THE EQUILIBRIUM OF BATTLESHIPS.

Dunstan Times, Issue 2480, 10 May 1909, Page 7

THE EQUILIBRIUM OF BATTLESHIPS.

(By General E. E.' Uoulaef, Member of the Society of Royal Naval Architects.) It is only since the terrible loss of 11.M.5. Victoria by capsizing (a disaster repeated in several cases during the late Russo-Japanese naval war) that it has at last been recognised that as soon as a ship of the present ordinary form, proportions and system of construction receives a blow either by a ram, torpedo, shot or collision, perforating the underwater part of the hull and causing more or less serious injuries, the vessel immediately heels over and loses her stability. This is owing to the fact that at some distance forward or aft the vessel nearly always acquires at the same time considerable longitudinal trim and gets depressed either by the bow or stern, immersing part of her upper structures. That at once jeopardises her longitudinal stability also, since the useful portion of the area of the load water line is seriously and very quickly diminished by the inrush of water. By these means the vessel gradually loses whatever stability she might have had originally, and finally upsets or capsizes so rapidly that there are cases recorded in which the actual time of capsizing amounted to less than two minutes. The helpless condition to which many modern warships of various nationalities might be reduced has been actually proved by calculation and model experiments, both in Russia and America, while in the recent war with Japan some ironclads of the Borodino class were seen floating after the battle of Tsushima bottom upward, looking like the back of some huge species of fish. Ever since the loss- of the Victoria — that is, for more than ten years—l have thought how to solve this problem in the most practical manner, and it is the results of my work in this direction that I believe will give us practically unsinkable and uncapsizable ships, even in the presence of* numerous underwater openings. Until the present time the most powerful -weapon against which we have to specially protect our 6hips is the torpedo,

The safety against explosion of the ship's own magazines and torpedo storeroom is also an. important point. The safety cellular corridors so effectively isolate all the vital parts and stores of the ship liable to explosion and ignition, such as magazines, torpedo store-room, etc., from the outer skin of the vessel, that the blowing up of these by detonation from the explosion of an enemy's torpedo or mine outside in the vicinity of these parts is most efficiently prevented—just such an explosion as caused the foundering and capsizing in the late war of H. I. M. S. Petropavlosk, with her gallant Admiral Makaroff, and nearly all his officers and crew. Mr C. Tennyson, M. I. N. A., studying the same subject, maintains that "a ship of my form, following in her motion that of the waves, will be always remarkablv dry, floating like a duck, whatever may be the condition of the waves about her, and therefore she will never be swamped, as this is prevented by the closing of all her above-water hatches, side-lights, ports and other openings; persons on board of

Bred either from torpedo craft, or, still worse, from the invisible submarine boats. Moreover, these torpedoes are being continually improved in speed, dirigibility and weight of bursting charges, and these latter are also being rapidly improved as regards their destructive effect per unit of weight. The external net defences, so much thought of formerly, cannot, since the Belleislo trials, be considered to effectively answer their purpose any longer, as they were partly burnt and melted by shell fire during theso trials. They possess, besides, many disadvantages, as they are cumbersome, difficult and slow to put in place, and they lessen the 6peed of the vessel when moving. Being entirely in sight of tho enemy, they are liable to be scon destroyed by the fire of comparatively light guns. In the proposed system of construction, comprising, as will be seen from the description, some modification of the form and proportions of vessels, I have endeavored, on the contrary, to protect the ship against this weapon by tho internal system of construction of the hull. I have attained this purpose by makin; vessels much broader than they have beei or aro at present, leaving their length th< same, or making them even somewha longer. This form and system of con struction provides threo broad longitu dinal cellular 6ide corridors, which an rendered possible by the increased bread tl of tho vessel, and are intended to reduc< to a minimum the quantity of water tha may enter the 6hip through injuries o: openings made in her underwater skin The increase of breadth is made at tin expense of the draught of water. The displacement is practically the sann as that of a ship of ordinary form, witl which tho comparison is made. In tin wide treble side there aro safety longi tudinal corridors surrounding nearly th( Avhole length of tho vessel, and I propose to have, as far as practicable, no watertight or other kind of doors, but only tin smallest possible permanently closed boilei manholes, for the purpose of giving access to the cellular compartments from the top. Tho introduction of the double bottom band double sides, in the early sixties, was due to the remarkable genius of the late Sir Edward Reed, and this innovation was undoubtedly of the greatest importance at that time, when the torpedo had scarcely come into general use. Nowadays, wlion the conditions of naval warfare have changed so much, and when the injuries that can be produced by a single torpedo are so terrible, some more efficient means must be found to protect ships from this most powerful weapon. The radius of action of the modern torpedo inside a vessel, counting from the outer skin inward, being about eighteen feet, I propose to make tho width of the cellular side corridors, about eighteen feet—that is, six feet for each corridor. Thanks to this, all the internal vital parts of the ship, especially those liable to explosion—such as steam boilers, magazines, shot rooms, etc.— are removed from the outer skin, for a distance of about eighteen feet inward on each side toward the centre of the vessel, thus very efficiently securing their greater safety from any outside explosion or any other mode of attack. In larger ships 1 would suggest having this distance increased to about twenty feet. When a few years ago I first brought forward, my proposal for such ships I was met by the criticism that the resistance of water to the progress of such broad vessels at any high speed would be altogether too great. But knowing the results of the late Mr W. Froude's investigations of broad and shallow forms, I felt sure that I was right, at least in this respect. Model experiments made in the St. Petersburg experimental tank show that while the displacement of both vessels is tho same (14,266 tons), the indicated horsepower of engines required to drive a ship of the Retvizan shape at a 6peed of 18 knots amounts to 23,600, while the indicated horse-power required to drive a ship of the broader and shallower form at practically the same speed of 18.42 knots amounts only to 19,412, and this difference in favor of the broader vessel increases if the speed be further increased. Take for comparison, a later and better shaped Russian ironclad, the Borodino, still of an ordinary form, with an ironclad of my form and proportions, both brought, as in the first case, to the same displacement of 17,220 tons. The Borodino shape, when driven at a speed of 19.65 knots requires 30,400 horse-power, while the indicated horse-power required to drive the broader and shallower ship even at a little higher speed of 20 knots, amounts only to 26,920. Tho higher tho speed at which we make our comparisons the more advantageous becomes my form of ship in respect to the resistance of water. This favorable result is no doubt obtained owing to the considerable reduction in the draught of water, and, consequently, of the pressure of water against which tho ship has to labor in her progress, the vessel, so to speak, skimming over tho water's surface. The superiority is so great that, as shown by this diagram, a steamer of my form would bo capable of developing nearly 27 knots as compared to 25 knots for a steamer of ordinary form of the same displacement and with the same power of engines.

