SM U - 66 SM " U - 66 was the lead ship of the Type U 66 submarine s or U - boat s for the German Imperial Navy ( ) during the First World War . The submarine had been laid down in November 1913 as U - 7 " , the lead ship 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 - 7 " from Germaniawerft of Kiel as the first 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 - 7 " , 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 - 7 " became " U - 66 " , and all were redesigned and reconstructed to German specifications . " U - 66 " was launched in April 1915 and commissioned in July . As completed , she displaced , surfaced , and , submerged . The boat was long and was armed with five torpedo tubes and a deck gun . As a part of the Baltic and 4th Flotillas , " U - 66 " sank 24 ships with a combined gross register tonnage of 69 , 967 in six war patrols . The U - boat also torpedoed and damaged the British cruiser in August 1916 . " U - 66 " left Emden on her seventh patrol on 2 September 1917 for operations in the North Channel . The following day the U - boat reported her position in the North Sea but neither she nor any of her 40 - man crew were ever heard from again . A postwar German study offered no explanation for " U - 66 " s loss , although British records suggest that she may have struck a mine in the Dogger Bank area . 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 double - 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 mm / 26 ( 2 . 6 in ) deck gun . " U - 7 " and sister boat " U - 8 " were both laid down on 1 November 1913 , the first two boats of the class begun . Their construction was scheduled for completion within 29 to 33 months , but neither " U - 7 " nor any of her sister boats were complete when World War I began in August 1914 . Because the boats were under construction at Kiel on the Baltic Sea , the Austrians became convinced that it would be impossible to take delivery : the boats would need to be transferred into the Mediterranean past Gibraltar , a British territory . As a result , " U - 7 " and her four sisters were sold to the Imperial German Navy on 28 November 1914 . " U - 7 " was renumbered by the Germans as " U - 66 " when her class was redesignated as the Type U 66 . The Imperial German Navy had the submarines redesigned and reconstructed to German standards , increasing the surface and submerged displacements by , respectively . The torpedo load was increased by a third , from 9 to 12 , and the deck gun size was upgraded from the size originally specified to . Early career . " U - 66 " was launched on 22 April 1915 . On 23 July , SM " U - 66 " was commissioned into the " Kaiserliche Marine " under the command of " Kapitänleutnant " Thorwald von Bothmer , a 31 - year - old , thirteen - year veteran of the " Kaiserliche Marine " . " U - 66 " was assigned to the Baltic Flotilla ( ) on 17 October . In late September , the British submarine flotilla in the Baltic began a submarine offensive against German ships , intending to deny free passage of cargo , especially iron ore , from neutral Sweden to Germany . In " A Naval History of World War I " , author Paul G . Halpern reports on part of the German response , which was an experiment involving " U - 66 " . The U - boat was towed behind an " innocent - looking vessel " and connected to the host ship by a telephone line in addition to the towline . " U - 66 " was able to cast off at a moment ' s notice to attack an enemy submarine . Halpern does not report on any encounters by " U - 66 " , nor does he provide any insight into the overall effectiveness of the plan . " U - 66 " was not credited with the sinking of any vessels of any kind during this time . On 15 January 1916 , she was transferred from the Baltic Flotilla into the 4th Flotilla ( ) , where she joined her sister boats and . Second German offensive . Germany began its second submarine offensive against shipping the month after " U - 66 " 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 . The first reported activity of " U - 66 " during this campaign reveals that she sank her first ship on 5 April 1916 . On that date she was in the vicinity of Fastnet Rock and came upon the 3 , 890 - ton British refrigerated cargo ship " Zent " headed from Garston to Santa Marta in ballast . " U - 66 " torpedoed " Zent " from Fastnet and sank the ship with the loss of 49 crewmen ; the master and nine sailors were rescued and landed at Queenstown . Over the next two days , " U - 66 " dispatched two French sailing vessels , the 151 - ton " Binicaise " , and the 397 - ton fishing smack " Sainte Marie " west of the Isles of Scilly . On 8 April , von Bothmer and " U - 66 " sank the Spanish - flagged " Santanderino " from Ushant . " Santanderino " , a 3 , 346 - ton ship built in 1890 , was sailing from Liverpool to Havana , and " U - 66 " gave 15 minutes ' notice for all the passengers and crew to abandon ship ; four drowned during the evacuation . " Santanderino " s 36 survivors were rescued by a Danish steamer and landed at a port on the Bay of Biscay . " U - 66 " continued her attacks on merchant shipping on 9 April with the sinking of three ships , the British steamers " Eastern City " and " Glenalmond " and the Norwegian ship " Sjolyst " . The 4 , 341 - ton " Eastern City " was sailing from Saint - Nazaire to Barry Roads in ballast when she was shelled by " U - 66 " and sent to the bottom from Ushant ; all of her crew survived and were landed by 11 April . " U - 66 " s next victim was the 2 , 888 - ton " Glenalmond " sailing from Bilbao to Clyde laden with iron ore . Torpedoes from " U - 66 " sank the ship north of Ushant , but all her crew were