X.
The protection of the secondary battery, considering its great and increasing importance, like the protection to the other elements considered above, is not in due proportion with the protection to heavy turret guns, though increased attention is now being paid universally to the subject.
The crews of the turret guns are small and constitute but a small fraction of the personnel stationed above the armor deck in action. Casualties among this larger fraction will be great. The destruction in the Chino-Japanese engagements, to personnel and objects, unprotected or protected only by shields, was terrible.
The case of the Chen Yuen, at the Yalu, may be cited. None of her heavy guns were injured, and yet 76 per cent, of her crew and officers were killed or wounded.
The explosion of projectiles produced terrible effect on everything- unprotected ; exploding between decks, whole sections of objects on both decks were disabled, and the effect was proportionally large for rapid-fire projectiles of small caliber. A 6-pdr. projectile exploding in a military top of the Ting Yuen killed seven men, probably all those present. The usual effects of such explosions must be of serious consequence in their terror or panic producing effects.
Additional protection, increase of light armor tending to reduce the number of explosions on the inside, would be more efficient than additional protection to heavy turret guns.
Referring to military tops, it is to be noted in this connection that the model represents the masts as rising and falling like the turrets, though no attempt is made to meet the practical impossibilities of the disposition.
As the fire of top guns could be most effective under certain conditions, at short ranges, particularly against the tops of barbettes, and uncovered redoubts, and as the exposure is very great, and the top guns, as shown in the Chino-Japanese war, cannot hope to survive for this close range, it would be a great gain, if some method could be devised for preserving their integrity until the desired moment. Though it is practically impossible to raise and lower the mast, it would not be so difficult to raise and lower the top or tops, leaving the mast standing permanently, needed as it is for signaling. The damage done by shell hitting the masts is not great; they pass through before exploding. The mainmast of the Ting Yuen at the Yalu was struck twenty times without undermining its power to sustain the top.
The same slight effect was noticed in masts and smokestacks generally. One smokestack of the same vessel was struck forty times without seriously affecting its efficiency.
The probability is that late in engagements the masts could still sustain the hoisting of tops and their contents. This operation, as well as the housing of the tops below deck with perhaps slight surrounding protection, the securing in place after hoisting and the securing of the masts, present obstacles which though great, are not impossible of being surmounted.
The idea need not be limited to the usual military masts, but could be applied to platforms raised on one or more supports in various parts from housed positions to positions of various elevations carrying light guns. This would add to the protection of the objects least protected. This feature of the model can be disposed of with the remark that it contains the germs of suggestive possibilities for useful application for purpose of protection, though in the form presented it is utterly impracticable and is unaccompanied by any attempt to meet the practical difficulties involved.
XI.
Summing up the results of the consideration of the relative protection of the heavy turret guns and the other elements of efficiency of a vessel of war as embodied in a battleship, it has been found that the latter, floatability, stability, uprightness, vital organs, secondary battery, and personnel, each and every one, are protected in a less efficient degree, supposing the use of shields or doors for the ports of the turret guns.
To advance toward the equality of protection that would produce the highest resultant efficiency of the vessel, toward the infliction of the maximum amount of injury under the conditions for which designed, toward arriving under such intended conditions of engagements, at the desired point where the offensive and defensive power would disappear together, when the last of the personnel and secondary battery would be destroyed, the vitals pierced, uprightness undermined, and the last heavy turret gun disabled at the moment that the vessel foundered, capsizing as the last vestige of buoyancy went under; to advance toward this ideal combination, it would be more advantageous to expand effort available for protection in increasing the protection of the elements enumerated rather than in increasing the protection of the heavy turret guns.
To subserve this purpose most effectively the effort should be directed toward the increase of the area covered by light side armor, employing it as much as possible for the protection of the secondary battery, and toward the working of a heavy splinter or armor deck well below the usual armor deck, and, where sufficient weight is not available, the division of the available deck armor between two decks instead of confining it all to one deck.
Thus increase of protection to the heavy guns of a battleship does not present a reason of weight for the adoption of a different mount. Heavy turret guns as now mounted may be said to be over-protected.
From the standpoint of protection, if the mount is adopted for other reasons, it would be well to provide for the possibility, where desired, of continued fire from the elevated position with adequate supply of ammunition without returning to the housed position for loading. For it would be better to invite fire on the gun than to have it concentrated on other elements less protected and equally essential to efficiency, particularly as the gun presents its small and slightly vulnerable target above the upper deck where most of the shots aimed at it would miss entirely, which, if aimed at other parts along the hull, though missing these parts, would hit the hull, many of them inflicting damage that might be of serious consequence.
Referring to the target (Fig. 9), it will be seen that if the center of the turret on the upper deck had been the center of fire, 129 shots would have passed over the vessel, wide of the turret, which, if the center of fire had been the water line, would all have struck the hull of a vessel of 17 ½' freeboard.
Of course it would have been unwise in the enemy to direct fire on the turret or turrets, instead of the hull, but the former offers to a gunner a definite, inviting, vertical target on which to train, which causes shots to be directed on it notwithstanding instructions to the contrary, depending of course on the discipline of the gunners and the intelligence and persistence of those directing the fire. In the Chino-Japanese engagements, the objects offering vertical targets, masts, smokestacks, turrets, sponsons, etc., invariably received a concentration of hits. Of course no instructions were given to direct fire on smokestacks.
It may be noted here that the feature of being able to remain and fire in the raised position, would materially enhance the value of the system, from the standpoint of offense, by providing for the events, where the saving of time or increase of rapidity of fire more than counterbalances the reduction of obstruction, or any gain in protection.
XII.
There is not only small advantage along the line of protection in an increase of total protection to the turret guns, but the amount of this increase realized in the system proposed, is only moderate, supposing the guns to disappear for loading each time.
