The Disappearing Gun Afloat.*(See No. 75.)
Chas. H. Cramp, Esq.—Prom an examination as exhaustive as the limited time would permit, the report on “The Disappearing Gun Afloat” seems to cover all points involved in the particular scheme which formed its subject-matter, and to that extent is perfect.
There can, in my opinion, be no question as to the advantage of the disappearing system in naval gun-mounts, provided mechanical devices can be found to operate it efficiently and reliably within the necessary limitations of weight and space. The system itself is by no means new, having been, as is pointed out, employed by the English un the Temeraire nearly 20 years ago, and by the Russians in the Catharine II, Tchesme, and Sinope ten years ago. The types differ in detail, but not in principle; both being hydraulic and both involving trunnioned guns working on levers; bell-crank in the case of the Temeraire and straight in the Russian ships. King, in his “War Ships and Navies of the World," published about 15 years ago, reports that the performance of the Rendel system in the Temeraire was satisfactory, but he does not describe the conditions of trial. The Russians did not publish the performance of their ships, but so far as I can learn, the Moncrieff system in use in the three battle-ships of the Black Sea fleet has functioned well in smooth water. I have no data as to any performance when the ship was rolling.
This brings me to remark that the principal, and possibly insurmountable, mechanical difficulty in adapting any disappearing system to all-around naval use, irrespective of sea conditions, is that of assuring proper function of the mechanism in all the different planes presented by a ship’s motion in a sea-way. Any properly designed and constructed disappearing gun-carriage will operate well when the line of recoil is perpendicular to the plane of a fixed base, as in shore mounts. But I do not know of any device which would insure proper action of the supporting levers and the mechanism controlling them when the gun is fired, say directly forward with the ship at an angle of heel such ns to throw a preponderating weight on one lever. It has been suggested that heavy guides in arc form might be fitted to take the sidewise thrust in such cases, but until such a device shall have been worked out and tried no reliable opinion can be formed as to its adequacy.
The scheme which forms the basis of the report contemplates the disappearance of the gun, shield and all, on a line perpendicular to the keel, into a barbette. This would necessarily involve a barbette of inside diameter equal to the length of the gun, besides suitable clearance, in order that the disappearance might occur at any angle of train. The 13-inch gun, for example, would require an interior diameter of something more than 40 feet in the barbette for a single gun, and about 48 feet for two guns if mounted with as much space between them as the Indiana’s are. Thus the designer would be at once confronted with a most formidable weight problem in the amount of armor required for a barbette of such dimensions.
But granting that the weight problem of the enormous barbette could be solved, the architect would straightway encounter another one not less difficult, namely, that of providing for the disappearance and re-lifting of the gun or guns with mounts, turntable and shield, not only with the ship on an even keel, but also at any angle within her arc of rolling. I will not attempt to analyze the mechanical elements of this latter problem here. But it should be observed that the majority of men who conceive schemes in a general way take no thought of the problems of applied mechanics involved in their practical execution. In fact most of them are incapable of applying mechanical practice to the solution of any problem or to the execution of any scheme. They simply think or imagine or dream of something and then expect the practical mechanic to effectuate it.
I have given some attention to the subject of disappearing naval mounts for heavy guns, and the result of my study and calculations in this direction took shape in No. VIII of the schemes which I recently submitted to the Navy Department in my bids for battle-ships in Class II, A. I made no attempt, however, to arrange for complete disappearance of the gun or guns. The device elaborated made provision simply for depression of the breech to a certain angle by recoil, to a loading position within a barbette of ordinary dimensions for the caliber of guns involved, leaving the muzzles exposed as usual in all modern mounts, whether of the barbette or turret or shield type. Using the very long guns of the present day, I see no practicable escape from muzzle exposure. Returning to the Temeraire by way of example, it is to be noted that her disappearing guns are the old type of 25-ton muzzle-loaders, and very short in comparison to modern breech-loaders of equal caliber, or even of equal weight. It was therefore comparatively easy to provide a barbette large enough to house such short guns entirely by recoil disappearance. This suggests the idea that, perhaps, in battle-ships destined to light at the closest quarters the length of even modern breech-loaders might be reduced without detriment to their real battle-power.
In conclusion I will say that while I think I have worked out a practicable plan of semi-disappearance or breech-depression to a point of mechanical satisfaction at which I was willing to submit it as a scheme accompanying a bid, I am yet not wholly without misgiving about it, and am not altogether prepared to recommend any disappearing system for naval gun-mounts in competition with any tried and proved system of fixed mounts, whether in turrets, barbettes or shields.
William Crozier,* Captain of Ordnance, U. S. Army.—The valuable action of a disappearing gun upon shore is that it drops, upon discharge or very soon thereafter, from an exposed position to one of greater security below. To compass this action, the only features about which military engineers have given themselves much concern have been those connected with the means of raising and lowering the gun. The elements of the security which is enjoyed in the lowered position, viz., a greater or less degree of invisibility and invulnerability, are so easy of attainment that they have been taken for granted without, thus far, any indication that too little concern has been felt in regard to them. But afloat the matter is very different; the mere statement why a lower position should be more nearly impenetrable or much less visible than a higher one, unless the lower position should be below the water-line, is not simple, and the complexity of the question as to the desirability at all of the disappearing principle afloat has been abundantly shown by the multitude of considerations which have been brought to bear in the able paper under discussion.
It may be assumed, from the experience had on shore, that if the secure lower position be provided, efficient means for dropping the gun into it will be forthcoming, although there may be room for difference of opinion as to the character of these means, particularly as to the relative merits of the general systems of the rocking lever and the vertical ram, to which I will allude briefly later. It is not for me, in my ignorance of naval construction, to indicate how a secure low position for the gun on board ship may be attained; but to criticise is much easier than to create, and to indicate the unsatisfactory envisagement of the question I will examine cursorily the sketch design of disappearing turret shown in Fig. 17, which the author presents as indicating, in a very general way, the plan which he has been led to regard as most feasible.
Considering the gun in the lowered position, suppose that portion of the armor plating of the fixed turret which is above the lower edge of the hood over the gun to be removed and distributed over the conical surface of the hood, increasing the thickness of the light armor of which the hood is formed; the protection in the lowered position is increased because, the surface of the turret removed being greater than the conical surface of the hood, the armor when applied to the latter surface will be thicker. If now we mount the fixed turret upon rollers, attach the gun and its carriage to it and suppress the lifting ram, we are back with our old friend the ordinary turret, having secured by the change constant protection slightly greater than that afforded by the disappearing turret to the gun in the lowered position and much greater than is afforded to it in the firing position; a saving of the weight and the complexity of the lifting mechanism, and an increased rapidity of Are by avoidance of the necessity for traversing to the lowering position, lowering, raising and traversing to the firing position. To offset these gains I cannot see that there has been any sacrifice unless it be the less command of the gun than when in the firing position. But as the disappearing principle has not been mentioned as a means for obtaining increased command, I am not considering it with reference to that object.
The estimated rate of fire with the disappearing turret would require a high degree of perfection for its attainment. In a recent trial of the gun-lift battery at Port Hancock, upon which are mounted two 12-inch guns having a vertical rise and fall of about 14 feet, produced by hydraulic ram mechanism, the rate of fire was one round per gun in something over eight minutes, the time required for raising or lowering, considered separately, being 15 seconds. As all hands engaged, though understanding their duties, were entirely without drill, the rate could probably be increased to one round per gun in about 6% minutes. With the estimated rate the author makes it plain that the advantage of ability to fire over a lowered turret is probably more than offset by the diminished rate of fire. This probability becomes, I think, certainty in view of the results at Port Hancock.
I have no data of the firing of a gun of as large caliber as 12 inches from a carriage of the rocking lever system, but a reasonably accurate estimate of the rate can be formed from the performance of guns of smaller caliber. An 8-inch gun was fired ten rounds at Sandy Hook from a Buffington-Crozier disappearing carriage at the rate of one round every 1.35 minutes, and a 10-inch gun from a carriage of the same type at the rate of one round every 1.07 minutes, the ratio of the rates being 1:1.235. The weights of the gun, projectile and charge for the 10-inch gun are about double those for the 8-inch. The weights for the 12-inch gun are about 1.75 times those for the 10-lnch, so that the ratio of the rates of fire of the two, based upon these elements, should be somewhat less than for the 8 and 10-inch above stated, so that if, on the contrary, we increase the ratio to 1:1.5, we should not be overrating the 12-inch gun. The latter ratio would give a rate for this gun of one round every 2½ minutes. This is so much greater than the rate indicated by the experience at Port Hancock for guns mounted upon vertically moving lifts as to probably more than offset the exposure due to the necessary final aiming of the gun when in the exposed position.
