SM UB - 13 SM " UB - 13 " was a German Type UB I submarine or U - boat in the German Imperial Navy ( ) during World War I . The submarine was probably sunk by a British mine net in April 1916 . " UB - 13 " was ordered in October 1914 and was laid down at the AG Weser shipyard in Bremen in November . " UB - 13 " was a little under in length and displaced between , depending on whether surfaced or submerged . She carried two torpedo es for her two bow torpedo tube s and was also armed with a deck - mounted machine gun . " UB - 13 " was broken into sections and shipped by rail to Antwerp for reassembly . She was launched in March 1915 and commissioned as SM " UB - 13 " in April . " UB - 13 " spent her entire career in the Flanders Flotilla and sank 11 merchant ships , about half of them British fishing vessels . In March 1916 , " UB - 13 " was responsible for sinking the Dutch ocean liner , raising the ire of the Dutch public . " Tubantia " was the largest neutral vessel sunk during the war and among the 30 largest ships sunk by U - boats . On 24 April 1916 , " UB - 13 " was sunk with all hands . 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 . 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 tube s . " UB - 13 " 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 . " UB - 13 " was laid down by Weser in Bremen on 7 November . As built , " UB - 13 " 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 - 13 " was rated to a diving depth of , and could completely submerge in 33 seconds . " UB - 13 " was armed with two torpedo es in two bow torpedo tube s . She was also outfitted for a single machine gun on deck . " UB - 13 " s standard complement consisted of one officer and thirteen enlisted men . After work on " UB - 13 " 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 on to eight railway flatcar s . In February 1915 , the sections of " UB - 13 " were shipped to Antwerp for assembly in what was typically a two - to three - week process . After " UB - 13 " was assembled and launched on 8 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 - 13 " on 6 April 1915 under the command of " Oberleutnant zur See " Walter Gustav Becker , a 29 - year - old first - time U - boat commander . On 26 April , " UB - 13 " joined the Flanders Flotilla ( ) , which had been organized on 29 March . When " UB - 13 " 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 . Submarines of the Flanders Flotilla sank over 14 , 000 tons of merchant vessels in June 1915 , and " UB - 13 " s first ship sunk , " Dulcie " , contributed almost one - seventh of that total . The British steamer " Dulcie " , listed at , was headed from Dunston for Le Havre with a load of coal when Becker torpedoed her east of Aldeburgh . One man on " Dulcie " lost his life in the attack . " Dulcie " was the only ship sunk by " UB - 13 " in June . On 27 and 28 July , Becker and " UB - 13 " sank three British fishing vessels while patrolling between off Lowestoft . All three of the sunken ships were smack s — sailing vessels traditionally rigged with red ochre sails — which were stopped , boarded by crewmen from " UB - 16 " , and sunk with explosives . In response to American demands after German submarines had sunk the Cunard Line steamer in May 1915 and other high profile sinkings in August and September , the chief of the " Admiralstab " , Admiral Henning von Holtzendorff , issued orders suspending the first offensive on 18 September . His directive ordered all U - boats out of the English Channel and the South - Western Approaches and required that all submarine activity in the North Sea be conducted strictly along prize regulations . On 20 February 1916 , under the command of " Kapitänleutnant " Karl Neumann , who replaced Becker in December 1915 , " UB - 13 " captured a Belgian ship named " Z10 David Marie " and retained her as a prize . There are no further details about where " Z10 David Marie " was taken or her final disposition , but other ships captured as prizes by Flanders boats were sailed into Zeebrugge by prize crew s . Second submarine offensive . By early 1916 , the British blockade of Germany was beginning to have an effect on Germany and her imports . The Royal Navy had stopped and seized more cargo destined for Germany than the quantity of cargo sunk by German U - boats in the first submarine offensive . As a result , the German Imperial Navy began a second offensive against merchant shipping on 29 