German Type UB I submarine: Wikis


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SM UB-1 seen after her sale to the Austro-Hungarian Navy for service as SM U-10
SM UB-1 seen after her sale to the Austro-Hungarian Navy for service as SM U-10
Class overview
Preceded by: Type UA
Succeeded by: Type UB II
Built: 1914–1915[2]
In commission: 1915–1918
Completed: 20[3][4]
Lost: 10[4][6]
Scrapped: 10[3][4][5]
General characteristics
Type: coastal submarine[2]
Displacement: 127 tonnes (140 short tons), surfaced[1]
142 tonnes (157 short tons), submerged[2]
Length: 92 ft 2 in (28.09 m), UB-1UB-8[3]
91 ft 6 in (27.89 m)[3]
Beam: 10 ft 6 in (3.20 m)[3]
Height: 7.3 m (24 ft)[7]
Draught: 9 ft 10 in (3.00 m)[3]
1 × Daimler (UB-1UB-8) or Körting 4-cylinder diesel engine, 60 bhp (45 kW)[3]
•1 × electric motor, 120 shp (89 kW)[3]
1 × shaft
Speed: 6.47 knots (11.98 km/h), surfaced[1]
5.51 knots (10.20 km/h), submerged[2]

•1,650 nautical miles @ 5 knots, surfaced (3,060 km @ 9.3 km/h)[3]
•45 nautical miles @ 4 knots, submerged (83 km @ 7.4 km/h)[3]

Test depth: 50 metres (160 ft)[3]
Complement: 14[3]
Armament: 2 × 45 cm (17.7 in) torpedo tubes[3] (bow, 2 × torpedoes)
1 × 8 mm (0.31 in) machine gun
Notes: 33-second diving time[3]

The Type UB I was a class of small coastal submarines (U-boats) built in Germany during the beginning of World War I. A total of twenty boats were built, the majority of which were in the service of the German Imperial Navy (German: Kaiserliche Marine). Boats of the design were also operated by the Austro-Hungarian Navy (German: Kaiserliche und Königliche Kriegsmarine or K.u.K. Kriegsmarine) and the Bulgarian Navy. The class is sometimes known as the UB-1 class after SM UB-1, the class leader. In the Austro-Hungarian Navy, the class was called the U-10 class.

Built in response to a need for small, maneuverable submarines able to operate in the narrow, shallow seas off Flanders, they were intended to be quickly constructed, shipped by railroad, and assembled at their port of operation. The design effort began in mid-August 1914 and the first fifteen boats were ordered in mid-October from two German shipyards. The German Imperial Navy ordered an additional pair later to replace two boats sold to Austria-Hungary, which ordered a further three in April 1915. The total number of UB I boats constructed was twenty. Construction on the first boats for Germany began in early November 1914; all twenty were completed by October 1915.

Several of the first boats underwent trials in German home waters, but the rest of the boats were assembled and tested at either Antwerp or Pola. The German boats operated primarily in the Flanders, Baltic, and Constantinople Flotillas. There were small size variations between boats from the two manufacturers, with the boats being about 92 feet (28 m) long and displacing between 127 and 142 tonnes (140 and 157 short tons). All had two bow torpedo tubes and two torpedoes, and were equipped with a deck-mounted machine gun.

In 1918, four of the surviving German boats were made into coastal minelayers. Of the seventeen boats in German service, two were sold to Austria-Hungary, one was sold to Bulgaria, and nine were lost during the war. One of the five Austro-Hungarian boats was sunk and another mined and not repaired. The five surviving German boats, the four surviving Austro-Hungarian boats, and the Bulgarian boat were all turned over to the Allies after the end of the war and were broken up.