To a landsman the type of vessel upon which disappearing guns could be used to advantage would appear to require the following:
A complete belt of armor at least as efficient as is now provided, a central armored citadel, the lower edge of the armor joining on to the belt, and carried up as high as the available displacement would permit; guns of the primary battery mounted within the citadel upon disappearing carriages of the rocking lever system. These requirements would seem to leave latitude to the naval constructor in regard to the use of armored decks, building up the ends, disposition of the secondary battery, and so forth. The type seems to come out very much that of the Russian Catherine II, but it may be stated that with a rocking lever carriage a drop of 6 feet for a 10-inch gun would be a very moderate requirement, and the 4 feet given by Messrs. Easton and Anderson to the 12-inch guns of the Catherine II seems altogether inadequate.
It is with great diffidence that these remarks are advanced. The subject is one of such difficulty that no one unfamiliar with naval construction is in a position to deal with it.
J. E. Compton Bracebridge,* Captain Third Middlesex Volunteer Artillery.—I am afraid the questions under discussion are to be dealt with rather by the naval architect than by the gun-mounting manufacturer, but I personally do not think that disappearing turrets can be made use of on board ship. The mechanical difficulties are very great, and are increased by the long chases of modern guns, and the advantages are rather dubious. So far as we know, the mountings of the Russian ironclads have worked well. The great disadvantage of disappearing mountings on board ship is the exposure to plunging lire. No system of shutters for the hole through which the gun goes has been worked out, and they would be very liable to jam if struck. I was much struck by the remark as to the fondness of even a Japanese blue-jacket for a good upstanding target. It reminded me of the naval officer who announced that he intended on going into action to paint his conning tower bright scarlet and work the ship from the roof of the turret.
J. H. Glennon, Lieutenant, U. S. Navy.—Leaving aside the question proper of the “disappearing gun afloat," which certainly does not at all simplify the already sufficiently complicated and delicate mechanisms of battle-ships—and simplification is the direction in which we are compelled to look—let us consider a little more closely one or more of Mr. Hobson's statements.
On page 631 we read: “To advance towards 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 ns 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.”
This is a statement in some detail, plausible enough of course; in fact it belongs to a class of statements which we generally accept as incontrovertible. But inasmuch as it is given as the basis of a scheme for armoring ships, we should look at it in some detail. Diminish the turret armor, increase by the same total weight the water-line armor, cease firing and slow down, allowing the enemy calmly and without excitement to approach closely, and three shots will do the whole thing, that is, effect the destructive combination quoted above. Battles on land seem to indicate that when seven per cent, of an army are killed it is time to retreat. I believe this was the rate at Waterloo, being nearly double that at Gettysburg. After the battles of seven per cent, wo come by a sudden jump to those of approximately 100 per cent, like Cannae. This indicates to me that when about one man in 13 is killed a panic seizes on the others, and they are no longer of much value for fighting purposes. The element of human nature must be more fully considered. It seems to me evident that the above 7 per cent., or the panic stage, whatever that may be, should be coincident with the loss of stability and buoyancy, simply from the view of their protection alone. But we must not consider their protection alone.
It is impracticable to armor the sides and bottom of a ship sufficiently to keep out all the projectiles which will be brought against it, or even to approach closely this proper thickness necessary to protection of buoyancy and stability. An inch of armor taken from the side would mean several inches to the turrets with absolute security there. The increased value to the offense, in view of security, would alone probably be the equivalent, as a defense, to the inch of armor on the side, not to mention the saving of personnel and gun mechanisms as a desideratum. In other words, the men themselves and the guns are the equivalent defensively of so much side armor, and as they are destroyed, we must imagine layers of the side armor to be dropped off. All this is as regards guns alone. When we come to consider torpedoes, the fact of the security of the personnel and gun offense has much greater value than the side armor, for that of the latter is nil; offense, here the destruction of the torpedo while still on board the enemy, and the consequent restraint due to objection to being “hoist with one's own petard,” being the principal, if not sole, defense. I will not go into the subject of the ram, as it is too intricate. The mind that guldes the ram should certainly not be “rattled” or have arrived at the panic stage.
I am happy to say that in most of the other parts of his essay I agree with the writer; and I would like to compliment him, if permitted, upon the thorough analytical way in which he handles his subject.
G. W. Van Hoose, Esq.—The official report made by Assistant Naval Constructor Richmond P. Hobson on the model with disappearing turrets, which was presented to the Navy Department by myself, contains many suggestions and observations which are far-reaching in their consequences.
This report is divided into two general classifications;
First. A discussion upon the model and the proposed plan.
Second. A general discussion upon certain features of the present type of warships.
This last-mentioned branch of the subject, in my Judgment, is as full of general interest to the student of naval warfare as the first would naturally be to myself.
This part of the report also clearly shows that Mr. Hobson is a practical thinker, and has been asking himself the grave question: What will the present type of warship do under a prolonged and heavy tire? He clearly thinks that the ship will, under many conditions, capsize and sink, with perhaps most of its turrets in good working order, and he demonstrates his conclusions in a most unanswerable manner.
In my Judgment, a careful study of this feature of the report will repay any friend of the Navy, even if he does not believe as yet in the proposed new departure.
The writer of this article does not belong to the class of persons who see nothing good in the new Navy, but he recognizes the fact that the genius of America has begun to take hold of the great problem of the coming warship; and such creations as the Indiana, Iowa, New York, and similar types, reflect great and lasting credit upon their designers.
The model which was submitted to the Navy Department and referred to the Bureau of Construction and Repair, and which was most carefully studied and considered by the author of this report, was not submitted with the idea that it illustrated any fixed or even accurate plan. It was only intended to be illustrative and show in a general form a certain plan, which could be modified or changed to suit different types of warships.
A kind and courteous invitation had been extended to me to contribute an article upon this subject, but the time was so short that I could furnish nothing better than the following short reply, which had heretofore been filed in the Navy Department, and which explains my plan in certain matters of detail. Taking this in connection with the printed official report will fairly show the proposed system. After a most careful consideration, the Patent Office Department allowed the writer all his specifications and claims, thus confirming the statement of Mr. Hobson that the main idea was novel.
In reply to Report No. 5801, made by the Bureau of Construction and Repair, I wish to file a short statement in explanation of some matters of detail relating to my model of a warship.
The military tops or masts shown by the model are not intended to represent the tall military masts of the present battle-ship or cruiser. It is utterly impossible to raise or lower such masts, and I did not intend to suggest this mechanical impossibility. I only intend to raise and lower a circular platform as suggested by the report. This could be raised by means of hydraulic, pneumatic or pulley power. The model is intended to suggest a top which can be run up at critical moments a distance of 25 to 35 feet. The report concedes this to be a valuable idea. I believe that several of these military tops can be used to great advantage. They can be located in many parts of the ship without interference with the machinery below the water-line. The machine guns in these tops can also be fired from the upper deck in many positions of the ship. The model also indicates a number of strong girders extending above and across the upper deck. This formation is intended to support a developed platform, which will carry the search-lights and a number of rapid-firing guns to repel the attacks of torpedoes. It is intended that these girders should be strongly braced and connected, so that some of them can be destroyed by shot without undermining the superstructure. Its open framework will permit shot and shell to pass through it in many cases.
It would be perhaps advisable in a close and heavy fire to withdraw the men from this upper platform during its continuance, but the probabilities are great that enough of the guns will survive to enable them to be used to great advantage at some critical moment.
The model was made to illustrate a large battle-ship, but this was only illustrative. The system can be applied equally as well to coastline battle-ships, or a special type of low freeboard coast-defense vessel.
I believe a low freeboard could be used to great advantage for river and harbor defense. The number and caliber of the guns would have to be proportioned to the tonnage of the craft.
