# SM UB-107

SM UB-107 was a German Type UB III submarine or U-boat in the German Imperial Navy (German: 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 26,147 GRT. UB-107 was sunk on 27 July 1918 by HMS Vanessa (D29) and HMT Calvis at 54°23′N 0°24′W﻿ / ﻿54.383°N 0.400°W﻿ / 54.383; -0.400.

## 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 (3.46 in) deck gun. UB-107 would carry a crew of up to 3 officer and 31 men and had a cruising range of 7,420 nautical miles (13,740 km; 8,540 mi). UB-107 had a displacement of 519 t (511 long tons) while surfaced and 649 t (639 long tons) when submerged. Her engines enabled her to travel at 13.3 knots (24.6 km/h; 15.3 mph) when surfaced and 7.4 knots (13.7 km/h; 8.5 mph) 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°23′N 00°24′E﻿ / ﻿54.383°N 0.400°E﻿ / 54.383; 0.400. 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°52′N 00°10′E﻿ / ﻿53.867°N 0.167°E﻿ / 53.867; 0.167.
In 1985 divers discovered the wreck of UB-107 one mile north of Flamborough Head at position 54°08′N 00°00′W﻿ / ﻿54.133°N -0.000°E﻿ / 54.133; -0.000 entangled with another wreck, the SS Malvina, a British steamer torpedoed and sunk on 3 August 1918 reported as being by 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).

## Summary of raiding history

| Date | Name | Nationality | Tonnage | Fate |
| 10 May 1918 | Erich Lea | Norway | 1,630 | Sunk |
| 10 May 1918 | Naparima | Sweden | 1,685 | Damaged |
| 6 June 1918 | Koningin Regentes | Netherlands | 1,970 | Sunk |
| 8 June 1918 | Hogarth | United Kingdom | 1,231 | Sunk |
| 13 June 1918 | Agnes | Sweden | 1,334 | Sunk |
| 13 June 1918 | Kalo | United Kingdom | 1,957 | Sunk |
| 15 June 1918 | Kieldrecht | United Kingdom | 1,284 | Sunk |
| 8 July 1918 | Chicago | United Kingdom | 7,709 | Sunk |
| 8 July 1918 | War Crocus | United Kingdom | 5,296 | Sunk |
| 9 July 1918 | Fryken | Sweden | 943 | Sunk |
| 27 July 1918 | Chloris | United Kingdom | 984 | Sunk |
| 27 July 1918 | John Rettig | Sweden | 1,809 | Sunk |

## 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.