This record was kindly provided by the generous assistance of Tony Cooper

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REPORT ON INTERROGATION OF SURVIVORS FROM U 517, A 740-TON
	U-BOAT, SUNK AT 1017 ON 21ST NOVEMBER, 1942.
	BY AIRCRAFT FROM H.M.S. "VICTORIOUS."
	________________
	I.  INTRODUCTORY REMARKS
	"U 517" was sunk by aircraft from H.M.S. "Victorious" at 1017 on 21st November, 1942, in position 46° 10' N., 17° 08' W.
	There were 50 survivors of her complement of 51, and all were available for interrogation in the United Kingdom a few days later.  The officers were extremely security-conscious; the ratings varied.
	The main features of this report are as follows:
	(1)  Narrative of "U 517's first patrol, which took place in the Gulf of St. Lawrence.  (Section IV).
	(2)  Further remarks on G.S.R. (Section IX).
	(3)  U-Boat routine in the St. Lawrence.  (Section XI).
	(4)  Use of air-bottles for securing maximum surface speed.  (Section VII (vii) (a) ).
	(5)  Look-out masts in U-Boats.  (Section X (x) ).
	The following are the British equivalents of German naval ranks mentioned in this report:
	Konteradmiral Rear Admiral. Kapitän zur See Captain. Fregattenkapitän Commander (Senior Grade). Korvettenkapitän Commander (Junior Grade). Kapitänleutnant Lieutenant-Commander. Oberleutnant zur See Lieutenant. Leutnant zur See Sub-Lieutenant. Oberfähnrich sur See Midshipman (Senior Grade). Fähnrich zur See Midshipman (Junior Grade).
	The addition of the suffix "Ing." indicates an engineer officer and the expression "der Reserve" a reserve officer.
	Unless otherwise stated, all times are German Summer Time.
	II.  COMPLEMENT OF "U 517"
	(i)  Composition
	"U 517's" complement was 51, composed of five officers, one of whom was borne as an Engineer Officer under training, three Chief Petty Officers, 12 Petty Officers and 31 other ratings.  All survived except one Torpedo Gunner's Mate.
	(ii)  Captain
	The captain was Kapitänleutnant Paul Hartwig, aged 28, of the 1935 term.  On commissioning he was appointed to the battleship "Deutschland" and served later in destroyers.  "U 517" was his first U-Boat command.  His men respected him chiefly for his efficiency and coolness.  The amount of liquor he put away frightened some of them.  There was more than a streak of jealousy in his make-up, he took great exception, for instance, to his original First Lieutenant's reputation as a more accurate torpedo-marksman than he.  His men complained that he was apt to make a mountain out of a molehill when it came to matters of discipline.  To meet, Hartwig was barely polite and unwilling to discuss even general topics.  He gave the impression of being a cold and calculating young Nazi, filled with ideals of false heroism and unyielding devotion to his Führer.  He was promoted Kapitänleutnant while in command of "U 517."
	(iii)  First Lieutenant
	The First Lieutenant, Leutnant zur See der Reserve Karl Brandi, aged 30, was a mining engineer in civil life.  He joined the German naval reserve in 1936 as an ordinary seaman and was a Chief Petty Officer at the time of the Norwegian campaign of 1940, after which he was commissioned Leutnant zur See der Reserve.  Like his commanding officer, Brandi was very security-conscious.
	(iv)  Second Lieutenant
	The Second Lieutenant, Leutnant zur See Rolf Pingel, aged 21, had joined the German Navy direct from school.  He refused to give any details of his career, but it is not thought that it was of any interest.  He was a typical Hitler Youth movement product, entirely lacking in manners and making a very poor impression.
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	(v)  Senior Engineer Officer
	Kapitänleutnant (Ing.) Helmut Martin, aged 30, was borne as Senior Engineer Officer at his own wish to gain experience.  He entered the German Navy at Stralsund in 1934 and did ten weeks of new entry training, after which he was drafted to the Naval College at Flensburg-Mürwik from autumn, 1934 to summer, 1935.  He then made a cruise as an engineer cadet in the cruiser "Karlsruhe," after which he spent summer, 1935, to spring, 1936, as Engineer Midshipman, again at Flensburg-Mürwik.  In spring, 1936, he went to the Naval College at Kiel and in spring, 1937, to the cruiser "Leipzig" for duty in home waters.  He was promoted Oberfähnrich (Ing.) on 1st January, 1937, and commissioned on 1st April, 1937.
	In the autumn of 1937 he entered the U-Boat arm, doing a course in torpedoes, and had remained in U-Boats ever since.  In the Norwegian campaign of 1940 he served as Engineer Officer in "U 56," but could not see eye to eye with his captain, Kapitänleutnant Zahn, and soon managed to obtain another appointment.  After a period with the Second U-Boat Flotilla at Lorient, Martin was appointed Flotilla Engineer at Salamis dockyard.  It is probable that he returned to Lorient later and spent some time there before joining "U 517" on her last patrol.
	In conversation, Martin proved far the most affable and talkative officer in "U 517" and appeared to have a better general education and experience than any of his colleagues.  He expressed grave doubts as to the outcome of the war for the Axis.  He had been promoted Kapitänleutnant (Ing.) in 1st March, 1942.  After completing his patrol in "U 517" he would, survivors expected, be given a post as Flotilla Engineer.
	(vi)  Junior Engineer Officer
	The Junior Engineer Officer was Leutnant (Ing.) Roland Becher, aged 29, who had recently been promoted from the lower deck.  He had served as a Petty Officer in "Scharnhorst."  Though not unpleasant to talk to he was fully security-conscious.  He was expected to take over the post of sole Engineer Officer in "U 517" after this patrol.
	(vii)  General
	The composition of "U 517's" complement followed the usual lines; a leavening of experienced men had been mixed with the bulk of young and totally inexperienced ratings.  Some of the experienced men, of whom there were five or six, had made several patrols with Kapitänleutnant Adalbert Schnee in "U 201."  One had served with Prien in "U 567."
	Many of the men complained of sickness while on patrol.  Two had severe boils in the groin and four had boils on the neck.  One of the seamen Petty Officers was addicted to fainting fits; he had an attack at the time of "U 517's" sinking and later collapsed during interrogation.
	III.  EARLY HISTORY OF "U 517"
	(i)  Launching
	"U 517" was launched in December, 1941.  Members of her future complement began to be drafted to her from then onwards.  She was a 740-ton Type IX C boat of the serial beginning "U 501" and was built at the yards of the Deutsche Werft, Hamburg-Finkenwerder, where her job number was 313.
	(ii)  Commissioning
	She was commissioned on 21 March, 1942.  The occasion was marked by a party that afternoon in the barracks attached to the yards.  Part of her ship's company was accommodated during building at those barracks and part on board the depôt ship "Warnow."
	(iii)  Original Officers
	"U 517's" original officers were as follows:
	Commanding Officer   Kapitänleutnant Paul Hartwig. First Lieutenant   Oberleutnant zur See Gustav-Adof von Dresky, of the October, 1937, term Second Lieutenant   Leutnant zur See Rolf Pingel. Third Lieutenant   Leutnant zur See Richter.         (N.I.D. Note.  This is probably one of the three officers named Richter of the October, 1938, term.) Engineer Officer   Oberleutnant (Ing.) Heller, of the October, 1938, term.
	The men spoke very highly of von Dresky, who was much more popular than Hartwig, chiefly on account of his freedom from pettiness.  He comes of a well-known German naval family and formerly served in a battle-cruiser.  Some said he now commands a U-Boat.
	Leutnant zur See Richter was carried during working-up as a supernumerary under instruction.

 