The report seems to state that this system would per se cause the hull to receive greater punishment. I cannot agree to this as a mechanical necessity due to the system. I believe that it will be admitted that at moderate range most projectiles are fired high by inexperienced gunners, and that the upper works, such as smoke-stacks, masts, military tops, etc., will receive a great number of hits, but I cannot see how elevating the guns so as to invite fire on them will save the hull, if the enemy’s crew are veterans and will aim at the weak parts of the ship.
The report, however, does point out with great ability the weakness of the protection to the hull, as compared with the turret, on the present type of ship.
My whole system is based in a great measure upon this idea. Armor 18 inches thick on the turrets cannot save the unprotected hull. The model is intended in a general way to illustrate a warship which can concentrate a superior fire upon an enemy of its class and overwhelm him with its battery power, and in this manner virtually protect itself.
The guns are not made to disappear simply to protect them. The main idea is to get them out of the way so as to double the battery power.
In my Judgment, the whole of the main battery fire of this ship should be aimed at the hull of the enemy. The secondary battery could be aimed at the ports of the turrets.
I wish here to state that the type of ship represented by the model is intended to carry a very heavy secondary battery, but as I had nothing very distinctive to illustrate, I did not show this feature to any great extent on the model. The report, however, treats of this important feature with great fairness, and it also points out the various ways of arranging a powerful secondary battery.
The report points out certain defects in proportions of scantlings, beams, form of armor protection over the guns, as shown by drawings, etc. I am aware of all these defects, but I only intended to illustrate general ideas, and did not make any claim to professional accuracy on some of the details of the model.
The value of this system will depend upon good mechanism, as the report states; and I confidently claim that hydraulic power can be utilized to lift the weight of the guns and armor to protect them, and that it can be regulated with unfailing accuracy.
The report concedes that the direct lift is the best method of elevating the guns, and this was the only method that I intended to illustrate. No details were specified, for it will be evident that details would have been useless in a mere preliminary exhibition of a new system. However, I promise to bring forward a general plan to lift the guns upon a system which will meet all necessary requirements. I had foreseen that good mechanics would state that certain indispensable conditions existed, namely, strength to resist shock of projectiles, the shock of the guns in firing, the support of the guns while in their elevated position, and a constant supply of ammunition. This can all be done by strong, simple and effective methods. I am willing, however, to admit that expert designers must aid in this work, and I sincerely hope that this system will receive the aid of their learning and ability.
I do not approve of any system of lever lifts, because all such as I have seen leave the guns utterly unprotected, and besides, one set of guns cannot be fired over another set. While the weight lifted by levers is much less, yet this system is worthless in developing increased battery power. My main object is to destroy an enemy in a naval combat, and this must be done by directing upon him a heavier fire than he can return.
Armor will protect the ship where used, but so much of the ship is left unprotected that sea-going vessels will have to do their work quickly, or else the unprotected parts will practically be destroyed.
I anticipated that some naval men would object to giving up the present upper works, but this must be done to gain the great increase in battery power. This great offensive fire is after all the best protection to the ship carrying limited armor.
I believe that my patent points out and covers the field for concentrating upon an enemy a greatly superior fire with the same number of guns. The various ways of lifting the guns are detailed at length in its specifications.
Assistant Naval Constructor Hobson.—in the valuable and interesting discussions above, the ideas advanced agree with and emphasize the conclusions arrived at in the paper, except in the following cases:
1. Where it is advanced in effect, (1) that the usual form of turret would present advantages over the form of disappearing turret suggested as best fulfilling the conditions, though the latter had perfected mechanism; and (2) that the rocking lever system presents advantages over the vertical lift or simple rise for use on board ship as well as ashore.
2. Where it is advanced in effect (1) that in the existing battle-ships of usual types the hull is better protected than the heavy turret guns; and (2) that the issue of probable engagements will be determined more by injury to the personnel than by the other forms of injury inflicted and sustained. The first two cases affect the disappearing gun proper, the last two involve the broad question of relative protection and the distribution of armor.
I.
1. Turrets, whatever their form, are destined to perform an office for guns whose positions of emplacement are determined or fixed.
To compare two systems of turrets with a view to determining their relative merits, particularly with regard to the question of weight, they should be considered as fulfilling their office for the same guns in the same position. The weight of armor in any system varies directly with the height of the gun above the protective deck. To compare rationally the weight in two different systems this height must therefore be taken the same in both.
In the case sketched in Fig. 17, page 611, the guns must fire at a certain height above the upper deck. The turret shown as fulfilling this condition cannot be compared for weight with one of its own or any other type that leaves the guns below the level of this deck.
2. Obviously the conversion into the usual turret, referred to for illustration in the discussion, should be made with the guns in the raised, and not in the lowered, position as advanced. The fixed armor, which is the same as the fixed armor in the usual case of barbette or turret, must remain the same. The armor to increase the thickness of the light turret must be additional. The condition of weight becomes the same as set forth in the paper, a small reduction in the weight of additional mechanism, and a heavy increase in the weight of turret armor, a net increase of about 180 tons for two 12-inch turrets. Thus the usual system compared with the disappearing system in the figure referred to, instead of economizing weight as advanced in this discussion, entails a substantial increase.
In the lowered position the turret guns are protected by the armor of the barbette, practically equal to that of the movable turret in the ordinary system, increased by the armor of the light turret—equal to about 1/3 this armor—and in addition by their invisibility.
Opposing battle-ships are destined in the course of engagements to come into close proximity with each other, and it is at these critical periods that protection will be overmatched by the weapons. Pointing will require but a short time, and the disappearing guns would be but a short time in the raised position, with the possibility of this time being made to occur more or less when the enemies’ guns are not ready for firing; while on the other hand, during the comparatively long period of loading which may extend, after firing, beyond the period of exposure, they will enjoy the protection of additional armor and invisibility.
In the critical periods of passage at close quarters this additional protection is of precious value. At such short ranges special targets will be selected, and their selection will play an important role in the issue, notwithstanding the allusions to the contrary contained in the discussions.
Invisibility, which is clearly the only method of protection practicable for the chaseB of modern guns, then becomes of enhanced value.
The maximum protection in the proposed system is thus seriously greater than the constant protection of the usual system, and is best available at the most critical moments, when weapons overmatch armor, and fire becomes accurate.
In view of this greater maximum protection afforded by the system, and in view of the fact that the minimum protection, occurring when the guns are in the raised position, overmatches the bulk of attacking weapons, while the time of exposure to weapons by which it is overmatched can be regulated at will to correspond to the probability of being hit, it becomes clear that the mean effective protection of the system is superior to the constant protection of the usual turret, which is overmatched by attacking weapons at critical moments of passage at close quarters and which, on the other hand, by virtue of inordinate weight, overmatches out of all proportion the weapons by which it is liable to be struck at moderate ranges.
Thus, for protection, as for weight, the advantage lies on the side of the proposed system.
3. The time required in the operation of turning to and from the position for lowering, the time for lowering and the time for rising depend on the efficiency of the mechanism. On the supposition of perfected mechanism, this time would bear but a small ratio to the time required for loading operations. Moreover, there is no reason why, after firing, the operation of opening breech, wiping breech plug, sponging powder chamber, and making other preparations for loading, could not take place during the time of turning to the disappearing position and during the lowering process, while at the same time charges and projectiles could be proceeding on their way up from the magazine; indeed, there is no reason why a lodging place could not be provided for charges and projectiles which would always be in readiness at or Just below the position for loading; and then the process of loading need not detain the guns in the lowest position unless such detention is desired, for there is no reason why the features of this process could not be carried on during the process of rising and turning to the bearing of the enemy. Further, as set forth in the paper, the guns could be loaded in any bearing while in the raised position.
Thus, on the assumption of perfected mechanism, the disappearing property superposed would be practically independent of the service of the guns, except, in the requirement involved by a single position for disappearing, necessitating turning, a process that is rapid and precise, and that could be rendered to a certain degree automatic if desired; and the time passed in the lowered position, practically or wholly lowered, would be regulated at the will of the mind in charge. When, then, the greater protection of the lowered position were utilized to its greatest extent, the guns descending after each round, and when at the same time the greatest execution with the guns' were sought, the lowered position could be made to correspond to the necessarily inert period of the guns, causing but a very small reduction in rapidity of fire.
