SM UB-12

SM ''UB-12'' was a German Type UB I submarine or U-boat in the German Imperial Navy () during World War I. The submarine disappeared in August 1918.

''UB-12'' was ordered in October 1914 and was laid down at the AG Weser shipyard in Bremen in November. ''UB-12'' was a little under in length and displaced between , depending on whether surfaced or submerged. She carried two torpedoes for her two bow torpedo tubes and was also armed with a deck-mounted machine gun. ''UB-12'' was broken into sections and shipped by rail to Antwerp for reassembly. She was launched and commissioned as SM ''UB-12'' in March 1915."SM" stands for "Seiner Majestät" () and combined with the ''U'' for ''Unterseeboot'' would be translated as ''His Majesty's Submarine''.

''UB-12'' spent her entire career in the Flanders Flotilla and sank 22 ships, about half of them British fishing vessels. The U-boat was also responsible for sinking the British destroyer in 1917. By early 1917, ''UB-12'' had been converted into a minelayer with the replacement of her torpedo tubes with four mine chutes. ''UB-12'' disappeared after 19 August 1918.

Design and construction

After the German Army's rapid advance along the North Sea coast in the earliest stages of World War I, the German Imperial Navy found itself without suitable submarines that could be operated in the narrow and shallow seas off Flanders.Miller, pp. 46–47.Karau, p. 48. Project 34, a design effort begun in mid-August 1914, produced the Type UB I design: a small submarine that could be shipped by rail to a port of operations and quickly assembled. Constrained by railroad size limitations, the UB I design called for a boat about long and displacing about with two torpedo tubes.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.

''UB-12'' was part of the initial allotment of seven submarines—numbered to —ordered on 15 October from AG Weser of Bremen, just shy of two months after planning for the class began.Williamson, p. 12. ''UB-12'' was laid down by Weser in Bremen on 7 November. As built, ''UB-12'' was long, abeam, and had a draft of . She had a single Körting 4-cylinder diesel engine for surface travel, and a single Siemens-Schuckert electric motor for underwater travel, both attached to a single propeller shaft. Her top speeds were , surfaced, and , submerged. At more moderate speeds, she could sail up to on the surface before refueling, and up to submerged before recharging her batteries. Like all boats of the class, ''UB-12'' was rated to a diving depth of , and could completely submerge in 33 seconds.

''UB-12'' was armed with two torpedoes in two bow torpedo tubes. She was also outfitted for a single machine gun on deck. ''UB-12''s standard complement consisted of one officer and thirteen enlisted men.Karau, p. 49.

After work on ''UB-12'' was complete at the Weser yard, she was readied for rail shipment. The process of shipping a UB I boat involved breaking the submarine down into what was essentially a knock down kit. Each boat was broken into approximately fifteen pieces and loaded onto eight railway flatcars. In February 1915, the sections of ''UB-12'' were shipped to Antwerp for assembly in what was typically a two- to three-week process. After ''UB-12'' was assembled and launched on 2 March, she was loaded on a barge and taken through canals to Bruges where she underwent trials.

Early career

The submarine was commissioned into the German Imperial Navy as SM ''UB-12'' on 29 March 1915 under the command of Kapitänleutnant (Kapt.) Hans Nieland, a 29-year-old first-time U-boat commander.Nieland was in the Navy's April 1905 cadet class with 36 other future U-boat captains, including Hermann von Fischel, Carl-Siegfried Ritter von Georg, Kurt Hartwig, Hans von Mellenthin, and Wilhelm Werner. See: On 18 April, ''UB-12'' joined the Flanders Flotilla (), which had been organized on 29 March. When ''UB-12'' joined the flotilla, Germany was in the midst of its first submarine offensive, begun in February. During this campaign, enemy vessels in the German-defined war zone (), which encompassed all waters around the United Kingdom, were to be sunk. Vessels of neutral countries were not to be attacked unless they definitively could be identified as enemy vessels operating under a false flag.Tarrant, p. 14.