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	(iv)  Period in Hamburg U-Boat Shelters
	On 23rd March, "U 517" entered side B of No. 1 pen of the U-Boat shelters in the Rusch Kanal at Hamburg-Finkenwerder, where she lay in company with her sister ship "U 515" and for part of the time with "U 516."  She was forced to remain there for about one month owing to severe ice conditions.  During this period, Hartwig seized the opportunity of perfecting his ship's company's discipline by frequently exercising turning out the watch and other drill.
	(v)  U.A.K. Trials
	About 23rd April, "U 517" left Hamburg for Kiel, where she made fast in the Wik harbour on 25th April.  On 27th April her U.A.K. trials began.  She made her first dive on 28th April, remaining submerged for over two hours.  On or about 30th April, she entered the Kiel pressure dock and was tested to 90 m. (295 ft.).  While performing her U.A.K. trials in the Kiel area, "U 517" was once rammed by an M-Boat believed to be either M.9 or M.11.
	(vi)  Silent Running Tests
	Contrary to normal procedure, "U 517" sailed for Rönne immediately her U.A.K. trial were completed, leaving Kiel at 2000 on 11th May and arriving at Rönne at 1200 next day.  The usual series of silent running tests was then performed (see C.B. 4051 (54) ) and "U 517" sailed at 1530 on 13th May for Danzig.
	(vii)  Speed and Crash-Diving Trials
	"U 517" reached Danzig on 14th May and on 15th May did a speed test over the measured mile.  On 16th May she did crash-diving tests, successfully reaching 20 m. (66 ft.) in 40 seconds, the rate stipulated by the Admiral U-Boats for all 740-tonners.  During the speed trials she was tested over a period of 10 hours.  The maximum speed was slightly in excess of 18 knots, but the exact figure was kept secret from the ship's company.
	(viii)  Torpedo Firing Practice
	Early on 18th May, "U 517" left Danzig for Gdynia, where she did the usual torpedo firing exercises offshore, firing in all 48 torpedoes.  Survivors said this is the routine number now fired by all 740-tonners.  On the afternoon of 20th May she proceeded to Hela.
	(ix)  Agru-Front
	"U 517's" Agru-Front exercises lasted from 21st to 30th May, during which period she was visited on three occasions by Kapitänleutnant (Ing.) Gerd Suhren, officer commanding the Agru-Front organisation.  Prisoners said that conditions at Hela were very congested.  They affirmed that "U 517" did not dive at a steeper angle than 45° during her Agru-Front exercises.
	(x)  Gunnery Trials
	On 31st May, "U 517" left Hela for Pillau for gunnery trials.  These lasted until 6th June.
	(xi)  Tactical Exercises
	On 7th June, "U 517" left Pillau for Danzig, where she arrived the same afternoon.  On 9th June, selected members of her ship's company were given theoretical instruction in tactics, and on 10th June, she sailed to Gdynia for her tactical exercises on the Bight of Danzig, which began the next day and lasted until 19th June.  They followed the usual routine of convoy attack, etc.
	(xii)  Appointment of new First Lieutenant
	On 20th June, "U 517" made Gdynia, where she lay at the Stichbrucke.  Here Oberleutnant zur See von Dresky left her and was replaced by Leutnant zur See der Reserve Brandi as First Lieutenant.  It was stated that the captain had engineered this change in order to rid himself of von Dresky, whose popularity with the men and whose excellent torpedo-firing he deeply grudged.  When von Dresky went ashore for the last time, the ship's company gave him three sheers, which infuriated Hartwig.  The same day, Hartwig was promoted Kapitänleutnant and von Dresky Oberleutnant zur See.
	That evening the officers celebrated the near approach of a few days' leave and the arrival of Brandi, the new First Lieutenant, by getting drunk.  In the middle of the party, Hartwig thought it fit to call out the watch for the amusement of guests he had invited on board.
	(xiii)  Leave at Stettin
	On 21st June "U 517" arrived in Stettin and the ship's company were granted local leave, most of them going sailing.  On the evening of 23rd June, they held a party in the "Haus der Seefahrt," sailing next morning at 0800 for Hamburg through the Kaiser Wilhelm Canal.  While in Stettin, the men were accommodated in barracks ashore.
	(xiv)  Final Adjustments
	"U 517" arrived back at the Deutsche Werft in Hamburg-Finkenwerder on 25th June.  Her ship's company were accommodated in the depot ship "Veendam" (15,450-ton Holland-America liner) before going on leave in watches.  She entered U-Boat shelter No. 1B, in the Rusch Kanal, later going into dry-dock for final adjustments and then entering pen No. 2A of the Howaldtswerke shelter.
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	Leutnant zur See Richter left the ship at this stage and was not replaced.
	"U 517's" yard number during final adjustments was R.311.
	During final adjustments, the K.D.B. gear S-gear and the V.H/F were removed.
	"U 517" sailed from the Deutsche Werft, Hamburg-Finkenwerder for Kiel on 5th August, having previously embarked her full torpedo outfit.  On arrival at Kiel, she lay in the Wik harbour, where she embarked ammunition and fresh provisions.
	Prior to setting out on her first patrol, two midshipmen, one named Margan and another Semikowski, came on board.  Their main duties were gunnery, but they were also allowed to assist in plotting her course from time to time.
	IV.  FIRST PATROL OF "U 517"
	(i)  Departure from Kiel
	"U 517" sailed on her first operational patrol from Kiel at 0700 on 8th August, 1942, with orders to proceed through the Rosengarten, and there await further instructions.  She was accompanied by "U 211" and two patrol boats.
	The Senior Officer of the 5th U-Boat Flotilla, Kapitänleutnant Oskar Mohle, and a number of senior officers, including Korvettenkapitän Lamprecht, saw her off.
	"U 517" had provisions sufficient for sixteen weeks.  The men had no idea at this stage of their patrol what was to be their destination, but they believed they would eventually put into Lorient, as their kit had been sent there.
	Through the Great Belt, Kattegat and Skagerrak she proceeded at speeds varying between dead slow and half speed, depending on the other craft in the convoy.
	"U 211" parted company before reaching Kristiansand S.
	(ii)  Call at Kristiansand S.
	She made Kristiansand S. in the early hours of 10th August, and made fast at the quay opposite the corn silos at Sölyst, where she topped up with fuel, fresh water and provisions.  The passage from Kiel had been made on the surface and there had been no aircraft alarms.  The ship's company spent the night on board.
	(iii)  Passage of North Sea and Rosengarten
	"U 517" sailed from Kristiansand S. about 0700 on 10th August, escorted by two patrol boats.  There was no other U-Boat with her.
	She hugged the Norwegian coast until making Lister Fjord, where she parted company with her escorts and altered course to 270°, holding it until she reached the 100-fathom line, when she steered 000°.  She remained on this course until in approximate position 64° N. 04° E., when she altered course again to 270°.  Between this point and passing through the Rosengarten she sighted a number of drifting mines, but exploded none.  She also sighted several aircraft diving each time.
	On reaching a position approximately 64° N., 10° W., she altered her mean course to 230° to make the passage of the Rosengarten, which was effected on the surface at half speed.  The quartermaster said that the position of the British minefields in this area was accurately marked on a secret chart available only to the Captain.  Navigation through the Rosengarten was based on this chart and involved three or four sharp alterations of course to negotiate the minefields, which he believed to be laid in the form of parallel lines with gaps in between.  Hartwig told the quartermaster in Kristiansand S. that they must expect to navigate through a minefield in the Rosengarten.
	"U 517" made her first test dive soon after leaving Kristiansand S., remaining submerged at 50 metres (164 ft.) for about one hour.
	(iv)  Atlantic Crossing
	She completed the passage of the Rosengarten on or about 13th August, signalled her position to the Admiral U-Boats and received orders to proceed to her operational area off the Labrador coast.
	She accordingly altered course to about 300° and steered in a wide circle between south of Iceland and Cape Farewell.  At no time, however, did she sight land.  The whole way across the North Atlantic she remained on the surface, apart from the regular daily test dives.  Owing to her captain's desire to economise in fuel so as to stay at sea as long as possible, she proceeded the whole way across the Atlantic on one Diesel, which her Engineer Officer recommended as the most economic method.  The sea was moderate and visibility good throughout.
	Soon after altering course south of Iceland, "U 517" sighted one fast steamer steering north.  She followed her for half an hour, but soon gave up the chase, since the steamer appeared to be bound for Reykjavik and "U 517" had, in any case, orders to reserve her torpedoes as far as possible for operations elsewhere.

 