4. Turret guns mounted in the most advantageous positions on battleships have a dead angle of about 90°.
Nearly the whole of this angle, as pointed out in the paper, is necessitated by the other gun positions, and one of the main objects sought by the disappearing system is the redemption of this dead angle, amounting to nearly a quarter of the horizon. The risks that are liable to be incurred by firing over the positions of guns while below deck are pointed out in the paper, but the difficulty of providing against these risks is by no means of the order of the difficulty involved in the assumption of perfected mechanism for raising and lowering. It is easily conceivable that by the closing of electrical circuits means could be provided for automatically preventing any gun from firing when other guns would be endangered, or more simply for signaling such danger in a manner impossible to escape the notice of the gun captains.
The discussion advancing the ordinary turret against the disappearing system falls to refer to this redemption of the dead angle and consequent increase of the effective angle of fire.
5. In sum, on the assumption of perfected mechanism, the disappearing system presents for heavy guns serious, incontestable advantages, offers a material economy of weight, affords superior protection for which, in effect, the vertical column of armor is rendered telescopic with one or two thicknesses of armor available at will, to correspond to the degree of exposure, and increases substantially the effective angle of fire; while with all these advantages it necessitates but slight, if any, reduction in the rapidity of fire.
6. But the assumption of perfected mechanism is not warranted. Such a mechanism would require, not only a large source and reservoir of energy and a medium of its direct application, but also a transmission of this energy across Joints broken by vertical rectilinear movement as well as horizontal rotary movement and its application on the far side of these Joints to varied forms of appliances; and further, would exact with all the complexity, accuracy, and delicacy of these mechanisms and these Joints great robustness and solidity to withstand the severe strains entailed by the varied movements of the vessel in a seaway and the shock of projectiles in action. The difficulties in the way of perfecting such mechanism are pointed out in the paper and are strongly depicted in the first discussion. Until they are overcome the advantages set forth cannot be considered as belonging to the system, for, as pointed out, they are rapidly nullified ns the mechanism departs from a high state of efficiency.
The assumption that efficient means of dropping a gun into the lowered position, and by inference of raising it again, would be “forthcoming” was made perhaps without consideration of the feature of raising and lowering armor with the gun, and of the limit of space imposed when a barbette of usual size is employed. The assumption was made probably with a picture in mind representing the simple problem of raising and lowering a gun mounted within a spacious redoubt as on the Russian battle-ships, the disposition afterward suggested as the one best adapted for the use of the disappearing gun afloat.
Reference need only be made to the total lack of cover and the entire exposure to plunging Are, even at small angles, particularly from Are from ahead and astern, to show how uneconomically this vast weight of armor is disposed, the exposure becoming greater as the extent and weight of armor increase. The heavy guns on these battle-ships will probably be disabled partially or wholly by the shower of rapid-fire projectiles, particularly those charged with high explosives, before the enemy comes within the range where the probability of hitting justifies the use of heavy guns. The protection for the guns in these vessels would be far greater if the redoubt were cut and the armor carried around into two barbettes; one enclosing the two forward pairs of guns, the others the after pair; even then it would be most advantageous to make covers or hoods revolving with the guns and having openings for the guns to pass through to protect these enormous barbettes from plunging fire.
The weight of such a barbette, large enough to receive a modern gun entire, would be enormous, as pointed out in another discussion; the two in the case cited amounting to about the weight of the entire redoubt.
Where, however, such an uneconomical disposition of armor is adopted, where such waste of weight is permitted, and where no effort is made to take up protection for the gun and gunner during the time of sighting, a system is readily "forthcoming”; and the lever systems, barring those which employ counterweights, advanced as the most suitable for use afloat, present all the advantages pointed out in the paper. But where armor is economized and a barbette of the usual size is employed, where no attempt is made to protect the robust chase of the gun otherwise than by its invisibility when lowered, where, further, substantial protection is provided for the gun and crew while in the raised position; when, in short, a turret with its guns is to be lowered into and raised from a barbette of but slightly larger diameter, a system is in no sense readily “ forthcoming," while any lever system is obviously out of the question. A system of simple vertical rise is the only one possible. Thus far, hydraulics alone can offer any chance of supplying the power under the conditions imposed.
In connection with the comparison of the hydraulic system of simple rise and the lever system as made in the discussion, it is to be noted that the results of the practical test of the Buffington-Crozier 8-inch mount at Sandy Hook were excellent for time made, though this system of lever mount is precluded from consideration for shipboard use on account of its counterpoise feature which economy of weight prohibits, but it should also be noted that the time required for the rising and falling process for the hydraulic mount tested at Fort Hancock was also excellent, requiring but 15 seconds for each process, which time could of course be very much reduced in the lowering process, and it should be noted further in the comparison that the lift was 14 feet, no doubt double that of the 8-inch gun, and further that there were two 12-inch guns raised together mounted on a single platform, while the estimate for the lever mount was based on the weight of a single gun.
In sum, as set forth in the paper, the system of disappearing turret as embodied in the sketch plan, page 611, offers incontestable advantages, provided the mechanism is efficient; obstacles of a serious nature are confronted in any endeavor to provide efficient mechanism, while the necessity for efficiency is absolute; the conditions impose a simple vertical rise, for which hydraulic power is best adapted.
II.
The permeating object of design in a vessel of war is the realization of a maximum efficiency for each element of weight in its contribution to the ultimate object of enabling the vessel in the probable conditions of service to fulfill the role for which it is intended.
The apportionment of the total weight among the features is regulated by the degree of efficiency of weight assigned to each. When finally made, this apportionment should be such that no unit of weight could be transferred from one feature to another with injury to the efficiency of the whole.
The distribution of the weight assigned to a particular feature is governed by the same principle, and when finally determined, the conditions should be such that no element of weight could be transferred from the locality assigned it to another belonging to the feature without injury to the efficiency of the feature as a whole.
The question of the apportionment of weights is not treated in the paper and is not referred to in the discussion. However, assuming the apportionment made, the distribution of the weight assigned to armor protection is intimately involved. It is advanced in the paper that the heavy turret guns are better protected than the features classed together as the hull, and that additional weight and expense, if available for armor, should be assigned to hull protection. It is advanced in the discussion, on the other hand, that in effect the hull is over-protected in comparison with the protection of the guns, and that it would be advantageous to transfer part of the hull armor to the guns. It is further advanced by partial inference that casualties to personnel will constitute the main factor in determining the issue of engagements, a conclusion not altogether in accord with inferences to be drawn from the conclusions arrived at in the paper and from considerations pointed out below.
It is not necessary for the present purpose to enter at length on the evaluation of the efficiency of the armor weight assigned each feature or element in the usual battle-ship.
In order to arrive at a general conclusion as to the relative protection of the hull and of the guns, and as to the advisability of a different distribution of armor weight, it will suffice to point out simply the salient features involved.
III.
Armor Weight assigned the Guns.
1. The efficiency of any element of armor weight protecting any feature is measured by the demand for protection, resulting from the importance and the vulnerability of the feature, and by the effectiveness of armor in supplying this demand.
2. (1) Every element of offense partakes essentially of the nature of defense from its silenclng effect on attacking weapons. In consequence, the quantity representing the importance of the guns should have an enhanced value, a greater exponential weight. But it is to be noted that the silencing effect varies in importance inversely as the degree of armor protection of the enemy’s guns, being greatest where protection is least, as in unarmored and unprotected vessels, and in partially protected and unprotected guns, and least where the protection is greatest, as in battle-ships and armored coast-defense vessels, and in heavy turret guns. Thus, though the dual nature of guns is an important consideration, it affects worst the cruiser classes, while on battle-ships it affects most the medium caliber and light guns.
(2) The value of a gun attacking armor passes rapidly from practically zero when the gun is overmatched, to a high maximum when the armor is effectually overmatched. The maximum is practically reached at the present stage of the development of explosives when the gun can drive an explosive projectile through the armor so that its explosion takes place on the inside, which at present may be considered as taking place when the caliber of the gun approaches twice the thickness of armor.
When this point is reached, further increase of caliber is disadvantageous as far aB the particular armor is concerned, being advantageous only where there is other armor to be attacked beyond the first armor.
When the armament of a battle-ship has been determined by this principle, and a developed battery is carried that overmatches the light armor of the usual battle-ship in the sense of being able to drive a semi-armor-piercing projectile whole through it, then such a battery, without diminishing the value of the heavy guns, must be ranked alongside of them in first importance, in view of the vast area of light side armor now carried and the grave features it protects. It follows, then, that such a battery should receive an equal consideration with the heavy guns in determining the distribution of armor.
