U-boat Archive - U-406-386-264 - Interrogation Report

COPY No.

This book is invariably to be kept locked up when not in use and is not to be taken outside the ship or establishment for which it it issued without the express permission of the Commanding Officer

C.B. 04051 (99)

"U 406," "U 386" and "U 264"

Interrogation of Survivors

May, 1944

This Report is not to be considered accurate in all respects, having been prepared before complete information was available. It is therefore not to be taken as historically correct.















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	SECRET

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	Official Secrets Acts.








	C.B. 04051 (99)



	"U 406," "U 386" and "U 264"


	Interrogation of Survivors







	May, 1944










	NAVAL INTELLIGENCE DIVISION,
	ADMIRALTY, S.W.1.

	N.I.D. 03050/44.
















	The following report is compiled from information derived from prisoners of war. The statements made cannot always be verified; they should therefore not be accepted as facts unless they are definitely stated to be confirmed by information from other sources.

iii

CONTENTS

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			Page
I.	Introductory Remarks		1
		(i) General; (ii) Commanding Officer; (iii) Complement of "U 73"; (iv) Equivalent Ranks.

II.	Details of "U 406," "U 386" and "U 264"		2
		(i) Type; (ii) Tonnage; (iii) Building Yard; (iv) Armament (v) Bridge Armour; (vi) Diesels; (vii) Motors and Switchboards; (viii) W/T Equipment; (ix) "Y" Service; (x) G.S.R.; (xi) Infra-Red Apparatus; (xii) Fübos (Contact-keeping Flare Buoys); (xiii) S.B.T.; (xiv) R.D.B.; (xv) Badge; (xvi) Flotilla; (xvii) Base; (xviii) Field Post Number; (xix) Cover Name.

III.	Last Patrol and Sinking of "406"		3

IV.	Last Patrol and Sinking of "U 386"		4

V.	Last Patrol and Sinking of "U 264"		6

VI.	General Remarks on U-Boats		8
		(i) Extensible Diesel Air Intake and Exhaust; (ii) New G.S.R. Equipment; (iii) Infra-red Detection Apparatus; (iv) Radar in Japanese Submarines; (v) "Y" Service; (vi) Bruges D/F Station; (vii) Small Submersible Craft; (viii) New Torpedoes Described as Walther Torpedoes; (ix) Deep Diving U-Boats; (x) 37-mm. Guns; (xi) Rocket Projectors in U-Boats; (vii) Armoured Bridge Protection; (xiii) Contact-keeping Flare Buoys; (xiv) Radar Decoy Spar-Buoy (Short title "R.D.S."); (xv) Increase in Number of Potash Cartridges Carried by U-Boats; (xvi) Gyro Sextants; (xvii) T.6 Torpedoes; (xviii) T.5 Boomerangs; (xix) U-Boat Anti-Invasion Tactics; (xx) U-Boat/Aircraft Co-operation in Convoy Attacks; (xxi) Meal Routine on Patrol.

VII.	Bases		12
		(i) St. Nazaire; (a) New S.O. for Sixth Flotilla; (b) Security Measures; (c) Shore Defences; (d) Sentry Duties in Harbour; (ii) Penang; (iii) Singapore.

VIII.	Surface Ship		13
		"Hipper"

IX.	"U 178"		14

X.	U-Boat Commanded by Oberleutnant Giersberg		15

______________________

APPENDIX "A" Previous History of "U 406"			16

APPENDIX "B" Previous History of "U 386"			16

APPENDIX "C" Previous History of"U 264"			17

APPENDIX "D" Nominal Roll of "U 406"			18

APPENDIX "E" Nominal Roll of "U 386"			19

APPENDIX "F" Nominal Roll of "U 264"			20

(C52594) B2


	1

	REPORT ON THE INTERROGATION OF SURVIVORS FROM "406,"
	U-386" AND "U 264," SUNK IN THE ATLANTIC BY THE SECOND
	AND TENTH ESCORT GROUPS ON 18th AND 19th FEBRUARY, 1944.
	______________________