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	(v)  Arrival off Belle Isle
	"U 517" sighted Belle Isle at 1400 on 26th August, in fine weather.  She approached it cautiously from the N.E., later passing between Belle Isle and Cape Bauld dead slow on the surface.  She made towards approximate position 51° 40' N., 55° 15' W., which she judged to be a favorable area for intercepting traffic through the Belle Isle Strait.
	(vi)  First Sinking
	At 1300 on 27th August, "U 517" sighted one northbound steamer proceeding through the Belle Isle Strait, escorted by a destroyer.  "U 517" took up a position to starboard of this ship's probable course and fired a salvo of two torpedoes from her bow tubes from periscope depth in approximate position 51° 40' N., 55° 15 W.  Range was about 1,000 yards.  One torpedo found its mark, but one went wide, exploding against the cliffs on the opposite shore.  "U 517" thereupon submerged and the destroyer was heard to circle the position twice, thereafter making off.  Survivors were very surprised at the destroyer's apparent lack of initiative; they fully expected a depth charge attack to develop.  They credited themselves with 3,000 tons for this sinking.
	"U 517" later surfaced and saw survivors from the torpedoed ship taking to the boats.
	Soon afterwards, she set course submerged at 30 metres (98 ft.) at about 100° until she reached a point roughly 52° 00' N., 55° 45' W., where she waited for some hours so as to give her ship's company an opportunity to study the charts and familiarise themselves as far as possible with the vicinity.
	(N.I.D. Note.  The U.S. Army Transport "Chatham" (5,649 tons) was sunk at 1255 local time in position 51° 51 N., 55° 30' W.  on 27th August, 1942, in Convoy S.G.6.)
	(vii)  Second Sinking
	In the night of 27th/28th August, "U 517" set course northwards to the east of Belle Isle, which she circled, arriving off Chateau Bay at about 0300 on 28th August.
	En route, she had been in communication with "U 165," another 740-ton U-Boat commanded by a Kapitänleutnant Hoffmann, which she had sighted on the surface five miles distant.  As the boats were closing, however, the appearance of an aircraft forced them both to dive temporarily and they passed recognition signals by U/T.  The aircraft made no attack.
	At about 0500, in approximate position 52° 00' N., 55° 45' W., "U 517" sighted what appeared to be a ship sailing independently making about 6 knots on a course between Labrador and Belle Isle.  She fired a salvo of two torpedoes at her from the surface, at least one of which was observed to hit.
	(N.I.D. Note.  At 0045 local time on 28th August the United States Ship "Arlyn" (3,304 tons), forming part of Convoy S.G.6, was sunk in position 51° 53' N., 55° 46' W.  It is possible that she was a straggler from this convoy.)
	At dawn, "U 517" submerged to periscope depth and altered course eastward.
	She claimed 2,500 tons for this sinking.
	(viii) Reconnaissance of Armour Point Harbor
	"U 517" spent the whole of 28th August circling Belle Isle once again and afterwards patrolling dead slow in a southerly direction off its western coast, but sighted nothing.  At this stage Hartwig received a signal from the Admiral U-Boats ordering him to operate at his discretion in this area and determined to make the passage of the Belle Isle Straits in search of further targets.
	On his way southwest down the Belle Isle Straits, Hartwig sighted a large vessel, estimated by some to be of about 12,000 tons, ashore in the neighbourhood of Four Mile Cove on the coast of Newfoundland.  It appeared impossible to attack her at the time and Hartwig shrugged his shoulders, remarking "She'll do for us on the way back!"  He had previously had orders to attack this vessel by gunfire, as she was known to be ashore.
	In the night of 28th/29th August he penetrated into the harbour of Amour Point, on the coast of Labrador, in search of ore ships, but saw none.  He used his electric motors.  His men were extremely excited at this adventure, the more so since they could see the lights of houses and motorcar headlights on the local roads.  Hartwig chose Amour Point because of the depth if water in the harbour.
	One man said that, as they were leaving the harbour, a destroyer entered but did not spot them.
	On leaving Amour Point, "U 517" proceeded into the St. Lawrence steering due southwest.
	(ix)  Third Sinking
	Throughout the period 29th August to 2nd September, "U 517" patrolled dead slow between Amour Point and the East Cape of Anticosti Island, proceeding submerged during the day-time for fear of aircraft and on the surface at night.
	In the evening of 2nd September, she sighted a convoy steering about 050° in approximate position 49° 00' N., 60° 30' W.  As it was still fairly light, however, she did not dare to attack it immediately for fear of being detected by aircraft, and decided instead to follow it to the N.E. and attack at dawn from the surface.
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	At about 0800 on 3rd September, she had penetrated on the surface into the centre of the convoy, put about, and fired two torpedoes from her after tubes at the two aftermost ships, allowing an interval of about three minutes between each shot.  Both scored hits and the two ships sank, "U 517" crediting herself with another 10,000 tons, 5,000 for each ship.
	(N.I.D. Note.  At 0600 local time on 3rd September, 1942, the British "Donald Stewart" (1,781 tons) was sunk in position 50° 30' N., 58° 46' W. in convoy L.N.7.  The escort vessels were attacked soon afterwards.)
	"U 517" submerged to 100 metres (328 ft.), but no D/C attack developed.
	She later surfaced and proceeded at slow speed S.W. to the west of Anticosti Island, later altering course to pass through the Gaspe Passage.  She submerged off South Point owing to the risk of aircraft attack.
	(x)  First Torpedo Transfer
	As far as can be ascertained, four air-torpedoes were transferred from "U 517's upper-deck containers to below decks soon after the attack of 3rd September, two through the forward and two through the after hatch.  Survivors stated that this took place between 0100 and 0600 in the Gaspe Passage and was accomplished without undue difficulty.  There was no aircraft attack during this operation.
	(xi)  Fourth Sinking
	Between 3rd and 7th September, "U 517" patrolled the Gaspe Passage in search of further targets.  She sighted a number of eastbound and westbound convoys during this period, but did not judge conditions favorable for attack.
	In the early hours of 7th September, as "U 517" was patrolling to the northwest of the Gaspe Passage, she sighted an eastbound convoy of about seven ships with destroyer escort and fired a salvo of four torpedoes from the surface from the starboard side of the convoy.  One ship was sunk.
	(N.I.D. Note.  At 0210 local time in position 47° 35' N., 62° 59' W., the Greek Aeas (4,729 tons) was sunk from convoy Q.S.33.)
	(xii)  Aircraft Bomb hits "U 517"
	At one point while patrolling the Gaspe Passage, "U 517" was hit by an aircraft bomb which failed to detonate.  This was the only occasion during this patrol that a bomb fell close to her, although she was many times attacked by aircraft.
	The incident took place at night, while she was surfaced.  The bomb, which prisoners said was small, fell forward near the 10.5 cm. gun ready use locker, but failed to explode.  Hartwig, the engineer officer, a seaman and a stoker between then threw it overboard.
	(xiii)  Fifth Sinking
	In the evening of 7th September, in a position midway between South-West Point on Anticosti Island and Cap des Rosiers (Province Quebec),  "U 517" sighted a westbound convoy, which survivors said consisted of four merchantmen and six destroyers.  Much to the admiration of his men, Hartwig manoeuvered himself into the centre of the convoy and fired three torpedoes, one from an after tube and two from Tubes 1 and 2 forward.  This resulted in the sinking of two ships for certain and possibly a third.  (N.I.D. Note.  At 2100 on 7th September, in position 48° 50' N., 63° 46' W., the following ships were sunk from Convoy Q.S.33:
	Greek "Mount Pindus" (5,729 tons).
	Greek "Mount Taygetus" (3,288 tons).
	British "Oakton" (1,727 tons).
	Survivors explained that Hartwig had originally intended to fire four torpedoes on this occasion, two from the forward and one from each after tube.  A technical fault in one of the after tubes however, prevented it firing.  Hartwig himself fired the after torpedo, using one periscope, while the First Lieutenant fired the two torpedoes from the forward tubes, using the other periscope.
	Immediately following this attack, "U 517" submerged and a fierce D/C attack from all six destroyers developed.  Hartwig was at his wits' end as to what to do next, when he suddenly remembered his S.B.T. gear and used it for the first time.  To everyone's relief, the bubble target itself was vigorously attacked while "U 517" made off submerged.
	Hartwig credited himself with 18,000 tons on 7th September.  This total included the ship sunk in the Gaspe Passage the same morning.  (See Section (xi).)
	In the D/C attack described above, "U 517's" distilling plant was damaged and supplies of fresh water for the rest of the patrol were very limited.  Hartwig reminded everyone to use as little as possible, even if it involved no coffee being brewed, as he certainly intended to remain at sea until all his torpedoes were expended.  From that time onwards, the plant, which normally produced 50 gallons per day, did not produce more than 10 a day; but after a substitute condenser had been made, this was increased to 30 gallons a day.

 

