Engineering Wonders of the World
Volume I

432 ENGINEERING WONDERS OF THE WORLD. guished from “ submarines ” proper, are driven on the surface by steam engines, and it is well to note here that several submarines possess but one engine in place of the dual means of propulsion employed in our own boats. The rapid development of the internal-combustion engine, as regards power for weight, makes for immense advances in the speed of submarine craft. In the DI we have already reached a horse-power of 1,200 and a speed of over 16 knots, and an even larger and faster vessel of her type is at the present moment being designed. Armaments have naturally increased, and many of the modern submarines carry from four to seven torpedo tubes. Many of the French submarines carry two or more tor- pedoes slung in discharging cradles outside the hull. These projectiles can be released from within, the action of release simultane- ously starting the engines. The time is cer- tainly not far distant when we shall have the armoured submersible ship of 1,000 tons or more, carrying disappearing guns for surface work against surface torpedo craft, and a huge battery of torpedo tubes to attack battleships and armoured cruisers. Twin propellers, too, are now being fitted. Another feature receiv- ing careful attention with a , . . Improvements, view to development is the microphone, which plays the part of a me- chanical ear,” and warns the ship carrying it of the approach of either friend or foe, and makes it possible to gauge the distance and direction of the advancing vessel fairly accurately. The form of submarines is altering con- siderably in favour of a nearer approach to the outward appearance of low-freeboard sur- face craft. “ Bows ” are being provided, as making for better surface speed, and sterns are being improved in shape. Displacements are continually increasing. It is interesting to compare the earliest with the latest sub- marines of various countries :— Displacement. Speed. Armament. Britain ..1902 (No. 3)..122 tons...8 to 9 knots..1 tube. „ ..1909 (DI)......604 tons...16 to 17 knots....3 tubes. France... 1901 (Frangais) ...139 tons... 12 knots.3 tubes. „ ...1910 (Q74) .....810 tons...14to 15 knots....6 tubes Russia... 1904 {Delfin}.200 tons. ..8 to 9 knots..4 tubes. „ ...1909 {Kaiman)... .500 tons... 15 knots....4 tubes. U.S.A....1898 {Holland} 74 tons...8 knots.........1 tube. „ ...1910 {Seal).....425 tons...14 to 16 knots.,..6 tubes. Italy...1894 {Delfino}..107 tons...9 knots........1 tube. „ ....1908 {Foca)....‘230 tons... 15J knots....2 tubes. LAUNCH OF A SUBMARINE. {Photo, Messrs. Vickers Sons and Maxim.)