In the earliest stages of World War I, the German Army's rapid advance along the North Sea coast found the German Imperial Navy without submarines suitable to operate in the narrow and shallow seas off Flanders.[8][9] By 18 August 1914, just two weeks after the German invasion of Belgium, the planning of a series of small, coastal submarines had already begun.[9]

The German Imperial Navy stipulated the submarines be transportable by rail, which imposed a maximum diameter of 10 feet 4 inches (3.15 m), the largest size transportable via rail. The rushed planning effort[8]—which had been assigned the name "Project 34"—resulted in the Type UB I design, created specifically for operation from Flanders. The boats, essentially submersible torpedo boats, were to be about 92 feet (28 m) long and to displace about 125 tonnes (138 short tons) with two bow torpedo tubes.[8][Note 1]

One of the minor differences in the Type UB I boats was the number and size of limber holes in the upper casing. Those on the Germaniawerft-built UB-2 (left) are larger than those on UB-16, built by AG Weser.

Boats of the UB I design were built by two manufacturers, Germaniawerft of Kiel and AG Weser of Bremen,[10] which led to some variations in boats from the two shipyards. The eight Germaniawerft-built boats were slightly longer at 92 feet 2 inches (28.09 m) (oa), while the twelve Weser-built boats came in 8 inches (20 cm) shorter. All were 10 feet 6 inches (3.20 m) abeam and had a draft of 9 feet 10 inches (3.00 m).[3] The boats all displaced 127 tonnes (140 short tons) while surfaced but had slightly different underwater displacement figures. The slightly longer Germaniawerft boats displaced 142 tonnes (157 short tons) while submerged, weighing 1 tonne (1.1 short tons) more than the Weser boats.[1] There were other mostly cosmetic differences among the boats, the major one being the number and size of vents in the upper casing; the Germaniawerft boats seem to have had fewer large vents, while the Weser boats had more, small vents.[11]

The drivetrain of the boats consisted of a single propeller shaft driven by a Daimler (Germaniawerft) or Körting (Weser) diesel engine on the surface, or a Siemens-Schuckert electric motor for underwater travel.[8] The Weser boats were capable of nearly 7.5 knots (13.9 km/h) on the surface and a little more than 6 knots (11 km/h) submerged. The Germaniawerft boats were about 1 knot (1.9 km/h) slower than their Bremen-made counterparts.[1] The boats were equipped with two 45-centimetre (17.7 in) bow torpedo tubes and carried two torpedoes.[3] They were also armed with a single 8-millimetre (0.31 in) machine gun affixed to the deck.[9]


The German Imperial Navy ordered its first fifteen UB I boats on 15 October 1914.[8][9] Eight boats—numbered UB-1 to UB-8—were ordered from Germaniawerft of Kiel,[8][10] and seven boats—numbered UB-9 to U-15—from AG Weser of Bremen.[10] After two of the class, UB-1 and UB-15, were sold in February 1915 to ally Austria-Hungary (becoming U-10 and U-11 in the Austro-Hungarian Navy)[12] the German Imperial Navy ordered UB-16 and UB-17 from Weser.[8] A further three for Austria-Hungary —U-15, U-16, and U-17—had been ordered from Weser by April, bringing the total number constructed to twenty.[12][Note 2]

UB-1 and UB-2 were laid down on 1 November 1914 at the Germaniawerft yard at Kiel.[13][14] UB-1 was launched on 22 January 1915,[13] just 75 working days later.[10] UB-2's launch followed on 13 February.[14] Among the Weser boats, UB-9 was laid down first, on 6 November 1914, and launched on 6 February 1915,[15] a week ahead of UB-2. These first three boats launched underwent trials in German home waters, but most of the other members of the class were shipped via rail and underwent trials at their assembly point.[16]

Sections of SM UB-13 on board railroad flatcars for transport to Antwerp, c. March 1915.

The process of shipping the submarines by rail involved breaking the submarine down into what was essentially a knock down kit. Each boat was broken into approximately fifteen pieces and loaded on to eight railway flatcars. UB I boats destined for service with the Flanders Flotilla (German: U-boote des Marinekorps U-Flotille Flandern) made a five-day journey to Antwerp for the 2- to 3-week assembly process. After assembly at Antwerp the boats were towed by barge to Bruges for trials.[16] Boats selected for service in the Mediterranean were sent to the Austro-Hungarian port of Pola, where the assembly process took place.[17] The total time from departure of the railcars from the shipyard to operational readiness for the boats was about six weeks.[16]

By July 1915, all seventeen of the German Imperial Navy UB Is had been completed.[18]


