DEFECTIVE TUBE

Evening Post, Volume CXXVIII, Issue 3, 4 July 1939, Page 9

DEFECTIVE TUBE

EXCESSIVE WEIGHT OF WATER

(By Air Mail, from "The Post's" London Representative.) LONDON, June 5. The naval correspondent of the "Daily Telegraph" says that after the Prime Minister's statement in the House of Commons, little doubt can remain as to what caused the disaster to the Thetis. Vessels of this type, of which 15 have been laid down since 1935, are officially described as '-patrol" submarines, designed for long-range cruising. The average displacement when on the surface is 1090 tons, which increases to 1575 when the ballast tanks are flooded for diving. The length of the Thetis is 265 ft, her beam is 26_ft, and her normal draught of water is 12ft. The speed is moderate, beirig only 15£ knots on tho surface and 9 knots below. It is obvious,

says tho correspondent, that spegd and armament have been subordinated to radius of aetien. Mounted on the {superstructure before the qopriing tower ig.fi' 4in gup, which can be brought into action- a few seconds after the vessel surfaces. In the bows are six 21in torpedo tubes, "nested"in two triple groups arranged vertically. ' '. Each tube is closed by a watertight (breech, while the muzzle is fitted with ja cap which can be removed by a Imechaniegl deyice before the torpedo iis fired, Normally all torpedo tube^are i properly closed and made secure before !a vessel dives. It is obvious, for some reason which may never be explained —but which- is as likely as net to have been due to a mechanical defect, says thg correspondent—.that the breagh of one tube was not made watertight ber fore the Thetis made her fatal dive. INRUSH OF WATER. To conoeive what happened next requires little imagination. As the subr marine dived, water would begin to flood through the defective tube into the torpe^e compartment, Which is fairly spacious, and the volume would naturally increase as the external pr§§-> sure of -water' rose as * the vessel plunged lower. Evidently it ivas im-: possible to secure the spouting breech ip time, and in a space of minutes or iggs the compartment would be filled with hundreds pf tons of water, The torpedo crew would therefore be'compelled' to retreat into the second compartment ab§*ft the bows, where spare torpedoes apd accessories are stored: 'riiig, too, was flooded, but the watertight door isolating it from the rest of the vessel was made fast, Too late, however, for by new, with, perhaps as mugh as sop tons of water in the forward QQmpartm§nt§ s the submarine would be unmanageable. Her bows would ge down te a "steep angle, i which the hydroplanes, or horizontal rudders, §guld not eprr-got, §nd she would "strike"" the' bottom with great! force. j 'ifad the depth of water at the scene of the disaster been more than SQBft,! it is practically eertais that th§ Thetis! would have continued her headlong plunge until,her sides were crushed in by the pressure ef water.