It is interesting at this point to note that the principle above enunciated is followed only in the case of our three battle-ships of the Indiana class, though with these vessels it cannot be said that the principle is wholly carried out on account of the armor for protecting the 8-inch guns not being proportioned to their importance, being of insufficient thickness, and not extending to the casemate armor; while our other three battle-ships, the Iowa, and the Kearsarge, and Kentucky, attain, after the Indiana class, a nearer approximation than any other vessels built, building, or designed.
The Iowa falls short on account of the caliber of her heavy guns, 12-lnch, not outclassing the usual heavy armor whose thickness is designed in view of this caliber; though, on the other hand, the 8-inch battery, with barbette armor extending to the level of the casemate armor, approaches nearer the required degree of protection, while the Kentucky and Kearsarge fall short in having but two 8-inch turrets instead of four, and having these hampered in their independence of action; though, on the other hand, an increased thickness has been given the armor protecting these guns, making their protection accord more nearly than in the other vessels with their importance. It should not, of course, be lost sight of that these last two vessels have superposed a more developed rapid-fire battery which would be very effective if vessels of the cruiser classes came within range in a general engagement where the silencing effect of this battery could be effectively employed. The Iowa approaches very near to being an ideal flagship for a fleet of the Indiana class; she would be an ideal battle-ship as far as battery is concerned if her 12-inch guns were 13-inch, and the thickness of armor on the 8-inch turrets were increased 3 inches. To make the Kearsarge and Kentucky approach the same ideal it would be necessary to add two more 8-inch turrets, one on each waist, completing a lozenge. In both cases there would have to be an increase of displacement and cost, though, if necessary, about 1/3 of the 5-inch battery of the latter vessels could be sacrificed to furnish part of the weight.
It is of further interest to note that the system of hull armor now adopted in English construction, studied on the Renown and developed on the Majestic class, is an effectual reply to the semi-armor-piercing projectiles, referred to as influencing the thickness of armor.
The 8-inch gun is overmatched entirely, and heavy guns can penetrate only with armor-piercing projectiles, whose destructive effect is not comparable with the destructive effect of explosive projectiles.
This veritable fleet of battle-ships, created at one call to the English nation, of themselves alone exceeding by ½ the number of all our battle-ships yet authorized, is comparatively invulnerable, and will remain so till a semi-armor-piercing projectile can be counted on to pass whole through 9 inches of armor.
Returning to the point established above, the heavy guns in an armament designed for use against all systems of armor now existing, except the one referred to above, now adopted in England, shares the first importance with the guns of next lower caliber, and should share with them the first consideration in assignment of armor weight.
3. (1) The mechanism, supports, communications, personnel, and other accessories of the heavy guns are of great innate frailty for resisting the attack of weapons and demand an absolute protection. This demand, however. Is fully met by the barbette or fixed armor as far as its protection extends.
(2) The vulnerability of the gun proper is small, and as far as its protection alone is concerned the protection of heavy armor as carried in the usual turret is altogether inordinate.
(3) If the personnel, mechanism, and accessories could be abstracted from the gun and could be placed and could remain below the level of the barbette, while an armored hood or cover, revolving with the gun platform, covered the top of the barbette, then the demand for a revolving turret would not exist, provided the breech plug and its vicinity could be protected during the operation of loading by having the breech sink below the level of the barbette cover, ns provided for in the most interesting semi-disappearing gun-mounts referred to in the discussion as submitted in one set of plans proposed in bids for battleships 5 and 6, or by means of vertical hood armor rising over and extending to the rear of the breech, carried by the revolving armored platform forming the cover of the barbette.
In sum, the gun itself is robust and but slightly vulnerable, while its mount and all accessories are frail and very vulnerable. Heavy armor is an absolute necessity for the protection of the latter, but is not required for the former, and in consequence a heavy revolving turret is not necessary if other heavy armor protection is available for the mount and accessories.
(4) For the turret guns of medium caliber the vulnerability is precisely the same as pointed out for the heavy guns.
4. (1) The natural envelope of the supports and accessories of turret guns is a vertical cylinder of moderate diameter of section.
(2) A vertical cylinder lends itself most advantageously for the application of armor, for it presents as a projected target a mean angle of impact of large obliquity, while its form is self-sustaining.
The armor applied to the protection of the heavy guns is thus most effective, presenting its face obliquely and sustaining itself by its inertia and the support of its own parts.
(3) The same observation applies with even greater force to the armor of turret guns of medium caliber.
5. Thus, in sum, in evaluating the degree of efficiency of armor weight assigned to the protection of the guns, the following facts are to be considered:
(1)For the barbette or fixed armor, the demand for the protection it affords is absolute, nothing but armor protection is available, and armor applied is effective; in consequence, armor weight applied to such barbettes or fixed turrets has a high degree of efficiency. In the case of heavy guns, the thickness of barbette usually adopted is sufficient, outmatching the heaviest calibered guns, and, in consequence, but slight advantage would be gained by increasing the thickness, while decreasing it would incur disadvantage.
In the case of medium caliber guns which overmatch light armor, this barbette in usual cases is insufficient in thickness, in some cases does not extend to the protective deck, in others is altogether lacking. The protection of such guns is not commensurate with their importance, their vulnerability, and the effectiveness of armor so applied.
(2) For the turret proper or revolving armor there is but slight demand for its protection from the gun proper; and for the accessories and personnel, which require such protection, it is possible to make other provision in the case of the heavy guns, though this is impracticable in the case of medium caliber guns, whose mechanism is grouped in close proximity to the gun itself.
Where, however, the heavy turret is employed, it is to be observed that the vulnerability of the accessories grouped near the gun is less than that of those below in the barbette, the personnel accessory being capable of relief, being replaced when injured. The thickness of armor employed, somewhat greater in usual cases than the thickness of the barbette armor, is not well proportioned to the demand for protection. It should be observed, however, that as long as any such turret is retained there should be an endeavor to place the accessories below in the barbette as much as practicable, and to dispose them in such a manner as to be the least vulnerable when retained in the turret; but even then the thickness should never be reduced, in a vessel expected to engage at close quarters, below the figure which gives perfect immunity from the penetration whole of any explosive projectile, or below the figure which excludes under all conditions all projectiles from guns other than the heaviest, not considering, of course, the case of a turret that has recourse, when needed, to the protection of the barbette and of invisibility. For a design at the present moment 10 inches would be such a minimum, this being a safe figure probably for some time to come.
On the other hand, with the medium caliber guns destined to overmatch light armor, carrying the vulnerable accessory more with the gun, the thickness of armor is insufficient, and as in the case of the barbette, is not properly proportioned to the importance and vulnerability of the guns and the effectiveness of armor applied to them.
In sum, a high degree of efficiency is enjoyed by the weight assigned to the barbettes for heavy guns, but a lower degree only belongs to the revolving turrets proper. A high degree belongs to the armor weight assigned for both barbettes and turrets for medium caliber guns, but the quantity of weight is insufficient.
There would be advantage in reducing the weight assigned to the heavy turrets and in increasing the weight of armor assigned the medium caliber guns.
As concluded in the paper, there would be no adequate advantage in increasing the weight of heavy turret armor, though there would be advantage in increasing the protection of the guns taken as a whole, this increase taking the form of increasing the protection of the medium caliber guns, which latter question is not treated in the paper.
IV.
Armor Weight assigned the Hull.
1. The great importance of the features protected by hull armor need not be entered into, being apparent. It will suffice to point out that the integrity of each one of these features, floatability, stability and uprightness, and vitals, is essential, not only to the use of the guns, but also to the use of the torpedo and ram, to the very existence of the vessel.
2. (1) The vulnerability of the features of floatability, stability, and uprightness is set forth in the paper, and not being questioned in the discussion, need not be entered into again. It will suffice to recall that the portion of the hull through which the enemy of all these features, the great enemy of all hollow floating bodies, the ever ready water, may enter has but n fraction of its area covered by armor. It will suffice to recall that but a fraction of the hull liable to alternate immersion and emersion is covered by armor, that vast areas are at the mercy of projectiles and fragments of all kinds, which coursing along the side can cut open long gashes, or flying outboard tear off whole lengths of plating, laying the wall open to the entrance of water, while the portion with armor is but partially exempt.