During their trials, the UB Is were found to be too small and too slow,[19] and had a reputation for being underpowered;[20] one commander compared his UB I to a "sewing machine".[20] According to authors R. H. Gibson and Maurice Prendergast in their 1931 book The German Submarine War, 1914–1918, the UBs did not have enough power to chase down steamers while surfaced, and lacked the endurance to spend any extended amount of time underwater, exhausting their batteries after little over an hour's running.[20] In-service use revealed another problem: with a single propeller shaft/engine combination, if either component failed, the U-boat became almost totally disabled.[19][Note 3]

Another reported problem with the UB Is was the tendency to break trim after the firing of one of the torpedoes. The boats were equipped with compensating tanks designed to flood and offset the loss of the C/06 torpedo's 1,700-pound (770 kg) weight, but did not always function properly;[21] as a result, when firing from periscope depth the boat could broach after firing or, if too much weight was taken on, plunge to the depths. When UB-15 torpedoed and sank the Italian submarine Medusa in June 1915, the tank failed to properly compensate, and it took all of the crewmen running to the stern to offset the trim imbalance.[21]

Despite the problems, the "tin tadpoles", as the Germans referred to them, were in active service from March 1915 through the end of the war,[22] with half of the twenty boats lost during the war.[4][6] Boats of the class served in three navies: the German Imperial Navy, the Austro-Hungarian Navy, and the Bulgarian Navy.[3] In German service, they served primarily in the Flanders Flotilla, the Baltic Flotilla, and the Constantinople Flotilla.[22]


German Imperial Navy

Flanders Flotilla

The first UB I to enter service was UB-10,[20] which formed the nucleus of the Flanders Flotilla, on 27 March 1915.[16][23] By the end of April, five more UB I boats had become operational.[24] UB-10 was eventually joined in the Flanders Flotilla by UB-2, UB-4, UB-5, UB-6, UB-12, UB-13, UB-16, and UB-17;[25] of these, only UB-2 made the journey to Flanders by sea rather than rail.[16]

UB-4 departed on the first patrol from Flanders on 9 April,[26] and was responsible for sinking the first ship sent down by the flotilla.[27] The UB I boats of the Flanders Flotilla originally patrolled the area between the United Kingdom and the Netherlands,[26] but began patrolling the English Channel after UB-6 pioneered a route past British antisubmarine nets and mines in the Straits of Dover in late June.[28]

Over the UB Is' first year of service, UB-4 and UB-13 were both lost,[29] and UB-2 and UB-5 were transferred to the Baltic Flotilla.[30] In March 1917, UB-6 ran aground in Dutch waters and, along with her crew, was interned for the rest of the war.[31] The four remaining UB Is in Flanders—UB-10, UB-12, UB-16, UB-17—were all converted to minelayers by 1918, having their torpedo tubes removed and replaced with chutes to carry up to eight mines.[3] All but UB-10 were lost in 1918;[32] UB-10, in poor repair and out of service, was scuttled in October 1918 when the Germans evacuated from Flanders.[31]

Baltic Flotilla

UB-9 was initially assigned to the Baltic Flotilla (German: U-boote der Ostseetreitkräfte V. U-Halbflottille), and joined by UB-2 and UB-5 in early 1916. All three became training boats at Kiel in 1916,[30] joining UB-11 in that duty.[33] Little information is available about the UB I boats operating in the Baltic.

Constantinople Flotilla

Four of the German Imperial Navy boats—UB-3, UB-7, UB-8, and UB-14—were selected for service with the Constantinople Flotilla (German: U-boote der Mittelmeer Division in Konstantinopel). Initial plans called for them to be shipped by rail to the Stenia Yard in Constantinople, but incompatible rail gauges and tunnels too small for the loaded railcars prevented this.[11] All were instead sent to Pola for assembly and trials there as part of the Pola Flotilla (German: Deutsche U-Halbflottille Pola), before sailing on to join the Constantinople Flotilla. UB-3 disappeared en route to Constantinople in May 1915,[17] but the other three arrived there by mid-June.[25]

