U-boat Archive - U-461 - Interrogation Report

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








	" U. 4 6 1"

	(A SUPPLY U-BOAT)





	INTERROGATION OF SURVIVORS
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	September, 1943.
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C O N T E N T S

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I.	INTRODUCTORY REMARKS.

	(i)	Complement
	(ii)	Captain
	(iii)	First Lieutenant
	(iv)	Second Lieutenant
	(v)	Midshipman
	(vi)	Engineer Officer
	(vii)	Surgeon Lieutenant
	(viii)	General.

II.	DETAILS OF U-461.

	(i)	Type
	(ii)	Displacement
	(iii)	Builders
	(iv)	Deck Plan and Lay Out
		(a) Stern Compartment.
		(b) Motor Room
		(c) Engine Room
		(d) Galley
		(e) Control Room
		(f) Officers, P.O.'s Messes and W/T Rooms
		(g) Bow Compartment
		(h) Battery Compartments
		(i) General
	(v)	Armament
	(vi)	Bridge
	(vii)	Propulsion
	(viii)	Oil Fuel
		(a) Type
		(b) Capacity and Stowage
		(c) Tank Arrangement
	(ix)	Pumps
	(x)	Oxygen Supply
	(xi)	Klima Equipment
	(xii)	Potash Cartridges
	(xiii)	Batteries
	(xiv)	G.S.R.
	(xv)	Radar
	(xvi)	R.D.B.
	(xvii)	Spares Carried for Supply to Other U-boats
	(xviii)	Diving Equipment
	(xix)	Diving Performance
	(xx)	Periscopes
	(xxi)	Rubber Dinghies
	(xxii)	Provisions
	(xxiii)	Badge
	(xxiv)	Field Post Number

III.	SIXTH AND LAST PATROL OF U.461.

	(i)	U.461 Sails from Bordeaux, but is Forced to Put Back
	(ii)	U.461 Sails
	(iii)	A U-boat in Company Puts Back; U.504 Joins

IV.	SINKING OF U.461.

	(i)	Aircraft Sighted; the U-boats remain Surfaced
	(ii)	U.461 Attacked and Sunk

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V.	GENERAL REMARKS ON U-BOATS.
	(i)		U-boat A/A Gunnery
			(a) (1) Training at A/A Gunnery School
			(b) (2) Passing Out Test
			(c) Range Finding and Fire Control in Practice
			(d) Independent Fire
			(e) Vertical Barrage
			(f) Point of Aim
			(g) Ammunition
			(h) Practice Shoots
			(i) Mimizan A/A Course
			(j) Development of U-boat A/A Fire
			(k) Manning of the 20 mm. Quadruple gun
			(l) 37 mm. (1.46") Gun
	(ii)		Fuel Transfer
			(a) Procedure
			(b) Supply
			(c) Supply in heavy sea
			(d) Fuel Supply between two Operational U-boats
	(iii)		U-boat with E-boat Engines
	(iv)		Japanese Technicians in Germany
	(v)		Damage to an Italian U-boat at Bordeaux
	(vi)		Glider-Carrying U-boats
	(vii)		Radio Listening
	(viii)		Western Limit for Night Diving in the Bay of Biscay
	(ix)		Torpedo-Carrying Supply U-boats
	(x)		U-boat with Underwater Camera

VI.	SURFACE SHIPS.

	(1)	"Narvik" and "Seetier" Class Destroyers
			(a) General
			(b) Details of Z.23.
			(i)	Discussions
			(ii)	Complement
			(iii)	Speeds
			(iv)	Armament - Guns
			(v)	Armament - Torpedoes
			(vi)	Minesweeping Gear
			(vii)	Depth-Charge Throwers
			(viii)	Mines
			(ix)	Smoke Floats
			(x)	Engines
			(xi)	General Appearance
			(xii)	Accommodation
			(c) Commanding Officers
	(2)	ALSTERUFER
	(3)	BATAVIA III
	(4)	600-Ton Torpedo Boats.

VII.	BASES.

			Bordeaux

	APPENDIX "A"	-	Building and Working up of U.461.
	(i)		Building
	(ii)		Commissioning
	(iii)		Working up.

	APPENDIX "B"	-	Previous Patrols of U.461.
	(i)		First Patrol
	(ii)		Second Patrol
	(iii)		Third Patrol
	(iv)		Fourth Patrol
	(v)		Fifth Patrol

	APPENDIX "C"	-	Nominal Roll of U.461.