(2) But the vulnerability of the most, important of all features, the vitals, should be looked at more closely. These comprise the organs of locomotion and explosive objects, including compressed gases as well as explosives proper.
The nature of all of these objects is most delicate, most susceptible to derangement that would cost the ship its existence; their protection, if possible, should therefore be absolute. In their position below the protective deck they are liable to injury from above and from the sides.
Wherever a deck, however heavily armored, can be reached by explosive projectiles it is liable to disruption, and it can be laid down as a principle for the present stage of naval progress that when a protective deck worked near the water-line can be reached by a projectile entering at an angle of fall of 7° from any bearing without first encountering armor, or where the side armor above it is outclassed by semi-armor- piercing projectiles, or where the side armor below it is outclassed by armor-piercing projectiles, then an armored deck must be worked below it; and inversely, where there is no armored deck worked below the protective deck situated near the water-line, armor must be placed so as to intercept a projectile entering at an angle of 7° from any bearing before it can reach this deck, and the side armor above this deck must outclass all semi-armor-piercing projectiles, and the side armor below this deck must outclass armor-piercing projectiles, or else the protective deck must descend at sides to the lower edge of this armor.
The first conditions are fulfilled only by the five latest French battleships, now building, the Masséna, Bouvet, Charlemagne, St. Louis, and Gaulois; the last conditions are fulfilled only by the nine latest English battle-ships, the Majestic class.
In all other vessels yet built or designed, including all of our own battle-ships, there is no armored deck below the protective deck, and at the same time the light side armor is outclassed by semi-armor-piercing projectiles, which are thus liable to reach the protective deck and explode in contact with it and hurl fragments below into the fragile or dangerous vitals, while the protective deck is exposed further in a greater or less degree to the explosion in contact of projectiles entering above the light side armor, particularly from bow and quarter bearings on which the turrets would not be encountered, and such explosion would blast the deck in the region, likewise hurling fragments on the dangerous mission into the vitals.
It is interesting to note that the disposition on the French vessels referred to, which were the first designs to fulfill the conditions above which provide for a lower armored deck at the level of the lower edge of armor, will provide greater security for the vitals, though it will admit greater internal destruction above, while the disposition adopted in the English vessels, though giving a less guarantee for the vitals, will reduce to a very great degree the internal destruction by excluding all explosive projectiles, by the uniform thickness, 9 inches of side armor.
The fact should be taken account of, however, that development is rapid along the line of explosive projectiles, while the life of a vessel of war is long.
The day is probably not very far distant when 9 inches of armor will be overmatched by semi-armor-perking projectiles, while there is certainly progress already for the penetration of armor by projectiles carrying high explosives. The English disposition, though perhaps offering better advantages for to-day, will tend to become obsolete, while the French disposition is good for all time.
Thus, in all vessels, with the exceptions above enumerated, the vitals are seriously menaced from above.
But their exposure is not limited to this direction alone. It was pointed out in the paper that the lower edge of armor emerges in the usual cases at an angle of roll below 10°, while the vessels would engage when rolling double that angle. In only a moderate seaway, when the vessel rolls but moderately, or where a wave trough passes along the sides, there will be exposed large unarmored areas below the lower edge of armor abreast the vitals.
In evaluating the time element to which the thickness of armor should in general be proportioned, it is to be remembered that the exposure takes place at the ends of the roll, where the pendulum lingers to reverse its swing, and though in this interval the probability of the unarmored zone being hit is small for the slowly-firing heavy guns, it is larger for the multitude of smaller calibers in proportion to their number.
Along the vast area of this exposed zone there is no obstruction to impede even the smallest rapid-fire projectile from reaching the magazines and steering engine and gear, while the coal obstruction abreast the boilers and engines is inadequate against rapid-fire projectiles of even reduced calibers. This exposure of the vitals from the sides, which appears in rolling, not infrequently experienced even in the usual sea swell, grows rapidly in seriousness as the sea rises, and in but a moderate fighting seaway becomes by far the greatest menace to the vessel of usual type, whose power of locomotion, whose very existence, stands a free though intermittent target to guns of practically all calibers.
This weakness is an attribute of the battle-ships, built or designed, of all nations. It is less pronounced in those destined to engage in the relatively smooth waters of the Mediterranean. Even for these waters the limit of 4 feet 11 inches set by the French for the desired depth of the lower edge of armor is insufficient, as are also the ameliorations adopted in recent English practice, 5 feet 6 inches in the Royal Sovereign class and 6 feet in the Majestic class, which with larger beam are destined for the high seas. As for our own battle-ships, the designed depths adopted for the lower edge of armor, 4 feet 6 inches in the Indiana class and the Iowa, reduced even to 4 feet for the Kearsarge and Kentucky, are better suited for still water than for the western Atlantic.
Thus the vitals, notwithstanding their careful location below the water-line and below the protective deck, are exposed from above and from below, and being of fragile and dangerous nature, constitute the most vulnerable feature of the usual type of vessel. Thus, for float- ability, stability and uprightness, and for vitals, the hull in the usual battle-ship is in the highest degree vulnerable.
3. (1) Each kind or disposition of hull armor, heavy side armor, light side armor, deck armor, must extend over a large area to be effective even in a small degree for the protection of floatability, stability and uprightness, or vitals.
(2) The vertical armor has approximately a plane surface, presented practically normally on certain- bearings; it is not self-sustaining, requiring special structural supports, which are of slight efficiency when a shock is received from the inside, an occurrence liable to happen with the light side armor, particularly when the enemy is employing armor-piercing projectiles, which, making but small breaches on the side of entrance, may drive whole armor plates overboard on the other side. The deck armor offers an advantageous oblique angle of impact, but is not supported sufficiently to realize anywhere near its full resisting power.
In sum, the degree of effectiveness of hull armor, spread over large areas and inefficiently disposed, is small in comparison with the degree of effectiveness of turret armor.
4. Thus, in sum, in evaluating the degree of efficiency of armor weight assigned to the protection of the hull, the following facts are to be considered:
(1) The importance of the features protected is commensurate with the importance of the vessel itself.
(2) The vulnerability of the feature is great, and increases as the sea rises, when the demand for protection becomes absolute.
(3) Though subdivision, water-excluding materials and obturating materials are available for the partial protection of floatability, stability and uprightness, features overthrown by the entrance of water, armor alone is available to supplement the sea outside in the protection of the vitals against the violence of missiles.
(4) For protection from injury from above, the vitals demand either an immunity for the protective deck from explosive projectiles, an immunity that can be insured only by an adequate height of side armor of sufficient thickness to exclude explosive projectiles, or else an armored deck below the protective deck.
(5) For protection from injury from the sides the vitals demand, in the case of vessels on the high seas, armor on the sides extending to a greater depth than in any vessel built or designed, a depth in usual cases such that when floating at the designed water-line a roll of 15° should not emerge the lower edge of armor.
(6) The effectiveness of armor weight applied to hull protection is not great, the armor being spread over large areas, which form only a fraction of the areas necessary to be armored to insure security, and the disposition on these areas not furnishing a high degree of efficiency.
(7) Thus, in the case of the hull, the demand for armor protection is absolute, but the meeting of this demand can at best be but partial on account of the ineffectiveness of the armor weight thus employed.
In sum, as advanced in the paper, the hull is but partially protected, and the protection becomes more and more inadequate as the sea rises, notwithstanding the reduction in the number of hits. The demand for protection is great, the feature being of the first importance and in the highest degree vulnerable, but the reduced effectiveness of armor renders the meeting of the demand most difficult, the weight of armor being limited. In the usual vessel this demand is not adequately met, though full weight be given to the difficulty of meeting it, for the vitals in particular lack provision for protection which they must have to enable the vessel to fight securely in a seaway.
Not only should any additional weight available be assigned to providing a lower armor deck and extending the depth of the lower edge of side armor, but armor weight variously distributed in usual vessels in other localities would be more efficient so applied.
V.
Comparing the results arrived at in considering the efficiency of the armor weight assigned the guns and the hull respectively, the following deductions are to be drawn:
1. Due principally to the greater effectiveness of armor applied to turrets, the latter should he to a certain degree more highly protected than the hull.
