A Proposed Non-Sinkable Battle-Ship with a Constant Water-Line.
Translated by Lieut. Albert Gleaves, U.S.N.
[Mittheilungen aus dem Gebiete des Seewesens, Vol. XVI., Nos. III. and IV.]
In 1886 the French ships Thetis and Reine Blanche collided off Hyeres Roads, and the latter would have been a total loss had it not been for the coolness and the skillful seamanship of her captain, the present Rear-Admiral Pallu de la Barriere.
In the August of that year, Captain Barriere had published in the Revue des deux Mondes a paper upon the theory of saving ships from sinking under such circumstances, and this experience gave him the opportunity of seeking further the practical means by which this could be accomplished.
The solution of the problem Barriere thought he had found in the discovery of the properties of the fibres that envelop the fruit of the cocoa-palm, and which are generally known as amorphous cellulose. His idea—and it did not seem altogether unreasonable—was to construct a powerful armed and protected ship that would compare favorably with the heaviest armored ship completed or on the stocks, whose vitals would be invulnerable to ram and torpedo, and whose speed would surpass that of the large ironclads, notwithstanding its much smaller displacement.
The present plan of Admiral Barriere should, according to the Yacht, from which these notes are excerpted, satisfy all these conditions. It was perfected by the competent engineers of the Ateliers et Chantiers de la Loire, the accuracy of whose calculations can be relied upon.
The principal dimensions of the ship (see Figs, 1 and 2) are:
Length between perpendiculars, 120.51 m.; greatest breadth of beam, 19.5 m.; depth from main deck beams to water-line, 9.85 m.; mean draft of equipped ship, 7 m.; displacement of equipped ship, 9767 tons.
The calculated speed for the maximum draft of 7 m. is 19 knots, and a coal capacity is guaranteed for 4500 sea miles at 10 knots. The conditions that this plan should fulfill are as follows:
- Non-sinkability, and steadiness of gun platform, or, in other words, absolute buoyancy.
- Complete protection from hostile shot of the vitals of the ship, such as the engine and boiler rooms, the magazine, and the steering gear.
- Complete protection of the heavy guns and the conning tower, which contains the appliances for steering the ship and directing the battery.
- Sufficient protection of the light guns and the upper works from the destructive effect of shell with large bursting charges.
- The most effective means of attack and defense, and great speed with a proportionally small displacement.
We shall now discuss generally the means by which the above conditions may be realized.
I. Absolute buoyancy. The maneuvering power and speed of the ship should be maintained, and the use of the ram and gun guaranteed, under all circumstances. The division of the hull into water-tight compartments cannot alone answer these requirements, for the filling of one or more of these compartments would not only change the trim and consequently diminish the speed and lessen the advantages of the ram, but would also cause the ship to heel, thus rendering the use of the guns difficult if not impossible. Armor fulfills its object only when it is of proper thickness and extent, but it is always limited by the dimensions of the ship.
In regard to modern battle-ships, the question is not alone one of penetration of shot, but it is also necessary to consider suitable means for protecting the crew from the terrible effects of ramming, or the explosion of torpedoes, and the devastation caused by a melinite shell. That, however, which is most important in a battle-ship is a "floating belt," in the real sense of the words, that is, a belt which, acting automatically when penetrated, will stop a leak and arrest the inflow of water, thereby preserving the buoyancy of the ship and keeping it on an even keel.
The material for the belt of the proposed ship is cellulose, which, as has been already stated, is a stuff obtained from the fruit of the cocoa-palm, and has the color and form of ground coffee. Its characteristics are lightness, great elasticity, expansion, and resistance to friction and decay. It is also proof against destruction by insects, which cannot live in it. It must, however, be kept from direct contact with steel, and this is effected by a light coat of paint on the bulkheads. Its most important quality is its elasticity; that is, it will immediately close up in the wake of shot passing through it; and it is claimed that a ship provided with a girdle of cellulose may be riddled with shot and yet remain afloat with unaltered trim. The patent consists in a process of extracting the glucose. Its opponents declare that the glucose is not entirely extracted, and that the cellulose is liable to decay, and that it gives off odors which would be a strong objection against its use in ships. It is one of the lightest substances known, its sp. gr. being only 0.8. It has been applied in the Haytien and French navies, and the English shipbuilders have used it in a few vessels, although it is a question whether it is really serviceable. The term "coffer-dam" has been applied to the material because it serves to keep water out of the breach caused by the projectile.
