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and energetic dep ortment in offensive operations, which is at the same time so consistent with its functions and so consonant with its spirit, we have shown that it must not be occupied with mere coast defence.
But if the navy is to be relieved from this home duty some other reliance must be substituted; the navy itself requiring, for its own establishments, not less than the towns and harbors, that the defence be complete. And this brings us to consider whether the floating defences mentioned above, namely, gunboats, floating batteries, and steam batteries, constitute the best reliance.
After considering these defensive means, we will examine the properties of forts and land batteries, these being the only other well-tried resort; and that a comparison may be instituted, we will confine ourselves to cases where the latter are properly applicable.
There are doubtlesss, situations where it may be necessary for us to present a defensive array, at the same time that to do so by fortifications alone would be impracticable; and it is not, therefore, prejudging the question we are about to eramine; it is neither underrating fortifications, nor overrating these floating defences, to say that these last are, some or all of them, indispensable in such positions.
Any very broad water, where deep soundings may be carried at a distance from the shores greater than effective gun range, and where no insular spot, natural or artificial, can be found or formed nearer the track of ships, will present such a situation; and we may take some of our great bays as examples.
Broad sounds and wide roadsteads, affording secure anchorage beyond good gun range from the shores, will afford examples of another sort; and harbors with very wide entrances and large surface exhibit examples of still another kind.
As, in all such cases, fortifications alone will be ineffectual, and, nevertheless, recourse to defences of some sort may be unavoidable, it has not failed to be a recommendation in the several reports on the defence of the coast, since 1818, that there should be a suitable and timely provision of appropriate floating defences. And until the invention of man shall have caused an entire revolution in the nature of maritime attack and defence, these or kindred means must be resorted to; not, however, because they are means intrinsically good, or suitable ander other circumstances, but because they are the only means applicable.
In the circumstances just referred to there is no alternative, and therefore no point to be discussed. The remaining question is, whether these floating defences are to be relied on in cases that admit of defence by fortifications.
And, first, as to gunboats. Although of undoubted use in peculiar circumstances, it will hardly be contended that gunboats afford a safe reliance in harbors that can be entered by vessels of magnitude. Ships becalmed or aground might be sorely harassed, if not destroyed, by a spirited attack from this force, and there are other situations wherein it would be very effective. But harbors defended by gunboats will not be attacked in calms nor with adverse winds; and it is not easy to believe that any probable array of these craft would impede or hinder for a moment the advance of a hostile fleet. Nelson, at Trafalgar, bore down in two divisions upon the combined fleet, each division being exposed to a raking fire; and, although suffering considerably from that fire, he was able, notwithstanding, to break the hostile line and defeat his superior adversary. What, comparatively with the raking fire of the combined dieet, would be the fire of a feet of gunboats ? Opposing no effectual obstacle to approach or entrance, these small vessels, scattered and driven upon the shoals
, would be kept, by the broadside of a few active vessels, at too great a distance to produce any serious effect upon the main attack by their desultory fire.
Although they might afford useful means of annoyance during a protracted occupation by the enemy of harbors that contained extensive shoal grounds and
shallow bays and inlets, they would be nearly useless in resisting the first assault, and in preventing the brief operation of levying contributions, or burning or spoiling national establishments.
The true reason of this feeble defence must not, however, be misunderstood. It is not that the boats do not carry guns enough or men enough for the object, but it is because, from the comparative weakness of the vessels, the guns and the men cannot be kept in an effective position.
There are, moreover, many harbors requiring defence in which there are no shoals whereon these boats could take refuge, and in such their capture or destruction would be inevitable should there be, at the same time, no river up which they might fly, or lateral issue through which they could escape to a safe distance.
Floating batteries, of which good use might be sometimes made in peculiar situations, would, we suppose, differ from gunboats in being larger, containing many guns, and in being stronger—that is to say, having thicker sides or bul. warks; and it has sometimes even been proposed to construct them with ball proof parapets, and with platforms open above, like, in these respects, batteries upon the shore. But, in whatever way formed, it is necessarily a part of the idea that they be strong and massive ; and, consequently, that they be unwieldy, incapable of sudden change of place, and incapacitated either to advance upon a defeated foe or to evade a victorious one. We are not, of course, now speaking of batteries moved by steam.
Being denied the power of locomotion, at least for any purpose of maneurring in face of the enemy, we are to consider these batteries as moored in position and awaiting his advance. Should the batteries be large, requiring deep water to float them, or should they be placed across or near the channel for the sake of proximity to the track of ships, the enemy would engage them at close quarters. All advantages of mobility—of concentrating his whole fleet upon one or two points, to which, under these circumstances, no relief can be sentof greater elevation and command, would be on the side of the assailant, with no countervailing advantage to the batteries, but greater thickness of bulwarks, Whether this excess of thickness should be considered a material advantage. since the introduction of large bomb-cannon into the armament of ships, is a doubtful matter. The batteries, if anchored across the channel, would have the further advantage of a raking fire: but we have seen that the raking fire of one squadron of ships upon another advancing is by no means decisive. The power of throwing the whole assailing force upon one or two points, of pouring upon the decks of the batteries a greatly superior force of boarders, would, of themselves, seem to leave little room to doubt as to the issue.