2. This degree is fully reached by the fixed armor, the barbettes of the usual heavy turret guns; it is overstepped by the revolving armor, the turrets proper of these guns; it is not fully reached for the barbettes and turrets of the medium caliber guns that outmatch light armor. With the proper apportionment among the guns, the protection as a whole would overstep the proper degree of superiority. A surplusage of weight would be available for the hull.
3. The vitals are not protected in due proportion with the usual vessel; another deck should be worked over them and armored, and the sides should be armored to about double the usual depth with reduced and tapering thickness.
The weight for the deck could be partially supplied with advantage by reducing the upper or usual armor deck, and the weight of additional depth of armor could be partially supplied with advantage by reducing by about one-fourth to one-fifth the maximum thickness of the heavy belt and tapering it to 3 inches at the lower edge. The additional weight required should be supplied for the surplusage from the heavy turrets; the insufficiency then remaining should be taken from the upper part of the light side armor, and from battery armor not included in turrets, if additional displacement is not available for armor.
If the draught will not permit of two armored decks over the vitals, then a disposition should be adopted resembling that on the Majestic class, with side armor extending from 10 feet below the water-line at a thickness of 3 inches tapering to a maximum thickness of 10 inches at the water-line and thence to a thickness of 5 inches at a height above the water-line permitted by the weight, with the single protective deck dropped at the sides to 5 or 6 feet below the water-line.
As advanced in the paper, the heavy turret guns are over-protected. Any additional weight available for armor should be applied to the following purposes in the order named: 1st, to increasing the depth of side armor abreast the vitals; 2d, to working a second armored deck over the vitals; 3d, to increasing up to 10 inches the thickness of the turrets of the guns designed to outclass light armor and protecting its supports; 4th, to erecting transverse bulkheads, partial or complete, armored with special hard 2-inch armor to explode high explosive projectiles coming from forward and aft; 5th, to increasing the height of light side armor if already a complete belt, or completing it if incomplete.
It may be added that in the case of existing vessels with insufficient depth of belt and without the second armored deck on which, of course, the above provisions cannot be made, the security can be increased by sacrificing some weight of coal or other feature, and by working a strip of 3-inch armor about 5 feet wide on the wing longitudinal bulkhead on each side of the vessel abreast the magazines, with its top at the level of the lower edge of armor, and by working 2 inches of armor of the same width abreast the engines and boilers, the same being supplemented by the coal; the armor to be of special hard quality, and due provision to be made for its securings and support; in addition to this, athwartship bulkheads of light hard armor to be worked as described above to prevent high-explosive projectiles from reaching the protection deck.
VI.
1. The discussion which advances the proposition that the guns are under-protected compared with the hull advances also that injury to the personnel will be the principal factor in determining the issue of coming engagements, and that the desired co-ordination of protection should be made in view of a certain panic era of the personnel of the guns’ crews, rather than in view of the silencing or destruction of the guns.
The drawing of such conclusions from the examples of history, as done in the discussion, is liable to be found illogical, for when examined closely the conditions existing on board vessels of war will be found radically different from those that existed on the vessels that fought the battles of history. The structure that was then a simple hull with platforms carrying a homogeneous cargo of men and guns with a simple function to perform, is now becoming a complex body filled and ramified with organs and objects of all degrees of power and all degrees of delicacy, performing functions of varied nature and of all degrees of complexity.
The motive power has been transferred from the upper deck to a position below the water-line, and though reducing the number and exposure of the personnel, has introduced a series of delicate and dangerous vitals along a large proportion of the vessel's length.
The open decks have become subdivided, and the once numerous personnel in close contact, having now recourse to mechanical power, has been reduced to less than half its former number and is distributed in small groups almost entirely isolated from each other. In addition, in the case of armored vessels, which constitute the bulk of power whose fate will decide the issue of engagements, the conditions of resistance are radically different. In the battles of the past the projectiles found no objects that could resist them—no places above water they could not enter. Now, the localities containing important elements offer resistance of varying degree. When these localities are confined in extent, as those containing the heavy guns, the resistance is made to overmatch all weapons, and these localities, with but a small fraction of the personnel, concentrate within their security the bulk of the vessel’s offensive power.
With these radical differences in conditions it is hardly warranted to draw extensive inferences. It is the utter inadequacy of the past to throw light on the subject that causes the world’s imagination to be haunted and the intellects of naval students to be baffled by the phenomena that are to take place when these gigantic creatures, evolved by the nations, meet each other in mortal combat.
It is not necessary for the present purpose to enter at length on this broad subject, particularly in view of the limits of the discussion in question and of the applicability of the conclusions arrived at in the paper and in the reply above. It will suffice in order to arrive at a conclusion as to the part to be played by the casualties to signalize certain additional considerations.
2. (1) A large portion of the personnel is stationed below the protective deck. On the Indiana, whose motive power requiring men below is very moderate compared with the battery power requiring men above, out of a total number of 462 officers and men, 206 are stationed below the protective deck in action. This large portion is abstracted from casualties and is identified with the vitals.
(2) Of the officers and men stationed above the protective deck, the greater part are well protected, the protection increasing with the importance of the function. On the Indiana, out of the 256 men stationed above the protective deck, only 24 are without armor protection, and these have the duties least necessary and are widely scattered; 26 have the partial protection of the armor protecting the 6-inch guns, being distributed in 4 groups at considerable distance from each other; 52 are in the 8-inch turrets, in 4 groups entirely isolated from the rest of the vessel; 28 are in the 13-inch turrets, in two groups entirely isolated, and comparatively speaking, enjoying absolute security.
(3) The casualties will thus not only be moderate and take place among those who least affect the vessel’s welfare, but they will have no effect to speak of on the rest of the crew, particularly those associated with the important guns, who will be in entire ignorance of casualties outside of the turrets. A panic can take place only when the hull is injured, affecting the ship as a whole, and then it will be greatest below the protective deck, where there would be the fear of being imprisoned if the vessel went down. The vitals, not the guns, would be neglected before real destruction took place. In regulating the co-ordination of protection, if consideration is given the possibility of a panic, it should cause the addition of protection to the hull, not to the guns as advanced.
- The exposure of the personnel on the Indiana is thus as follows: for motive power, no exposure; for the 13-inch guns, 22 men in the magazines, no exposure, 28 men in the turrets, practically no exposure; for the 8-inch guns, 24 men in the magazines, no exposure, 52 men in the turrets, exposure to heavy guns only; for the 6-inch guns, 10 men in the magazines, no exposure; 26 men partially protected; at machine guns, 6 men with slight protection; wholly exposed, as above, 24 men.
Thus a battle-ship may be considered as having her motive power exempt from the effect of casualties, her heavy guns practically exempt, her medium caliber guns partially exempt, and the other personnel exempt in proportion to importance, while danger of panic can arise only from injury to the hull, when the vitals, not the guns, will be most affected.
Thus in sum, the issue where battle-ships are engaged will be but slightly affected by casualties to the personnel.
3. It is injury to the hull that will determine the issue in usual cases. The form the injury will take, whether sustained by floatability, stability, uprightness, vitals, or by combinations of these features, will vary with, and should be studied for, each individual vessel; it will be seriously affected by the condition of the sea and by the manner in which the attack is made. Taking our own battle-ships for examples, and speaking broadly, it will probably be injury to the vitals that will decide their fate. They will probably blow up from a boiler or magazine explosion, or have the engines or steering gear wrecked; the Indiana, Oregon and Massachusetts will probably have their stability overcome and turn turtle, if not first disabled or destroyed by injury to the vitals. In each case, all of the heavy turret guns and a part of the 8-inch guns, the proportion being greater as the sea runs higher, will probably still be in action when the end comes.
A. CRONEAN,* Naval Constructor, French Navy.—The objections raised by Assistant Naval Constructor R. P. Hobson, U. S. N., to the adoption of disappearing guns are of the most serious kind.
I wrote, a few years ago, in my essay on Guns, Torpedoes and Armor:* “The protection to be given to the water-line is proportionate to the protection afforded to guns. . . . If ships are constructed in which the guns have little or no protection, it will be sufficient to give the water-line comparatively small protection. The danger of sinking or turning over must be just a little less than that of having all the guns on board disabled one after the other.” As it is easier to protect a gun by thick armor than to protect the hull, the weak point of modern war vessels is consequently (as Mr. Hobson clearly points out) the protection of the vessel itself, either below the waterline or a little above. An increase of protection to guns is then by no means to be wished for, at least in the present state of things, unless it should be obtained without any increase whatever of obstruction or weight.