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	(xiv)  Penetration of St. Lawrence Narrows
	Encouraged by his constant success, Hartwig then decided to penetrate further upstream than hitherto and sailed into the St. Lawrence Narrows to a point midway between Cape Chat and Pointe des Monts.  He waited there at periscope depth for one day, but sighted nothing, and on 9th September returned to the Gaspe Passage.
	(xv)  Sixth Sinking
	"U 517" then returned to approximate position 49° 20' N., 64° 30' W., where at about 1300 on 11th September she sank what survivors claimed to be a British A.M.C. of about 3,500 tons displacement.  An entry in a diary also confirms this date.  They said it was clear that she was an A.M.C. since she was seen to be heavily armed.
	This ship was stated to be zig-zagging westwards at about 14 knots and was very difficult to pursue.  "U 517" attacked from the north at periscope depth and the ship cost her two torpedoes, one of which did not score a hit.
	Survivors were quite certain that she was sunk, as they heard no more H.E. after their torpedoes had struck and later heard sounds of explosions which they took to be from D/Cs carried on board.
	(xvi)  Seventh Sinking
	On 15th September, at about 1830, "U 517" was patrolling off Cap des Rosiers when she fired a salvo of four torpedoes from periscope depth at a westbound convoy.  Survivors claimed that she sank one 5,500-ton ship for certain, while they thought it possible that a second had also been sunk.  As Hartwig was uncertain, he only credited himself with 5,500 tons.
	(N.I.D. Note.  At 1649 local time on 15th September, 1942, the Netherlands "Saturmus" (2,741 tons) and the Norwegian "Inger Elisabeth" (2,166 tons) were sunk from Convoy S.Q. 36)
	Following on this attack, "U 517" sustained a heavy D/C attack.  There was no structural damage, but survivors said that her after torpedo angling gear was put out of order, and her remaining upper-deck torpedoes damaged.  They blamed these events for the less satisfactory results achieved from then onwards.
	(xvii)  Second Torpedo Transfer
	"U 517" had by then expended 19 of her 23 torpedoes and Hartwig decided to transfer his remaining four air-torpedoes to below decks.
	For this purpose he proceeded immediately to approximate position 48° 20' N., 62° 40' W. and effected the transfer on the night of 15th/16th September.  The whole process lasted about three hours in a calm sea.
	This position was chosen because Hartwig thought it well removed from any shipping lanes.
	(xviii)  Patrol to Cabot Straits
	As soon as the transfer was complete, "U 517" steered south-east through the Cabot Straits in search of further targets.
	About 19th September she sighted a 50-ton sailing vessel in approximate position 48° 00' N., 60° 00' W. and passed very close to her.  Survivors spoke laughingly of the panic which "U 517's" proximity caused on board her.  Hartwig decided, however, that it was not worth attacking.
	Weather was very foggy and no one was surprised when, about 21st September, in approximate position 47° N., 59° W. Hartwig gave the order to turn back into the St. Lawrence.
	When in approximate position 48° N., 60° W. a day or so later, "U 517" sighted what she estimated to be a 1,000-ton steamer.  She pursued her for a short while, but fog conditions were very bad and Hartwig shortly gave up the chase.
	(xix)  Sighting of Three Neutrals
	About 0300 one night during this time, when midday between Cap des Rosiers (Quebec Province) and South West Cape (Anticosti), "U 517" sighted three fully illuminated ships, the latter two estimated at about 10,000 tons each, proceeding on an easterly course at about 12 knots.  Hartwig was at first puzzled as to the nature of these ships and many of his men suspected them of being some kind of a trap.  Their upper decks were flood-lit and all ports illuminated.  He accordingly followed them to a position off Cormorant Point (Anticosti Island) where, at about 0700 the same day, he decided they were genuine neutrals and abandoned the chase.
	(N.I.D. Note.  The three Swedish ships, "Fenris" (1,950 tons) "Bardaland" (2,595 tons) and "Mongabarra" sailed on 1st October from Montreal with grain cargoes for the Piraeus.)
	(xx)  Final Convoy Attack
	Between the time of her leaving the Cabot Straits westward and her final abandonment of her operational area, "U 517" patrolled once more in the Cape Passage.  Hartwig did not, however, judge the moment ripe for attack until 5th October when, at about 0500, he fired a salvo of four torpedoes at long range from his bow tubes at a 21-ship eastbound convoy which he had followed for two days.  All went wide of their mark, however, and it was decided to put about for home.  All 23 torpedoes had been expended.
	Some survivors said that a probable reason for these four torpedoes having missed was that they had been damaged in previous D/C attacks, others said that the range was too great for accuracy.
	(C47999)                                                                                                                         a**

 

	12
	Hartwig claimed in all to have sunk 44,000 tons of shipping and the ship's company thought they had done extremely well.
	They were particularly gratified at having heard on their W/T that the St. Lawrence had been declared a danger area as soon as their presence became known.
	(xxi)  Passage of Atlantic Homewards
	On 6th October, "U 517" sailed for home.  She passed out of the Cabot Straits and then kept well to the south of the Newfoundland Banks for fear of aircraft, which she believed patrolled this area unceasingly.
	By contrast with her westward passage, she pursued a southerly course homewards.  She claims to have sighted no shipping, though survivors admitted that once when north of the Azores they sighted and exchanged recognition signals with another U-Boat.  Prisoners thought they would be ordered to fuel this boat, but when it was decided not to do so, "U 517" switched from one Diesel to two and proceeded at full speed until she made Lorient.  Apart from her daily practice dives she remained on the surface throughout.
	While making the passage of the Bay of Biscay, she was forced to dive on three or four occasions owing to the sighting of aircraft.  On her way home, she and "U 515" received a signal of good wishes from the Admiral U-Boats.
	Prisoners said that on this patrol they had counted 27 aircraft bombs and 118 D/Cs.
	(xxii)  Arrival at Lorient
	About 0700 on 21st October, "U 517" arrived off Lorient ad met her escort of two "Sperrbrecher" and two patrol boats.  At 1530 she was taken in tow and brought to her berth opposite the Arsenal where she made fast at 1700.  A band was playing and the senior Officer of the 10th U-Boat Flotilla, Kapitänleutnant Günther Kuhnke, made a speech of welcome.
	A few hours later she proceeded to the shelters at Keroman, where she entered pen No. 8, lying next to another 750-tonner.
	Survivors said she had about 10 tons of fuel remaining on arrival.  They were very pleased to be told that the Admiral U-Boats had decided to credit them, not only with the 44,000 tons claimed, but with an extra 8,000, representing one of the ships fired at in the attack on 15th September and not claimed sunk, but later reported to have been sunk by another U-Boat.
	(N.I.D. Note.  From Allied sources "U 517" appears to have sunk 31,112 tons on this patrol.)
	The ship's company was given long leave in watches after undergoing the usual medical examination.
	Survivors said that they had heard that the Admiral U-Boats was extremely pleased at their return and had been particularly anxious regarding their fate throughout their patrol, since on many occasions "U 517" had been unable to reply to his signals asking for her position.
	After arriving at Lorient, the First Lieutenant gave a broadcast description of her first patrol.
	(xxiii)  Period in Lorient
	Towards the beginning of November, "U 517" began to prepare for her next patrol.  The German Search Receiver gear was built in.
	On 9th November she underwent basin trials in the water next to the Keroman shelters and fired a series of dummy torpedoes, on 11th November she did trials locally, from 14th November to 16th November she embarked provisions, and on 16th November she did trimming tests and compass adjustments and passed over the D/G range.
	Kapitänleutnant (Ing.) Martin and Leutnant (Ing.) Becher joined "U 517" at this time, replacing Oberleutnant (Ing.) Heller.
	V.  LAST PATROL OF "U 517"
	"U 517" sailed on her last patrol from the pier opposite the Arsenal at Lorient at about 1630 on 17th November, 1942.  There were no official celebrations, the Senior Officer of the flotilla came on board to wish the ship's company good luck and, failing a band, "U 517's" own radio was turned on.
	She was escorted by one "Sperrbrecher" proceeding her and three patrol-boats following astern.  She proceeded on the surface down river and out into the Atlantic to starboard of the Banc des Truies.  The ship's company had no exact idea of their destination, but as all had been issued with tropical kit, they felt certain they would be sailing south, probably to some distant point.
	Her escort parted company at about 2000 and "U 517" set course 270° on the surface.  From then until day of her sinking, she proceeded generally on the surface on one Diesel at night and submerged in the day-time.
	Survivors said that they several times detected aircraft and each time submerged.

 

	13
	In the night of 18th/19th November, she received a W/T signal from the Admiral U-Boats ordering her to a given operational area.  Hartwig did not make known to his men the position of this area, but a telegraphist rating said that it lay to the south.  Other survivors spoke of Trinidad, Panama and the Caribbean.
	An E.R.A. said that after leaving Lorient he experienced trouble with the Diesels due to the presence of dirt in the fuel.  He suspected the French of having sabotaged his boat, though he could not understand how it came about, as he was convinced the installations from which they had fuelled were clean.  He was forced to dismantle and clean all filters and pumps.
	VI.  SINKING OF "U 517"
	On the morning of 21st November, 1942, Hartwig judged that he was out of the aircraft danger zone and decided to remain on the surface.  His German Search Receiver was retained in position.
	At about 1000, the German Search Receiver gear gave a reading and the operator immediately informed Hartwig, who was at first in two minds whether or not to submerge.  He thought it was a seaplane, which he considered too slow to necessitate a hurried dive.  A moment later, however, the reading ceased and Hartwig decided to remain surfaced.  "U 517" was proceeding due west at half speed on one Diesel, probably making about six knots.
	A few moments later, however, the bridge watch sighted an aircraft and the order to dive was immediately given.  Not all on board were aware of the situation, some men thinking that it was the normal daily practice dive that was being carried out.
	At a depth of between 12 and 20 meters (39 and 68 ft.), however, there were three loud explosions of the kind normally associated with D/Cs.  The main lighting failed, many of the depth-gauges and other delicate gear were broken and there was a water entry through the after hatch.
	(N.I.D. Note.  At 1017 B.S.T. on 21st November, 1942, Albacore aircraft B.F.597 of Naval Air Squadron 817, was carrying out an A/S reconnaissance from H.M.S. "Victorious," which formed part of a naval force proceeding at 19 knots on course 000°, in approximate position 46° N., 17° W.)
	The aircraft was flying at approximately 1,000 ft. when it sighted a fully-surfaced U-Boat 20 on its port bow, proceeding at about 10 knots on approximate course 280°.  It closed immediately to attack from astern along the U-Boat's course.  The U-Boat did not take action until about 20° seconds later, when she dived, her stern finally disappearing when the aircraft was 500 yards astern.
	The first D/C was aimed at the centre of the swirl, the remaining three being dropped with a spacing of 45 ft. along the U-Boat's track from a height of 40-50 ft.
	Survivors said that they afterwards realised that the whole of the bridge and part of the conning-tower had been blown away by one of the explosions and they estimated that the other two had taken place on either beam.  The motors continued to function.
	Great confusion prevailed in the boat, but most of the crew kept their heads.  One of them; however, lay on the deck shouting, "I don't want to die yet !"
	Hartwig made no attempt to dive deeper, owing to the seriousness of the water entry, and immediately ordered her to surface.
	(N.I.D. Note.  After two minutes, the U-Boat's bows were seen to appear above the surface at an angle of about 60° to horizontal.  The aircraft then proceeded north for five miles before reporting the attack.)
	The Diesels had been shaken from their foundations, it was impossible to start them.  Chlorine gas fumes began to form and it was appreciated that the situation was serious.  The water entry aft was, moreover, causing her to lose trim.
	At this stage two British destroyers and two more aircraft appeared on the scene and Hartwig gave the order to form up on the upper-deck.  The Engineer Officer remained below to ensure that all had left and gave the order to open the vents.
	A Torpedo Gunner's Mate was then sent below to fire the scuttling charges, but did not return.  Survivors were certain that he had been overcome by the battery fumes.  It appears, however, that he had first carried out his orders, since the three charges later detonated.
	As soon as the Torpedo Gunner's Mate had gone below, the Ship's company sang a verse of "Deutschland Ueber Alles" and gave three cheers, whereupon Hartwig gave the order to abandon ship.  His men sprang into the water and were picked up by one of the two British destroyers which had meanwhile arrived on the scene and fired two warning shots across "U 517's" bows.  Hartwig and his Senior Engineer Officer were the last to leave her.
	The Senior Engineer Officer said that, before she finally sank, "U 517" had lost trim by the bows, so that her stern was high in the water, thus reversing the previous situation.  This he attributed to their having blown their after fuel tanks when she at first lost trim by the stern, in an effort to restore trim.  Meanwhile, however, water had also entered forward.  An E.R.A. said that she had blown about 160 tons of fuel oil.
	Hartwig said that the fact that the aircraft was not a seaplane made him realise that an aircraft carrier was probably in the neighbourhood.  He was therefore more than ever aware of the futility of trying to escape.  He said he would have fired a few shots at the destroyers, but he had not time to get at his ready-use ammunition.
	Before Abandoning ship, he had signalled the Admiral U-Boats his fate and added that all secret documents had been destroyed.

