3 October 1917
| 23 September 1916|
31 October 1917
| 3,341,000 German Papiermark|
lost in collision, 7 December 1917 at , raised, training boat, surrendered 26 November 1918, broken up
SM UB-84 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 31 October 1917 as SM UB-84.
UB-84 was lost in a collision on 7 December 1917 in the Baltic Sea at 54°35′N 10°11′E. She was later raised and used as a training boat. On 26 November 1918 she was surrendered to the French in accordance with the requirements of the Armistice with Germany and broken up in Brest in 1921.
SM UB-84 Wikipedia
She was built by AG Weser of Bremen and following just under a year of construction, launched at Bremen on 3 October 1917. UB-84 was commissioned later that same year under the command of Kptlt. Max Bräutigam. Like all Type UB III submarines, UB-84 carried 10 torpedoes and was armed with a 8.8 cm (3.46 in) deck gun. UB-84 would carry a crew of up to 3 officer and 31 men and had a cruising range of 8,180 nautical miles (15,150 km; 9,410 mi). UB-84 had a displacement of 516 t (508 long tons) while surfaced and 647 t (637 long tons) when submerged. Her engines enabled her to travel at 13.4 knots (24.8 km/h; 15.4 mph) when surfaced and 7.5 knots (13.9 km/h; 8.6 mph) when submerged.