Now, it is obvious that the introduction of disappearing guns on board ships would necessitate new organs, which would render a modern warship more obstructed than ever. A vessel of war may be compared to a sort of clockwork, the different “movements” of which are not to be multiplied ad infinitum.
As far as regards weight, it seems to result from Mr. Hobson’s note that, in some cases which it is beyond our purpose to examine, some advantage might be gained by the adoption of the disappearing gun. This, however, in my opinion, would only hold good for coast-defense vessels. Mr. Hobson himself (see page 610) makes a distinction between coast-defense vessels and sea-going battle-ships. With the former, the gun remaining at the same level, we can, if we suppose that it will be raised only for a very short time, reduce the thickness of its armor, taking for granted that there is less danger of its being struck. In that case some advantage might be gained. But, if the ship under consideration is a battle-ship, as the fitting of a medium caliber battery will oblige the constructor to place his turrets one deck higher up than in the case of a coast-defense vessel, the aforesaid advantage must needs prove to be a mere loss. Judging from the sketches, the pit is protected by very thick armor, as thick as that of the armored turrets for the heavy guns now in use; and indeed it ought to be so, for a fragment falling into the pit might prevent the turret from rising and revolving, and consequently disable the gun. But that pit is larger than one of our modern turrets, not only in breadth, but also lengthwise, since it must be long enough to house the chases of the guns. In short, the protection to pits has the same height as the armor of one of the Iowa turrets, and a larger horizontal section; it then weighs more, and as the weight of armor of the moving part and the weight of the hydraulic raising gear have still to be added, the increase will indeed be considerable if the use of that system is not strictly limited to coast-defense vessels.
I have but little to say as regards the increase of defensive power. On shore the disappearing gun is rational, because as soon as it has disappeared, the projectile which would have struck it falls further on, with little or no damage. On the contrary, on board ships the gun cannot be considered apart from its floating carriage. It may be hoped that modern turrets, besides shielding the gun from the shots that strike its armor plating, will in some measure protect the decks and hull. But the disappearing turret would by no means afford the same protection, since in most cases the vessel would be reached instead of the turret, and the damage would be still greater.
The most interesting point of Mr. Hobson’s paper is that the constructor might seek to obtain through the adoption of the disappearing gun an increase of offensive power by increasing the arc of fire so as to avail himself of the successive disappearance of the guns immediately after firing. Mr. Hobson’s remarkable calculations give us a correct idea of the importance belonging to the improvements of the raising gear. In this there may be Borne theoretical advantage. But, practically speaking, it would certainly be difficult to avail one's self of the advantage thus gained. The period of loading would not be exactly the same for two turrets of equal caliber; the rise and fall would be more rapid with one than with the other, and turret No. 1, when raised, would hide the enemy from gun No. 2. Besides, it will be difficult to avoid delay in the command of the two turrets, especially if the commanding officer bears in mind that one of his guns may fire upon the other in case of slow working of the turrets, or simply if his commands have been misinterpreted. Moreover, circumstances will happen at sea in which all the guns on board cannot fire; in bad weather, for instance, the aft gun alone will be available. In such cases there would be considerable loss of time if the gun had to disappear after each round; or otherwise safety would be diminished if the gun remained in its firing position, since we take it for granted that the thickness of plating of the moving part would be reduced in disappearing turrets.
Besides, it seems probable that, in an engagement, an officer who has been for some time in command of his vessel will prefer using his turrets in their firing positions, and will altogether renounce the questionable advantage to be gained by the increase of offensive power.
On the other hand, Mr. Hobson clearly states that the increase of offensive power would be of some importance, especially for heavy guns, such as the “Peace-maker,” for instance. In this discussion Mr. Hobson compares the quantities of energy developed in a given time by two guns, one of 8-inch, the other of 12-inch, and concludes as follows: “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-inch projectiles and 8-inch 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.”
In this assumption Mr. Hobson is quite right. Though it would be beyond our purpose to examine whether the target would indeed be equally vulnerable to the 8-inch and 12-inch guns, I think that guns below the 12-inch caliber can be used with advantage to-day. Then, if the 12-inch gun is too heavy, and lighter guns are better suited to the purposes of modern war, there is no reason why we should have recourse to mounts which would only be advantageous in the case of heavy guns firing a comparatively small number of rounds.
In short, the adoption of the disappearing gun on vessels of war, though interesting in the theoretical point of view, seems, practically speaking, to be especially suited to vessels armed with heavy guns and exposing a reduced target to hostile fire—to vessels of the Katahdin type, which, instead of being ram-ships, would be changed into monitors. This, at least, seems to clearly result from Mr. Hobson’s interesting paper.
Assistant Naval Constructor Hobson.—The above interesting and valuable discussion arrived after the reply to the other discussions had been prepared. This reply, however, requires no modification, for the dlscussion is covered by the remark at the beginning of the reply, that the ideas advanced agree with and emphasize the conclusions arrived at in the paper. There is one exception, however, though it proceeds from the misinterpretation, the one likewise made in the first discussion, that the treatment of the paper in its consideration of the general principles was intended to apply to the pear-shaped barbette shown as inclosing the entire gun. Fig. 13, page 609.
This figure was suggested to accompany the inventor's sketch and illustrate how it would appear when reduced to the form of a possibility. The protection by heavy armor of the robust chase of the modern gun, with its oblique surface, narrow rectangular target drawn out horizontally. Is not desirable, and the increase in weight of armor involved is altogether inadmissible. It is not the disposition shown in this figure, but that of the figures on page 611, which is treated in the paper; in this case the barbette is circular in section and of about the usual diameter, with gateways cut for the chases of the guns in descending. When it is further recalled that the command of the guns there shown remains the same as for the usual turret guns, that they are not supposed to be raised a deck higher in order to be above the medium caliber guns, but that the latter are placed lower, the difficulty of so disposing them being elsewhere treated, it will be seen that the difference, advanced as to the question of weight, disappears altogether. The conclusion on this subject arrived at in the paper is beyond question.
There is no occasion to take issue with the idea advanced that conditions can be imagined such that, as when a portion of the battery is out of action, it might be disadvantageous to have the disappearing privilege, not caring for it at the time while it entailed inferior protection. It need only be remarked that this observation, founded on a conception of the employment of unperfected mechanism, enters the category of the disadvantages pointed out as incurred by such mechanism, annulling quickly all the advantages sought. On the conception of perfected mechanism, where the gun is below when desired only during its inert period, being raised but a fraction of this time, assuming a gun of large caliber, for the purpose of firing, while thus losing little, if anything, in rapidity of Are, enjoying a mean protection equal to or superior to the uniform protection of a heavy turret, it still possesses a possible recourse to greater security. Indeed, admitting perfected mechanism, the more precious the guns become, the more precious become the advantages pointed out. The supposition of perfected mechanism being made, the conclusions of the paper cannot be avoided.
Among the conclusions in the valuable discussion referred to, special note should be taken of the one that confirms the value of the 8-inch guns by the admission of equality with the 12-inch guns in quality of energy generated, an admission that perhaps could not be allowed under all conditions, though easily granted for a general comparison. In view of the great area of-most important armor outclassed by the 8-inch guns. It will be seen, referring to page 612, that though in a single round the 12-inch guns of the Iowa generate 104,000 foot tons, and the 8-inch guns but 64,000 foot tons, yet in a given time, sufficiently long, the total energy of the 8-inch guns will exceed that of the 12-inch guns in the ratio of 16 to 13.
Finally, it should be remarked that where special reply has not been made to divergence in any discussion from the conclusions of the paper, it will be found in each case that opposing positions taken in other discussions form ample reply.
* Further discussion on tire subject-matter of this paper is requested.—Ed.
* Joint inventor and designer of the Buflington-Crozier system of disappearing gun mount.
*Expert for Easton, Anderson & Goolden Ltd., London, builders of disappearing mounts on the Russian batlle-ships.
* Instructor at the French National School of Naval Design, author of " Construction Pratique des Navires de Guerre,” ” Canons, Torpllles et Culrasse," etc.
* "Canons, Torpllles et Cuirasse.”