	I. INTRODUCTORY REMARKS

	(i) General
	"U 406," "U 386" and "U 264" formed part of a formation of about 26 U-Boats detailed to attack Convoy KMS 29 in the Atlantic. During determined attacks made on the pack by the Second and Tenth Escort Groups on the 18th and 19th February, 1944, these were the only U-Boats sunk from which prisoners were taken.
	"U 406" was sunk by H.M. Ships "Lossie" and "Spey" of the Tenth Escort Group at 1530 on 18th February in position 48° 32' N., 23° 36' W. and "U 386" by the same group at 1435 on 19th February, in position 48° 31' N., 22° 31' W.
	"U 264" was sunk by H.M. Ships "Starling" and "Woodpecker" of the Second Escort Group at 1700 on 19th February, in position 48° 31' N., 22° 05 'W.
	While "U 406" was blown to the surface and abandoned by her crew after the first series of depth-charges, which exploded right under the boat aft, the other two boats showed more fight, and "U 264" was subjected to a series of depth-charge attacks lasting several hours.
	Each of the boats presented some item of outstanding interest, in addition to all possessing the new armament of a 37 mm. fully automatic gun on the lower bandstand and two twin 20 mm. guns on the upper bandstand.
	"U 406" had on board a G.S.R. expert with the shore rank of Kapitänleutnant, who had with him two leading telegraphist assistants. No less than 24 different pieces of equipment comprising various G.S.R. sets and accessories were carried, giving cover from below 5 cm. to 380 cm. with different combinations of sets and aerials. A new type of infra-red detection apparatus was also carried on board. Details of this equipment will be found in Section VI.
	"U 386" included two trained "Y" service operators in her complement, whose duty was to intercept convoy R/T traffic. This U-Boat also had a new type of armour protection on each side of the bridge, as also did "U 406." (See Section VI.)
	"U 264" was believed to be the first U-Boat fitted with an extensible Diesel air intake and exhaust, which enabled her to charge her batteries while proceeding submerged. This operation, after the causes of various minor mishaps during trials had been remedied, could be carried out while proceeding at periscope depth. (See Section VI.)
	Of the Commanding Officers, only Kapitänleutnant Hartwig Looks of the 1936 term and Oberleutnant zur See Fritz Albrecht of the 1937 term, of "U 264" and "U 386" respectively, survived. "U 406's" commanding officer, Kapitänleutnant Horst Dieterichs of the 1934 term, was killed on the bridge by machine-gun fire from the destroyers when his U-Boat surfaced.
	Only one of them, Looks, was the subject of favourable comment by his men, although in his case it only amounted to a grudging admission that his harsh sense of discipline was tempered by his undoubted efficiency.
	Dieterichs was elegant, selfish, stern and unpopular. He used fresh water to wash himself, but denied its use to his men. He drank the ship's real coffee alone, the remainder of the crew receiving the "Ersatz" coffee. He instructed the cook to bake him elaborate tarts and cakes, which he ate by himself. Extremely stern, he inflicted severe punishment for the most trivial offences.
	It was rumoured that he had been reprimanded by Dönitz for only sinking 40,000 tons in eight patrols. He came on board for the last operation proclaiming his determination to sink a destroyer.
	In St. Nazaire he was intimate with the widow of a French officer whom he frequently brought down to the U-Boat shelters, although she was not allowed on board. Prisoners had no doubt that this lady was an Allied spy.
	Both Dieterichs and Albrecht were regarded as vacillating and even cowardly. Dieterichs came in for particularly venomous comment for being the first man up the conning-tower hatch after giving the order to abandon ship.
	Of Albrecht it was said that he showed no confidence in the ability of his petty officers to do their work properly and was continually poking his head into the various compartments to convince himself that everything was in order, even when he happened to know very little about the particular job in question. His pusillanimity when on patrol was only matched by the fine figure he cut when ashore, where he liked to be regarded as a bon viveur.
	Dr. Greven, the G.S.R. specialist from "U 406," was a highly strung and obviously most intelligent man, whose security consciousness could occasionally be shaken.
	Nothing good could be said of any of the other officers, who to a man exhibited the particular Nazi brand of bloody-mindedness, which is the ultimate in unpleasantness.
	Oberassistenzarzt Wolfgang Junghans of "U 264" had distinguished himself by introducing a Spartan health routine for the luckless crew, who found themselves ordered to take cold baths at 0600 every morning. He was equally unpopular with the officers, who rounded off a merry party one night by cornering him in a narrow alley-way and beating him up soundly.

	(C52594) B*

"U 406" was the only boat to have had even moderate success during her career, having sunk a total of about 42,000 tons during her eight patrols, all claimed during one attack on a convoy in her fourth patrol. "U 264" claimed to have sunk about 14,000 tons, and "U 386" one small ship of 3,500 tons.

The following are the Royal Navy equivalents of German Naval ranks used in this report:

Kapitän zur See	Captain.
Fregattenkapitän	Commander.
Korvettenkapitän	Lieutenant-Commander.
Kapitänleutnant	Lieutenant.
Oberleutnant zur See	Sub-Lieutenant.
Leutnant zur See	Junior Sub-Lieutenant.
Oberfähnrich zur See	Senior Midshipman.
Fähnrich zur See	Junior Midshipman.
Oberassistenzart	Surgeon Lieutenant.

The suffix "(Ing.)" after a German rank in place of "zur See" denotes an Engineer Officer. The suffix "der Reserve" denotes a Reserve Officer.