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PLATE I	-	"Seetier" Class destroyers

PLATE II	-	U.461 General arrangement of Compartments
		Bulkheads and Tanks.

PLATE III	-	Bow Section

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	REPORT ON INTERROGATION OF SURVIVORS FROM U.461, A 1600-TON SUPPLY U-BOAT, SUNK AT 1205 on 30TH JULY, 1943.
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I.	INTRODUCTORY REMARKS.

	U,461, a 1600-ton supply U-boat, commanded by Korvettenkapitän Wolf STIEBLER, was sunk at 1205 on 30th July, 1943, in position 45⁰ 42' N. 011⁰ 00' W., by Sunderland "U" of 461 Squadron, R.A.A.F., assisted by Halifax "B" of 502 Squadron and U.S.A. Liberator "O" of 53 Squadron. At the time, U.461 was outward bound in company with U.462, who was also sunk (N.I.D. NOTE: See C.B. 04051 (82)) and a U-boat commanded by Kapitänleutnant LUIS. Survivors from U.461 and U.462 were picked up by "WOODPECKER" of the Second Support Group.

	U.461 was on her sixth patrol when sunk. During the eighteen months since her commissioning, she had supplied U-boats eighty times.

	(i) Complement.

	Of U.461's complement of sixty, fifteen survived. These included the Captain, the First Lieutenant and a Midshipman.

	(ii) Captain.

	Korvettenkapitän Wolf STIEBLER, aged 36, is of the 1932 term. He had been in U-boats since before the war. Although STIEBLER, himself, was silent on the point, prisoners previously captured have intimated that he was in command of U.21, a 250-ton U-boat interned in Norway on 28th March, 1940. The U-boat was later recaptured by the Germans and STIEBLER released from internment. There was much speculation among U-boat officers at the time as to whether STIEBLER would be court-martialed, but he managed to extricate himself from the affair. STIEBLER is a bluff, hearty man and he was popular on board. He was security conscious on naval maters.

	(iii) First Lieutenant.

	Oberleutnant zur See Herbert LUDWIG, the First Lieutenant, was injured at the time of sinking and at the time this report was written he was still too ill to be interrogated. He was 39 years of age.

	(iv) Second Lieutenant.

	Leutnant zur See FALK, the Second Lieutenant, did not survive. He was of the 1938 Naval term.

	(v) Midshipman.

	Oberfähnrich Carston SCHRÖCK, aged 20 and Acting Third Watch Keeping Officer, was unwilling to discuss his career in any way. He was a typical Hitler Youth product.

	(vi) Engineer Officers.

	Very little is known of Oberleutnant (Ing.) MAHNKOPF, the Senior Engineer Officer, who did not survive. He does not appear in the 1940 Navy List. He had taken part in all of U.461's patrols. He was assisted by a Leutnant (Ing.) WALDORF, who was sailing in U.461 for the first time. This officer did not survive.

	(vii) Surgeon Lieutenant.

	Marinestabsarzt Dr. GERD, who was sailing in the U-boat was not among the survivors. Nothing is known about him.

	(viii) General.

	The average age of the ten other ratings who survived was barely

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twenty. The surviving Supply Petty Officer was aged twenty-five and the Chief Stoker who survived was twenty-nine.

Features of this report are:

(a) Further details of U-boat anti-aircraft armament (Section V).

(b) Further details of fueling at sea. (Section V).

Equivalent Ranks

The following are the Royal Naval equivalents to 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.
Marinestabsarzt	-	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 OF U.461.

(i) Type. . . . . . . . . . . . . . . . . . . . . XIV.

(ii) Displacement . . . . . . . . . . . . . . 1600 tons.

(iii) Builders . . . . . . . . . . . . . . . . . . Deutsche Werke, Kiel (Series U.459 to U.464).

(iv) Deck Plan and Lay Out . . . . . . (See Plate II)

U.461 belonged to the same series of U-boats as U.459, U.462 and U.464 (N.I.D. Note: See C.B.s 04051 (79), (82) and (50) respectively.)

The description below is believed to hold good for all these U-boats and is probably more accurate than that given in C.B. 04051 (50).

The construction of this series present two features in which they differ radically from the types VII C and IX C.

The ends of the pressure hull are sealed with concave ends, as opposed to the more normal convex ends, and the transverse "T" frames of the U-boat are external to the pressure hull instead of being internal. This arrangement is alleged to be a measure designed to make the hull less liable to damage by depth charge attacks.

The lay-out of tanks and bulkheads id shown on plans "A" and "B" and the bow construction on plan "C".

