German submarine U - 33 ( 1936 ) German submarine " U - 33 " was a Type VIIA U - boat of the Nazi German " Kriegsmarine " during World War II . Her keel was laid down on 1 September 1935 at the Germaniawerft in Kiel . She was launched on 11 June 1936 and commissioned on 25 July with Ottoheinrich Junker in command . He was relieved by Kurt Freiwald on 22 November . " Kapitänleutnant " ( " Kptlt . " ) Hans - Wilhelm von Dresky took over on 29 October 1938 and commanded the boat until her loss . Rotor s from the " Kriegsmarine " ' s Enigma machine were captured from the survivors , the wiring of which was unknown at that time to British codebreakers at Bletchley Park . Service history . " U - 33 " took part in Operation Ursula — the German submarine operation in support of Franco ' s naval forces during the Spanish Civil War from November 1936 . During World War II , " U - 33 " sank 10 ships for a total of in just three war patrols . On Monday , 20 November 1939 she sank three British steam trawlers . At 10 : 30 am , the " Thomas Hankins " 14 miles north - west of Tory Island ; at 4 : 00 pm , the " Delphine " 18 miles north - northeast of Tory and at 5 : 05 pm the " Sea Sweeper " 25 miles west - northwest of Tory . The crew of the " Thomas Hankins " , under the master , M . Hankins , was rescued by another trawler ten hours later and landed in Northern Ireland . They reported that they had been shelled without warning . The second shell went through the bows and the fifth through the boiler , causing the trawler to sink in about 25 minutes . On Tuesday , 21 November 1939 at 08 : 30 in rough seas , the trawler FD87 " Sulby " ( from Fleetwood ) , was sunk by gunfire from " U - 33 " 75 – 80 miles north - west of Rathlin Island . The crew had just managed to launch and push off the two lifeboats as the submarine fired two shells into the trawler amidships and she sank within two minutes . The U - boat commander pointed at the crew as they rowed from their ship and laughed . One of the lifeboats , whose occupants were Harold Blackburn , James Hay , James Geddes , Fred Brunt , Augustus Lewis , Sydney Mellish and Jack Threlfall were picked up the following day by the Tobermory lifeboat . The other lifeboat was lost with five men including the Skipper , Clarence Hudson ; Mate John Michael ( Jack ) Dawson ; and deck hands Raymond Randles , James Wood and R . A . Lister . An hour or so later at the same location , " U - 33 " sank another trawler , the " William Humphries " . The entire crew of 13 men were lost . Two of them were buried in the graveyard of Cill Chriosd on the Isle of Skye . Fate . In February 1940 , " U - 33 " , then captained by Hans - Wilhelm von Dresky , had been ordered to lay mines in the Firth of Clyde , in Scotland . However , the minesweeper , captained by Lieutenant - Commander Hugh Price , detected the U - boat on the 12th and dropped depth charge s over a period of several hours . Eventually , the damaged " U - 33 " was forced to surface and the crew abandoned the boat , which sank soon afterward . 25 men died while 17 survived . Before the boat was abandoned , the U - boat ' s secret Enigma rotor s were distributed amongst a few of the crew , who were instructed to release them into the sea to avoid capture . This was not done , however , and as a result the British captured three rotors , including two ( VI and VII ) , that were only used by the " Kriegsmarine " and for which the wiring was then unknown .