__________________

II. DETAILS

		"U 406"	"U-386"	"U 264"
(i)	Type	VIIC.	VIIC.	VIIC.
(ii)	Tonnage	500 tons.	500 tons.	500 tons.
(iii)	Building Yard	Danziger Werft, Danzig. Commissioned 22nd October, 1941.	Howaldtswerke, Kiel. Commissioned October, 1942.	Vulkan Werft, Vegesack. Commissioned 22nd May, 1942.
(iv)	Armament:
	(a) Guns	One fully automatic 37 mm. gun on the lower bandstand (see Section VI). Two twin 20 mm. guns on the upper bandstand, one on each side. Two M.G.s, Type 81, on the bridge.
			140 clips of five rounds each of "Minemunition" were carried for the 37 mm. gun.
	(b) Torpedoes	Eleven carried on the last patrol; five T.5 "Gnats" and six electric "Curlies."	Eleven carried on the last patrol; four were T.5 "Gnats" and the rest electric torpedoes.	Ten carried on the last patrol; four T.5 "Gnats" with flattened noses, and six normal electric torpedoes.
(v)	Bridge Armour	New type protection for bridge watch, known as "Kohlenkasten" (coal scuttles). (See Section VI).		Normal. The armoured doors between the bridge and the bandstand had been removed.
(vi)	Diesels	G.W.	G.W.	M.A.N. An extensible air intake and exhaust, known as the "Schnörkel," had been fitted before the last patrol. (See Section VI).
(vii)	Motors and Switchboards	B.B.C.	A.E.G.	A.E.G.
(viii)	W/T Equipment	Standard.	Standard.	Standard.
(ix)	"Y" Service	Not carried.	A special set for intercepting convoy R/T was carried. (See Section VI)	Not carried.
(x)	Radar	Gema set, operating on the 80 cm. wavelength, carried.	Not carried.	Not carried.
(xi)	G.S.R.	About 24 pieces of apparatus carried, making up five sets with a wavelength cover of 5-380 cm. Four different aerials on the bridge. (See Section VI for details).	Wanze II, Borkum and Naxos sets carried, with Naxos and basket-type aerials.
(xii)	Infra-Red Apparatus	"Seehund" and "Flamingo" apparatus carried (See Section (VI).	Not carried.	Not carried.
(xiii)	Fübos (Contact-keeping flare buoys).	Not carried.	About 24 carried. (See Section VI).	Not carried.
(xiv)	S.B.T.	Carried.	Carried.	Eight boxes, each containing six pills, carried. Six charges ejected each time S.B.T. was used, and seven of the boxes had been expended by the time "U 264" was sunk.

		"U 406"	"U-386"	"U 264"
(xv)	R.D.B.	Carried.	Carried.	Carried. Two hydrogen bottles were fitted on each side of the bridge fairing.
(xvi)	Badge	Nominally, the Berlin bear, although this was not painted on the conning-tower	The Flotilla badge, the prow of a Viking ship with a U-Boat superimposed was painted on the port side of the conning tower.
(xvii)	Flotilla	Seventh.	Sixth.	Sixth.
(xviii)	Base	St. Nazaire.	St. Nazaire.	St. Nazaire.
(xix)	Field Post Number	M.42202.	M.50010.	M.02981.
(xx)	Cover Name	"Spatz."	"Kohlenklau."	"Amigo."

__________________

III. LAST PATROL AND SINKING OF "U 406"

"U 406" was lying in Pen No. 14 of the St. Nazaire shelter during December, 1943, when it became known on board that the boat was to undertake a special mission. A G.S.R. expert named Dr. Greven, with the shore rank of Kapitänleutnant, came on board shortly before Christmas, together with two leading telegraphist assistants and several cases of secret apparatus.

The ship's company was told that Dr. Greven was a meteorologist, and shortly before she sailed Korvettenkapitän Sohler, S.O. of the Seventh Flotilla, came on board and gave them a security lecture, telling them that they were going to sea as "guinea-pigs," and that if the trials were successful, they would have helped to bring back the old days of successful U-Boat warfare.

The men's chief reaction to Dr. Greven's presence was to repeat the old adage "Wenn ein Silberling einsteigt, dann säuft das Boot ab. ("When a Silver-ringer sails with you, the boat is bound to sink." In the German Navy officers holding technical shore appointments have silver rank stripes, as distinct from the gold stripes of sea-going officers.)

The U-Boat left St. Nazaire in her last patrol on 5th January, 1944, and spent about two weeks operating independently while Dr. Greven conducted his trials. They then joined the group of U-Boats to which "U 386" and "U 264" also belonged, although this caused no interruption to Dr. Greven's activities, a full description of which will be found in Section VI.

The group was ordered to attack an Atlantic convoy, and the attack was expected to mature about 18th February. However, on the same morning, the C.O., considering that the fuel remaining, which was reduced to 29 tons, had reached the minimum, signalled Control reporting this fact and requesting permission to return to base.

No reply was received to the first signal, and it was repeated, not once, but twice, which caused serious misgivings among the men, who ascribed their subsequent sinking to the fact that one or more of the signals had been d/fd.

From about 1039 onwards, the C.O. received several reports from the hydrophone ratings of suspicious noises and went into the hydrophone room to listen himself. However, he dismissed the noises as emanating from the gambolling of porpoises and retired to his bunk, ordering the hydrophone ratings not to bother him any further with such nonsense.

The noises continued on and off at intervals, and the crew was by no means reassured by the C.O.'s lack of interest in them. At about 1500 the U-Boat came to periscope depth, and the First Lieutenant made the routine observation of the neighbourhood. However, the Engineer Officer was having some difficulty in keeping the boat trimmed, and the periscope was lowered without anything of note having been observed.

After about 20 minutes the porpoise noises were again heard, and suspicions as to their real nature intensified. However, before any definite steps could be taken, there was a tremendous explosion under the boat aft, which shot the watch below out of their bunks and sent the U-Boat to the surface, out of control, from a depth of 50 m. (164 ft.).

