SM UB-4

SM UB-4

Seiner Majestät UB-4 was a German Type UB I submarine (U-boat) in the German Imperial Navy (German: Kaiserliche Marine) during World War I. She was sunk by a British Q-ship disguised as a fishing smack in August 1915.

UB-4 was ordered in October 1914 and was laid down at the Germaniawerft shipyard in Kiel in November. UB-4 was a little more than 92 feet (28 m) in length and displaced between 127 and 142 metric tons (140 and 157 short tons), depending on whether surfaced or submerged. She carried two torpedoes for her two bow torpedo tubes and was also armed with a deck-mounted machine gun. UB-4 was broken into sections and shipped by rail to Antwerp for reassembly. She was launched and commissioned as SM UB-4 in March 1915.

UB-4 conducted the first sortie of the Flanders Flotilla in April, during which she sank the Belgian Relief ship Harpalyce, the first ship credited to the flotilla. She sank three more ships from mid-April to mid-August. On 15 August, UB-4 surfaced near the British Q-ship Inverlyon and was sunk by gunfire from the sailing vessel. None of UB-4's 14 crewmen survived the attack.