her will feel as though the ship does not roll at all; and the work onboard will not be impeded by rolling." That such will be the actual sea-going qualities of ships of the proposed form, notwithstanding their large metacentric height, is fully confirmed by practical experience as proved by the evidence and opinions of such high authority as the late Sir Edward Reed: based on the behavior of the yacht Livadia in the Bay of Biscay, and' the opinion of the late Vice-Admiral Sir Houston Stewart, Sir William White, Vice-Admiral Selwyn, and the late Sir William Pearce. In view of the extremely favorable opinions of such authorities in regard to the excellent behavior of the Livadia, only 235 feet long, 150 feet beam, drawing only 7 to 8 feet, and therefore possessing, owing to her unprecedented beam, a very great metacentric height, I believe that the application of this form and system of construction to the modern ocean .passenger steamers ought to be eminently successful, both as regards high speed on the passage, > and also for comfort and safety which passengers would enjoy on board such steamers. In Sir Edward Reed's paper on the Livadia an the Bay of Biscay, he pointed out that "a ship of extremely light draught and of almost perfect steadiness receives violent upward blows from the ascending water, and this more especially forward, where the onward motion of the ship naturally subjects the bow to the additional violence. This certainty was the case with the Livadia during the gale we then experienced in the bay. ' To this I must answer that ships of the proposed form and proportions differ so very much from the Livadia in that they certainly draw not less than 20 to 21 feet, instead of, as in the Livadia, only 7 to 8 feet, and in being of much larger displacement, greater length and' finer entrance, so that they would behave in this respect more like ordinary steamers in ballast, whose draught of water happens to be at times even less, and which still make very good passages across the North Atlantic, even in the severe winter seasons. Seeing that ships of the proposed' type and of large displacements, such as that of modern battleships and ocean steamers of ordinary form, would certainly be as much and even more than 100 feet in breadth, objection has been raised as to the difficulty of finding docks wide enough to accommodate such broad ships for the •purpose of under-water repair and paintarog. At first sight this may seem to be a serious disadvantage, but it does not present an insurmountable obstacle, for floating docks now offer a most ready and suitable way out of this difficulty, and their cost is so moderate that there was lately an offer from a well-known shipbuilding firm to our Government to build an ironclad' of my form, together with a floating dock to accommodate this ship, for exactly the same price as an ironclad of the 6ame size but of ordinary form is being built in a Russian yard. The Dewey floating dock, built by the American Government for their new naval station at Cavite, has an internal width of 100 feet in the clear, and floating docks of still greater breadth might easily be built. The width of the new Brooklyn dock is 120 feet.

The final results of these investigations of ship resistance prove that with the ordinary form of ships we have _ nearly reached tho limit of advantageous increase of speed, beyond which, however, much wo may increase the propelling power of machinery, we get scarcely any adequate increase of speed. Practically this has been proved for several years past by the enormous sacrifices which naval arch’tects have to make in order to obtain the last few additional knots out of a ship of the usual form. The proposed type of ship would, moreover, admit of placing ou board, thanks to its great beam, any required number of turbine-driven propeller shafts. . An ironclad of my form after being struck even by several torpedoes still remains perfectly able to fight her guns or to proceed under her own steam to her destination. The adoption of this system of construction in mercantile steamers would, therefore, enormously, increase their safety in cases of collision, and would, consequently, reduce the rates of insurance required by underwriters. Reduced draught of water by this plan would amount in big battleships to some six or seven feet, and an even greater reduction in large merchant marine steamers. In ships of ordinary form the limit of draught available has already been practically attained by the limiting depth of water in certain important channels and ports, unless we resort to a vast amount of artifical dredging. This would take time, and would, moreover, be too costly. Rather let us adapt our ships to that depth of water which is given us gratis by nature. My form and system of construction would not only satisfy this condition, bub Avould greatly reduce the number of cruses of ships grounding on shallows or rocks, thus offering additional security for navigation in shallow seas and channels.

Increased breadth insures so much additional internal capacity that great quantities of fuel or other cargo may be stowed on board such ships as compared with ships of ordinary narrow form, and this favors the adoption of such ships either for distant cruising purposes or for carrying a large cargo in hold;, and passengers above in the central upper structure. In a tentative design of an ocean steamer of high speed, of my form, thanks to the height to which her central superstructure could be raised, most of the passengers—numerous as they were—could have been each accommodated with an excellent and spacious stateroom, and the natural lighting and ventilation much improved besides.