The three UB I boats of the Constantinople Flotilla seem to have patrolled primarily in the Black Sea. UB-8 was transferred to the Bulgarian Navy in May 1916,[34] and UB-7 disappeared in the Black Sea in October 1916,[35] leaving UB-14 as the sole remaining German UB I in the flotilla;[36] she was surrendered at Sevastopol in November 1918 to French armies stationed there during the Russian Civil War.[37]

Austro-Hungarian Navy

UB-1 and the still incomplete UB-15 were sold to the Austria-Hungary in February 1915; both were dismantled and shipped to Pola in May.[38] After one cruise under the German flag, each boat was commissioned into the Austro-Hungarian Navy. The pair—renamed U-10 and U-11, respectively—were joined by U-15, U-16, and U-17 in October.[4] Known as the U-10 or the Okarina (English: Ocarina) class as a part of the Austro-Hungarian Navy,[39] the five boats operated primarily in the Adriatic in patrols off Italy and Albania.[40] U-10 (ex UB-1) hit a mine in July 1918 and was beached, but had not been repaired by the end of the war. U-16 was sunk after she torpedoed an Italian destroyer in October 1916, but the remaining three (and the unrepaired U-10) were ceded to Italy at the end of the war.[4]

Bulgarian Navy

After UB-8 was transferred to the Bulgarian Navy in May 1916, she was renamed Podvodnik No. 18 (in Cyrillic: Пoдвoдник No. 18). While in Bulgarian service, the submarine was engaged primarily in coastal defense duties off Bulgaria's main Black Sea port of Varna. Podvodnik No. 18 survived the war but was ceded to France after the end of the war.[5]

List of Type UB I submarines

There were a total of 20 Type UB I submarines built—17 for the German Imperial Navy and 3 for the Austro-Hungarian Navy.[3][4] Two of the German submarines—UB-1 and UB-15—were sold to Austria-Hungary and commissioned into the Austro-Hungarian Navy as U-10 and U-11, respectively.[3] Those two and a further three built by AG Weser comprised the virtually identical U-10 class for the Austro-Hungarian Navy.[4] Another of the German submarines, UB-8, was sold to Bulgaria in May 1916,[34] becoming Podvodnik No. 18, that nation's first submarine.[41]

German Imperial Navy

Austro-Hungarian Navy

In the Austro-Hungarian Navy the Type UB I boats were known as the U-10 class, which consisted of two former German UB I boats and three built specifically for Austria-Hungary.

In addition, five of the German UB Is assigned to the Pola Flotilla (German: Deutsche U-Halbflotille Pola), based at the Austro-Hungarian Navy's main naval base at Pola, were assigned Austro-Hungarian designations.[12][Note 4]

These five boats remained under commission in the German Imperial Navy, retained German crews and commanders, and received orders from the German flotilla commander at Pola.

Bulgarian Navy

Germany and Bulgaria negotiated the purchase of two UB I boats for the Bulgarian Navy, UB-7 and UB-8 in 1916. Two crews of Bulgarian sailors were sent to Kiel for training. Before the purchase could be completed, UB-7 was sunk, leaving only one boat for Bulgaria.[5] On 25 May 1916, UB-8 was officially transferred to Bulgaria for the remainder of the war.[34]

Type UB I submarines
Date launched Name of U-boat Date commissioned Ships sunk, damaged, or taken as a prize
01915-01-22 22 January 1915 UB-1/U-10[13] 01915-01-29 29 January 1915 1
01915-02-13 13 February 1915 UB-2[14] 01915-02-10 10 February 1915 11
01915-03-05 5 March 1915 UB-3[42] 01915-03-14 14 March 1915 0
01915-03 March 1915 UB-4[27] 01915-03-23 23 March 1915 4
01915-03 March 1915 UB-5[43] 01915-03-25 25 March 1915 5
01915-03 March 1915 UB-6[44] 01915-04-08 8 April 1915 9
01915-04 April 1915 UB-7[45] 01915-05-06 6 May 1915 1
01915-04 April 1915 UB-8/Podvodnik No. 18[34] 01915-04-23 23 April 1915 2
01915-02-06 6 February 1915 UB-9[15] 01915-02-18 18 February 1915 0
01915-02-20 20 February 1915 UB-10[23] 01915-03-15 15 March 1915 37
01915-03-02 2 March 1915 UB-11 01915-03-04 4 March 1915 0
01915-03-02 2 March 1915 UB-12 01915-03-29 29 March 1915 24
01915-03-08 8 March 1915 UB-13 01915-04-06 6 April 1915 12
01915-03-23 23 March 1915 UB-14[37] 01915-03-25 25 March 1915 7
01915 1915 UB-15/U-11 01915-04-11 11 April 1915 1
01915-04-26 26 April 1915 UB-16 01915-05-12 12 May 1915 26
01915-04-21 21 April 1915 UB-17 01915-05-04 4 May 1915 16
01915-09 September 1915 U-15 01915-10-06 6 October 1915 6
01915-08-31 31 August 1915 U-16 01915-10-06 6 October 1915 3
01915 1915 U-17 01915-10-06 6 October 1915 1


