Navies of the world

by Edward W. Very

Turreted vessels having a low freeboard should naturally have a smaller percentage of weight of hull, which is found in the heavier types to range between 30 and 34 per cent (excluding the Peter the Great, which is of a comparatively early construction). As an offset to this, armor is applied until the difference is made up, bringing the total weight about the same. The Onondaga deserves especial examination, as showing the attention (?) paid by Americans to this point. Her weight of hull is 15 per cent more than that of the heaviest wooden hull amongst the French frigates, and 33 per cent more than that of the Javary, a vessel of an exactly similar type. Her armor, turrets included, is 3 per cent less than that of the Gloire, instead of being, as it should, 15 per cent more, and 25 per cent less than that of the Javary. Hull and armor together are at least 10 per cent above the average. By a bad construction of hull a clear 30 per cent of weight was completely wasted.

The very low percentage of ordnance seems no doubt strange to many who talk loosely of heavy guns and projectiles without thinking that this element is one of solid dead weight occupying an immense space. From 5 to 7 per cent includes the entire range, from the vessel sacrificing ordnance to speed to the one with a maximum of ordnance and moderate speed, the Duke of Edinburgh being again an exception. The limits of weights of engines and boilers may be placed at from 11 to 13 per cent, and those of the coal supply from 8 to 11 per cent. Great diversity should be expected in the percentages of ordnance, engines, and coal in the second-rates, depending upon their special objects, yet as is seen there is scarcely 4 per cent difference between the extremes. The remaining percentage should be about the same throughout, with a slight variation for the proportion of sail-power, the total allowance for this latter being from 1 to 3 per cent.

By means of these tables the beginner may get an adequate idea of the limiting proportions of the main elements of a vessel. It is seen that the factor absorbing the greatest proportion of the displacement is the one that calls for a reduction, all others requiring extension. Weight of hull is an obstacle. In armor, by an increase of percentage an increase of defensive power is gained; with ordnance, an increase of offensive power; with boilers and engines, an increase of general effectiveness; with coal, an increase in endurance; while the percentage of spars, crew, and stores is a necessary constant. Thus the development of naval construction is seen to be a matter of vital importance. Had the Onondaga been properly constructed there would have been a useful percentage of fully 20 per cent to have been distributed in making her a sea-going vessel. This fact is plainly brought out in the breastwork modifications of the monitor type, in which the breastwork is a clear addition of dead weight on a similarly formed and proportioned body without being of any assistance as additional freeboard. From the results attained in the Tegetthoff the lowest limit of weight of hull attainable with present perfections of steel construction may be placed at 34 per cent for first-rate frigates and about the same for second-rates. For turreted vessels it may fall to 28 or 27 per cent.

Although weight of armor is in a manner a direct measure of defensive power, it is an objectionable feature and one whose difficulty of counteraction has been almost insurmountable owing to the excessive cost of steel, whose superiority in the end was extremely doubtful. Within the past few years, however, a happy combination of iron and steel has been made which will go far towards saving percentage in weight, although apparently it will for some time to come make a saving in this direction of only the percentage between iron and steel framing. With iron framing and compound armor the same results of weight of hull and armor together may be attained that now hold with steel framing and iron armor, with the advantages of an increase in defensive power at about the same cost.

Wherever it is a question of rearmoring vessels, the compound armor is a great gain to the fighting power of the vessel, although in general the expense of the change is more than the result would warrant. The highest advantages of this armor are reaped by the second-rate cruisers, who retain their speed and coal capacity with an increase of defensive power that brings them within the fighting lines of first-rates.

Capacity for fuel is a matter of the greatest importance in time of war. England alone of all the maritime nations can afford to neglect this point. A man-of-war without steaming-power in war-time is helpless, and yet by the precepts of international law she is debarred from getting this material in foreign ports. Russia, having a peculiarly vulnerable home coast, easily closed and hard to reach, has with great wisdom sacrificed all qualities in her fast cruisers to the two of speed and coal capacity. Keeping her sail-power as the constant factor, the two important ratios of ordnance and armor are reduced to the lowest point, their gain being entirely transferred to the coal capacity.

In considering the most advantageous method of placing and distributing armor, problems without end arise whose consideration requires the most careful weighing of all the different circumstances of its use, and yet it is in this particular that are generally found the most positive assertions and criticisms from those who have given but little or no attention to the subject. For the protection of the battery and above-water sections of a vessel the extremes of position of armor are the vertical, giving the greatest possible extent of protection, and the horizontal, giving none.

Arguments without end are found in favor of this or that type, varying between the two limits. The truth is, however, that there is scarcely any choice between these extremes. Experiment has fully proved that inclining armor at any angle less than 50° is of itself no advantage as regards preventing penetration. Beyond this angle the great increase of weight necessary to make up the vertical space required necessitates a curtailment in extent of armor entirely neutralizing all the benefits of the inclination. There is left then no choice between the vertical complete protection and the horizontal or armored-deck system giving none whatever. In the vertical protection the question of distribution presents itself anew, varying between the long rectangle and the circular turret. The minimum turret diameter may be safely taken at 20 feet inside. Here the greatest economy of room is attained, but this economy involves a reduction in the number of guns, a limitation in the position, and, unless the French barbette turret be used, the possibility of disabling at one blow the greater part of the offensive power of the ship by jamming the turret. With the same amount of armor that is used in a turret of 20 feet, the broadside may be well covered for a length of from 15 to 18 feet, giving protection to double the number of guns. This advantage, however, is purchased at the expense of a more unfavorable disposition of weight and a complication of upper-work framing. These points bear directly upon the service for which the vessel is intended, and are so intimately connected with the whole general type of the vessel that it becomes the most complete absurdity to assert that turrets alone or armored broadsides alone shall be used. As weight of armor increases, the extent of its protection becomes one of the most serious of questions. In ten years from the date of its introduction it became impossible to completely protect the hull of the frigate, and in fifteen years we find it necessary to commence to strip the turreted vessel with her minimum of freeboard. If the greatest architects of the world find themselves almost at a loss to retain the effectiveness of the armor carried whilst keeping within proper bounds in weight, it is certainly idle for those who barely appreciate the necessity for covering battery and steering-gear to assert that armor should be carried thus and so.

The application of horizontal armor presents problems equally abstruse; more so in fact to the designer who does not fully appreciate all the obstacles to be surmounted and the real advantages which are to be obtained. A vessel having a heavy steel deck that shall fully protect her under-water sections and yet permit of such a division of above-water spaces as to permit her to be pierced with impunity whilst that space is left available for the many necessities of circulation and storage, is a consummation of architectural skill the most difficult of attainment.

The matter of properly proportioning the vital factors of a man-of-war, be she iron-clad or unarmored, is one of the highest consideration. To speak of designing ships to carry 40-ton guns and have a speed of 16 knots, and at the same time not to consider what are the absolute limitations in their construction, is as senseless as to attempt to rebuild a monitor without first finding out whether she will float or not after she is built. The Onondaga is an example of the first method of construction, the Puritan of the second. These two vessels represent the condition of naval architecture and construction in the United States for a period of ten years during which the naval architects of all the rest of the world have been advancing at giant strides.