On 24 July, Nieland and ''UB-12'' sank four British fishing vessels while patrolling between east-northeast of Lowestoft.Helgason, Guðmundur. , , , . ''U-Boat War in World War I''. Uboat.net. Retrieved 30 March 2009. All four of the sunken ships were smacks—sailing vessels traditionally rigged with red ochre sails—which were stopped, boarded by crewmen from ''UB-12'', and sunk with explosives. The information on the website is extracted from ''UB-12'' similarly sank a pair of smacks off Lowestoft on 4 August,Helgason, Guðmundur. , . ''U-Boat War in World War I''. Uboat.net. Retrieved 30 March 2009. and another trio from 23 to 25 August.Helgason, Guðmundur. , , . ''U-Boat War in World War I''. Uboat.net. Retrieved 30 March 2009.

On 21 November, Nieland was succeeded by Oberleutnant zur See (Oblt.) Wilhelm Kiel in command of ''UB-12''. Under Kiel's command, ''UB-12'' sank three ships on 21 February 1916: the 92 GRT Belgian fishing ship ''La Petite Henriette'', the largest sunk to-date by ''UB-12'', and another pair of British smacks, ''Oleander'' and ''W.E. Brown''.Helgason, Guðmundur. , . ''U-Boat War in World War I''. Uboat.net. Retrieved 30 March 2009.

''UB-12'' sank her largest ship, ''Silksworth Hall'' of , on 10 April. The British-registered ship was en route from Hull to Philadelphia in ballast when Kiel torpedoed her without warning a little more than one nautical mile (two kilometers) from the Corton Lightvessel.Tennent, p. 175. Other ships picked up 31 survivors from ''Silksworth Hall'', but 3 men were lost. Later in the month, Admiral Reinhardt Scheer, the newest commander-in-chief of the High Seas Fleet, called off the merchant shipping offensive and ordered all boats at sea to return, and all boats in port to remain there.

Grand Fleet ambush attempts

In mid-May, Scheer completed plans to draw out part of the British Grand Fleet.Gibson and Prendergast, p. 97. The German High Seas Fleet would sortie for a raid on Sunderland,Tarrant, p. 32. luring the British fleet across nests' of submarines and mine-fields". In support of the operation, ''UB-12'' and five other Flanders boats set out at midnight 30/31 May to form a line east of Lowestoft.The other five boats for the May action were , , , , and . This group was to intercept and attack the British light forces from Harwich, should they sortie north to join the battle. Unfortunately for the Germans, the British Admiralty had intelligence reports of the departure of the submarines which, coupled with an absence of attacks on shipping, aroused British suspicions.

A delayed departure of the German High Seas Fleet for its sortie (which had been redirected to the Skagerrak) and the failure of several of the U-boats stationed to the north to receive the coded message warning of the British advance caused Scheer's anticipated ambush to be a "complete and disappointing failure". In ''UB-12''s group, only ''UB-10'' sighted the Harwich forces, and they were too far away to mount an attack. The failure of the submarine ambush to sink any British capital ships allowed the full Grand Fleet to engage the numerically inferior High Seas Fleet in the Battle of Jutland, which took place 31 May – 1 June.Tarrant, pp. 32–33.

Kapitänleutnant Georg Gerth took command of ''UB-12'' on 26 June,
''Oblt.''Kiel was assigned to command the new minelaying submarine . Two months later, Admiral Scheer set up another ambush for the British fleet with plans for another High Seas Fleet raid on Sunderland (as had been the original intention in May). The German fleet planned to depart late in the day on 18 August and shell military targets the next morning. As in May, ''UB-12'' was part of a group intended to attack the Harwich forces. As one of five boats forming the second line of boats from the Flanders Flotilla,The other four boats for the August action were ''UB-6'', ''UB-16'', , and . ''UB-12'' was stationed off Texel by the morning of 20 August.Tarrant, p. 33. Once again, British intelligence had given warning of the impending attack and ambush, causing the Grand Fleet to sortie at 16:00 on 18 August, five hours before the German fleet sailed. Faulty intelligence caused Scheer initially to divert from Sunderland, and then to eventually call off the whole operation. Although U-boats to the north sank two British light cruisers, sank ; and teamed up to sink . ''UB-12'' and her group played no part in the action.

In September, Gerth led ''UB-12'' in sinking two more ships and capturing a third ship as a prize. The 313 GRT Norwegian steamer ''Rilda'' was sunk on 6 September, while the 55 GRT ''Marjorie'' was sunk on the 28th. In between the Dutch ship ''Niobe'' was seized as a prize on the 7th.