  1. ^ A further refinement of the design—replacing the torpedo tubes with mine chutes but changing little else—evolved into the Type UC I coastal minelaying submarine. See: Miller, p. 458.
  2. ^ In the Austro-Hungarian Navy, the UB I boats were known as the U-10-class submarine.
  3. ^ Many of the problems with the UB I design were rectified in the larger Type UB II which had twin propellers, larger engines, and a higher top speed. Williamson, p. 13.
  4. ^ After Italy had entered World War I by declaring war on Austria-Hungary on 23 May 1915, Germany felt treaty-bound to support the Austrians in attacks against Italian ships, even though Germany and Italy were not officially at war. As a result, German U-boats operating in Mediterranean were assigned Austro-Hungarian numbers and flags. After 28 August 1916, when Germany and Italy were officially at war, the practice continued, primarily to avoid charges of flag misuse. The practice was largely ended by 1 October 1916 except for a few large U-boats that continued using Austro-Hungarian numbers. Gardiner, p. 341.


  1. ^ a b c d e Tarrant, p. 172.
  2. ^ a b c d e f g Helgason, Guðmundur. "German Type UB I submarine". U-Boat War in World War I. Retrieved 26 January 2010. 
  3. ^ a b c d e f g h i j k l m n o p q r s t u Gardiner, p. 180.
  4. ^ a b c d e f g h i Gardiner, p. 343.
  5. ^ a b c d Gardiner, p. 412.
  6. ^ a b Messimer, pp. 127–36. Messimer lists UB-3, UB-4, UB-6, UB-7, UB-10, UB-12, UB-13, UB-16, and UB-17 as being sunk, scuttled, or missing during the war.
  7. ^ Myszor, Oskar. "Austria-Hungary: Submarines". Historical Handbook of World Navies. Retrieved 25 February 2009. 
  8. ^ a b c d e f g Miller, pp. 46–47.
  9. ^ a b c d Karau, p. 48.
  10. ^ a b c d Williamson, p.12.
  11. ^ a b Koehl, Tom. "UB I Type Coastal UBoats UB 1 through UB 17, 1915". The Dreadnought Project. Retrieved 26 February 2009. 
  12. ^ a b c Gardiner, p. 341.
  13. ^ a b c Helgason, Guðmundur. "WWI U-boats: UB-1". U-Boat War in World War I. Retrieved 2 March 2009. 
  14. ^ a b c Helgason, Guðmundur. "WWI U-boats: UB-2". U-Boat War in World War I. Retrieved 2 March 2009. 
  15. ^ a b Helgason, Guðmundur. "WWI U-boats: UB-9". U-Boat War in World War I. Retrieved 2 March 2009. 
  16. ^ a b c d e Karau, p. 49.
  17. ^ a b Messimer, pp. 126–27.
  18. ^ Tarrant, p. 16.
  19. ^ a b Miller, p. 48.
  20. ^ a b c d Gibson and Prendergast, pp. 38–39.
  21. ^ a b Stern, p. 25.
  22. ^ a b Tarrant, pp. 23, 34, 56, 74–75.
  23. ^ a b Helgason, Guðmundur. "WWI U-boats: UB-10". U-Boat War in World War I. Retrieved 2 March 2009. 
  24. ^ Tarrant, p. 16.
  25. ^ a b Tarrant, p. 23.
  26. ^ a b Karau, p. 50.
  27. ^ a b Helgason, Guðmundur. "WWI U-boats: UB-4". U-Boat War in World War I. Retrieved 2 March 2009. 
  28. ^ Karau, p. 51.
  29. ^ Messimer, pp. 129, 134.
  30. ^ a b Tarrant, p. 34.
  31. ^ a b Messimer, p. 132.
  32. ^ Messimer, pp. 133, 135–6.
  33. ^ Gibson and Prendergast, p. 63.
  34. ^ a b c d Helgason, Guðmundur. "WWI U-boats: UB-8". U-Boat War in World War I. Retrieved 2 March 2009. 
  35. ^ Messimer, p. 131.
  36. ^ Tarrant, pp. 74–75.
  37. ^ a b Helgason, Guðmundur. "WWI U-boats: UB-14". U-Boat War in World War I. Retrieved 2 March 2009. 
  38. ^ Imperial and Royal Navy Association, p. 12.
  39. ^ Baumgartner and Sieche, as excerpted here (reprinted and translated into English by Sieche). Retrieved 2 March 2009.
  40. ^ Imperial and Royal Navy Association, pp. 13–17.
  41. ^ Йорданов, pp. 130–145.
  42. ^ Helgason, Guðmundur. "WWI U-boats: UB-3". U-Boat War in World War I. Retrieved 10 February 2010. 
  43. ^ Helgason, Guðmundur. "WWI U-boats: UB-5". U-Boat War in World War I. Retrieved 10 February 2010. 
  44. ^ Helgason, Guðmundur. "WWI U-boats: UB-6". U-Boat War in World War I. Retrieved 10 February 2010. 
  45. ^ Helgason, Guðmundur. "WWI U-boats: UB-7". U-Boat War in World War I. Retrieved 10 February 2010. 