Referring again to the target it will be seen that thirty-eight shots would have struck a turret for 12" guns, if the center of the turret had been the center of fire. This is the result of deliberate practice in time of peace, in smooth seas, at short ranges, with good marksmen. This excellent marksmanship for even these concurring favorable circumstances, gave only one hit in ten. Considering the limited number of shots that could be fired by guns of a caliber to match the turret armor when attacking it normally; considering the cylindrical form of the turret, offering oblique surfaces for impact ; considering the slight probability of a projectile, of large caliber, directed against the turret, striking the chase or a gun port; considering the fact that the chase of the gun, even if disposed most favorably for attack, at right angles to the line of fire, offers but a narrow rectangle drawn out horizontally, which, selected for the center of fire in the target, would have been hit only once in thirty shots, and that the chase is cylindrical in form and of great resisting nature, so that but few if any, of the total number of shots striking, of the ordinary calibers that would be directed against it, would be effective; considering these facts, it is evident that in the conditions of battle, the heavy turret guns as at present mounted, are but slightly exposed. (It is assumed, as above, that doors or shields exist protecting the vulnerable gun-ports. As a matter of fact they are not fitted on any turrets now in existence, but, as mentioned above, there is no great difficulty in the way of fitting them, and this point should not enter to throw out the conclusions as to the system. It may be added that, with the turrets now afloat, a shot would be effective striking anywhere within the area presented by the port, when presented direct, except perhaps, in the case of a very small projectile striking the outer part of the annular surface presented by the muzzle of a gun. A projectile entering the bore to score the wall and strike the breech plug if closed and explode, or to pass through into the turret if the breech is open, or striking on the outside of gun, glancing along the surface of slight incline to enter the port and explode inside ; under either of these conditions the probabilities of disabling the guns are great, even for projectiles of very small caliber. As mentioned above, taking into consideration the large number of shots fired by rapid-fire guns, the probabilities are that in an engagement many projectiles, if fire is properly directed, will strike this area. In the case of the target cited above, the center of the port presented direct being- the center of fire, twelve shots would have struck it, or about one in twenty-eight. The probabilities would be smaller in action for the reasons cited above ; but the large figure indicates the great exposure of this vulnerable point).
The disappearing system as proposed reduces the exposure to practically zero while the guns are below deck, provided the cover is sufficient for protection from above, and the amount of exposure of the turret guns usually mounted being small as just pointed out, the gain in reducing this amount to zero is equally small. This gain lasts while the guns are below deck which would probably be about 2/3 of the time. When the guns are in the firing position the exposure is greater than that of the turret guns, incident to the protection of only light armor, which would offer probably about ½ to 1/3 the resistance or protection of heavy turret armor.
If only part of the guns appeared at the same time, an operation necessary for the realization of the increase of angle of fire, the enemies' guns could be concentrated on them, to be shifted to the others replacing the first when they disappeared. Under these conditions the guns with their inferior protection though exposed but about one-third of the time, would receive not a great deal less than the same total amount of fire. In addition the guns with their accessories and fittings are more delicate and more easily damaged in the proposed system.
The total possible gain of protection by the proposed system thus depends on the length of the time spent in the raised position of greater exposure compared with the length of time spent in the loading position of greater security.
Considering the time required in lifting the weight through the altitude needed, the guns beginning to be exposed the moment the top of the shield rises above the deck, the time required for training to the bearing of the enemy, for deliberation in aiming on account of the unsteadiness of the platform, for training back to the position for disappearing and for descending gently to the position for loading ; considering that during all this time, probably one-third of the total time, the more fragile objects are under greater exposure, the resulting total gain in protection realized by the system can be but moderate under the best conditions of solution of the mechanical problems.
Thus, in sum, there can be but slight advantage in increasing the total protection of turret guns, and the maximum possible gain in total protection to be derived from the proposed system is small and will depend on the perfection of the mechanism. Thus, from the standpoint of mean total quantity of protection there is not sufficient advantage in the disappearing system proposed to warrant a departure from the usual turret mount. However, if the property of remaining at will in the raised position is reserved, the nature of the protection which is constant in usual cases will be variable at will with the disappearing guns proposed varying from a minimum sufficient for projectiles from rapid-fire guns, to a maximum greater than that of the heavy turret guns.
The exposure of the guns will vary between wide limits during all probable engagements of battleships. During times when the probability of being hit by projectiles from heavy guns is small, the protection to heavy turret guns in usual cases is excessive and out of proportion to the exposure ; the great thickness of armor is a useless weight ; thickness sufficient for projectiles from rapid-fire guns would be sufficient.
During the times when the probability of hitting with heavy guns is almost certain, an absolute protection for the heavy guns would not be excessive; at moments when the power to withdraw the heavy guns entirely from exposure might be most valuable, particularly, if perchance, the other heavy guns had already been disabled; at these moments of close range the time required for sighting is small and the time of exposure with the proposed system in order to use the guns' powers of offense is resultantly small and could probably be regulated without great delay of fire to correspond more or less to the time of loading for the enemies' heavy guns.
On a vessel of war, where everything is compromise, where every addition to one element entails a sacrifice to other elements, protection is best when it is proportioned to exposure. With the variable exposure of the guns of a battleship, the protection afforded by the disappearing system proposed, varying more or less at will from a minimum sufficient for projectiles from rapid-fire guns to a maximum greater than the protection afforded by a heavy turret, is superior in quality or nature to the protection of heavy turrets.