Conversion to minelayer

''UB-12'' and three sister boats—''UB-10'', ''UB-16'', and ''UB-17''—were all converted to minelaying submarines. ''UB-12'' was at the dockyard from November 1916 to January 1917, and it is likely the boat was converted during this timeframe. The conversion involved removing the bow section containing the pair of torpedo tubes from each U-boat and replacing it with a new bow containing four mine chutes capable of carrying two mines each. In the process, the boats were lengthened to , and the displacement increased to on the surface, and below the surface.

During this same time, ''Kapt.'' Gerth was transferred to , and replaced on ''UB-12'' by ''Oblt.'' Friedrich Moecke in early November. Moecke was, in turn, replaced by ''Oblt.'' Ernst Steindorff in January 1917.

By March, the newly converted submarine had begun laying mines off the French coast. The French Navy trawler ''Elisabeth'' struck one of ''UB-12''s mines off Calais on 13 March and sank. Five days later, the British auxiliary minesweeper HMS ''Duchess of Montrose'' sank with a loss of 12 men after detonating a mine laid by ''UB-12'' off Gravelines.
On 23 March, , a destroyer with the Dover Patrol, struck one of ''UB-12''s mines off Cape Gris-Nez and went down with the loss of 59 men.

In May, ''UB-12'' was on a patrol with in the English Channel.Bridgland, p. 81. On the night of 14/15 May while ''UB-12'' was on the surface,Messimer, p. 161. Steindorff noted a large underwater explosion some miles away in a British minefield, and when ''UB-39'' failed to return to Zeebrugge, one of the bases for the Flanders Flotilla, reported what was likely the demise of ''UB-39'' at the hands of a British mine.McCartney, p. 161.

April found two more victims added to ''UB-12''s tally. On the 20th, ''Nepaulin'', another British auxiliary minesweeper was lost on one of ''UB-12''s mines near the Dyck Lightvessel. Six days later, the British steamer ''Alhama'' was mined while loaded with pit props destined for Dunkirk. The 1,744 GRT cargo ship was the largest ship sunk by ''UB-12'' since the ''Silksworth Hall'', sunk the previous April. ''UB-12'' sank another two ships under Steindorff's command, one each in June and July. The steamer ''Dulwich''—carrying coal from Seaham for London—was mined and sunk with the loss of five men on 10 June. One month later, the French patrol vessel ''Jupiter I'' was mined off Calais. These were the last two ships credited to mines from ''UB-12'' for the next fourteen months.

Fate

''UB-12''s activities over the next year are not well documented, and no specific record of her can be found in English-language sources. However, it is known that during this period, she was helmed by four different commanders, with the final officer, ''Oblt.'' Ernst Schöller, assuming command in May 1918. Under Schöller's command, ''UB-12'' departed Zeebrugge on 19 August to lay mines in the Downs off the Kentish coast, but never returned.Messimer, p. 133 According to one British source, ''UB-12'' was herself mined off Helgoland sometime in August.Gibson and Prendergast, p. 318. Author Dwight Messimer considers this unlikely given that Helgoland is nowhere near the route that ''UB-12'' could have taken to get to the Downs. A postwar German study concluded the two most likely fates for ''UB-12'' were that she either struck a British mine or was destroyed by one of her own mines that malfunctioned during deployment. Messimer also considers it possible that ''UB-12'' may have had a diving accident related to her conversion to a minelayer.

Some two months after ''UB-12''s presumed loss, she was credited with the sinking of her final ship. On 27 October, two weeks before the end of the war, the 92 GRT British ship ''Calceolaria'' struck one of ''UB-12''s mines near the Elbow Lightvessel and sank.

Summary of raiding history

Notes

References

Bibliography

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External links

'UB-12 off Ramsgate: Marine Geophysical Survey and Archaeological Report'

'Historic England project to research First World War submarines'

{{DEFAULTSORT:Ub012
German Type UB I submarines
Ships built in Bremen (state)
Ships built in Belgium
1915 ships
U-boats commissioned in 1915
World War I submarines of Germany
Maritime incidents in 1918
U-boats sunk in 1918
World War I shipwrecks in the Atlantic Ocean
Submarines lost with all hands
Missing U-boats of World War I