UB-148 at sea, a U-boat similar to UB-84
History
German Empire
Name	UB-84
Ordered	23 September 1916[1]
Builder	AG Weser, Bremen
Cost	3,341,000 German Papiermark
Yard number	284
Laid down	21 January 1917[2]
Launched	3 October 1917[3]
Commissioned	31 October 1917[3]
Fate	Lost in collision, 7 December 1917 at 54°35′N 10°11′E / 54.583°N 10.183°E / 54.583; 10.183, raised, training boat, surrendered 26 November 1918, broken up[3]
General characteristics [3]
Class and type	Type UB III submarine
Displacement	516 t (508 long tons) surfaced 647 t (637 long tons) submerged
Length	55.85 m (183 ft 3 in) (o/a)
Beam	5.80 m (19 ft)
Draught	3.72 m (12 ft 2 in)
Propulsion	2 × propeller shaft 2 × Daimler four-stroke 6-cylinder diesel engines, 1,050 bhp (780 kW) 2 × BBC electric motors, 780 shp (580 kW)
Speed	13.4 knots (24.8 km/h; 15.4 mph) surfaced 7.5 knots (13.9 km/h; 8.6 mph) submerged
Range	8,180 nmi (15,150 km; 9,410 mi) at 6 knots (11 km/h; 6.9 mph) surfaced 50 nmi (93 km; 58 mi) at 4 knots (7.4 km/h; 4.6 mph) submerged
Test depth	50 m (160 ft)
Complement	3 officers, 31 men[3]
Armament	5 × 50 cm (19.7 in) torpedo tubes (4 bow, 1 stern) 10 torpedoes 1 × 8.8 cm (3.46 in) deck gun
Service record
Commanders:	Kptlt. Max Bräutigam[4] 31 October – 1 December 1917
Operations:	No patrols
Victories:	None

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.^{[Note 1]} UB-84 was lost in a collision on 7 December 1917 in the Baltic Sea at 54°35′N 10°11′E / 54.583°N 10.183°E / 54.583; 10.183.

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.^[3]

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.

• 
  Stele in Nordfriedhof, Kiel, Germany, to commemorate the casualties of UB-84 who was lost in a collision on 7 December 1917