Moreover, this variable property permits the regulation, within limits, of the gun protection to suit the protection of the other elements, which together may be called the hull. Under certain conditions of engagement, the full possible protection may be reduced and a corresponding increase in the offensive power realized. For instance, engaging bows on in a smooth or moderate sea at moderate ranges or in a heavier sea at shorter ranges, the after guns would remain in the raised position, the forward guns alone disappearing after firing. The exposure of the after guns would be somewhat increased, as it would last during the loading period of the forward guns and the partial protection offered by these would continue only while they were in the firing position ; but this protection would be ample under the conditions and the rapidity of lire of these guns could be increased and the advantage of their increase could probably be realized without conflicting with the fire of the forward guns. Under these conditions the protection would be adequate, while the offensive power would be nearly double that of guns mounted in the usual manner where the after guns could not be brought to bear.
There is another difference in the nature of the protection in the two cases of ordinary turrets and of the system proposed arising from the moral effect on the personnel of the guns. The consciousness of invisibility would give to the disappearing crew a strong sense of security out of proportion even to the actual security while the same invisibility would cause the crews of attacking turrets to have a sense of disparity of security out of proportion to the reality. The disappearing crew would feel at advantage, and the crew of the attacking turret of usual form at a disadvantage, causing a marked effect on the efficiency of the service in the two cases to the advantage of the disappearing system.
Summing up the comparison of the protection in the two systems it is found:—
That the possible mean total quantity of protection does not differ largely ; the slight difference being in favor of the disappearing system. That the nature of quality of the protection differs; that for the disappearing system being superior on account of its variability, allowing adjustment to correspond to the exposure and to the relative protection of the hull, and on account of its moral effect on the guns' crews, causing a disparity in the sense of security due to the element of invisibility favorable in the case of both crews to greater efficiency of the disappearing crew.
Combining quantity and quality the resultant protection is superior in the case of the disappearing system.
Summing up the comparison of the total effective power of heavy battery it has been found that in the proposed system, (1) the effective offensive power has been increased by the increase in angle of fire overbalancing the loss in rapidity of fire. (2) The protection is superior on account of the possible maximum protection being as great or a little greater, while the adjustable nature makes it more adaptable for shipboard, permitting adjustment to correspond to the exposure and to the relative protection of the hull, while a moral effect on the crews is produced to the advantage of the system.
Combining offensive power and power to use same, the resultant total of effective power of the main battery is greater in the case of the disappearing system.
However, as stated above, the gain in offensive power depends wholly and the gain in protection partly on the efficiency of the mechanism.
XIII.
Another important element in naval design besides the power of the main battery is involved in the question of weight, which differs in the proposed system from the usual turret system.
Armor of one-third to one-half the weight of heavy turret armor would suffice 'for the heavy guns. The saving of two-thirds the weight of heavy turret armor would amount to about 120 tons for a pair of 12" guns. For two pairs the total saving would be about 240 tons.
On the other hand the mechanism required for raising the necessary weight, 120 tons, through the necessary height, 6 feet, in a reasonable time, 15 seconds, once every three minutes would require an addition to the weight of the hydraulic plant of a 12" turret of about 30 tons, including additional pumping power and the quantity of water involved, one or more accumulators and a small air compressing engine for same, additional piping and fittings, account being taken of the fact that training and lifting will not take place together.
It may be remarked at this point that the additional weight and power required would be materially reduced if the energy of recoil and the energy of descent could be partly utilized to store up energy for ascent. It would be practically impossible to utilize the energy of recoil on account of the difficulty of connections to the accumulator, but the difficulty of utilizing a part of the energy of descent is not so great. Taking the additional weight for the two 12" turrets at 60 tons, the net weight saved would be about 180 tons. With the 8" guns, the conditions would not be exactly the same. It would be advisable, on account of their more rapid fire, to keep them in the raised position, except when a 12" gun wishes to fare across the position. In consequence, it would not be advisable to reduce the turret armor to the extent taken for the 12" guns.
On the other hand, a single plant amidships could serve for all four 8" turrets and the additional weight of hydraulic plant would not be proportionally so large as for the 12" turrets. (A single central plant might serve for all the turrets with an economy of weight.)
It may be taken that only sufficient weight is taken from the turret armor to compensate for the small increase in weight of hydraulic plant, and that the result does not affect the total weight.
The total saving in weight would thus be about 1 80 tons.
This amount is less than the saving in the case of simple barbette guns, and is less than the saving in the case of barbette guns protected by shield armor as on the English battleships Barfleur and Centurion, but it would still be a valuable saving, sufficient to aid materially in armoring a splinter deck over the boilers and engines or in increasing the extent of light side armor.
XIV.
Besides the general ideas or principles involved in the model, as considered above, there are certain necessary inherent features of this system which influence the desirability, possibility, and practicability of its application on board ship.
1. An architectural feature is involved in the change in the position of weights.
Supposing the thin armor carried by guns to be about one-third the weight of turret armor and the lift to be 6 feet, the raising and lowering of the weight involved in the 12" guns would cause a change of about 1/15 in the metacentric height. If in addition the 8" guns were mounted on the same principle and had a lift of 5 feet, the total effect would be a change of about 1/10 in the metacentric height.
In passing from one position to the other, the radius of gyration of the vessel would be altered, increasing for the raised position.
The reduction in metacentric height would combine with the increase of radius of gyration to cause an increase in the period of roll for the raised position, which would give a steadier platform for the guns in the firing position.
Since the vessel would be designed for adequate stability with the guns in the raised position, the effect of this feature of the system is advantageous, both to stability and to steadiness of gun platform, though the effect is but small in extent.