Complete panic reigned. All the lights were out, the engine rooms were wrecked, the switchboards flew from their mountings, and there were several small water entries. Dieterichs leapt for the conning-tower ladder in his under clothes and was the first man on the bridge, shouting the order to abandon ship as he ascended.

The Engineer Officer remained long enough to open the vents before he joined in the general scurry. No attempt was made to man the guns and the crew abandoned ship immediately.

Dieterichs endeavoured to justify his precipitate exit by counting the members of the crew as they appeared up the hatch, which the crew claimed he could have done equally well from the bottom of the ladder, where he could at least have remained in control of the situation.

Fire had been opened on the boat by the destroyers of the escort group immediately she surfaced, and a further series of depth-charges was fired at the boat.

Dieterichs was hit by a bullet during the course of his arithmetical activities, and was not seen again by the crew.

(C52594) B*2



	4

	H.M.S. "Spey" picked up 45 survivors, but four of these died on board. Some of the remainder had a grand-stand view of the sinking of "U 386" the next day, which, with the knowledge gleaned on board "Spey" that four other U-Boats had almost certainly been sunk, gave rise to considerable alarm and despondency.
	(N.I.D. Note. At 1523 on 18th February in position 48° 32' N., 23° 36' W., H.M.S. "Spey" obtained Asdic contact.
	At 1530, ten Mark VII depth-charges were fired (setting C.). After the charges had exploded, the U-Boat broke surface in the middle of the pattern 500 yards astern on even keel. Fire was immediately opened with the port bridge oerlikon and very shortly afterwards all weapons that would bear joined in. The U-Boat was lying apparently stopped and down by the bows. Despite withering fire, several ratings were seen to abandon ship and a certain amount of return fire was experienced.
	"Spey" did not believe that the U-Boat had been mortally damaged and altered course across her bows to lay another shallow pattern. only half this pattern was fired, however, as the shambles made by the gunfire could be seen and there were a number of men in the water to leeward. "Rother" closed and opened fire, which was checked by "Spey."
	The U-Boat remained afloat for about ten minutes, becoming increasingly down by the bows, and there were several unexplained explosions which were taken to be scuttling charges, or in two cases when they sounded distant to be "Gnats" exploding at the end of their run. "Spey's" whaler managed to get alongside and the First Lieutenant and one rating scrambled on board. There was one dead rating on the gun platform and the commanding officer was lying seriously wounded in the stomach alongside the conning-tower hatch. The First Lieutenant got down to the control room, finding the inside in complete darkness but free from fumes. At the bottom of the hatch was a large bag possibly containing books, but it was too heavy for him to get up the conning-tower. He therefore climbed up again to get a line, the rating on board being fully occupied securing the whaler and keeping an eye on the wounded captain. The First Lieutenant had barely gained the open air when the boat began to sink, and he and the rating jumped clear and swam to the whaler.)

	__________________

	III. LAST PATROL AND SINKING OF "U 386"

	"U 386," which had been lying in the same shelter at St. Nazaire as "U 264," sailed initially on her last patrol with four other U-Boats on 10th December, 1943, but returned to base within four days owing to engine trouble. It had also been found that the hydrophones were defective at depths below 50 m.(164 ft.).
	Putting back to sea again about 20th December, defects again developed in the engines, and they had to put back once more. A small leak had also been detected in one of the vents.
	"U 386" finally sailed alone on 29th December, and was ordered to join the Igel group of U-Boats operating in the North Atlantic. This group was subsequently divided into Igel I and II. Practically the same boats formed the Hinein and Stürmer groups for a short while, and then Hai group was formed, sub-dividing shortly before "U 386's" sinking into Hai I and II.
	About 15th January, 'U 386" received a signal from Control ordering her to proceed to a point between Islay and Rathlin Island, and to be in that position by 21st January. The operation was timed to coincide with a period of moonless nights.
	Conflicting reports have been received from survivors concerning the purpose of this operation, one of the more reliable prisoners stating that they were to carry out reconnaissance duties only, and were to refrain from attacking shipping, and another equally well-informed survivor asserting that they were to proceed further into the North Channel and attack the convoys assembling there.
	It is doubtful if the men received definite information as to the purpose of the operation, as all the signals referring to it were received in a special code which could only be deciphered by the officers. None of the W/T operators therefore had direct knowledge of their contents.
	Most survivors agreed, however, that it was intended, by one means or another, to create a diversion in the North Channel with the intention of drawing off some of the escort groups from the Atlantic and so ease the pressure on the U-Boats operating there.
	Part of the mission was certainly to observe traffic in and out of Londonderry and the Mersey, and to make detailed reports on beacons, light buoys and other aids to navigation. As it turned out, this was the only part of the operation to be accomplished with any measure of success, and even this had to be abandoned when air and surface attacks on the U-Boat reached an unhealthy intensity.
	Even if it had not been their subsequent intention to advertise their presence by attacking vessels in the area, survivors who tended to the opposite view stated that the U-Boat intended to provide as many contacts as possible for Allied shore and ship-borne Radar sets by surfacing and releasing Radar Decoy Balloons.
	Survivors also stated that the C.O. disliked the operation, and was glad of an opportunity to break it off. They thought that they were the only U-Boat in the area at the time, but had heard that other boats in the Atlantic had received special instructions of some nature, and that they might be carrying out similar operations. Prisoners insist that the question of landing or taking off saboteurs never arose.



