SURFACE CAPITAL SHIPS.

Northern Advocate, 4 June 1920, Page 5

SURFACE CAPITAL SHIPS.

SIR E. D'EYNCOURT'S DEFENCE

LOWER FIGHTING POWER OF

iSUBMERSIBLES.

At the yearly meeting of the Institution of Navaii Architects Sir Eustace d'Eyncourt, tne director oi Naval Construction, gave some interesting particulars oi tne results ox the trials ot the battle-cruiser Hood. The designs ior the riood were approved in April } iout the battle of Jutland, which Look place in the following month, emphasised the advisability of increasing the armour protection in this type of ship, and in September alteration in the first design was approved, it is now finished and several trials took place last week.

Sir Eustace d'Eyncourt said that the result of the trials which had already taken place had not yet been thoroughly analysed, but that in the speed trials at normal draught excellent results were obtained. On the full power trial at a displacement of 42,000 tons, which was considerably in excess of the normal load draught, a speed of 32.07 knots was obtained as a means of runs taken on the measured mile course off the Island of Arran in deep water This was obtained with a mean horse-power of somewhat over 150,000 and witn 206 mean revolutions of the propellers. The day was not altogether satisfactory, as there was a very high wind. The engines worked very satisfactorily and a power of between i 45,000 and 150,000 was maintained for a period of albout seven hours. In the two-fifths power trial a mean speed of over 25 knots was obtained.

With regard to the utility of such gigantic vessels in warfare, Sir Eustace d'Eyncourt said that a good deal had been written and said lately about the surface capital ship beingdead, and about the necessity for suhmersibles, but with our present knowledge it would be quite impossible to design a submersible ship which on the same displacement and cost, would have anything like the fighting qualities on the surface which was possessed by the Hood. Every ship was a compromise, and if, in addition to the ordinary qualities of a battleship, she was required to submerge or even partially submerge, a very considerable percentage of weight would have to be added to give her additional capacity. She would become still more of a compromise, and the added weight would detract from the fighting qualities of the ship when on the surface, so that whatever was done, other things being equal, the submersible ship would oe inferior to a surface ship in an ordinary action. EXAMPLE OF JAPAN AND " AMERICA.

There were many difficulties in the design of a submersible battleship, and although there was 110 doubt that submarines were capable of great development, a little thought .would make it clear to anyibody that if naval warfare was to' continue the surface ship of the line must still hold the field as the principal fighting unit of any great navy. This view was apparently snared by other cduntries who were developing their navies, and both Japan and the United States were building large capital ships.

The torpedo protection in the Hood consisted of the "(bulge" arrangement with an outer compartment of air and an inner one specially strengthened with the necessary separating bulk heads. ' This protection extended the whole length of the machinery spaces and magazines, and rendered the ship as safe against attack from torpedoes under water as she was against gun attack above water. Additional pro tection was gained by arranging the oil fuel tanks along the sides. It was to be noted that no ship provided with the original or later form of "bulge" Was lost nor even seriously damaged by torpedo attack during the war, nor was there any loss of life in any case. This was chiefly due to the special form of "bulge" and to its ibeing external to the ship proper. By careful attention to the form, the re-, duction in speed was only that due to the added displacement, amounting in the case of the Hood to only a fraction of a knot. Experience and trials had shown that the Hood as protected, 'could receive the blows of several torpedoes and still remain in the line without serious loss of speed.

In connection with the size of the ship and the general considerations of design it was noteworthy that ; of recent capital vessels built, in the Queen Elizalbeth we had a well-arm-oured ship of about 28,000 tons with eight 15in. guns and a speed of 25 knots. In the Renown and Repulse, of slightly less displacement though of greater length, we had vessels with seven knots more speed than the Queen Elizabeth, but with only six 15in. guns against eight. In the Hood we were providing eight 15in. guns, as in the Queen Elizabeth,equa; armour protection, six knots more speed, making the speed nearly equal to that of the Renown and Repulse, and in addition a full bulge protection against torpedo attack. The coit of the vessel was £6,000,000, and she took two years to fbuild.