2. In seeking to utilize the possibility of firing across the positions of other guns there will be danger of injuring the guns that may be in the operation of rising at the moment of the firing. This is a serious danger for the conditions of battle, however trained and careful the gun captain may be ; in fact, it is dangerous to allow a gun the possibility of training to the extent of bringing into the field any other gun mounted on the same level. To remedy even partially this danger there would have to be a single mind in constant knowledge of the position, raised, lowered, rising or falling, of every turret, with the power to influence the firing of the guns in accordance with such knowledge. The difficulty of providing a single mind with such knowledge and with such control is a serious detraction from the plausibility of wholly utilizing for fire angles that are subtended by turrets. For volley firing, for a single volley or for successive volleys, in which the moral effect of invisibility, of appearing to fire and then disappearing, referred to above, would be great; for such firing, where the commanding of other special officer would direct and control the fire, the danger to guns would be less.
3. However efficient the mechanism may be, there must always be a loss in rapidity of fire of any gun. The influence of this loss has been considered above. Its effect will become greater and greater as the caliber decreases ; the time required for the additional operations increasing in its proportion to the total time.
4. As mentioned above, the presence of turrets on the upper deck would cause many shots to miss. With the disappearing system the hull would receive much greater punishment, while, as demonstrated above, it is the weaker part.
5. The increase of mechanism, with its accessories and fittings would increase the complexity, and every increase in complexity increases the probability of accident and the danger of some important part not working properly in action when the smooth working of every part is of paramount importance. Simplification would result from the use of explosives or chemicals to shoot the weight up gently ; but at present such a method is beyond the sphere of practical possibility and reliance must be placed on hydraulic power with or without association with compressed air, with the complexity of mechanism necessarily incident thereto.
6. A serious mechanical difficulty is met with in providing security when the guns are not in the housed position, against the friction when the guns are raised with the vessel inclined, against inertia of rolling and pitching and against the shock of recoil, the turning moment when a single gun is fired, and the shock when struck by a projectile. To reduce the friction in rising, the bearing surface must not be large, and rollers would have to be introduced to reduce this friction ; and yet these bearings must form a rigid support or else the shocks and forces will affect the ram on which the system is supported, reducing its efficiency, if not destroying its action. However efficiently this difficulty may be met, the system will always be more fragile and more liable to be jammed or otherwise put out of working condition.
7. The rising will cause mechanical difficulties to be involved in the joints for the supply of power to the guns for elevating, loading, etc., for the supply of ammunition, particularly when the gun remains elevated, the transmission of power controlling the training gear and ammunition hoists, and in all other connections between the guns and the outside—difficulties in which electricity alone could avoid the undesirable features of telescopic joints.
Thus, though slightly favorable to stability and steadiness, the features inherent in the system involve complexity and liability to accident, a loss in rapidity of fire, an exposure of guns to danger from other guns on board, an increase of punishment to the hull, serious mechanical difficulties, and greater fragility or liability to be jammed or put out of action. The gravity of these objectionable features on board ship is evident.
XIV.
The details of the features of the method proposed will not be considered at length for the reason stated in the beginning. The applicant could not have proposed any reasonable details. It would be impossible for any one but an expert to even approximate reasonable designs for the system with its complicated mechanism.
It will suffice to point out simply certain features of two sketches, Figs. 1 1 and 1 2, furnished by the applicant :—The proportions are not good ; scantlings exaggerated ; weight of movable parts enormous ; thickness of armor fabulous. The box form of armor is inefficient and without support. It would be impossible to make armor of the form indicated and impossible to support it efficiently. It is impracticable to attempt to have two positions for disappearing ; the weight of armor required would be utterly inadmissible. The only practicable form that would fulfil the idea of the form proposed, would be something like that shown in sketch Fig. 13, which represents the gun run out. No adequate method is shown or proposed for sustaining or securing the lifted weight against the friction when the guns are raised with the vessel inclined, against the inertia of rolling and pitching, against the turning moment when a gun fires, against the shock of firing and the shock when struck by a projectile. The combination of rollers and hydraulic ram presents the difficult situation that if supports are fitted to take the above forces and shocks sufficiently rigid to protect the ram from their effects, the rigidity will interfere with the efficient working of the rollers; while, on the other hand, if the rigidity or support is not secured, the forces and shocks will affect the ram.
It would be difficult, if not impossible, to pack the ram efficiently with its angular form, particularly on its inner surface, which could not be reached for adjustment; further, this form of ram entails excessive weight and is easily injured and thrown out of working order.
No system is shown or explained for transmitting power into the turret for the purpose of elevating and loading, or for transmitting motion from the turret for controlling the training and the supply of ammunition. With the lifting movement, it is difficult to make any transfer of power or even of force or motion from the outside to the turret, or vice versa. As stated above, any but electrical arrangements would require long telescopic joints of difficult and more or less fragile construction.
No method of hoisting ammunition is shown or described, though the vertical movement makes this feature a difficult one with the form of ammunition tube adopted. The ammunition tube as shown is inadmissibly small.
Thus, in sum, the features of the method proposed do not face many necessary and difficult problems, theoretical and practical, involved by the system, and those that have been faced have not been solved within the remotest degree of practicability.
However, the method involves features which, in proper shape, are probably the best adapted to use on board ship, the use of a simple vertical rise accomplished by a hydraulic piston acting directly.
The simple direct rise in the disappearing mount is not new. It was employed on shore in France toward the end of the last century in a crude form where the platform carrying the gun was carefully counterbalanced and only moderate force from hand power sufficed to cause the rise through a large altitude. It has recently been perfected in France by Canet for use ashore on an armored turret raised directly by a hydraulic ram, the fall being sufficient to cause the gun-port to pass below the level of the pit over which the gun fired, the gun having recoiled till its muzzle entered the turret, whose top when down rests on the rim of the pit. It has, however, never been adopted on board ship.
A more definite idea of these two principles cited can be had from sketches Figs. 17 and 18 of a form that suggests itself for putting them in a more practicable shape.