 

	14
	VII.  DETAILS OF "U 517"
	(i)  Displacement  740 tons.
	(ii)  Type  IX C.
	(iii)  Building Yard  Deutsche Werft, Hamburg.
	(iv)  Armament
	(a)  Guns:
	One 10.5 cm. (4.1 in.) forward.
	One 3.7 cm. (1.45 in.) aft.
	One 20 mm. on bridge.
	Mountings for four M.G.s on conning-tower.
	(b)  Torpedoes:
	Twenty-three carried, distributed as follows:
	Six electric torpedoes in tubes.
	Four electric torpedoes in bilges forward.
	Two electric torpedoes on bow compartment floor plates.
	Three electric torpedoes on after torpedo compartment floor plates.
	Eight air torpedoes in upper-deck containers.  (G.7 L. pistols)
	(G.7e (electric) were 2-bladed, G.7a (air) six-bladed.)
	(c)  Torpedo Tubes:
	Four forward and two aft.
	(v)  Ammunition
	In addition to the ammunition stowed in the magazine below, ready-use ammunition was stowed in lockers in the conning-tower.
	(vi)  Propulsion
	(a)  Diesels:
	Two 9-cylinder four-stroke Type M9 V.40/46C M.A.N. Diesels, each developing 2,200 h.p. at 480 r.p.m. with supercharger.  Each developed 1,700 h.p. at 400 r.p.m. without supercharger.  The engines are built to withstand an exhaust temperature of 500° C.  In normal circumstances, however, this must not exceed 480 C.  At high speeds, no account is taken of engine revolutions, the most important factor being exhaust temperature.  In emergency, 10 per cent. more r.p.m. can be achieved by the use of air bottles.
	Cylinder bore:  400 mm. (15.75 in.).
	Cylinder stroke:  460 mm. (18.11 in.).
	(N.I.D. Note.  The Type number of the engine indicates its specification.  Thus in Type M.9 V.40/46C M.A.N. Diesels, the 9 indicates number of cylinders and the 40 and 46 refer respectively to stroke and bore in centimetres.  The C indicates the type of supercharger, in this case direct coupled.)
	(b)  Diesel Supercharger:
	"U 517" was fitted with a supercharger called a "Mechaniches Autladgebläse," which is gear driven from the main engines.
	(c)  Diesel Vibration Damper:
	The Diesels were fitted with a vibration damper forward which was said to absorb about 50 per cent. of the vibration.  This consisted of a form of flywheel, around which was a hub with springs in between.
	(d)  Electric Motors.  Siemens.
	(vii)  Speeds
	Survivors had little knowledge of "U 517's" speeds, since during almost the whole of both her patrols, she proceeded either surfaced on one Diesel or at slow speed when submerged.  The following are, however, rough estimates:
	(a)  Diesels:
	(1)  On one Diesel (in calm weather).
	160 r.p.m. 5 knots (dead slow).
	240 r.p.m. 8 knots (slow).
	She did not normally go faster than this on one Diesel, owing to the amount of rudder required.
	(2)  On two Diesels (in calm weather).
	160 r.p.m.  7 knots (dead slow).
	240 r.p.m.  11 knots (slow).
	300 r.p.m.  15 knots (half speed).
	400 r.p.m.  17.5 knots (three-quarter speed).
	460 r.p.m.  19 knots (full speed).
	480 r.p.m.  20 knots (utmost speed)
	528 r.p.m.  21 knots (emergency speed).
	(The latter speed could only be achieved with the use of air bottles.)
	The Diesels are not permitted to run at over 480 r.p.m. for over two hours, nor at 528 r.p.m. for over half an hour.
	Automatic Cut-Out.  The automatic cut-out operates at 460 r.p.m.  To achieve 480 r.p.m. the cut-out must be removed.

 

	15
	(b)  Electric Motors.  The following r.p.m. were given:
	60 r.p.m.  (dead slow).
	90 r.p.m.  (silent speed).
	110 r.p.m.  (slow).
	160 r.p.m.  (half speed).
	180 r.p.m.  (three quarter speed).
	210 r.p.m.  (utmost speed).
	One man estimated a speed of 6.8 knots at 210 r.p.m.
	(c)  General.  She only used Diesel-Electric procedure when charging batteries.  The Engineer Officers considered that to proceed on one Diesel was more economic.  Both Diesels were only used in very rough seas to maintain speed.
	On her trials "U 517" never proceeded at a higher speed than just over 18 knots.
	On passage from Kiel to her operational area, she changed over from one Diesel to the other every four hours.  On the return passage, she adopted the same procedure until halfway, when she used both at half and full speed.
	(viii)  Fuel
	(a)  Capacity.  "U 517" had a fuel capacity of about 280 cubic metres (about 260 tons).
	(b)  Consumption.  About 2.5 cubic metres (2.3 tons) per day at slow speed on one Diesel.
	(ix)  Communications
	(a)  W/T Sets.  She carried three W/T sets, consisting of:
	(1)  40/70 watt emergency receiver-transmitter.
	(2)  150-watt short and medium wave receiver-transmitter.
	(3)  200-watt long wave receiver-transmitter.  (All manufactured by Telefunken.)
	(b)  U/T was carried throughout.
	(c)  V.H/F.  None.
	(d)  Radione radio set in captain's cabin.
	(x)  Hydrophones.  Gruppen Horchgerät fitted.
	(xi)  S-Gear.  None.
	(xii)  R.D.F.  None
	(xiii)  D.F.  Fitted.
	(xiv)  K.D.B. None.
	(xv)  Echo Sounder.  Fitted.
	(xvi)  Electrolot.  Carried
	(xvii)  S.B.T.  Fitted.
	(xviii)  German Search Receiver.  Fitted after first patrol.  (See also Section IX.)
	(xix)  Distilling Plant.  Capacity was two gallons an hour, but was reduced by D/C damage to 10 gallons a day.
	(xx)  Diving Angle.  Maximum 25°.
	(xxi)  Diving Depths.  Tested to 90 metres (295 ft.).  Maximum depth dived 160 metres (524 ft.).
	(xxii)  Crash Diving Time.  20 metres (66 ft.) in 40 seconds.
	(xxiii)  Scuttling Charges.  "Sprengbüchse" and "Sprengpatrone."  Duration of fuse, 9 minutes.
	(See also Section X (vi).)
	(xxiv)  Depth Gauges.  Prisoners said that "U 517" was fitted with a new type of depth-gauge, so constructed as not to be so sensitive to D/C attacks.  They were all graduated from 0-200 metres (656 ft.).
	(xxv)  Badge.  A grey U-Boat painted on either bow.  This is stated to be the badge of the 10th U-Boat flotilla.
	(xxv)  Look-Out Perch.  "U 517" carried a small look-out perch between her two periscopes large enough for one man.
	VIII.  BASES, TRAINING ESTABLISHES, ETC.
	(i)  France
	(a)  Lorient.  Prisoners said that Oberleutnant (Ing.) Henningsmeier is now second Flotilla Engineer to the 2nd U-Boat Flotilla at Lorient.  Describing an air-raid on the town while "U 517" was there, prisoners said that a U-Boat shelter had been hit but the bomb only penetrated about 2 ft.  The whole of the Siemens installation had been wrecked.  There had been almost no Flak evident.
	(b)  Paris.  A Petty officer Telegraphist from "U 660" described the Naval Signals Station at Paris (Marine Funkstelle Paris), where he had been employed for some months prior to May, 1941.
	The station was situated near the Bois de Boulogne.  It employed about 50 ratings and a small number of officers.  Its functions were:
	1.  To intercept and control traffic between all German surface vessels off the French Atlantic coast and their bases.
	2.  To give occasional orders to German surface craft off the French Atlantic coast.
	This station had nothing to do with U-Boats, for which Admiral U-Boats maintained a separate organisation at Lorient.  It maintained contact, however, with the Paris H.Q. of the Admiral U-Boats.