February . The final ground rules agreed upon by the German " Admiralstab " were that all enemy vessels in Germany ' s self - proclaimed war zone would be destroyed without warning , that enemy vessels outside of the war zone would be destroyed only if armed , and — to avoid antagonizing the United States — that enemy passenger steamers were not to be attacked , regardless of whether in the war zone or not . The day after the beginning of the second offensive , Neumann and " UB - 13 " sank four more fishing smacks northeast of Lowestoft . All four ships were boarded and sunk in the same manner as the three sunk the previous July . Shortly after , Neumann was transferred to command in early March , and was replaced by " Oberleutnant zur See " Arthur Metz , who had been in command of for the preceding month . SS " Tubantia " . Shortly after 02 : 30 on 16 March , a torpedo from " UB - 13 " struck the starboard side of the neutral Dutch ocean liner , which was at anchor near the North Hinder Lightship , about off the Dutch coast . The Royal Holland Lloyd ( ) ship had been fully illuminated , with her name spelled out in electric lights between the twin funnels . Distress calls from " Tubantia " were heeded and all 80 passengers and 294 crew were rescued by three nearby ships before the ship foundered . " Tubantia " was the largest neutral ship sunk during the war , and among the 30 largest ships sunk by U - boats . Germany initially tried to implicate British mine s or torpedoes , but relented when confronted with evidence that it was one of their own torpedoes — which had been assigned to " UB - 13 " — that had sunk " Tubantia " . The Germans , however , presented a forged log from " UB - 13 " that showed her nowhere near " Tubantia " at the time of the attack . Further , they reported , " UB - 13 " had fired that specific torpedo at a British warship on 6 March — ten days before " Tubantia " was sunk — which would have been under her previous commander , " Kapitänleutnant " Neumann . The U . S . Minister to the Netherlands , Henry van Dyke , writing in " Fighting for Peace " in 1917 , called this explanation " amazing " and derided it : This certain U - boat had fired this particular torpedo at a British war - vessel somewhere in the North Sea ten days before the " Tubantia " was sunk . The shot missed its mark . But the naughty undisciplined little torpedo went cruising around in the sea on its own hook for ten days waiting for a chance to kill somebody . Then the " Tubantia " came along and the wandering - Willy torpedo promptly , obstinately , ran into the ship and sank her . This was the explanation . Germany was not to blame . The Dutch public was furious at what they believed a hostile German act , which caused German diplomats to spread rumors of an impending British invasion of the Netherlands to divert the unwanted attention . Amidst all of the denials and diplomatic wrangling over " Tubantia " s sinking , " UB - 13 " continued to sink ships . On 31 March , off Lowestoft , Metz and " UB - 13 " sank the Norwegian steamer " Memento " . The ship was carrying a load of coke destined for Porsgrunn when she went down with one crewman . Twelve days later , in the Kentish Knock area , " UB - 13 " sank the Danish ship " Proeven " . The 276 - ton sailing vessel was the last ship sunk by " UB - 13 " . Sinking . On the evening of 23 April 1916 , " UB - 13 " departed Zeebrugge for a patrol off the mouth of the Thames and was never heard from again . Author Dwight Messimer , in his book " Verschollen : World War I U - boat Losses " , reports that the British had deployed a new explosive anti - submarine net at position in the early morning hours of 24 April . He suggests that it was possible " UB - 13 " had set off some of the contact mines on the net , or possible that the submarine had struck a mine in one of the many British minefields off the Flemish coast . However , according to authors R . H . Gibson and Maurice Prendergast , in their book " The German Submarine War , 1914 – 1918 " , " UB - 13 " fouled the anchor cable of the British naval drifter " Gleaner of the Sea " on 24 April , and was depth charge d by " E . E . S . " . Then for good measure , the British destroyer deployed explosive sweeps against the submarine . Whatever the specific cause of her demise , all seventeen crewmen on board the submarine were killed . Ships sunk or damaged . < nowiki > * < / nowiki > captured as a prize