The turret is of thin armor with sloping sides, and, like the barbette, is circular in section like the barbettes found in connection with turret guns on French battleships. The gun, the turret, and all its contents are carried on a central built-up tube somewhat similar to the tube of the Farcot system of turret adopted on French vessels, though cylindrical over a greater part of its length. The base of the tube ends as a ram plunger in a hydraulic cylinder fitted on the inner bottom, with a stroke of 6 feet. The traininggear is hydraulic, fitted as on French battleships, though the drum or band on the central tube, over which the chains reeve for revolving, carries a feathered jacket or sleeve that permits the free vertical movement of the tube, while it transmits the movement of rotation.
Separate ammunition tubes are fitted, the central tube not being used for this purpose on account of the difficulty presented by the rise. These tubes lead to the loading platform, and when it is desired to continue fire without descending to load, the ammunition is wheeled on a car around a track until it comes beneath the rear end of the gun, and from this position is hoisted into the turret by a hoist fitted to the turret cover. In the raised and trained position the weight rests on the ram. In the housed position it rests on a ring base covered by hard rubber for a buffer, supported from the armor deck in the usual way. At the passage of the central tube, through the decks and platforms there are strong roller bearings, to reduce the friction in the rise, and to offer rigid support for shocks and forces acting on the weight lifted. To this end, the accurate bearing could be insured by having the rollers on part of the circumference adjustable. A guide support, not indicated, is built around the ram just above the cylinder, to save the cylinder from strain.
The barbette is about 30' external diameter ; is self-sustaining, without backing. Gates are cut to allow the entrance of the chase of the guns in descending. These are closed by armor-doors in two sections, both sections closing when the guns are up and completely closing the gates, the upper ones only closing when the guns are down.
The weight lifted is about 230 tons. The diameter of ram is 30". An accumulator, with air chamber, made up of tubes or pipes, weighing about 7 tons, supplying about 30 cu. ft. of water under a pressure of about 900 lbs. per sq. in., suffices to effect the rise without the assistance of the pumps. Pumps of about 90 horse-power can charge the accumulator in two minutes. Air is kept supplied by a small pump weighing about 500 lbs. The presses for training are fed from the accumulator.
It may be pointed out that the development of the disappearing principle has been principally along the lines employing rocking shafts and levers. The early examples, covering the first half of this century, employed the principle of the eccentric and the inclined plane, but the important developments since, excepting the case of the Canet turret, cited above, have employed rocking shafts and levers in single or double pairs, actuated by counterbalance, spring, hydraulic, pneumatic, hydro-pneumatic, and hydraulic-spring power. The rocking shaft lever system has the inherent advantage of being required to lift only the weight of the gun, the recoil gear being below, associated with the raising gear and utilizing or not, for subsequent raisings, a part of the energy of recoil and descent. It has also the inherent advantage of economizing time by returning automatically at recoil to the position for loading, and by permitting the elevation and sighting from below, the gun rising to its firing position all ready for fire. In addition it throws the muzzle forward over the parapet or redoubt or turret for firing.
It is the lever form that has been adopted in all five of the systems cited, notwithstanding the fact that on board ship the unsteadiness of the platform requires the gun to remain in the firing position, personally directed by the gunner, for a period more or less extended, during which time the gun is exposed, though, as demonstrated above, this exposure is not of so great consequence, the vulnerability of the gun not being great and the probability of being hit by projectiles of large caliber being small.
If the gunner follows the gun up, which is more or less necessary on board ship, his exposure would be very great.
In connection with the disadvantage incident on board ship to the impossibility of employing satisfactorily the method of indirect sighting used ashore, on account of the unsteadiness of the gun platform, it may be pointed out that the first Russian ship to adopt the system was a coast defense vessel of the Black Sea squadron, and the three recent battleships having it all belong to the Black Sea squadron. The only vessel carrying the system on the high seas, the Temeraire, is having the guns replaced, abandoning the system, though the system was not abandoned till the guns mounted, which were muzzle loading, became obsolete.
Though it is difficult to draw exact conclusions, the fact that the experiment was not repeated on the high seas would indicate that, on the whole, the system was not considered as entirely satisfactory for adoption on board ship.
The levers require also a large horizontal sweep which will always increase the space required for their action. In the cases thus far adopted on board ship, the guns have recoiled back entirely within the armor defense, though they cannot be said to meet the difficulty due to the great length of recent guns, for the guns on the Temeraire and the Vice Admiral Popoff are of the old short type, and those of the Tchesme and her sister ships are all six mounted in a large redoubt, where space is but a small item.
The mount of the Temeraire, outlined in sketches, Figs. 15 and 16, was the Randel system. The guns were 25-ton guns, and were raised out of towers and barbettes 7 feet high by hydraulic rams acting on bell-crank levers, no use being made of recoil energy, which was taken by usual hydraulic recoil cylinders. The rotating platforms carried the hydraulic training gear. The hydraulic pumps were below the water line, controlled from the platform. When firing against time, the interval between shots for four rounds was one and one-half minutes.
The mounts of the Russian vessels are of the Moncrieff system, simple hydraulic. An outline is given in sketch Fig. 14 of the type used on the three battleships cited above for three pairs of 12" guns.
The hydraulic cylinders serve the double office of raising the guns and taking up the energy of recoil and descent. They work through the intermediary of a hollow plunger connected by levers with the rocking shaft.
The training gear is of the ordinary type, worked by steam. Water is supplied from an air accumulator, sufficient to raise the gun once without the assistance of pumps.