saved . The 20 - year - old Norwegian steamer " Sjolyst " was sailing in ballast from Nantes to Manchester when " U - 66 " sank her about two nautical miles ( four kilometers ) from where " Glenalmond " went down . " Sjolyst " s master and entire crew were picked up by the British steamer " Libra " and landed at Cardiff . " U - 66 " finished out her busy month the next day by sinking one British and one Italian ship . " U - 66 " sank the British steamer " Margam Abbey " southwest of the Lizard while the ship was en route from Bordeaux to Barry Roads in ballast . " Margam Abbey " , at 4 , 471 tons , was the largest ship sunk by " U - 66 " to that time . The Italian freighter " Unione " was sailing with a load of coal from Clyde for Genoa when " U - 66 " torpedoed her off Land ' s End . The sinking of " Unione " , with a tonnage of 2 , 367 , raised " U - 66 " s tally for the month of April to eight ships with a combined tonnage of 22 , 848 , all sunk in a six - day span . Near the end of April 1916 , Admiral Reinhard Scheer , the new commander - in - chief of the High Seas Fleet ( under which " U - 66 " 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 ambushes . 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 - 66 " was one of nine U - boats that put out to sea beginning on 17 May to scout the central North Sea for signs of the British fleet . Completing five days of scouting , " U - 66 " , 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 , including " U - 66 " , to receive the coded message warning of the British advance caused Scheer ' s anticipated ambush to be a " complete and disappointing failure " . Although she had not received the advance warning of the coded message , " U - 66 " was one of the two ambush U - boats that actually saw parts of the British fleet . At 09 : 00 on 31 May , " U - 66 " sent out a wireless report of eight battleships , light cruisers , and destroyers on a northerly course east of Kinnaird Head . " U - 66 " was unable to make any attacks on the ships she reported because of the screening ships . 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 . The next mention of " U - 66 " in sources is on 11 August , when she sank " Inverdruie " , a 613 - ton three - masted Norwegian bark . " Inverdruie " was carrying a load of pit prop s from Sandefjord to Hartlepool when she was sunk some east of Aberdeen . Later in August , the Germans set up another ambush for the British fleet , when they drew up 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 . " U - 66 " was one of 24 U - boats that formed five lines ( ) in the expected paths of any Grand Fleet sorties . " Standlinie II " , consisting of " U - 63 " , , , " U - 66 " , and , formed a front off Flamborough Head . The other four " Standlinie " formed similar lines to the north and south ; all were to be in place by 08 : 00 on 19 August . 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 . At 04 : 45 on 19 August , " U - 66 " fired a spread of two torpedoes at the British light cruiser from a distance of . Both torpedoes scored hits on " Falmouth " s starboard side , flooding the warship forward and aft . The cruiser ' s mechanical spaces — located amidships — remained intact and in working order , so she was steered to the Humber with an escort of three destroyers and an armed trawler . " U - 66 " tried repeatedly to deal the stricken cruiser a " coup de grâce " , but narrowly missed with torpedoes on several further attacks . " U - 66 " broke off her pursuit after two hours , having endured multiple attacks from " Falmouth " s screening destroyers . One depth charge attack blew out all the lights on " U - 66 " and knocked clips off two hatches that caused the boat to flood with a considerable quantity of water before the leaks could be sealed . " Falmouth " continued under tow at until she crossed " Standlinie II " and was attacked and sunk by " U - 63 " around noon the next day . Records on " U - 66 " next appear in late 1916 , when she is reported as one of the U - boat escorts assisting the German merchant raider into the North Atlantic . " Wolf " , under the command of Karl - August Nerger , began a 15 - month raiding voyage on 30 November that took the ship into the $ 3 and Pacific Oceans before a safe return to Germany . " U - 66 " s specific locations for this duty are not reported , but on 11 December she sank a Norwegian steamer and a Swedish sailing ship . " U - 66 " shelled the 1 , 090 - ton Norwegian steamer " Bjor " southwest of the Norwegian island of Ryvingen . The ship and her general cargo , headed from Göteborg to Hull , were sent to the bottom without loss of life , and her crew was safely landed by 14 December . The same day , " U - 66 " also sank the 311 - ton Swedish sailing ship " Palander " off the island of Oxö , near the town of Tornio on the Sweden – Finland border . Unrestricted submarine warfare . From the early stages of the war the Royal Navy 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 . " U - 66 " s first victim under the new rules was encountered on 1 March . The Norwegian steamer " Gurre " , reported as 1 , 733 tons , was crossing the North Sea while steaming from Narvik and Fredrikshald for Hull with a cargo of iron ore . " U - 66 " torpedoed her at position , sending down the Norwegian ship with 20 of her crew . The same day , " U - 66 " encountered another Norwegian cargo ship , the 1 , 005 - ton " Livingstone " , headed from Skien to Charente with a cargo of ammonium nitrate . " Livingstone " s cargo , used in the making of explosives and munitions , was too valuable to destroy . " U - 66 " s captain seized the ship as a prize east of Shetland . Further details of the encounter do not appear in sources , but it is known that the 11 - year - old " Livingstone " not only survived the war , but remained in service under a variety of names until she was scrapped in 1962 . In late March , " U - 66 " sank another two vessels . The 3 , 597 - ton cargo ship " Stuart Prince " was headed from Manchester and Belfast to Alexandria with a general cargo when " U - 66 " came upon her off Broad Haven , County Mayo . " U - 66 " s torpedo attack was successful , sinking the ship and killing 20 men , including the ship ' s master . Five days later , " U - 66 " encountered the five - masted bark " Neath " south by east of Fastnet Rock . Equipped with an auxiliary triple - expansion steam engine , " Neath " was the former German bark " R . C . Rickmers " which had been seized by the Admiralty at Cardiff in August 1914 . After " U - 66 " torpedoed " Neath " at 08 : 45 , the bark , en route from Martinique to Le Havre with a load of sugar , sank in seven minutes . The master of " Neath " was taken prisoner , but had been released and landed at Queenstown two days later . During April 1917 , German U - boats sank 860 , 334 tons of Allied and neutral shipping , a monthly total unsurpassed in either of the two world wars . " U - 66 " s sole contribution to this figure came when she torpedoed the tanker " Powhatan " from North Rona in the Outer Hebrides . The 6 , 117 - ton ship , which was carrying fuel oil from Sabine to Kirkwall , bested " Margam Abbey " as " U - 66 " s largest ship sunk when she went down with 36 of her crew . As was done with the master of " Neath " , " Powhatan " s master was taken prisoner aboard " U - 66 " . 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 - 66 " did not contribute to the May tally but , with her most successful month since April 1916 , added to the June figures . On 5 June , " U - 66 " torpedoed the 3 , 472 - ton Italian steamer " Amor " which was on her way to Liverpool from Galveston ; " Amor " sank approximately from Fastnet Rock . The same day , " Manchester Miller " , a 4 , 234 - ton steamer sailing from Philadelphia for Manchester with a load of cotton , was sunk about away from " Amor " when she was hit by a torpedoes from " U - 66 " . Eight crewmen died in the attack ; the survivors , who included three Americans , were landed on 9 June . Two days after the attacks on " Amor " and " Manchester Miller " , " U - 66 " attacked two more British steamers . The 4 , 329 - ton " Ikalis " , carrying wheat from New York to Manchester , was torpedoed and sunk from Fastnet Rock . The cargo ship " Cranmore " , of 3 , 157 tons , was headed to Manchester from Baltimore with a general cargo when torpedoed some northwest of Fastnet . Though the ship was damaged , " Cranmore " s crew was able to beach her ; the ship was later refloated and re - entered service . " U - 66 " sank her largest ship , the 6 , 583 - ton British steamer " Bay State " on 10 June . The Warren Line cargo steamer had departed from Boston ( the capital of Massachusetts nicknamed , coincidentally , the " Bay State " ) with a $ 2 , 000 , 000 war cargo destined for Liverpool . " U - 66 " intercepted the ship northwest of Fastnet and sank her , but there were no casualties among her crew of 45 . Four days later , " U - 66 " encountered the Norwegian bark " Perfect " , laden with grain , headed from Bahía Blanca for Copenhagen . " Perfect " , which had been built in 1877 , was dispatched by " U - 66 " s deck gun at position , east of Shetland . On 17 June , " Kapitänleutnant " von Bothmer was replaced by " Kapitänleutnant " Gerhard Muhle as commander of the U - boat . " U - 66 " was the first ( and ultimately only ) U - boat command for the 31 - year - old Muhle , who had been a classmate of von Bothmer when both had joined the " Kaiserliche Marine " in April 1902 . On 9 July , " U - 66 " sank her first ship under her new commander , when she sent the Spanish steamer " Iparraguirre " to the bottom . The 1 , 161 - ton steamer was headed to Santander from Piteå and Bergen with a cargo of pitwood , when " U - 66 " attacked her west of the Orkney Islands . " U - 66 " scored another success when she torpedoed and sank the outbound British steamer " African Prince " on 21 July north - northwest of Tory Island . The freighter — a Prince Line line - mate of " Stuart Prince " , sunk by " U - 66 " in March — was carrying china clay from Liverpool to Newport News . The same day , " U - 66 " also sank the 1 , 322 - ton British sailing ship " Harold " about from where " African Prince " went down . These two ships were the last sinkings credited to " U - 66 " . During six successful patrols , " U - 66 " had sunk 24 ships and seized a 25th as a prize , for a combined total tonnage of 69 , 967 . " U - 66 " began her seventh and what was to be her final patrol on the morning of 2 September when she departed from Emden destined for operations in the North Channel . Shortly after noon on 3 September , " U - 66 " reported a position in the North Sea that placed her beyond known British minefield s , in what was her last known contact . A postwar German study offered no explanation for " U - 66 " s loss . British records suggest that " U - 66 " may have either struck a mine in an older minefield in the Dogger Bank area , or that a combination of destroyer s , submarines , and anti - submarine net tenders sank " U - 66 " sometime between 1 and 11 October . Author Dwight Messimer discounts this latter theory as not being supported by operational details . Ships sunk or damaged . < nowiki > * < / nowiki > damaged but not sunk < br > < nowiki > * * < / nowiki > captured as a prize