  • Baumgartner, Lothar; Erwin Sieche (1999) (in German). Die Schiffe der k.(u.)k. Kriegsmarine im Bild = Austro-Hungarian warships in photographs. Wien: Verlagsbuchhandlung Stöhr. ISBN 9783901208256. OCLC 43596931. 
  • Gardiner, Robert, ed. (1985). Conway's All the World's Fighting Ships, 1906–1921. Annapolis, Maryland: Naval Institute Press. ISBN 9780870219078. OCLC 12119866. 
  • Gibson, R. H.; Maurice Prendergast (2003) [1931]. The German Submarine War, 1914–1918. Annapolis, Maryland: Naval Institute Press. ISBN 9781591143147. OCLC 52924732. 
  • Imperial and Royal Navy Association. "Tengeralattjárók" (in Hungarian) (pdf). Imperial and Royal Navy Association. Retrieved 2 March 2009. 
  • Йорданов, Николай (1999) (in Bulgarian). Първата българска подводница ("The First Bulgarian Submarine"). кн. 3. София: Военно-исторически сборник. pp. 130–145. 
  • Karau, Mark D. (2003). Wielding the Dagger: the MarineKorps Flandern and the German War Effort, 1914–1918. Westport, Connecticut: Praeger Publishing. ISBN 9780313324758. OCLC 51204317. 
  • Messimer, Dwight R. (2002). Verschollen: World War I U-boat losses. Annapolis, Maryland: Naval Institute Press. ISBN 9781557504753. OCLC 231973419. 
  • Miller, David (2002). The Illustrated Directory of Submarines of the World. St. Paul, Minnesota: MBI Pub. Co. ISBN 9780760313459. OCLC 50208951. 
  • Stern, Robert Cecil (2007). The Hunter Hunted: Submarine versus Submarine: Encounters from World War I to the Present. Annapolis, Maryland: Naval Institute Press. ISBN 1591143799. OCLC 123127537. 
  • Tarrant, V. E. (1989). The U-Boat Offensive: 1914–1945. Annapolis, Maryland: Naval Institute Press. ISBN 9780870217647. OCLC 20338385. 
  • Williamson, Gordon (2002). U-boats of the Kaiser's Navy. Oxford: Osprey. ISBN 9781841763620. OCLC 48627495. 


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