The ammunition hoist is of ordinary type, worked by steam. The guns together weigh 100 tons, and the carriage complete, including training gear, accumulator, etc., weighs 120 tons and costs about 175,000, which compares favorably with carriages for ordinary mounts. The mechanism has worked well in service. It is to be noted that the weight to be lifted is only about 2/3 of the weight lifted in the proposed mount, and the rise, 4 feet, is only 2/3 as great, while using the lever system avoids those serious difficulties of joints, and bearings, and supports cited above. But the guns and gunners in the raised position are entirely exposed, and, as mentioned above, the lever system is unsuited for carrying up protection, —which is essential on board ship, except under exceptional conditions of sea, on account of the length of time it is necessary to remain in the raised position in order to sight properly, the platform being unsteady and indirect sighting being impracticable.
These three vessels realize a great saving of weight, practically the total weight of three turrets, but it may be pointed out that weight is lost in the adoption of an armored redoubt instead of barbettes, and the protection is insufficient even for the lowered position of the gun on account of the entire lack of cover, leaving complete exposure to plunging fire.
Thus, though the cases cited are interesting as examples of the disappearing principle afloat, they only fulfill the object of saving of weight and utilizing invisibility for protection, without attempting to realize any increase of angle of fire, without realizing an increase of mean security, and without attempting to realize any security for the guns in the firing position, while they throw no light of experience on the practicability of the difficult mechanical features inherent in the system. They show the practicability of employing hydraulic power, in connection with an air accumulator, to perform the work of lifting the weight ; but even here, the work is only one-quarter of the work necessary in the proposed system.
SUMMATION AND CONCLUSIONS.
A.
Examination was requested on the ideas or principles involved and illustrated without reference to details. Investigation showed, however, that the entire value of the system depends on the success of method or the perfection of details, and, in consequence, it has been necessary to pass in review the main inherent features of the method, and the main features of detail proposed, in order to form a just estimate of the value of the system, and the value of the model.
B.
The examination has led to the establishment of facts as follows:
I.
1. The model, as a piece of workmanship, is in good proportion, and indicates extended thought, ingenuity, care, perseverance and patience in building.
2. The object of the system is to increase the effective power and efficiency of the main battery by increasing the effective angle of fire and the mean security of the heavy guns.
3. The main features in the proposed accomplishment of this object are the use of an unobstructed flush upper deck and the use of disappearing mounts in a form to permit fire over gun positions while the guns are below deck.
4. The second feature has not been adopted in any naval design, and, as far as research showed, has not been previously proposed.
II.
FEATURES OF A FLUSH UNOBSTRUCTED UPPER DECK.
1. The realization of this feature presents disadvantages and difficulties, the most important of which are connected with the sweeping away of mounts for guns of the secondary battery. These disadvantages and difficulties are not, however, without the possibilities of adequate remedies.
C.
Effect on Effective Power of Main Battery.
I.
EFFECT ON OFFENSIVE POWER.
Gain in Angle of Fire.—1. The possible gain is large.
2. The gain on the Iowa, by complete application, would be ½ for the 12" guns and double for the 8" guns. Taking the amount of offensive energy generated as the term of comparison for two batteries, the mean gain would be .7, or the mean angle resulting would be 1.7 times the mean present angle.
Loss in rapidity of fire.—1. It is impracticable to have more than one position for disappearing. If the guns are lowered after each round, loss is incurred in lifting, in training to the bearing of fire, in training back to the position for lowering, and in lowering. Assuming a perfected mechanism these losses would cause a loss in rapidity of fire estimated at 1/6.
2. With imperfect mechanism, loss could be double the above figure or even larger.
3. The resultant effect on offensive power assuming perfected mechanism would be an increase in the proportion of 1.45 to 1.
It would be less with imperfect mechanism, depending on the degree of imperfection.
II.
EFFECT ON SECURITY.
(A). The Extent of the Need of Additional Protection to Heavy Guns.
I.
PROTECTION OF HEAVY GUNS AS MOUNTED IN TURRETS OF USUAL FORM.
1. Heavy turret armor may be taken as an over match for guns.
2. The gun proper, chase and breech are but slightly vulnerable and have slight probability of being struck effectively.
3. The platform and all gear associated with it is vulnerable but runs very slight chance of being hit if doors or shields are provided for gun-ports.
4. The gun's crew is exceedingly vulnerable but runs slight chance of being hit if gun ports are protected.
5. Fixed portions, all within barbette or below protective deck, may be considered as having perfect protection.
6. On the whole, the system comprising heavy turret guns as usually mounted is well protected.
II.
THE PROTECTION OF THE REST OF THE VESSEL.
1. Protection to Floatability—In a sea-way, but a small fraction of area exposed to both submersion and emersion is protected by heavy armor, and a smaller fraction by light armor. The ameliorating measures are of but slight importance, except the one of developed subdivision. Protection to floatability is inferior to protection to turret guns. Increase would take the line of increase of area of light armor and increased power of secondary battery.
2. Protection to Stability.—The principal factors of danger, the loss of moment of inertia of water-plane and the accumulation of water above the armor deck, are badly exposed in a sea-way. Protection to stability is less than protection to turret guns. Increase would take the line of increase of area of light side armor.
3. Protection Against Heel and Change of Trim is similarly disproportionate. Consequences of same affect battery and stability and floatability.
4. Protection of Vitals.—Weak point; lack of an armored splinter deck. Protection to vitals is less than protection to turret guns. Increase would take the line of fitting an armored splinter-deck.
5. Protection to Secondary Battery and Personnel. —Not in proportion to protection of turret guns.
Additional light armor as a remedy.
Remarks on military-tops as to the feature of being raised and lowered.
III.
SUMMATION OF RELATIVE PROTECTION TO TURRET GUNS AND TO OTHER PARTS OF VESSEL.