 

	16
	(ii)  Germany
	(a)  Aurich.  Kapitänleutnant Zadowski commands the 2nd Company of the Aurich W/T School, of which a Kapitän zur See von Dresky, father of "U 517's" original First Lieutenant, is in command.  (As at September, 1941.)
	(b)  Flensburg.  Oberleutnant zur See Papendieck, of the 1934 term, commands the 2nd Company of the Torpedo School.  (March, 1941.)
	(c)  Hamburg-Altona.  The Merchant Navy Navigation School ("Steuermannsschule") at Hamburg-Altona continues to function, according to the Quartermaster of "U 517."
	(d)  Kiel.  Kapitan zur See Lamprecht, of the 1911 term, holds a staff appointment at Kiel.  (August, 1942.)
	(e)  Lübeck.  The Merchant Navy Navigation School at Lubeck was closed soon after the commencement of the war, according to the coxswain of "U 517" who had attended it.
	(f)  Neustadt.  Leutnant (M.A.) der Reserve Bormann commands the 6th Company of the 2nd U-Boat Training Division at Neustadt.  (As at October, 1941.)
	(iii)  Poland
	Gdynia.  The 5th Company of the 2nd Division of the Gdynia U-Boat School is commanded by Kapitänleutnant Hesse.  (Autumn, 1942.)
	IX.  GERMAN SEARCH RECEIVER (G.S.R.)
	Prisoners from "U 660" (sunk 12.11.42) and "U 517" provided further details regarding the appearance and operation of German Search Receiver gear.  (See also C.B. 04051 (53) Section VII.)
	(i)  Appearance of Aerial
	It seems there are at least two main types of G.S.R. aerial now in existence, both used experimentally.  Prisoners say that it is the intention of the Admiral U-Boats to collect reports on the functioning of these sets before making any decision regarding a more permanent type to be fitted to all U-Boats later.
	(a)  "U 660" Type.  The aerial carried by "U 660" was similar in outline to that fitted in "U 353."  It was diamond-shaped and made of wood about 1 in. thick.  Across the centre ran a piece of wood of the same size.  Two "jam-jars" of a material resembling quartz were mounted on the central bar.  From each of these a rubber-insulated wire lead ran down to the set in the W/T room.  Each "jam-jar" was, moreover, connected with an antenna, one of which ran horizontally across the base of the central bar and the other on the outside of both sides of the upper isosceles triangle.  Prisoners insisted that these antennae, which were very thin and rubber-insulated, ran out from the relative "jam-jar" turned at the end of the wooden bar and ran back to the "jam-jar."  The height of the aerial was about 50 cm. (about 19 in.) and the width about 40 cm. (about 15.5 in.).  (N.I.D. Note.  Roughly the same measurements as the aerial carried by "U 353.")
	Whereas the aerial fitted in "U 363" was attached to the periscope shaft, "U 660's" aerial was fitted into two holders on the port side of the conning-tower.
	The horizontal antenna is for reception of "horizontal" R.D.F. transmissions, while the antennae fitted to the sides of the upper triangle are for "vertical" transmissions.
	(b)  "U 517" Type.  The G.S.R. aerial fitted in "U 517" was diamond-shaped, as in the case of "U 660" and "U 353."  It had, however, no "jam-jars."  The vertical antenna stretched between the centre of the cross-piece and the apex of the aerial, while the horizontal antenna stretched along the wooden centre piece.  Both antennae are connected at the base of the aerial to leads passing to the receiving set.  The horizontal antennae in "U 517" were described as nothing more than curved dipoles.
	(ii)  Appearance of Receiving Set
	In broad outline the sets fitted to both "U 660" and "U 517" were the same as that fitted to "U 353."  Both were manufactured by Metox.  The lead from the horizontal antenna or that from the vertical antenna may be plugged into the upper joint on the set, which will then receive either vertical or horizontal R.D.F. transmissions.  The central tuning dial is graduated from 0 to 100, reading from right to left.
	The P.O. Telegraphist from "U 517" said that half the interior of the receiving set resembled an ordinary radio receiver, while the other half contained a copper wire about 5 cm. thick, coated with silver and shaped like a horseshoe.  Both ends of this horseshoe are connected by two wires, which can be moved up and down.  This arrangement is said to function as a combined coil and condenser, the copper wire being the coil proper and the space between the two arms of the horseshoe the condenser.

 

	17
	(iii)  Operation of G.S.R.
	G.S.R. in both "U 660" and "U 517" was used almost solely to give protection against aircraft A.S.V.  For this reason, it was most frequently manned at night when aircraft could not be spotted, or when cloudy weather prevailed.  In clear daylight conditions, both captains preferred to rely on the bridge watch, except in the Mediterranean, when "U 660" always mounted hers.
	Some boats turn their aerial frequently, others not at all.  A P.O. Telegraphist from "U 600" stated that, in the case of his aerial, it was never turned.  He had been told, when attending a course of instruction at Brest, that, although failing to turn the aerial frame meant risking the appearance of an aircraft in a blind spot, this was a very small risk to take.  If the aircraft approached close enough, he was told, its transmissions would in any case be picked up at once.  A P.O. Telegraphist from "U 517," however, said that his aerial was turned every few minutes.
	While the aerial is in place, the receiver is constantly manned.  It is the duty of the operator to inform the Captain the moment a transmission is heard.  It is then left to the discretion of the Captain to submerge or remain on the surface.  Whereas Baur ("U 660") invariably submerged immediately, Hartwig ("U 517") did not always do so, a habit which eventually cost him his boat.
	The German Navy works on an increasing sound force scale of 1 to 5.  P.O. Telegraphists stated that they never received a transmission on a force less than 4.  They did not know for certain the range of the set, as "U 660" never waited for the aircraft to appear and "U 517" had not had enough experience to determine it with accuracy, but they estimated it to be about 20 kilometers (10-8 miles).  It is not capable of giving a bearing.
	There is no automatic volume control on the set.  The hand volume control is normally kept at full.
	British aircraft A.S.V. gives a low note, while ship-borne R.D.F. gives a higher note.
	Both "U 660" and "U 517" invariably plugged in only their horizontal antenna lead, since they were under the impression that British aircraft only transmitted horizontally.  Prisoners admitted it was strange that the vertical antennae should not be mounted vertically and added it was quite possible that some horizontal transmissions might be received at the same time as vertical by antennae so placed.  They did not, however, regard this problem as of great importance, as they virtually never used their vertical antennae.
	The set works on A/C power obtained from the rotary converter.
	A P.O. Telegraphist from "U 517" said he thought the set would be made automatic by amplifying the sound and putting it through the loud-speaker.  He thought it would also be a simple matter to have an automatic tuner, which would cover the frequency range, and that the apparatus could be developed to be automatic and need no operator.
	(iv)  Wavelengths Employed
	U-Boat telegraphists are informed before sailing of the following wavelengths:
	50 cm. (about)   German land-based H/A R.D.F. 80-90 cm.   German surface craft R.D.F. 130-135 cm.   British destroyer R.D.F. 168-172 cm.   British aircraft A.S.V. 242 cm.   German land-based coastal R.D.F.
	Prisoners said that they invariably listened in throughout on the 168-172 cm. wavelength, which they received when the knob on the central dial pointed to 34.
	They ignored transmissions on their own wavelengths and paid little attention to transmissions on the British destroyer wavelength of 130-135 cm., which are received at a point 22 on the central dial.
	The range of the set is stated to be over wavelengths of 125 to 250 cm.  Prisoners explained their references to lower wavelengths by saying that the set was capable of receiving shorter wavelengths by using harmonics of the receiver oscillator, although at very much reduced volume.
	Prisoners added that all German R.D.F. transmissions were vertically polarised and all British as far as they knew, horizontally.
	X.  GENERAL REMARKS ON U-BOATS
	(i)  Vibration Dampers
	M.A.N. Diesels are stated to be fitted with vibration dampers known as M.A.N. "Hübenfederschwingungsdämpfer."  These consist of a notched flywheel fitted on the forepart of the crank case with springs inside the notches.  Over this is fitted a fairly heavy hub, the whole being enclosed in a casing.
	Each notch of the flywheel contains about eight horseshoe-shaped springs measuring about 4 in. across.  These can easily be replaced if they wear out.  The "Hübenfederschwingungsdämpfer." is a M.A.N. patent.  Although invented six years ago, it has been found so effective that all U-Boat Diesels are to be fitted with it.
	On the forward part of the compensator is fitted a vibration gauge.  This is stated to be an electrical device which measures the torque of the crankshaft and indicated the engine's critical speed on a special revolution indicator.  Its principle is said to be a M.A.N. Secret.