Compartments from stern to stem were:

(a) Stern Compartment

Contained workbench and lathe on port side, grinding wheel aft, and borer and heads on starboard side. Under the deck plating were the hydroplane motors. Above working level on either side was a bunk, which was in fact, used for stores. The lathe was by Sulzor and would take about 45" between centres and would swing work up to 24" diameter. With chuck, would take bar up to 16" diameter through headstock. There were two lubricating oil pumps in the bilges.



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	(b) Motor Room.

	Contained two Siemens 500 H.P. double commutator type motors, with their switchboards above. Abaft the motors and on a higher level were two electrically driven compressors, and above these two Siemens water distillation plants, each capable of producing 20-22 gallons per hour.

	There was one compressed air bottle group, each of four bottles, with air at 205 kg/cm2 (2900 lbs/sq.in) on either side of the compartment. S.B.T. was fitted aft on the starboard side.

	(c) Engine Room.

	Contained two G.W. Diesels with Rootes type super-chargers, quill type vibration dampers. Two multi-plate dry clutches. Two Junkers free piston compressors, one on either side, supported near the forward bulkhead. Also oil pumps, separators etc.

	(d) Galley.

	On port side, normal refrigerator above, low temperature (-18 deg. C) doe 1/2 ton of meat below it. Electric cooking range on starboard after bulkhead. Below on the starboard side, was Provision Room No. I and Drinking Water Tank No. I.

	(e) Control Room.

	In addition to the normal control gear of a 500 ton U-boat, valves and pumps for fueling were fitted on the after bulkhead. An air conditioning plant was also fitted.

	Below the control room were Provision Room No. II. Drinking Water Tank No. II and the Magazine.

	(f) Officer, P.O.s' Messes and W/T Rooms.

	Living accommodation was all forward of the control room. On the port side were the Captain's cabin, the Engineer Officer's cabin, the Executive Officer's cabin and the Chief Petty Officers' cabin. On the starboard side were the W/T Room, the Listening Room, and the Sick Bay. Forward of the foregoing was the Petty Officers' Mess taking up the full width of the U-boat.

	(g) Bow Compartment.

	The ratings were messed in the Bow Compartment with washing accommodation on the port side and heads on the starboard side. Provision Room No. IV was below the Bow Compartment, together with forward hydroplane motors and a group of oxygen bottles.

	(h) Battery Compartments.

	Battery compartments I and II were on the centre line of the U-boat below the officers' quarters and the after part of the P.O.s' Mess. To starboard of them were fuel oil internal tanks No. I(i) and No. III(i) and to port , No. II(i) and No. IV(i). Before the batteries and below the fore end of the P.O.s' Mess was Provision Room No. III. On the port side the boat had been modified to increase the fuel capacity by providing an additional fuel tank connected with Internal Fuel Tank IV(i) instead of the provision space.

	(i) General.

	There were six dished pressure bulkheads (a) to (f) (see Plate II) as follows:

	(a) One forward of the after end of the pressure hull.
	(b) One between the stern compartment and the Motor Room.
	(c) One between the Engine Room and the Control Room.
	(d) One between the Control Room and the Officers' and P.O.s' Messes.



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	(e) One between the Officers' and P.O.s' Messes and the Bow Compartment.
	(f) One abaft the forward end of the pressure hull.
	All above bulkheads were built to withstand a head of 197 ft. of water. In addition there was a certain number of collision bulkheads designed to withstand a head of about 23 ft. of water. All those bulkheads are shown on Plan "A" and were stated to be 5 mm. (.197") thick.

	(v) Armament . . . . . . . . . . . . . . . . . Guns.

	One 20 mm. (0.79") quadruple mounting on lower bandstand. One 20 mm. gun on each side of bandstand proper; mountings for twin M.G.s 81 on bridge. The M.G.s did not stand up to naval conditions, and were never used.

	One 20 mm. gun mounted forward of bridge structure. The chief purpose of this gun was to afford additional protection during fuel transfer. The quadruple gun had an extra high pedestal which enabled aircraft attacking from dead ahead to be engaged over the bridge structure. Depression control rails were fitted as an additional precaution to ensure adequate bridge clearance.

	Armored shields, about 1-1/2 cm. (.59") thick, were fitted on each side of the gun and were sufficiently high to protect a man of average size. There was also armour in front. The armour was claimed to offer complete protection against .303 and safety against .5" machine guns, although prisoners were not convinced of this. It was no protection against 20 mm. H.E.