	5

	Without possessing definite knowledge on the subject, survivors state that "U 386" approached Ireland on a more or less easterly course and first sighted land off the coast of Donegal. The U-Boat then proceeded parallel to the coast round towards Londonderry, the boat being often in very shallow water, and the coast frequently sighted through the periscope.
	Prisoners stated that the U-Boat proceeded about half-way between a minefield lying between 55° 19' N., 06° 30' W.; 55° 30' N., 06 13' W.; 55° 42' N., 06° 58' W.; 55° 32' N., 07° 10' W. and the shore.
	By 2030 on 23rd January they had arrived in a position off Bengore Head. The U-Boat was surfaced, and soundings indicated about 30 fms. of water. G.S.R. watch was kept on the Wanze II and Naxos sets.
	Half an hour later they received a strong G.S.R. contact on 170 cm., which they assumed to come from a shore-based station. The beam remained focused, and it was accepted on board that the U-Boat had been detected. The "Y" service set was manned and watch kept on 2,410 kc/s. The C.O. proceeded seawards, surfaced, with both Diesels, deeming it useless to submerged in such shallow water.
	At 2115 another Radar contact was registered, this time on 135 cm., and the operators assumed that this was a ship-borne set. Almost simultaneously, and aircraft was sighted, which dropped a flare. The U-Boat turned away, releasing R.D. balloons. G.S.R. contacts were now being received on the Naxos set, but suddenly all contacts ceased abruptly, and it was assumed that the balloons were fulfilling their purpose. At the same time, machine-gun fire was heard astern, which was thought to come from the aircraft.
	By 2200 contacts were being received again on the Wanz II set, and the "Y" service began to pick up R/T traffic. A shore station was heard announcing that it was going to transmit in clear. Most of the signals were addressed to a surface unit with the code name "HORSEFLESH." The shore station wa heard to ask if the U-Boat was proceeding out to sea.
	Depth-charge detonations were now heard well inshore, but shortly afterwards the shadows of two destroyers were discerned astern. At 2205 a T.5 torpedo was fired from the stern tube, the only torpedo fired during the whole patrol. Two minutes and 47 seconds after the torpedo was fired an explosion was heard, and it was assumed that one of the destroyers had been sunk. This belief was strengthened by the fact that G.S.R. contacts on 135 cm. ceased, and further signals from the shore station to "HORSEFLESH" remained unanswered.
	About 2215 an aircraft flew overhead, but "U 386" refrained from engaging it, and the crew thought for a moment that they had remained undetected. They continued to release R.D. balloons, but heard an aircraft reporting their position to the shore station, and G.S.R. contacts began to be received again on the Naxos set.
	At least one enemy surface unit was still astern, and gun flashes were seen. "Y" service intercepts indicated that the surface unit was requesting further aircraft to take off from an aerodrome ashore.
	"U 386" was still heading out to sea, but at 0055 on 25th January the "Y" service intercepted a signal from a surface vessel stating that the U-Boat had been sighted. The submerged almost immediately, only to hit the bottom at 50 fms., although the chart indicated a depth of 80 fms. The U-Boat was trimmed, and they continued at slow speed submerged seawards.
	Distant depth-charge explosions could still be heard further inshore, and the crew were convinced that Albrecht had deceived the enemy by proceeding out to sea close to the minefield mentioned above, under the correct assumption that the U-Boat would be sought closer inshore.
	The U-Boat remained submerged for nearly 30 hours, only surfacing at 0730 on 25th January with 3.9 per cent. of CO2. "U-386" only remained a short time on the surface, and then submerged again until about 2300, when she surfaced and signalled Control reporting that she had been detected and compelled to break off the operation. The sinking of one destroyer was claimed. Control in reply ordered her to rejoin the Igel group.
	About the middle of February, the group of about 26 U-Boats to which "U 386" belonged, and which now bore the code-name HAI, was ordered to attack a convoy. The position of the intended attack was signalled to the group, and it was indicated that the convoy should be in position on 16th February.
	However, the convoy proceeded more slowly than had been estimated, and the attack was postponed to 18th February.
	It has been arranged that German aircraft should take up position over the convoy and transmit signals for the U-Boats to home on. It was also intended to drop contact-keeping flare buoys astern of the convoy and light up the whole area so as to place the merchant ships in silhouette.
	During this period a signal was received from Admiral Dönitz which greatly annoyed the crew. It urged them to do their duty with the old U-Boat spirit.
	It was the general opinion in "U 386: that the "old fogeys" at the German Admiralty should come and take a crack themselves, as they seemed to show a complete lack of understanding of what U-Boats were up against nowadays.
	On the night of 18th February, "U 386" was proceeding surfaced at about 2230 when the U-Boat was attacked by a four-engined searchlight aircraft. Fire was opened with the 20 mm. guns as the aircraft tracked along the U-Boat's port side. The searchlight went out and there was a splash of falling bombs astern.