 

	18
	(ii)  M.A.N. Diesels
	Survivors spoke with enthusiasm of their M.A.N. Diesels, which they preferred to all other makes.  They seemed to think that all U-Boats should be fitted with them.  Nine-cylinder M.A.N. Diesels are stated to develop 1,700 h.p. at 400 r.p.m. without the use of the supercharger.  The engine is built to withstand an exhaust temperature of 500 C.  The difference in weight between a Krupp six cylinder Diesel and a similar M.A.N. product used to be 6 tons, with Krupp the heavier.  Krupp later reduced its weight by two tons and M.A.N. increased by two, so that the present difference is only two tons.
	(iii)  Welding Gear on Conning-Tower
	All U-Boats are now being fitted with an oxy-acetylene connection on their bridge to facilitate structural repairs on the upper deck while at sea.
	(iv)  Duplication of Angling Gear
	It has been the intention of the German naval authorities for some time to duplicate U-Boats' torpedo-angling gear to mininise the risk of damage from depth charge attacks, but difficulties of production have held up implementation.  "U 517," for instance, carried no such duplication.
	(v)  "Uberseekühe"
	Prisoners thought that the type of boat most commonly referred to as an "Uberseekühe" is a 1,200-tonner.  These are said to have a radius of action of between 20,000 and 22,000 miles (presumably at 10 knots).  They were stated to be fitted with four Diesels, two of which are sometimes M.A.N. nine-cylinder type and the other two six-cylinder G.W.  One man said the larger Diesels are intended to drive the boat, the smaller being for charging the batteries, though occasionally they were coupled and all four used for driving.
	(vi)  Scuttling Charges
	Two types scuttling charge are used in the German navy, as follows:
	1.  Sprengpatrone (cartridge type).  These contain 1,800 grammes (about 4 lbs.) of high explosive No. 18 and 140 grammes (5 oz.) of an explosive called "Ecrasit."
	2.  Sprengbuchse (canister type).  Similar to Sprengpatrone, except that they contain only 140 grammes (5 oz.) of "Ecrasit" and no high explosive.  They are concealed near the pressure hull, so that they would not be found by a boarding party.  (For further description of Sprengpatrons, see C.B. 4051(43) Section VII (iv).)
	Both charges take exactly nine minutes between firing and detonation and both have the same priming and detonating arrangements.
	(vii)  High Explosives
	Three kinds of high explosive used in the German Navy were mentioned:
	1.  No. 12.  Older type.  Now seldom used.
	2.  No. 18.  As used in modern scuttling charges.
	3.  No. 38.  Said to be a more powerful explosive than No. 18.
	(viii)  Torpedoes
	G.7.v. type torpedoes (19.7 in.) are no longer in production; remaining stocks are being used by surface raiders.
	Since 1941, German torpedoes are said to have been fitted with a new type of tail-piece.  The after bearing of the propeller shaft is no longer lubricated with oil, a form of graphite brush bearing having been substituted.
	A green band along the tail-piece of a torpedo indicates that it is fitted with an engine of increased horse-power.
	A green ring around the depth-setting indicates a new type, to be set from 12 to 0 metres instead of from 0 to 12 previously.  In the new type setting, the spring is only tensioned when the torpedo is in the tube.  Prisoners stated that the new method of setting the depth from 12 metres downwards is more accurate.
	A red bar on G7a, torpedo indicates that it is not to be fired with a speed setting of 44 knots during trials, in order to preserve its mechanism.
	(ix)  Torpedo Containers
	Upper deck torpedo containers weigh 6 to 7 cwt and are made of reinforced light metal.
	(x)  Look-Out Mast
	All 1,200-ton U-Boats are fitted with look-out masts between their periscopes.
	(xi)  Reception of Long Waves
	The longest types of W/T wave penetrate sea water to a depth of about 15 metres.  These waves are described as about 20,000 metres in length and are emitted by several stations.

 

	19
	(xii)  Determination of Sinkings
	A P.O. Telegraphist said that he could generally estimate the number and type of ships sunk by his boat by switching to the merchant marine wavelength the moment after his boat had attacked a ship.  He could then listen in to her making SOS calls on the usual international wavelength and could thus determine her name and position.
	(xiii)  1,600-ton Minelaying U-Boats
	Prisoners spoke of the existence of 1,600-ton minelaying U-Boats.  They described them as having a pressure hull resembling that of a 740-tonner, but with broad extensions built on either side.
	(xiv)  1,200-ton Minelaying U-Boats
	Prisoners spoke of the existence of 1,200-ton minelaying U-Boats.
	(xvi)  R.D.F. in U-Boats
	A P.O. Telegraphist said that all U-Boats are to be fitted with R.D.F. around the conning-tower.
	(xvii)  Intercommunication between U-Boats
	According to a P.O. Telegraphist, W/T intercommunication between U-Boats (known as "Bord zu Bord") only takes place very rarely.  Nearly all W/T traffic is direct between the U-Boat concerned and the Admiral U-Boats.  As, however, most of the U-Boats in any given operational area are listening in continuously on the wavelength concerned, they generally intercept signals passed.
	(xviii)  Tactics in Depth-Charge Attacks
	Prisoners outlined the following procedure adopted by U-Boats during a depth-charge attack:
	(1)  Proceed at "Schleichfahrt" (90 r.p.m.).
	(2)  If the destroyer Asdics can be heard and an attack is, therefore, expected to develop, increase speed to "A.K." (210 r.p.m.) until attack is over.
	(3)  After explosions are over, revert to "Schleichfahrt" (90 r.p.m.).
	XI.  OPERATIONS IN THE ST. LAWRENCE GULF
	(i)  Tactics
	U-Boats operating in the St. Lawrence do so independently of other U-Boats.  On reaching the Cabot or Belle Isle Straits they are usually given freedom of action at the Admiral U-Boat's discretion.  To date, there have probably not been more than two, or at most three, U-Boats operating simultaneously in the Gulf.
	(ii)  Inter-Boat Communication
	U-Boats do not normally communicate with each other in the St. Lawrence.  If they wish to do so, they prefer to use visual methods or U/T.  They dislike using W/T for such a purpose.
	(iii)  Communications with Admiral U-Boats
	It is left to individual captains' discretions as to whether or not they communicate with the Admiral U-Boats by W/T while in the St. Lawrence.  "U 517," for instance, communicated only when her captain thought there were no enemy vessels or aircraft in the neighbourhood.  She confined herself to success signals and to weather reports, both always made at night.  She did not send more that ten weather reports all the time she was in the St. Lawrence.  All signals were made as short as possible as were sent on the usual wavelength.
	(iv)  Area of Operations
	U-Boats do not like to operate in the neighbourhood of the Cabot Straits, as they regard the weather there as too foggy.  They prefer the Belle Isle Straits and Gaspe Passage areas.  They claim that they can penetrate the St. Lawrence narrows without difficulty or undue danger as far as the Sauguenay River.
	(v)  Newfoundland Banks
	U-Boats always avoid the passage of the Grand Banks by Newfoundland as far as possible owing to the presence of aircraft there.
	(vi)  Camouflage
	U-Boats are not specially camouflaged for operations in the St. Lawrence.  They wear their usual North Atlantic grey.

 