1. All features are less protected than turret guns.
2. It is advisable to direct effort toward an increase of the protection of weaker features.
3. The method of procedure would be an increase of the area protected by light side armor, and the working of a heavy splinter deck.
IV.
BUT SLIGHT VALUE CAN ACCRUE BY INCREASE OF TOTAL PROTECTION OF HEAVY TURRET GUNS.
Additional Protection is not Needed.—1. Guns are over-protected.
2. It would be advisable under certain conditions to have heavy turret guns on deck and invite fire on them to divert it from the hull.
(B). The amount of Additional Protection to Guns Afforded by the Proposed System.
Exposure of Heavy Turret Guns.—As at present mounted, the turret guns are very slightly exposed.
Exposure of Guns in Proposed System.— 1. Exposure is reduced to zero while below deck, which position is occupied about two-thirds of the time assuming perfected mechanism ; but this reduction is not great.
2. Exposure is greater while above deck which position is occupied about one-third of the time.
3. If the guns descend for loading after each round, what may be termed the mean total quantity of protection will not differ largely in the two systems. With perfected mechanism, the proposed system would realize but very slight additional protection to guns.
(C). The Difference of Nature or Quality of the Protection,
1. The protection of usual turret guns is constant,
2. The protection of the disappearing guns, remaining above deck or disappearing at will, is variable.
3. The exposure of guns will vary between large limits during all probable engagements of battleships.
4. On a vessel of war, which is entirely made up of compromises between conflicting elements, protection is best when only proportional to exposure.
5. The protection on the disappearing system proposed, varying at will, is superior in quality or nature to the protection of heavy turrets.
6. The feature of variability permits the adjustment of the protection of the guns in the proposed system to correspond to the protection of hull.
7. The moral effect of the protection is to the advantage of the crews of the guns of the disappearing system.
8. In sum, the variable nature of the protection in the disappearing system gives it a superiority of quality over the protection of ordinary turrets.
(D). Results of Examination of Effect on Security.
1. But slight advantage can accrue from any increase of the mean total quantity of protection to heavy guns.
2. The mean of this possible total gain in quantity of protection realized by the proposed system can be but slight, even with perfected mechanism. From the standpoint of mean total quantity of protection, but slight advantage can be realized by deviation from the usual turret mount.
3. The variable nature of the protection in the disappearing system gives it a superiority of quality over the protection of ordinary turrets.
4. In sum, the proposed system offers advantages for the security of the guns, but the slight advantage in possible quantity of protection, and the decided advantage in quality of protection both depend for their realization on the efficiency or perfection of the mechanism.
III.
RESULTS OF EXAMINATION OF EFFECT ON EFFECTIVE POWER OF MAIN BATTERY.
1. The offensive power would be increased in the ratio of about 1.4 to 1, with perfected mechanism.
2. The security of the guns necessary for the use of offensive power would be increased, slightly increased in quantity, and decidedly enhanced in quality, with perfected mechanism.
3. In sum, the effective power would be decidedly increased in both its elements with perfected mechanism.
4. Perfection or efficiency of mechanism is essential to both elements of increase.
D.
Various Features Influencing the Advisability of Adoption.
I.
THE QUESTION OF WEIGHT.
1 In properly designed form, there would be a gain of two-thirds the weight of the turret armor for 12" guns.
2. A loss of about 30 tons would be incurred in increase of mechanism for 12" guns.
3. A slight gain would be realized in weight of turret armor for 8" guns.
4. A slight loss would be incurred in increase of mechanism.
5. The net gain or saving would amount to about 150 tons for the battery in question.
II.
FEATURES INHERENT IN THE SYSTEM.
1. The change in position of weights influences favorably, though in a small degree, the stability and steadiness of platform.
2. The system incurs danger to guns on board.
3. More hostile shots will hit; the hull will receive more punishment, though less able to bear it.
4. Complexity will be increased with increase of liability to get out of order.
5. The system is more fragile and more easily deranged or disabled.
6. Serious difficulty is involved in providing, even partially, against shocks, inertia, and deranging friction.
7. Serious mechanical difficulties are incurred in joints and fittings.
8. In sum, grave difficulties stand in the way of practicability.
III.
FEATURES OF THE DISPOSITIONS PROPOSED BY THE APPLICANT.
1. Proportions, scantlings, weights are all abnormal.
2. Barbette armor is of fabulous thickness, impossible form, and without possible support.
3. Two disappearing positions are provided; an inadmissible feature.
4. No method is shown for security against the forces of vertical friction, inertia, and shock.
5. Friction rollers requiring play are associated with a hydraulic piston requiring rigidity.
6. The form of ram is heavy, fragile, and difficult, if not impossible, to pack.
7. No method is shown of transmitting power into the turret or cage, for purposes of elevating, loading, etc., across the difficult joint between rising and fixed parts.
8. No ammunition hoist is shown, and it would be difficult, if not impossible, to fit one.
9. The ammunition tube is inadmissibly small.
10. In sum, grave practical difficulties are not faced, and the attempts to face others are all inadequate and impracticable, where not impossible, of execution.
11. The disposition involves, however, the idea of the method along which the difficulty of lifting can be best accomplished, that of a hydraulic piston acting directly to produce a simple vertical movement.
IV.
FEATURES OF THE SYSTEMS FOUND ON BOARD SHIP ABROAD.
1. In the British Navy.—On the battleship Temeraire. Lever system—Randal type—three short muzzle loading 25-ton guns, mounted singly, disappearing in barbettes ; no increase of angle of fire ; no protection in firing position ; moderate weight ; moderate lift ; simple mechanism ; long use in service ; good results for rapidity of fire ; example not repeated in British service ; guns obsolete being replaced by modern guns of usual type.