	(C52594) B*3



	6

	Shortly afterwards, an aircraft tracked along the starboard side, but fire was not opened as the target could not be seen, although "U 386" was subjected to machine-gun fire. No bombs were dropped, and the U-Boat was not further molested; she submerged at about 0400.
	(N.I.D. Note. Liberator S of 53 Squadron attacked a U-Boat at 2229 on 18th February in position 49° 32' N., 23° 10' W. The aircraft homed on to a Radar contact and at a distance of about a mile experienced intense and accurate light flak.
	The aircraft attacked, releasing six Torpex depth-charges from 150 ft., which straddled the track about 150 ft. astern of the U-Boat. The tail gunner opened fire with 150 rounds. Returning to the scene about 20 minutes later, the U-Boat was sighted at 70 yards' range, but the aircraft could not get into a position to attack.)
	The plans for attacking the convoy had received a last-minute setback as the convoy had altered course, and the German aircraft could not find it. It was only at about 0300 on 19th February that they started to make homing signals.
	It was not long before "U 386's" crew realized that the attack on the convoy was to be no sinecure. Distant depth-charge explosions began to be heard as early as 0600, and continued at intervals during the whole of the forenoon and the early part of the afternoon.
	During the whole of this period, "U 386" remained submerged, coming occasionally to periscope depth, with the crew in a state of increasing trepidation.
	About 1430 screw noises were heard, and one vessel appeared to pass almost immediately overhead. There was a sudden violent explosion below the boat aft, putting the main motors out of action, wrecking the lighting system and causing a considerable water entry.
	The C.O. ordered full speed on both motors, but on learning that they were out of action, ordered the tanks to be blown. The U-Boat surfaced at a steep angle more or less out of control.
	An attempt was made to man the guns, but heavy fire had been opened on them, and the C.O. gave the order to abandon ship. In the confusion the Engineer Officer was heard calling for a fire extinguisher, and several survivors thought that the acid in the batteries had been spilt as a result of the steep surfacing angle and that chlorine gas was being developed.
	Several of the men had already abandoned ship when the Diesels were started, and the U-Boat began to gather way. However, further bursts of fire from the attendant destroyers caused a change of heart, and the rest of the crew jumped overboard.
	"U 386" sank rapidly by the stern, and shortly after she had disappeared there was a considerable under-water explosion, which survivors assumed to be caused by the batteries. Several of the 18 survivors felt the effects of the pressure for two or three days after being picked up by H.M.S. "Spey."
	(N.I.D. Note. At 1426 on 19th February in position 48° 31' N., 22° 31' W., H.M.S. "Spey" obtained an Asdic contact and at 1435 ten Mark VII depth-charges were fired.
	The U-Boat broke surface at a range of about 800 yards at a very steep angle, bows first. Fire was immediately opened with starboard bridge Oerlikon and all armament that would bear joined in shortly afterwards. "Spey" then passed close ahead and straddled the U-Boat with a pattern of depth-charges.
	During the approach there was quite a lot of return fire from the enemy, but no damage of importance was caused. They showed considerable courage in attempting to man their guns in the face of a hail of Oerlikon and pom-pom fire and several 4 in. direct hits.
	After the second pattern six or eight men were seen to abandon the U-Boat and "Spey" checked fire, thinking she had given up, turning to port under full wheel close to her. She was only half-way round when the U-Boat started to go ahead again at speed, apparently on her Diesels, although she was still down by the stern and badly knocked about by gunfire.
	"Spey" at once opened up again with everything she had, while the U-Boat succeeded in getting inside her turning circle. The guns made excellent shooting, especially the 4 in., which scored many more direct hits, and in a short time, with the U-Boat still forging ahead at good speed and becoming increasingly down by the stern, another party of men came pouring out of the conning-tower hatch in great haste. Finally the bows reared right up out of the water, and the boat then disappeared below the surface.)

	V. LAST PATROL AND SINKING OF "U 264"

	After her penultimate patrol, "U 264" lay in St. Nazaire for over three months. Damage to her stern was repaired and the extensible Diesel air intake and exhaust was fitted and tested. (For details, see Section VI.) It was learned that on 20th January, 1944, she berthed in Pen 13B. On 29th January, she embarked torpedoes and ammunition, also completing with lubricating and fuel oil. On the following day, provisions, water and oxygen bottles were shipped. On 1st February, the final trimming tests were held. On the forenoon of 2nd February, she was topped up with fuel and held her routine diving trial. By noon she was ready to sail.
	"U 264" sailed on the afternoon of 2nd February, 1944, escorted by a Sperrbrecher and several patrol craft.
	She had received orders to operate with units of the German Air Force. No VH/F set was carried for this purpose, but the U-Boat was supplied with a special wavelength schedule and was to be informed by Control when to look for signals. Signals from aircraft were received on the D/F set. The planes were described by prisoners as being Ju.88's or F.W.200's. Orders were received from the Operations Division of the Naval Staff (Seekriegsleitung) that the U-Boat was to remain on the surface as much as possible and was not to dive when a G.S.R. contact was received.



