SM U - 70 SM " U - 70 was a Type U 66 submarine or U - boat for the German Imperial Navy ( ) during the First World War . She had been laid down in February 1914 as U - 11 " the final boat of the " U - 7 " class for the Austro - Hungarian Navy ( ) but was sold to Germany , along with the others in her class , in November 1914 . The submarine was ordered as " U - 11 " from Germaniawerft of Kiel as the last of five boats of the " U - 7 " class for the Austro - Hungarian Navy . After the outbreak of World War I in August 1914 , the Austro - Hungarian Navy became convinced that none of the submarines of the class could be delivered to the Adriatic via Gibraltar . As a consequence , the entire class , including " U - 11 " , was sold to the German Imperial Navy in November 1914 . Under German control , the class became known as the U 66 type and the boats were renumbered ; " U - 11 " became " U - 70 " , and all were redesigned and reconstructed to German specifications . " U - 70 " was launched in July 1915 and commissioned in September . As completed , she displaced , surfaced , and , submerged . The boat was long and was armed with five torpedo tubes and a deck gun . A part of the 4th Flotilla throughout the war , " U - 70 " sank 53 merchant ships with a combined gross register tonnage ( GRT ) of 137 , 775 . Included in that total was — at , one of the largest ships of the war sunk by a U - boat — sunk in June 1917 . In addition she sank one British and damaged four merchant ships ( ) . On 20 November 1918 , nine days after the Armistice , " U - 70 " was surrendered to the British . She was broken up at Bo ' ness in 1919 – 20 . Design and construction . After the Austro - Hungarian Navy had competitively evaluated three foreign submarine designs , it selected the Germaniawerft 506d design , also known as the Type UD , for its new " U - 7 " class of five submarines . The Navy ordered five boats on 1 February 1913 . The " U - 7 " class was seen by the Austro - Hungarian Navy as an improved version of its " U - 3 " class , which was also a Germaniawerft design . As designed for the Austro - Hungarian Navy , the boats were to displace on the surface and while submerged . The doubled - hulled boats were to be long ( OA ) with a beam of and a draft of . The Austrian specifications called for two shafts with twin diesel engines ( total ) for surface running at up to , and twin electric motors ( total ) for a maximum of when submerged . The boats were designed with five torpedo tubes ; four located in the bow , one in the stern . The boats ' armament was to also include a single 66 cm / 26 ( 2 . 6 in ) deck gun . " U - 11 " was laid down on 11 February 1914 , the final boat of the class begun . Her construction was slated to be complete within 29 to 33 months . Neither " U - 11 " nor any of her sister boats were complete when World War I began in August 1914 . With the boats under construction at Kiel , the Austrians became convinced that it would be impossible to take delivery of the boats , which would need to be towed into the Mediterranean past Gibraltar , a British territory . As a result , " U - 11 " and her four sisters were sold to the Imperial German Navy on 28 November 1914 . " U - 11 " was renumbered by the Germans as " U - 70 " when her class was redesignated as the Type U 66 . The Imperial German Navy had the submarines redesigned and reconstructed to German standards , which increased the surface displacement by and the submerged by . The torpedo load was increased by a third , from 9 to 12 , and the deck gun was upgraded from the gun originally specified to an one . Early career . " U - 70 " was launched on 20 July 1915 . On 22 September , SM " U - 70 " was commissioned into the German Imperial Navy under the command of " Kapitänleutnant " Otto Wünsche . " U - 70 " was the second U - boat command for the 30 - year - old officer ; he had commanded from August 1914 until a week before assignment to " U - 70 " . In January 1916 , Wünsche and " U - 70 " escorted the German blockade runner " Marie " through the North Sea . On 9 February , " U - 70 " was assigned to the 4th Flotilla ( ) in which she remained for the duration of the war . " U - 70 " served as an escort again in late February , when she accompanied the German merchant raider Greif . The second German offensive . Germany began its second submarine offensive against shipping in February 1916 , the month " U - 70 " had joined the 4th Flotilla . As in the first submarine offensive , U - boats were sent independently around Scotland to patrol the Irish Sea and the western entrance to the English Channel . " U - 70 " sank her first ship on 16 March , when she dispatched the British sailing vessel " Willie " northwest by west of Fastnet Rock . The same day she also damaged the British cargo ship " Berwindale " , en route to Avonmouth with a load of wheat from Galveston , Texas . Throughout the rest of March and into early April , " U - 70 " sank an additional five ships of ; the largest being the British cargo vessel " Eagle Point " , carrying a load of hay and oats from Saint John , New Brunswick , torpedoed and sunk on 28 March . Near the end of April 1916 , Admiral Reinhard Scheer , the new commander - in - chief of the High Seas Fleet ( under which " U - 70 " s 4th Flotilla operated ) , 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 . In mid - May , Scheer completed plans to draw out part of the British Grand Fleet . The German High Seas Fleet would sortie for a raid on Sunderland , luring the British fleet across " ' nests ' of submarines and mine - fields " . " U - 70 " was one of four U - boats that put out to sea beginning on 18 May to scout the central North Sea for signs of the British fleet . Completing five days of scouting , " U - 70 " , along with , , , sister boat , , and , took up position off the Firth of Forth on 23 May . The other two other boats , and , were stationed off Pentland Firth , in position to attack the British fleet leaving Scapa Flow . All the boats were to remain on station until 1 June and await a coded message which would report the sailing of the British fleet . 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 fleet for its sortie ( which had been redirected to the Skagerrak ) and the failure of five U - boats to receive the coded message warning of the British advance caused Scheer ' s anticipated ambush to be a " complete and disappointing failure " . Although " U - 70 " had received the advance warning of the coded message , her crew did not ever see any part of the fleet . 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 . " U - 70 " s next success came in December when she sank the 5 , 587 - ton British steamer " Pascal " on 17 December . Over the next month she sank an additional 15 ships ( ) . Unrestricted submarine warfare . From the early stages of the war the British had blockaded Germany , preventing neutral shipping from reaching German ports . By the time of the so - called " turnip winter " of 1916 – 17 , the blockade had severely limited imports of food and fuel into Germany . Among the results were an increase in infant mortality and as many as 700 , 000 deaths attributed to starvation or hypothermia during the war . With the blockade having such dire consequences , Kaiser Wilhelm II personally approved a to begin on 1 February 1917 to help force the British to make peace . The new rules of engagement specified that no ship was to be left afloat . The first recorded action of " U - 70 " under the new rules of engagement occurred near the end of February 1917 , when the U - boat shelled the British - flagged " SS San Patricio " . The tanker , encountered by " U - 70 " off the Orkney Islands , survived the attack . In March , " U - 70 " sank twelve ships totaling 25 , 708 tons and damaged a thirteenth of 4 , 666 tons . During the month of April 1917 , German U - boats succeeded in sinking 860 , 334 tons of Allied and neutral shipping , a total unsurpassed by any month in either of the two world wars . " U - 70 " s contribution came in the form of ten ships of 23 , 530 tons sent to the bottom , four of them on the same day , 24 April . Although the monthly total of tonnage sunk by all U - boats had peaked in April , the losses were over 600 , 000 tons in each of May and June . " U - 70 " did not contribute to the May tally but her commanding officer , Wünsche , was awarded the House Order of Hohenzollern . " U - 70 " began another productive month in June by sinking the American Line ocean liner on 4 June . At , " Southland " was the largest ship sunk by " U - 70 " , and one of the largest ships sunk during the war by a U - boat . " Southland " was carrying a general cargo from Liverpool to Philadelphia when " U - 70 " sank her at position , some from Tory Island . Throughout the rest of June , " U - 70 " sank another seven ships totaling 26 , 131 tons . After June 1917 , " U - 70 " only sank another three ships throughout the rest of the war , one of which was the British on 5 May 1918 . " Rhododendron " had been constructed in 1917 as a purpose built Q - ship , a warship disguised as a merchant ship to lure German submarines within range of their concealed gun batteries . The sloop was patrolling off Mull Head in the Orkney Islands when struck by a single torpedo from " U - 70 " . The captain , Lieutenant Commander Charles Arthur Peal , became disoriented in the aftermath of the explosion , and instead of ordering away a " panic party " to draw the submarine within range , ordered the complete evacuation of the ship , which was carried out in great haste and confusion . " U - 70 " approached the burning ship and observed the chaotic evacuation , seizing a petty officer from a liferaft who revealed the ship ' s true identity . " U - 70 " shelled the wreck and escaped without coming under fire . " Rhododendron " capsized and sank the following morning , with the loss of 15 men , four killed in the explosion and 11 drowned during the evacuation . Peal and the rest of the crew were heavily criticized for their conduct under fire by an Admiralty board . In total " U - 70 " sank 54 ships with a combined tonnage of 139 , 065 and damaged four with a tonnage of 20 , 369 in her twelve war patrols . She was surrendered to the British on 20 November 1918 , nine days after the Armistice , and broken up at Bo ' ness in 1919 – 20 . Ships sunk or damaged . < nowiki > * < / nowiki > damaged but not sunk < br >