The proposed belt which is to maintain the ship buoyant is arranged in three parts as shown in Fig. 3, which are separated by steel bulkheads. The outer part is filled with loose cellulose mixed with cellulose in different degrees of compression. At the midship section it has a thickness of one meter, and reaches 0.6 meter above the water-line, gradually rising as it approaches the ends of the ship until it attains a height of 2 meters above the water-line at the bow and 1.8 meters at the stern. It extends to 4 meters below the water-line throughout the length of the ship. As shown in Fig. 3, the belt is intersected by the protecting deck, and it is further divided by transverse steel bulkheads into water-tight compartments. The volume of these compartments in the centre of the ship is about 3.6 m2. It is known by experiment that the passage of a 42-cm. shot through this part of the belt (the outer part) will make a hole whose volume is 0.3 m2 or about one twelfth the volume of the compartment, and the thickness of the cellulose is diminished by compression from .12 to .11 of its original thickness. This proportion gives the amount of elasticity to be expected from the cellulose.
The other parts of the belt are divided by steel bulkheads five or six meters apart, and are entirely filled with bricks of cellulose. The middle part is 0.8 meter thick, and the inner one 0.7 meter thick. The three parts of the belt extend the entire length of the ship and have a total thickness of 2.5 meters. On the armored deck over the belt is a "rampart walk" from which the condition of the upper part of the belt can be observed.
The splendid results that cellulose as a leak-stopping material gave at the trials at Toulon in 1881-82, when a "coffer-dam" target was fired at with 14-cm. and 27-cm. guns, led to the conclusion that, with sufficient thickness and depth under water, a belt of this material would render a ship innocuous to wounds from either ram or torpedo.
II. Protection of the vital parts of the ship from the effects of artillery. The engines, boilers, magazines, and steering gear are protected by an armored deck that extends over the entire length of the ship. The crown of the deck amidships is 1.2 meters below the water-line and is 10 cm. thick; it dips down to the ship's side 2 m. below the water-line and on the inclined portions is 14 cm. thick. It is of compound steel, and shot can penetrate it only at moderately sharp angles. Therefore, this deck, which until recently was opposed, must be considered one of the most efficient means of defense.
III. Protection of the heavy guns and the conning tower. The ship carries two 42-cm. guns mounted in barbette, and two 27-cm. guns in revolving turrets. The barbettes are placed in the bow and stern; the forward gun has a sweep all around the bow from right ahead to 54° abaft the beam, and the after gun is so placed as to fire around the stern through an arc of 256°. The two 27-cm. guns are mounted in turrets on each side of the ship and have a lateral train of 180°. The barbettes and turrets are armored with 38-cm. plates backed by 20 cm. of teak. The additional twelve i6-cm. guns are installed in a superstructure that is plated with 10-cm. steel plate, and is therefore only protected from melinite shell.
The conning tower is shown in Fig. 4. Its form is that of a cupola with a somewhat elliptical profile; the plating is in two parts, and diminishes in thickness towards the top. The inside diameter of the tower is 10 m. The lower part is 30 cm. at the base and 20 cm. at the top; the upper part is 20 cm. thick at the lower edge, and this reduces to 15 cm. at the crown of the cupola. The two parts are separated by a space 15 mm. wide, which gives the greatest view possible of the horizon, and is at the same time sufficiently protected from shot from rapid-firing guns of small calibres. It is 1.8 m. above the floor of the tower, and a circular platform is provided for convenience when looking through. Twenty-one people are supposed to be stationed in the tower—the captain, executive officer, navigator, torpedo officer, midshipmen, and wheelsmen. The wheel, speaking-tubes, etc., are also placed here. The foremast passes through the tower, and is made strong enough to bear its entire weight. (See Fig. 3.) The mast itself is clad with a 10-cm. plate in which are cut rectangular sight-holes; a narrow door in the mast permits ascent to a platform inside.
IV. Protection of the upper works and the secondary battery against shell with large bursting charges. This protection consists of a compound steel plate which is fastened to the side and extends from 1 m. under the water-line to 3 m. above. Amidships it is 10 cm. thick, and diminishes to 8 cm. about twenty meters from the end of the ship. As already stated, the superstructure is plated with the same material.
A light splinter deck covers the redoubt and protects the gun's crew from shot out of the enemy's tops. It consists of two layers of chrome steel plates 4 mm. thick.
V. Means of attack and defense. Great speed. The armament of the ship, as we have seen, consists of four heavy guns, twelve medium guns, and twelve rapid-firing cannon, of which four are 65 mm. and eight are 47 mm., and also six 37-mm. revolving cannon. Two of the 65-mm. guns are placed forward and two aft; the forward ones fire through an arc of 135°, and the after ones through 200°. The 47-mm. guns are mounted in the tops, two in the main, and three each in the fore and mizzen.
A considerable amount of ammunition is allowed:
75 rounds for each of the 42-cm. guns,
110 rounds for each of the 27-cm. guns,
110 rounds for each of the 16-cm. guns,
500 rounds for each of the R.F.G.
700 rounds for each of the machine guns
The weight of metal that the ship can deliver ahead and astern is 1212 kg., and on the broadside 1776 kg.