	7

	For a time, the co-operation with air search was unsatisfactory, the U-Boat being unable to locate enemy shipping in the areas to which she had been directed.
	On 17th February, an aircraft was sighted and the flak guns were manned. The plane approached the U-Boat, but Looks, not being sure of its nationality, ordered the guns' crews to hold their fire. Recognition signals were fired but no reply was received from the plane, which flew away without attacking. Looks then decided that the plane had been a Sunderland; he released several R.D.Bs. and submerged.
	On the night of 18th/19th February, "U 264," following directions received from a German aircraft, approached a convoy. A G.S.R. contact was received on a wavelength of 135 cm. and was judged to have originated from a destroyer. About 30 minutes later, the contact-keeping aircraft dropped a contact-keeping flare, and the convoy was sighted.
	The U-Boat attempted to signal Control giving the usual particulars of the convoy, but, due to the fact that the cypher machine jammed, only a fragmentary message was sent. Suddenly the escorting vessels fired star shells, illuminating the U-Boat and revealing that one of the destroyers was dead astern. "U 264" fired a T5 torpedo from her stern tube, but the destroyer came to a dead stop and the torpedo passed across her bows at a distance of about 10 yards. Some of the prisoners attributed the miss to an imperfection in the mechanism of the torpedo.
	The U-Boat then dived and took evasive action. Several patterns of depth-charges were dropped, but they fell wide of the mark. The destroyers then gave up the search and at about 0500 the entire convoy was heard passing directly over the U-Boat.
	(N.I.D. Note. At 0325 on 19th February, H.M.S. "Forester" obtained a Radar contact and fired a star shell which revealed a U-Boat on the surface. The U-Boat dived and, at 0404, "Forester" attacked with hedgehog. She followed the U-Boat through the convoy until 0449 when contact was lost.)
	"U 264" remained submerged for some time after her contact with the convoy. At about noon on 19th February, she came to a depth of about 20 m. (65 ft.) in order to signal Control. She was then discovered by a group of destroyers which immediately began a prolonged attack. The U-Boat immediately submerged to a greater depth and, taking evasive action, released several S.B.T. charges. She was unable to shake off her pursuers and depth-charges continued to rain down on her. After about the fourth attack considerable damage was sustained.
	(N.I.D. Note. The Second Escort Group gained contact on a U-Boat at 1011 on 19th February. At 1035, H.M.S. "Starling" dropped a ten-charge pattern set to 150/300 ft. At 1101 and 1110, S.B.Ts. were noted. At 1125, H.M.S. "Woodpecker" made a creeping attack of 26 depth-charges set at 500/700 ft. A third pattern of 26 charges was dropped by "Starling" at 1129. The fourth attack was made at 1251 by "Woodpecker" who dropped 26 charges in a creeping attack. They were set for 500/850 ft.)
	The damage was described by the prisoners as not of a serious nature, but its cumulative effect was fatal. The lights failed, a high pressure air line fractured, the Diesels were shaken from their seats and the extensible Diesel intake and exhaust was broken. Several small leaks appeared and water entered through the packing of one propeller shaft. The gland was tightened in an attempt to stop the leak and this resulted in overheating and filling the after compartment with smoke.
	The depth-chare attacks continued with unrelenting fury. The U-Boat submerged to great depth, but was unable to get clear. The prisoners estimated that between 150 and 200 depth-charges were dropped. Asdic noises were heard, but they were of a higher pitch than usual and the prisoners believed that a new type of gear was being used. The crew became increasingly nervous throughout the attack. The din was so terrific that it was impossible to man the hydrophones. Pumps were kept going, but were not able to cope with the flow of water into the boat. The boat dived deeper and deeper, at one time reaching a depth of 210 m. (689 ft.).
	When at last it became apparent to Looks that the U-Boat must be abandoned, he gathered his men together and said, "We are going to surface. If we must die, we'll die for Greater Germany. Three 'Sieg Heils' for our Führer."
	(N.I.D. Note. "Woodpecker" and "Starling" made a total of seven attacks on the U-Boat between 1035 and 1621. Over 150 depth-charges were fired.)
	At about 1700, "U 264" surfaced. Looks gave the order to abandon ship and personally supervised the execution of the order. He and the Engineer Officer were the last to leave, having remained below to see to the scuttling. The prisoners believed that the U-Boat was flooded and that no scuttling charges were set. When the U-Boat appeared on the surface, the destroyers opened fire, scoring several hits and slightly wounding three or four of the crew. The boat was abandoned in an orderly manner and the entire ship's company was rescued by destroyers of the Escort Group.
	(N.I.D. Note. At 1659 the U-Boat broke surface, bows first. "Starling" opened fire with all weapons and five hits were observed. At 1707 the U-Boat sank in position 48° 31' N., 22° 05' W. At 1735 a heavy underwater explosion was heard.)

