Russian submarine Forel

Forelle was a single-hull boat designed with internal ballast and compensating tanks. She had fixed angled aft planes, and movable forward units for dive control. This boat had to be carried into action on board a surface ship and launched close to its target, as she was not fitted with a separate surface propulsion system. She was equipped with two external Whitehead torpedoes. Forelle had an overall length of The boats' beam was without torpedoes and with the external torpedoes. The boat displaced when surfaced and when submerged. She was fitted with one electric motor producing for surface and submerged propulsion. This engine gave the boat a top surface speed of , and when submerged. Without torpedoes, top speed increased to on the surface and submerged. Maximum range was at with torpedoes and at without torpedoes. Power for the electrical engine was provided by 180-cells Lead–acid battery which used peat fibres to isolate the posite and negative plate, and absorbed the acid, allowing the battery to be used in any inclined position without the acid overflowing. ==Operational history==

Forelle made her first trials on 24 June 1903 in Eckernförde and Kiel. She underwent a few modifications which rose her displacement forst to and then finally . The Imperial Russian Navy purchased the submarine in May 1904 for service in the Russo-Japanese War. It was shipped from Kiel to Liepāja by railway, together with a team of German engineers to train the Russian crew, and was commissioned at Kronstadt on 21 August 1904. It was then sent via the Trans-Siberian Railway to Vladivostok, arriving on 29 September, and joined the Siberian Flotilla on 2 October, becoming the first Russian submarine in the Pacific. The submarine did not see combat during the Russo-Japanese War, but the Russians believed its mere presence deterred the Japanese from attacking Vladivostok. Forel continued to operate out of Vladivostok after the war; however, by 1908 it was considered obsolete and was re-classed as a training vessel. The submarine sank in an accident on 17 May 1910. The crew managed to escape, and the ship was salvaged from a depth of . Vice Admiral Ivan Grigorovich authorized it to be returned to Liepāja for repairs, but shipping was never implemented. ==Citations==