Vice-Admiral Bourgeois was of the opinion that the 42-cm. guns should be placed in turrets, and the 27-cm. guns in barbette. Indeed, the great importance of the heavy 42-cm. guns makes it essential that they have the greatest amount of protection when at close quarters, and this can be obtained only by turrets. The Director of the Chantiers de la Loire, who recognized the force of this objection, had also prepared a plan for installing the guns in this way, but found it impracticable owing to the colossal dimensions and great weight of the turret, and the fact that the smallest variation in the revolving mechanism would render the training of the guns impossible. The question was therefore decided in favor of barbette towers.
Of the twelve 16-cm. guns, eight are mounted in broadside; the other four are placed in the angles of the superstructure, and can be trained in line with the keel as well as on the beam.
The proposed ship will have a speed of 19 knots, and will therefore be superior in this respect to almost all other battle-ships completed or in course of construction.
The most difficult part of the problem was the selection of the type of engines and boilers sufficiently powerful to realize this, and at the same time of such dimensions as would permit their being placed entirely under the armored deck, which is 1.2 m. below the water-line amidships and 2 m. at the sides. It was finally decided to have two horizontal triple-expansion engines for each screw placed in line. Each engine is in a water-tight compartment, and so arranged that the two engines working the same shaft can be uncoupled and worked singly. This arrangement is considered the most economical, especially with reference to the consumption of coal and lubricants, owing to the great variations of speed that would probably be required of such a vessel.
Steam is supplied by twelve cylindrical boilers. Each boiler has two furnaces with corrugated fire-tubes of the Fox system. On each side of the fire-room are six boilers, arranged in three groups, each boiler in its own watertight compartment. The two forward groups have the same smoke-stack, and are separated from the after group by an athwartship coal-bunker. Each of the six fire-rooms contains a ventilator for forcing the draft when the fire-room is closed, and for ventilation when the fire-room is open and the draft normal.
The coal capacity is 650 tons, which is sufficient for 4500 miles at 10 knots.
We have outlined the plan suggested by Rear-Admiral Pallu de la Barriere of a modern battle-ship of the first class that would be a suitable antagonist of such vessels as the Nile or Trafalgar of 11.900 tons, or the Re Umberto and Sardinia of 13,800 tons. It only remains to speak briefly of the construction of the hull.
From Fig. 3 it is seen that the inner bottom comes against the lower edge of the cellulose belt. The space between the inner and outer bottoms is divided by four longitudinal bulkheads on each side of the keel. A longitudinal water-tight bulkhead is placed amidships over the keel, and reaches upward to the armored deck. A great number of transverse water-tight bulkheads serve to brace the ship and give it great strength and stiffness.
The ram is of cast steel and supported from the armored deck and by stout bow braces.
The Yacht concludes its report with the wish that the plan of Admiral Pallu de la Barriere, which is at present undergoing a rigid investigation by the Minister of Marine, may yield him enduring honor.
From the result of the recent exhaustive trials in France with cellulose, no positive conclusion can be as yet deduced as to the value of the proposed belt, and consequently of the proposed ship. In case, however, the peculiar characteristics claimed for cellulose are established by actual practice, we are not wrong in attributing to it a very important and significant value.
As the armored deck is considerably below the water-line and combined with the belt, by its thickness and the great strength given to it by the transverse bulkheads and division walls of steel, it will oppose a very strong resistance to the ram, and will prevent the penetration and destruction of the belt. Trials with the Belliqueuse at Toulon and the Resolute at Portsmouth show that the belt is also proof against torpedoes.
The decision of the French Minister of Marine, which will probably soon be made public, will be waited with great interest. Indeed, it may help to the final solution of the vexed question, "What is the best type of battle-ships?"
Gyroscopic Torpedoes.
By Chief Engineer N. B. Clark, U.S.N.
Two torpedoes are represented in which as much as possible of the machinery is arranged to revolve in order to secure the "directiveness" that accompanies gyroscopic action.
No. 1 is an electric torpedo driven by storage batteries, AA, which are keyed on the shaft and revolve with the screws. The batteries are not all coupled at first, but, by the aid of a clock-work, which is started at the launch of the torpedo, metallic brushes are successively depressed upon the collars, B, in order to throw on the power of fresh batteries and so maintain or, if desired, accelerate the speed at the close of the run.
No. 2 is a pneumatic torpedo in which the air-reservoir, C, is revolved with the screws by the pneumatic engine, D, the hollow shaft serving as a conduit for the air. A clock-work, E, regulates the admission of the air to the valve chest of the engine by moving a slide across an orifice whose shape and dimensions are such as best to maintain the speed near the close of the run. Direct gearing from the moving parts of the torpedo may be substituted for the clock-work in both torpedoes.
The trajectory of both torpedoes is governed by the cylindrical bellows, F, which is open to the sea, the water pressure being counterbalanced by the springs.
The tension on the springs is adjusted by the spindle. If, in obedience to the index and scale of depths, I.
When the torpedo dives too deeply, the springs yield to the increased pressure of the sea, and the accumulating weight at the stern throws the head of the torpedo up. When the surface is approached, the reverse action takes place.