If now we suppose these floating batteries to be smaller, so that, having a lighter draught, they might be placed near the shores or upon the shoals, they might certainly be thereby saved from the kind of attack which would proves fatal if anchored more boldly in deep water ; but they would, at the same time, lose much of their efficiency from their remoteness, and positions wherein they would be secure from being laid alongside, while they would be in a proper attitude to contribute materially to the defence of the harbor, are afforded but rarely. It is doubtful whether, as a general rule, these smaller floating batteries, notwithstanding their greater capability of endurance, would afford a better defence, gun for gun, than gunboats; or, in other words, whether this capability of endurance in the one would be more than a compensation for the power of locomotion in the other.
But whether near the shore or in the channel, whether large or small, this description of defence, owing to its fixedness, connected with the destructibility of the material of which it must be made, will be exposed to attacks analagous to those made by gunboats on ships aground. The enemy, knowing of what the defensive arrangements consist, will come provided with the requisite number of sailing or steam vessels, armed with bomb-cannon, against which the thicker bulwarks of the floating batteries would avail nothing. He would, besides, hardly fail to provide himself with bomb-ketches armed with heavy seamortars; and as there could be no guarding against the effects of the long ranges of these, a few such vessels would, with great certainty, constrain the floating batteries to quit their position, abandoning every disposition approaching to a concentrated array. Not to mention other modes of attack which would seem to leave the chances of success with the enemy, it will be noticed that this kind of defence, whether by gunboats or floating batteries, has the same intrinsic fault that an inactive defence by the navy proper has; that is to say, the enemy has it in his power to bring to the attack a force of the same nature, and at least as efficacious as that relied on for defence; hence the necessity not of mere equality, but of superiority, on the part of the defence at every point liable to be attacked ; and hence, also, the necessity of having an aggregate force as many times larger than that disposable by the enemy as we have important places to guard. Should we, for example, have ten such places, and the enemy threaten us with twenty ships-of-the-line, we must have in all these places an aggregate of gunboats and floating batteries more than equivalent to two hundred ships-of-the-line; for it will be hardly contended that these defences can te transported from one place to another as they may be respectively in danger.
But what will be the relative state of the parties if, instead of gunboats or floating batteries, we resort to steam batteries ? Although much has been said of late of the great advantage that defence is to derive from this description of force, we have not been able to discover the advantages; nor do we see that sca-coast defence has been benefitted in any particular by the recent improvement in steam vessels, except that, in the case before adverted to, where, from the breadth of the waters, defence from the shore would be unavailing, a more active and formidable defence than by gunboats and floating batteries is provided. It must be remembered that by far the greatest improvement in steam vessels consists in having adapted them to ocean navigation; and one inevitable consequence of this improvement will be that, if the defence of harbors by steam batteries be regarded as securing them from the attacks of ships of the line and frigates, or, at least, of placing the defence quite above that kind of attack, they will no longer be attacked by sailing vessels, but by steam vessels, similar in all warlike properties to those relied on for defence.
Not only is there no impediment to transferring these vessels across the ocean, but the rapidity and certainty of these transfers are such as to enjoin a state of the most perfect readiness everywhere and at all times, and also a complete independence of arrangement at each particular point; both the state of preparation and the independence of arrangement being much more important than when the enemy's motions were governed by the uncertain favor of winds and weather.
It is not easy to conceive of any important properties belonging to steam batteries acting defensively that the attacking steam vessels may not
bring with them, or, at least, may not have imparted to them on their arrival upon the coast, unless it should be thought proper to give to the former a greater thickness of bulwark than would be admissible in sea-going vessels.
But the peculiar advantage conferred by steam lies in the facility of moving with promptitude and rapidity; and any attempts to strengthen the harbor vessels by thickening their bulwarks considerably would unavoidably lessen their mobility, thereby partially neutralizing the advantage sought. At the same time, it is extremely doubtful whether any benefit would be derived from the thicker sides. It is probable that the best kind of bulwark for these vessels and all others is that which will be just proof against grape and canister shot fired from moderate distances; because, with such bulwarks, a shell fired from a bomb-cannon within a reasonable distance would pierce both sides; that is to say, would go in at one side of the ship and out at the opposite, producing no greater effect than a solid shot of the same calibre, while, with thickened sides, every shell would lodge in the timbers, and produce terrible ravages by bursting.
In the practice with these missiles in this country it has been found difficult to lodge a shell in thin targets, even when the load of the gun was so reduced as to increase materially the uncertainty of aim. As it is probable, therefore, that the protection from solid shot afforded by massive bulwarks would be more than counterbalanced by the greater injury horizontal shells would inflict by means of these bulwarks, we may conclude that the harbor steam battery will not differ in this respect materially from the attacking steamships, and, if they do differ in having more solid and impervious bulwarks, that no advantage over the enemy will result therefrom. We come, therefore, to the same result as when considering the application of the other kinds of floating force to the defence of harbors; and this result is, that there is no way of placing the coast in a condition of reasonable security but by having at any point the enemy may happen to select a force in perfect readiness which shall be superior to that brought to the attack.
