ORP Kaszub (1921)

The newly completed V108 and V107 joined the 10th Torpedo Boat Flotilla in the Baltic Sea in April 1915.[6] That month, the German Army had begun an offensive in the Baltic as a diversion for the Gorlice–Tarnów Offensive, with the Navy deployed in support of the Army's operations.[7] On 24 April 1915, V108 shelled Russian troops near Palanga, Courland (now part of Lithuania).[6] On the night of 30 April/1 May 1915, V107 and V108 made a sortie into the Gulf of Riga, reconnoitring the island of Ruhnu and shelling lighthouses.[8]

From 3 to 5 June 1915, German naval forces, including V108 carried out an attempted penetration of the Irben Strait with the intention of mining the southern entrance to the Moon Sound, while the seaplane carrier Glyndwr's aircraft would attack a factory near Daugavgrīva. The presence of large numbers of Russian warships (including 16 destroyers and torpedo boats) resulted in the operation being abandoned, but on the return journey to Libau, Glyndwr ran into a previously undiscovered Russian minefield off Windau on 4 June, striking one mine, which badly damaged the seaplane carrier, causing serious flooding. V108 took Glyndwr under tow, and with the assistance of minesweepers took Glyndwr back to Libau.[9][10]

In August 1915, V108 took part in the Battle of the Gulf of Riga, an attempt by German forces, supported by the High Seas Fleet, to enter the Gulf of Riga, destroy Russian naval forces in the Gulf and to mine the northern entrances to the Gulf in order to prevent Russian reinforcement. The attempt failed with Germany losing the torpedo boats S31 and V99 and the minesweeper T46, while failing to destroy any major Russian warships or lay the planned minefield. On 20 August, in one of the last actions of the battle, V108 took part in an attack on Pernau, with blockships being used to block the entrance to the harbour.[11][12]

In 1916, V108 was relegated to training duties,[3] remaining on training duties at the end of the war.[13]

In June 1919, Treaty of Versailles required that the German Navy surrender most of its remaining warships for division between the victorious powers. In December 1919, Poland was allocated six torpedo boats, which were to be supplied unarmed for police duties. One of the ships chosen by Poland was V-108, which was renamed Kaszub together with sister ship V-105 (which became Mazur) and four smaller A-class coastal torpedo boats. Kaszub, after refit at Rosyth Dockyard, arrived at Danzig on 3 October 1921. (Like all of the torpedo boats transferred to Poland, Kaszub suffered mechanical problems and was delivered under tow).[14][15]

Kaszub was initially fitted with two 47 mm guns and two machine guns for service with the Polish Navy,[16] but was rearmed in 1924–25, with two 75 mm guns and two 450 mm torpedo tubes, together with rails for laying mines.[16][17]

On 20 July 1925, a boiler explosion wrecked Kaszub while in dock in Danzig, with the forward part of the ship sinking.[16][17][18] Three crewmen died. The remains were salvaged on 26 July 1925 and scrapped.[19]