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	(C52594) B*4



	8

	VI. GENERAL REMARKS ON U-BOATS

	(i) Extensible Diesel Air Intake and Exhaust
	"U 264" was fitted with an extensible Diesel air intake and exhaust, referred to in the U-Boat Arm as a "Schnörkel." Its purpose was to permit the batteries to be charges while proceeding submerged.
	The fitting consisted basically of a trunk, about 15 ins. in diameter and about 40 ft. in length, which normally lay housed on deck on the port side forward of the bridge, and which, when raised vertically, was as high as the extended periscope.
	The trunk contained an air intake and an exhaust, the open ends of which, faced aft and terminated in a perforated bulb. It was raised into the vertical position hydraulically and was connected through the pressure hull and trunked to the normal Diesel air intake and exhaust, the trunking passing round the forward bulkhead of the control room and along the starboard side.
	Self-sealing valves, apparently working on the ball-cock principle, were fitted at the inboard end of the trunk to prevent water entry, and intermediary and main hand-operated valves were fitted for disconnecting the supply of air when the "Funnel" was lowered.
	It required considerable dexterity on the part of the Engineer Officer to keep the boat in trim, and careful concentration on the part of the duty E.R.As. to cut out the Diesels the moment the intake became blocked, as otherwise the engines drew air from inside the boat, leading very quickly to split ear-drums and lung-bleeding, and was extremely uncomfortable even for the shortest period.
	However, after a certain amount of practice, reasonable efficiency was achieved, and with an officer at the periscope to make sure the U-Boat was not running into danger, the main object of recharging the batteries without having to surface and present a Radar target was achieved.
	"U 264" was the first boat in St. Nazaire to be fitted with the "Schnörkel.," and the new device was supposed to be kept secret, the ship's company being required to sign additional "security certificates."
	However, it was impossible to keep secret from other U-Boats using the same shelter, and whenever a man from "U 264" appeared in the "Zillerthal, a café reserved exclusively for U-Boat personnel, he was greeted with derisive jeers of "Here comes one of the boys with a funnel on his boat!"
	The day for testing the "Schnörkel." for the first time came in January, 1944, when Korvettenkapitän Emmermann, S.O. of the Sixth Flotilla, Korvettenkapitän Sohler, S.O. of the Seventh Flotilla, the Flotilla Engineers of both flotillas, plus a number of Engineer Officers from other boas and one or two "distinguished guests" came on board, representing such a weight of authority that ten members of the crew had to be left behind to make room for them.
	The U-Boat proceeded to the 100-fathom line and submerged to 30 ft. to test the "Schnörkel." The test was reasonably successful, and after a period the trunk was lowered, the U-Boat submerging deeper to 100 ft.
	The trunk was naturally full of water up as far as the main hand valve, and the routine was to drain the section between the intermediary and the main valve by opening the main valve and allowing the water to drain into the bilges. On coming to 30 ft. again, the trunk would be raised and the section between the top of the tube and the intermediary valve would than be drained in the same manner by opening the intermediary valve, thus rendering the "Schnörkel." ready for use again.
	Unfortunately, when the main valve was opened, someone had forgotten to close the intermediary valve. A solid column of water shot into the boat at high pressure, and in the ensuing panic, no-one thought of looking to see if the intermediary valve was closed, assuming that some major defect had occurred.
	Three men who tried to get near the main valve were knocked flying by the jet, and in desperation, Emmermann gave the order to blow the tanks. The forward tanks were blown, and with the ever increasing weight of water aft, the boat assumed an angle of about 50° as she rose. Everyone lost their footing, and the crew, the visiting Engineer Officers and the "distinguished guests" all tumbled in a sprawling, sodden heap in the after compartment, half drowning in oil sea water.
	The boat was brought to the surface and trimmed just in time to prevent a disaster, and it was not until they returned to the shelter that the real cause of the trouble was discovered. The base rocked with laughter when the story of the failure of the base's star engineering talent to find such an obvious defect was recounted.

	(ii) New G.S.R. Equipment
	"U 406" had about 24 pieces of G.S.R. gear on board, and these were combined into five different circuits, which gave cover between about 3 cm. and 380 cm. All the gear was kept in the hydrophone room under the personal supervision of Dr. Greven, and any curiosity on the part of the crew was punished by heavy penalties.
	Four of the combinations were known under the code names of "Bulldog," "Pude;," "Spitz" and "Dackel" (Bulldog, Poodle, Pomeranian and Dachshund); the larger the dog the higher the wavelength covered.
	There were four types of aerial; a large and a small aerial of the basket type already familiar; the other two were a large and small "Parabolspiegel" (parabolic dipoles with reflector). The larger "Paradolspiegel" was raised by air pressure on the shaft which had previously carried the radar mattress, since removed, and the smaller one had to be raised by hand. The four parabolic reflectors were at 90° to each other in the horizontal plane.



	9

	Details of the various sets and the wavelengths covered are as follows:
	"Bulldog." The large basket type aerial plus a Borkum set and a Samos set, together with an amplifier, an oscillograph and a polarisation switch. Waveband covered 80 cm. to 380 cm.
	"Pudel." The small basket-type aerial plus a Borkum set and a Fanö set, together with an amplifier, an oscillograph and a polarisation switch. Waveband covered 40 cm. to 80 cm.
	"Spitz." The large "Parabolspiegel," which contained a detector unit, plus an amplifier, an oscillograph and a sector switch. Waveband covered approximately 12 cm. to 40 cm.
	"Dackel." The small "Parabolspiegel" plus an amplifier,