2. In the Russian Navy.—Four vessels of the Black Sea squadron, three battleships and one circular coast defense vessel. Lever system—Moncrieff type—simple hydraulic in connection with air accumulator. On the battleships six 30-caliber, 12", 50-ton B. L. R., mounted in pairs, disappearing in a single armored redoubt; no increase in angle of fire; no protection in firing position ; moderate weight ; moderate lift ; simple mechanism ; successful tests and use in service ; looked on with favor.
3. All five mounts are of the lever system, which involves moderate weight to lift and simple mechanism, but is not adapted to increasing the angle of fire and the carrying of protection for the firing position. All demonstrate the efficiency of hydraulic power to accomplish the work of lifting, though the amount of work is but a fraction of the amount required by the proposed system. The systems do not seek to realize the main objects of the proposed system, and do not involve its principal inherent mechanical difficulties.
E.
CONCLUSIONS.
The facts above enumerated lead to the following conclusions:
I
1. Realized under perfected conditions, the proposed system would materially increase the power and effectiveness of the main battery by increasing the offensive power, and by improving the conditions of security. The offensive power is increased by the increase of angles of fire, an increase which, under the conditions supposed, would largely overbalance the decrease due to loss in rapidity of fire, while the efficiency of the security is improved by the variability of its nature, an important characteristic afloat, permitting adjustment to suit exposure, and to suit the relative protection of the hull. By regulating the extent and frequency of recourse to disappearing, the factor which enhances the angles of fire and increases the protection, but which reduces the rapidity of fire, the interdependent elements of offensive power and defense of the heavy guns can be regulated at will to suit the needs of the occasion, a valuable quality on board ship not realized in any existing system.
2. The same would realize a material saving in weight, the saving in weight of turret armor largely overbalancing the increase due to additional mechanism.
3. The same would create a moral force in its own personnel and the personnel of the enemy setting to its advantage in both cases.
4. The same would have an ameliorating effect on the stability and steadiness of gun platform slight in extent.
II.
On the other hand,
1. The power and effectiveness of the secondary battery would be reduced. Remedy would be sufficient on large displacement; it could be only partial on small displacement.
2. The realization of the advantages incident to disappearing, cited above, would entail loss in rapidity of fire. The extent of this loss, affecting the offensive power, would depend' on the efficiency of the mechanism.
3. The same would cause more shots to hit, and increase the punishment of the hull, which is already underprotected compared with the heavy guns.
4. The same would cause danger to guns on board if advantage is taken of the feature permitting increase of angle of fire by firing across gun positions. This danger would be small in volley firing in which the moral effect cited would be greatest, where the fire is controlled by a single mind.' It would be serious where firing was independent.
5. The system is more fragile than the usual systems, it being practically impossible to provide other than hydraulic support in the raised position. This could be ameliorated by special provision being made to provide the training gear and the vertical bearings against the forces and shocks acting on the sustained parts.
6. The same would involve greater complexity than the usual systems, increasing the liability to derangement The extent of this disadvantage would depend on the mechanism—being moderate for perfected mechanism but inadmissible for imperfect mechanism. It could be ameliorated by providing for abandoning the disappearing feature, if need be—the guns remaining constantly above deck.
7. The same would involve mechanical difficulties in joints and fittings, difficulties that are serious but not insurmountable.
III.
Summing up, the ideas of the system offer advantages ; the principal advantages of increase in effective power of mam battery and economy of weight and the incidental advantages of a favorable moral effect and favorable effect on stability and steadiness of gun platform, which would preponderate heavily over the disadvantages incurred—disadvantages of reduction of power of secondary battery, reduction of rapidity of fire of the individual disappearing guns, the increase of punishment to the hull, the increase of fragility and complexity, and the difficulties of execution—provided the mechanism for accomplishing the various operations is efficient and substantial.
The necessity of this provision is absolute ; with imperfect mechanism, with slowness and uncertainty of action, the gain in effective power of main battery is rapidly undermined in both its elements, in offensive power and in efficiency of protection, while the gravity of the disadvantages increases in rapid proportion.
As to the practical features to be embodied in a system of successful mechanism some suggestions are found in the Farcot system of turret, in the disappearing mounts on the Russian battleships, and in the Canet disappearing turret for land use, but they cover but a small part of the ground ; as yet no adequate design has been made or attempted.
Expert design must be entered into in full detail, and must be experimented upon before the final value of the system can be passed upon, or the advisability of its adoption fully considered.
Within the limits of this examination it may be said that the difficulties pointed out above do not appear to be insuperable, while the possibilities for usefulness are large, particularly if their full realization is rendered possible by the adoption of sufficient displacement to allow for raising to a higher degree the weaker hull protection.
But this field for usefulness lies wholly within the domain of the expert. The model is original, interesting, and suggestive, suggests the novel features and possibilities pointed out above,, but its field is limited from evident necessity to suggestion alone. Detailed examination, and design, and experiment, three necessary steps between suggestion and adoption, still remain, and it would not be advisable to take them along the lines indicated by the applicant.
Attention is called to the points of professional interest which have come up.
1. The disparity between the protection of heavy turret guns and the other elements together classed as the hull. The substantial nature of the exposed part of the gun, and the slight probability of being struck effectively. The need of extending the area covered by light armor for protection to floatability, stability, and the other elements of efficiency, and the need of an armored splinter deck.
2. The grave exposure of turrets from their unprotected gunports. The extreme vulnerability to projectiles entering of even small caliber, and the large probability of many projectiles entering. The practicability of fitting doors or shields.
Editor's Note.—Discussion by members is particularly requested upon this article, the same to be printed as a part of the next number of the Proceedings. Any such discussion should be in the hands of the Secretary by Dec. 10, or as soon thereafter as practicable.