At the commencement of the War the Austro-Hungarian Navy included six submarines in the active flotilla and five others were being completed at the Germania Yard, Kiel, but it is doubtful if they had been delivered. In which event they must be added to the strength of the German flotilla. In addition to these, several larger vessels, mostly of the latest “U” or Krupp design, had been ordered, but were not expected to take their place in the active flotillas before the end of 1915.

Austria commenced the formation of a submarine flotilla in 1908 by the acquisition of two vessels of the Improved Holland type from Messrs. Vickers Ltd., and two others of the American Lake type. In the following year two more submarines were ordered, this time from Krupp’s Germania Yard. All these vessels were delivered during 1910, and Austria’s first submarine flotilla came into being.

U.1 and U.2.

These two vessels are of the American Lake type. They have a submerged displacement of 250 tons and petrol surface motors of 720 H.-P. Their speed is 12 knots on the surface and 8 knots when submerged. The armament consists of two bow and one stern torpedo tube. This type of submarine has three special features which distinguish it from all others. It is fitted with a kind of underframe and wheels, and is designed to travel in four different positions: (1) on the surface; (2) semi-submerged, with only a look-out cowl above water; (3) submerged, with nothing but the periscope showing; (4) totally submerged and running along the sea-bed on wheels, like a submarine motor car. It is drawn down from the surface to the sea-bed by an ingenious system of wire-hawsers and drop-weights, which can be released in the event of accident. A “diving chamber” enables members of the crew to don diving-dresses and leave the submarine when on the sea-bed, for the purpose of laying or destroying submerged mines. The Lake type of submarine is also used in the Russian Navy.^[6]

U.3 and U.4.

These two vessels are of the Krupp design, and have a submerged displacement of 300 tons. The horse-power of their heavy-oil surface engines is 600. The electric motors develop 200 H.-P. The surface and submerged speeds are 13 knots and 8 knots respectively. The surface range of action is 1,500 miles, and the armament consists of two bow and one stern tube with five 18-inch torpedoes. Their complement is fifteen officers and men.

U.5 and U.6.

These are submarines of the Improved Holland type. Their submerged displacement is about 316 tons; length 135 feet, and beam 13½ feet. The horse-power of the petrol engines is 600 and that of the electric engines 189. The speed averages 12 knots on the surface and 8 knots when submerged. The surface cruising range is 1,300 knots at 10 knots an hour. Their armament consists of two bow tubes with four to six 18-inch Whitehead torpedoes. Their complement is sixteen officers and men.

U.7-U.11.

These five vessels are of the Krupp-Germania type, and are similar to those completed for the German Navy in 1912–13. They are large sea-going submarines with a submerged displacement of 800 tons. They are propelled on the surface by heavy-oil engines of 1,200 H.-P., and when submerged, by electric motors of 500 H.-P. Their speed is 14 knots and 9 knots, above and below, respectively. The surface range of action is 3,000 miles, and the submerged endurance 120 miles at economical speed.

Their armament consists of two bow and two stern torpedo tubes, with eight torpedoes, and one 14-pdr. quick-firing gun and two 1-pdr. high-angle guns, for defence against hostile destroyers and air-craft. Their complement is twenty-five officers and men.

One or two Austrian submarines are supposed to have been sunk by the Allied Fleet during the first few weeks of the war, but exactly which vessels they were is not known.

Several other submarines have been ordered in foreign countries for the Austrian Navy, but cannot be delivered while the war lasts.

Submarine Flotillas of Neutral European Powers.