The reason of this coincidence of result is, that no peculiarity in form or de tails can disguise the difficulties or essentially modify the conditions inseparable from the nature of a floating force.
Buoyancy is a condition necessary to every variety of the force, and to observe this condition a common material must be used in each—a material that is combustible, weak, and penetrable to missiles. If the weakness and penetrability be in part remedied by an increase of the quantity of the material, it must be at the sacrifice of buoyancy, activity, and speed-properties of great value. If a small draught of water be desired, it can only be obtained at the expense of that concentration of power which is a great and almost characteristic quality of naval armament.
It might not be strictly true to say that as much would be lost in one respect as would be gained in another; but, though modifications of this floating force, made with a view to adapt it to peculiar services, will somewhat disturb the equilibrium of the several kinds, there will still be no great disparity when acting in their appropriate way, and a little superadded force to the weaker party will restore the balance. None of these modifications, it should be observed, touch, on the one hand, the means whereby injury is inflicted, nor, on the other, the susceptibility to injury. All are still timber structures, carrying à common armament.
The necessity of having at each point a force at least equal to the attacking force will require large preparations on any supposition. With the navy proper, however, with gunboats and floating batteries, something has already been done; the existing navy will be an important contribution. Small vessels supplied by commerce would afford tolerable substitutes for gunboats, and from the class of merchant ships many vessels might be drawn for service as floating batteries; still there will remain great efforts to be made and great amounts to be expended to complete the defensive array. But a reliance on steam batteries would lead to expenditure vastly greater, because with them all has yet to be provided. Having at present no force of this kind on hand, (or next to none.) the preparation by the enemy of (say) twenty steam frigates would require the construction of two hundred of equal force on our part, supposing that we design to cover but ten of our principal harbors, leaving all others at his mercy.
Having shown that steam batteries cannot be substituted for shore defences, we will here add that they will, on the other hand, in certain cases necessarily increase the number of these defences, and in other cases augment their force. Channels which admitted only small vessels-of-war would, in peculiar positions, need no defence; in other positions their defence might be safely trusted to works of moderate force. The introduction of these vessels of small draught
and great power requires, however, that these passages should be defended and defended adequately.
We should not have gone so much at length into a branch of our subject wherein the general conclusions appear to be so obvious and incontrovertible, but for the prevalence of opinions which we consider not erroneous merely, but highly dangerous, and which, we think, must give way before a full exhibition of the truth. We do not anticipate any formidable objections to the positions assumed nor to the illustrations; but even should all these, in the form we have presented them, be objected to, we may still challenge opposition to the following broad propositions, namely:
1st. If the sea-coast is to be defended by naval means exclusively, the defensive force at each point deemed worthy of protection must be at least equal in power to the attacking force.
2d. As, from the nature of the case, there can be no reason for expecting an attack on one of these points rather than on another, and no time for transferring our state of preparation from one to another after an attack has been declared, each of them must have assigned to it the requisite means; and,
3d. Consequently this system demands a power in the defence as many times greater than that in the attack as there are points to be covered.
Believing that a well-digested system of fortifications will save the country from the danger attending every form of defence by naval means, and the intolerable expense of a full provision of those means, we will now endeavor to show that such a system is worthy of all reliance.
There has been but one practice among nations as to the defence of ports and harbors; and that has been a resort to fortifications. All the experience that history exhibits is on one side only; it is the opposition of forts, or other works enmprehended by the term fortification, to attack by vessels; and although history affords some instances wherein this defence has not availed, we see that the resort is still the same. No nation omits covering the exposed points upon her seaboard with fortifications, nor hesitates in confiding in them.
In opposition to this mode of defence much stress is laid on certain successful attacks that have been made by ships on works deemed strong. We have no doubt that all such results might be accounted for by circumstances independent of the naked question of relative strength; but at any rate, when carefully considered, how little do these results prove, in comparison with numerous other instances, in which there was an immense disparity of force in favor of vessels that have been signally defeated. These latter instances are those that should be received as a test of the actual relation between the two kinds of force; not certainly because they were successful, but because the smaller the work, its armament, its garrison, the less the probability that any extraneous influence has been in operation. A single gun behind a parapet, provided its position be a fair one, and the parapet be proof, need, as regards its contest with ships, owe unthing else to the art of fortification; and its effect will be the same whether the battery were fresh from the hands of the ablest engineer of the age, or were erected at the dawn of the art. The gun is in a position to be used with effect; the men are as fully protected by the parapet as the service of the gun
will allow; they are brave and skilful, and there is nothing to prevent their doing their duty to the utmost. These are all conditions easily fulfilled, and therefore likely to be so. The state of things is not less just and fair toward the vessel ; she chooses her time and opportunity; the battery goes not to the ship, but the ship to the battery; taking the wind, the tide, the sea—all
, as she would have them; her condition and discipline are perfect, and her crew courageous and adroit. Nothing, under such circumstances, can prevent the just issue of battle bat some extraordinary accident-possible, indeed, to either party, but easily recognized when occurring.
The contest between larger works and heavy squadrons may be much more