Circular Iron-Clads in the Imperial Russian Navy.

We have been favoured with the following description of the Popoffka Novgorod, on of the new class of circular iron-clads designed by Admiral Popoff for the Russian Imperial Navy. This description faithfully represents both the ideas on which this class of vessel has been designed, and the manner in which the designer has embodied those ideas in the first circular iron-clad. The accompanying engravings exhibit bow and stern views of the ship, copied from photographs taken recently at Nicholaev.

Three years ago the first design for a circular iron-clad was submitted by Admiral Popoff to the Imperial Russian Admiralty with the object of obtaining a ship of small dimensions which should carry an armament of a few guns of the heaviest class, be capable of steaming at a speed sufficient for all purpose of coast defence, and at the same time be well protected by armour-plating. The principle on which the design was made is -- that, in comparison with ships of ordinary form, circular vessels have greater displacement with the same weight of hull, and therefore increased means for protecting the water line with a strong belt of armour, the decks with thick plating, and the guns with a strong armoured breastwork, thus insuring, in accordance with modern principles of design, the highest attainable amount of safety for ship and crew. The great advantage of the circular form is that it enables a vessel to be built of small draught of water, with the greatest displacement as compared with weight it is possible to give her. From this account it is evident that the present idea of a circular vessel has nothing in common with any project of the kind which has hitherto appeared, but is in fact an extraordinary development of the principle, carried out by Mr. Reed in the British Navy, of shortening ships for the purpose of obtaining handiness and reduction of weight, and broadening them to increase the displacement.

Having thus shortly stated the broad principle of circular ship design, we pass on to a description of the first Popoffka -- that being the name given to this type of vessel by the Emperor of Russia to perpetuate the name of the inventor. Popoffka Novgorod was launched in May last, in the presence of the Grand Duke Constantine, to whom, as High Admiral of the Fleet, and to Admiral Krabbe, Minister of Marine, belongs the credit of accepting the design, and ordering the construction of this vessel in accordance with it.

The extreme diameter of the hull of the Novgorod is 101 feet, her draught of water with all weights on board 12 feet 6 inches; to which draught must, however, be added the depth of the longitudinal false keels. Her displacement is 2,491 tons. The form of the midship (and of any radial) section may be best understood from the following description: -- The bottom is circular and flat, and parallel to the load water line, with a diameter of 76 feet; and from the turn of the bilge round the bottom the sections are curved, ascending in the form of quadrants of circles whose semi-diameters are equal to the depth of the vessel. The framing of the hull is composed of a network made of radial frames and circular stringers, plated both outside and inside. The armour extends 1 foot 6 inches above, and 4 feet 9 inches below, the load water line; the plates being placed upon a compound backing formed of T. Hughes' patent hollow girders, 7 inches deep, with the spaces between and within them filled in with teak. The plates of the upper strake are 9 inches, and of the lower 7 inches thick. Hollow girders are riveted to the plates behind armour, which are worked in two thickness each of 3/4 inch, and are supported from behind by strong frames, forming continuations of the deep beams of the upper deck: 7 hollow girders are equivalent in resisting power to two additional inches of armour; thus the thickness of solid armour plates is reduced to 9 inches instead of 11 inches, so that superiority in the material of which the solid armour-plates are made is secured, and at the same time good support is afforded to the armour from behind, and the general strength of the ship increased.

The upper deck beams run radially, and are connected with circular carlings. The protective deck plating is 2" 3/4 thick, and is worked in three thickness. In the centre of the ship stands the breastwork, 30 ft. 9 in. in diameter, and 7 ft. high. The sides of the breastwork are composed of the same skin and hollow girders as the belt along the load water line and the armour plates are 9 in. thick. The breastwork is open at the top to allow the guns to be fired over it en barbette, thus facilitating accuracy of training and giving an all-round fire. Two 11-in. 26-ton guns, firing projectiles 550 lbs. (Russian weight), with a charge of 91 lbs. (Russian weight), are mounted on separate platforms which can be moved independently or together when it is required to point both guns at the same time on one object. For that purpose there is a hollow cylinder in the centre, which serves as a scuttle through which powder, shot, and shell may be taken within the breastwork, and forms the axis round which each of the platforms with its carriage and guns rotates. The rollers on which the platforms rest move in two concentric circular paths., the motion being regulated by a special circular brake, which will stop the gun at any moment. The recoil of the guns is governed by a frictional compressor, worked by hydraulic power, and partly by wedges placed in the after part of the platform on which the carriage slides. The men who work the guns are completely under the protection of the breastwork.

The engines for propelling the ship, 6 in number, each of 80 nominal horse-power, working in the aggregate up to 3,000 indicated horse-power, give motion to 6 independent screws, having parallel shafts placed in a longitudinal directions. There are two principal reasons for this arrangement: -- First, the draught of the ship is so small that with fewer screws the large engine power required could not be developed; and, secondly, ships which are made to depend solely on steam as the motive power should be provided with as many independent engines as possible in order to reduce to a minimum the chances of breaking down by any cause which might stop their action. The engine and boiler-rooms in the Novgorod occupy the after half of the ship. In the middle are the powder-magazines and the shot and shell rooms. In the forepart, below the lower deck, are chain lockers and holds for provisions, water, and warrant-officers' stores. Two separate boiler-rooms, with four boilers in each, are placed symmetrically on each side of the diameter. Coal-bunkers are fitted alongside the boiler-rooms close to the wing-passage, which runs round the side of the ship. Under the breastwork on the lower deck are two parallel rows of officers' cabins, with a middle passage between them, running longitudinally, uniting the men's quarters in the forepart of the lower deck with the engine-room in the aft-part. The ward-room and captain's cabins are placed inside of the light superstructure built over the armoured deck at the forepart adjoining the breastwork. In this superstructure most of the space is allotted to the crew. In front of the superstructure, under the jack-staff, are placed the arms of the old Russian town Novgorod, and on each side of it Martin's anchors are stowed. The cables are carried through the side of the superstructure at its lower part and thence to the lower deck, where they are worked by steam windlasses. In the after part of the ship is a hurricane-bridge on a level with the deck of the superstructure and the top of the breastwork. The engine-hatch is fitted with high coamings which reach up to the hurricane-bridge. All openings in the deck are provided with armoured covers of the same thickness as the deck, and when these are closed the ventilation is maintained in an efficient state by forcing large volumes of air through the bottom of the breastwork and distributing it in all directions inside. Steam-fans are employed for this purpose. Two steam-launches and two other boats are usually carried on the deck, but are stowed on elevated supports whenever the ship goes to sea. The bottom of the ship is sheathed with wood and copper similarly to the Inconstant. The materials were all prepared at St. Petersburg, and were sent by rail to Nicholaev and there put together. It may interest our readers to know that a second ship of the Popoffka class, named the Kiev, has been recently built at Nicholaev, and will soon be ready to join her sister ship in the Black Sea.

When the Novgorod was lying at Sevastopol the Emperor honoured her with a visit, and examined all the details of her construction and her qualities during a cruise round the bay which he took in her. Last August she made a successful passage from Nicholaev to Sevastopol, and several times since Admiral Popoff has taken her out to sea to test her behaviour, taking advantage of high winds and heavy seas. The results of the trials, both as regard speed and other performance, have in all cases given great satisfaction to the Russian authorities.

Naval Science Vol. III (1874), pp 1-4, 2 plates.
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Copyright © 1996 Lars Bruzelius