	20
	(vii)  Allied A/S Methods
	Survivors were unanimous in describing A/S methods of Allied surface craft in the St. Lawrence area as "quite primitive."  They said that on several occasions, escorts made no effort whatsoever to pursue and attack their boat, despite reasonable proximity.  They did not think that the escorts had any idea of their using S.B.T., which may have accounted for the depth-charges thrown having gone so wide of the mark.
	They described aircraft patrols locally, however, as a very grave danger to them, especially as the aircraft seemed capable of picking them out on the surface at night without their being able to spot the aircraft.
	(viii)  U-Boat speeds
	U-Boats proceeding to the St. Lawrence area do their best to conserve fuel the whole way across and back.  This they do by proceeding generally on only one Diesel.
	(ix)  Convoys
	Survivors claimed to have no knowledge in advance of the destination and composition of St. Lawrence convoys.  They said that, although in the Atlantic they sometimes knew of the movements of a convoy ten or twelve days before attacking it, they did not have such information in the St. Lawrence.  They had no means of distinguishing between main and local convoys except by their size and the size of their escort.
	(x)  Health
	The health of the crew on such a long cruise is liable to suffer and hence much fruit is carried.
	(xi)  Type of Boats Used
	As far as prisoners were aware, only 740-ton boats are used for operating in this area.
	(xii)  Attacking Tactics
	"U 517" attacked shipping either by firing torpedoes angled from astern of the convoy or by submerging to periscope depth and waiting for the ships to pass over her before firing, sometimes from both forward and after tubes.
	(xiii)  Effects of Water Stratification
	A prisoner said that the sudden appearance of fresh water in parts of the St. Lawrence where they operated made a great difference to the navigation of their boat.  As she entered the area of brackish water, submerged, her bow would tend to rise, and all hands would be ordered forward until the hydroplanes could be adjusted to meet the new conditions.
	(xiv)  D.F.
	The P.O. Telegraphist said he usually fixed his position in the St. Lawrence by local D.F. stations which, to his great relief, appeared to be functioning on a peacetime basis.
	XII.  SURFACE CRAFT
	(i)  "Gneisenau"
	A seaman who had taken part in the Channel dash of the "Gneisenau" in early 1942, said that twenty-one units participated, including the fleet minesweepers and the E-Boats escorting.  The average speed maintained was 27 knots, the maximum 29.
	On leaving Brest, "Gneisenau's" ship's company were told that they were sailing on engine trials in company.  It was not until the next morning that the true purpose of their putting to sea was learned.
	Prisoner said that "Gneisenau" sustained no damage or casualties, though "Scharnhorst" was stated to have struck two mines.
	"Genisenau's: complement at the time was 1,800, compared with a peacetime complement of 1,500.
	Among "Gneisenau's" officers at the time were:
	Kapitan zur See Fein, of the 1913 term, who left the ship in April, 1942, and was promoted Konteradmiral.  (Captain)
	Kapitan zur See Peters, of the 1917 term.  (Commander)
	Fregattenkapitän (Ing.) Kannegiesser of the 1923 term.  (Engineer Officer)
	Korvettenkapitän Spörel, of the 1923 term.  (Gunnery Officer)
	Oberleutnant zur See Benthin, of the 1935 term.
	Oberleutnant zur See Heinz Radau, of the 1934 term.
	"Genisenau's" bow is now being altered to give extra buoyancy for the 42 cm. (16.5 in.) guns now being fitted.
	(N.I.D. Note.  There is no confirmation that this size of gun is being fitted.)
	She has thirteen divisions on board:  Nos 1 to 6 are seamen, 7 to 10 technical, and 11 to 13 special branches.

 

	21
	(ii)  "Veendam"
	The ex-Holland American liner "Veendam" (15,450 tons) is used as an accommodation ship for U-Boat ships' companies at Hamburg.  (January, 1942.)
	(iii)  "Warnow"
	The ex-merchantman "Warnow" is stated to be used as an accommodation ship for all kinds of naval ratings at Hamburg.  (January, 1942.)
	(iv)  "S.48"
	Oberleutnant zur See Freiherr Götz von Mirbach took command of "S.48" in September, 1941.
	(v)  "Lützow"
	A prisoner said that an officer named Brinkmann commands the "Lützow."  (N.I.D. Note.  This may be Kapitän zur See Brinkmann of the 1913 term.)
	(vi)  "Admiral Scheer"
	The commanding officer of the "Admiral Scheer" is stated to be Kapitan zur See Moendsen-Bohlken, of the 1915 term, who succeeded Kapitan zur See Krancke, of the 1912 term.
	The R.D.F. aerial in "Scheer" was stated to be about two metres by one metre in size and fitted on the fighting top.  It can be rotated 180 on either side.  There are said to be twelve dipoles, each section of which is 40 cm. long.  The set operates on a wave-length of 80 cm.
	When "sheer" fires her guns, the apparatus cannot be used on account of the vibration.

 

	22
	APPENDIX I
	_________
	Ship's Company of "U 517"
	(i)  Survivors:
Name. Rank. English Equivalent. Born. Hartwig, Paul Kapitänleutnant Lieutenant-Commander 14.  9.15 Martin, Helmut Kapitänleutnant (Ing.) Lieutenant-Commander (E) 7.  4.13 Pingel, Rolf Leutnant zur See Sub-Lieutenant 13.  8.21 Brandi, Karl Leutnant zur See Sub-Lieutenant 24.  1.13 Becher, Roland Leutnant (Ing.) Sub-Lieutenant (E) 23.12.13 Mischke, Richard Obermaschinist Chief Mechanician, 1st Class 15.10.14 Schad, Eugen Obermaschinist Chief Mechanician, 1st Class 22.  7.13 Speralski, Karl Heinz Steuermann Chief Q.M., 2nd Class 21.  1.21 Dömkes, Josef Bootsmannsmaat Boatswain's Mate, 2nd Class 2.  7.21 Mack, Fritz Bootsmannsmaat Boatswain's Mate, 2nd Class 5.  3.20 Cyffka, Theo Bootsmannsmaat Boatswain's Mate, 2nd Class 12.10.17 Hoffmann, Herbert Maschinenmaat Mechanician, 2nd Class 10.  9.19 Palzer, Georg Maschinenmaat Mechanician, 2nd Class 5.  6.20 Fischer, Alois Maschinenmaat Mechanician, 2nd Class 25.12.17 Schwanke, Frithjof Maschinenmaat Mechanician, 2nd Class 3.  9.20 Creuzmann, Albert Maschinenmaat Mechanician, 2nd Class 10.11.19 Conen, Johann Maschinenmaat Mechanician, 2nd Class 17.  9.19 Triller, Hans Funkmaat P.O. Telegraphist, 2nd Class 10.12.19 Strobel, Erwin Funkmaat P.O. Telegraphist, 2nd Class 4.  3.21 Lippert, Erich Matrosenobergefreiter Able Seaman 31.12.21 Lobs, Otto Matrosenobergefreiter Able Seaman 3.  2.22 Kupczyk, Werner Matrosenobergefreiter Able Seaman 18.  9.22 Schüler, Kurt Maschinenobergefreiter Stoker, 1st Class 16.  4.23 Lucas, Alfred Maschinenobergefreiter Stoker, 1st Class 24.  2.21 Weitusch, Gerhard Maschinenobergefreiter Stoker, 1st Class 29.  1.23 Smotzok, Günther Maschinenobergefreiter Stoker, 1st Class 8.  8.21 Nowak, Wilhelm Maschinenobergefreiter Stoker, 1st Class 4.  1.22 Hartleb, Erich Maschinenobergefreiter Stoker, 1st Class 3.  2.22 Mowe, Werner Mechanikerobergefreiter Artificer, 1st Class 8.  8.22 Schwerdt, Hellmoth Matrosengefreiter Ordinary Seaman, 1st Class 9.12.21 Weis, Otto Matrosengefreiter Ordinary Seaman, 1st Class 18.  3.24 Steinhoff, Karl Matrosengefreiter Ordinary Seaman, 1st Class 7.  9.20 Eisermann, Erich Matrosengefreiter Ordinary Seaman, 1st Class 26.10.23 Gudrat, Gerhard Matrosengefreiter Ordinary Seaman, 1st Class 12.  3.23 Leitner, Haus Matrosengefreiter Ordinary Seaman, 1st Class 8.  8.24 Lenk, Gerhard Matrosengefreiter Ordinary Seaman, 1st Class 9.  8.24 Peters, Karl-Heinz Maschinengefreiter Stoker, 2nd Class 27.11.21 Eimler, Johannes Maschinengefreiter Stoker, 2nd Class 1.  8.21 Huber, Alois Maschinengefreiter Stoker, 2nd Class 23.  7.22 Salomo, Kurt Egon Maschinengefreiter Stoker, 2nd Class 9.  3.24 Schwindling, Peter Maschinengefreiter Stoker, 2nd Class 14.  3.23 Steinmüller, Armin Maschinengefreiter Stoker, 2nd Class 8.  8.22 Schrader, Eduard Maschinengefreiter Stoker, 2nd Class 2.  9.23 Thun, Fritz Maschinengefreiter Stoker, 2nd Class 6.10.22 Hintzen, Peter Maschinengefreiter Stoker, 2nd Class 27.  2.21 Knauerhase, Walter Maschinengefreiter Stoker, 2nd Class 29.  8.23 von Riegen, Kurt Funkgefreiter Ordinary Telegraphist, 1st Class 23.  1.21 Wenke, Johannes Funkgefreiter Ordinary Telegraphist, 1st Class 9.  5.24 Rolhmann, Heinrich Mechanikergefreiter Artificer, 2nd Class 15.12.23 Kupper, Johan Jakob Matrose Ordinary Seaman, 2nd Class 6.  8.23
	Officers . . 5 Chief and Petty Officers . . 14 Men . . 31         Total   50
	(ii)  Casualties:
Siebert, Rudi Mechanikersmaat P.O. Artificer, 2nd Class
	Officers . . nil Chief and Petty Officers . . 1 Men . . nil         Total   1
	(iii)  Total Crew:
	Officers . . 5 Chief and Petty Officers . . 15 Men . . 31         Total   51
	APPENDIX II
	_________
	Message from Kapitänleutnant Paul Hartwig, Commanding Officer of "U 517," to his men, while on boar rescuing vessel:
	(Translation)
	"Comrades!
	"I regret that I am not permitted while on board to thank you for your admirable behaviour and to shake you all by the hand as i say good-bye.
	"My thoughts are ever with you and I trust you are all saved.  Think of what I have always told you* and be mindful of fulfilling your duty, as always.
	Your Captain."
	*Hartwig is clearly referring to his security instructions.  He was at no time allowed any contact with his men after capture.
	(C47999)  423  2/43

 

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