SM UB-107

SM UB-107 was a German Type UB III submarine or U-boat in the German Imperial Navy (Kaiserliche Marine) during World War I. She was commissioned into the German Imperial Navy on 16 February 1918 as SM UB-107.

The submarine conducted 4 patrols and sank 11 ships during the war for a total loss of. UB-107 was sunk on 27 July 1918 by HMS Vanessa (D29) and HMT Calvis at 54.38333°N, -0.4°W.

Construction
UB-107 was ordered by the GIN on 23 September 1916. She was built by Blohm & Voss of Hamburg and following just under a year of construction, launched at Hamburg on 21 July 1917. UB-107 was commissioned early the next year. Like all Type UB III submarines, UB-107 carried 10 torpedoes and was armed with a 8.8 cm deck gun. UB-107 would carry a crew of up to 3 officer and 31 men and had a cruising range of 7,420 nmi. UB-107 had a displacement of 519 t while surfaced and 649 t when submerged. Her engines enabled her to travel at 13.3 kn when surfaced and 7.4 kn when submerged.

Fate
The first recorded fate of UB-107 was noted as sunk by depth charge on 27 July 1918 by the Royal Navy trawler Calvia and destroyer Vanessa  at position 54.38333°N, 0.4°W. It has since been argued that the UB-107 was probably not present for the attack by Calvis and Vanessa  as it was the only U-boat that could have been responsible for the sinking of steamers Chloris and John Rettig two and a half hours later at position 53.86667°N, 0.16667°W. In 1985 divers discovered the wreck of UB-107 one mile north of Flamborough Head at position 54.13333°N, °W entangled with another wreck, the SS Malvina, a British steamer torpedoed and sunk on 3 August 1918 reported as being by SMU UB-104, though UB-104's record says it was not in the area nor that it attacked a ship on that day. UB-107 was identified by the markings on her propellers. It is suggested that either UB-107 suffered an accident of some sort or was lost on a British mine between 28 July and 3 August 1918, leaving all hands lost (38 dead).

Television Documentary
The fate of UB-107 was the subject of an episode of the documentary television series Deep Sea Detectives: "Mystery U-Boat of WWI". The documentary offered various scenarios for the sinking based on historical evidence and exploratory diving at the wreck site.