	The gun trained on its mounting complete with armour, but armour did not move when the gun was elevated, nor did the gunlayer on his seat.

	The guns were elevated by means of a cable arrangement, which could be seen in a slot in each side of the front shield. The cable was protected by a strip of armour, which was removed in U.461 to facilitate greasing and maintenance.

	A vulnerable point was the center pivot on which the whole gun revolved. One burst of fire from an attacking aircraft in U.461's last action penetrated beneath the armour and put the training gear out of action. As a result an aircraft which attacked to within 40 to 50 yards escaped unscathed. What were described as "artillery glasses" to assist estimation of range were available. (N.I.D. NOTE: The artillery glasses mentioned were possibly short base Stereo range finders or spotting glasses). There were ring sights available for the quadruple gun, but control was entirely by tracer.

	Filling sequence was three HE/AP to one tracer. The firing pedals were so connected that one foot fired the left upper and the right lower guns and the other foot fired the right upper and left lower guns. Hand firing gear was also provided. The guns were converged at 1500 or 2000 meters (1640 or 2187 yards). It was done at the factory and subsequently when returning to base from patrol. No such adjustment was done on patrol.

	Bullet pattern was believed to be 25 - 30 meters at a range of 500 meters, 8 - 10 metres at 1000 metres coming to its narrowest cone of about two meters, at 1500 metres. Between 1500 and 200 metres it splayed out again. Very gentle training at 100 meters range gave a pattern of 50 - 60 meters. (1 metre = 1.09 yards) (N.I.D. NOTE: While the estimate of the size of pattern at 1500 metres seems reasonable, the other figures given are excessive and cannot be reconciled with the pattern at 1500 metres).



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	Ammunition and Stowage.

	Seven tons of ammunition were stored in the magazine below the Control Room. There were four ready use ammunition lockers on the lower bandstand, two each side, each containing 8 to 10 clips of twenty rounds each. Fifty clips of 20 mm. ammunition were stowed inside the bridge structure.

	Guns fitted on Previous Patrols.

	The above armament was fitted for U.461's last patrol. Previously she carried one 37 mm. (1.46") forward, one 37 mm. aft, and one single 20 mm. on the bandstand.

	Torpedo Tubes.

	None.

	Torpedoes.

	None carried for supply to other U-boats.

	Torpedo Containers.

	Four were originally fitted but were wrecked by bombs from a Sunderland on the Second Patrol. They were never replaced.

	(vi) Bridge.

	2 cm. (.78") armour plate had been added to the bridge and extended from both sides forward. The bridge was divided from the bandstand by two swing doors, also 2 cm. armour which were secured back against the fairing when the U-boat dived. This protected men on the bridge when in action. Abaft the bridge was the bandstand proper and below and abaft the bandstand, the lower bandstand reached by port and starboard companions ways. The lower bandstand adjoined to the bandstand proper and was not a separate platform as in U.462 (N.I.D. NOTE: See C.B. 04051(82).)

	Two bottles of hydrogen for use with R.D.B. were carried, one on each side of the bridge structure. These were for use with R.D.B. The valves and connections projected above the fairing to facilitate inflating the balloons.

	For welding purposes two acetylene bottles were carried below the bridge, one on each side. The bottles could be opened from the bridge by means of rod gearing. Piping carried oxygen and acetylene to connections inside the bridge. Welding could thus be carried out on the bridge by means of short tubes. If necessary, welding could be done inside the U-boat by means of long tubes, which could be connected and led down through the galley hatch in the bandstand.

	(vii) Propulsion.

	Speeds: Maximum surface speed was 14-1/2 knots; surface cruising speed was 10-1/2 knots.

	Cruising speed submerged was approximately 2 knots at about 100 r.p.m.

	(viii) Oil Fuel.

	(a) Type: This U-boat was designed for synthetic fuel with a specific gravity of 0.87, but in fact she was still using natural fuel with an average specific gravity of 0.843 to 0.846.

	(b) Capacity and Stowage: (see Plate II) Capacity was 727.5 m3 (618 tons). 24 m3 (20.4 tons) of this was carried in internal tanks, and the remainder in external tanks which completely surrounded the pressure hull, except for a width of about 6.6 ft. on deck. Diving tank No. 6 was an exception in that it completely surrounded the pressure hull. Tanks were not pressure tight and pressure outside and inside had always to be equalized,

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Wasserdichtes Heck		(Stern buoyancy tank)
Tauchnelle 1		(No. I main ballast tank)
Tauchnelle 2		(No. II main ballast tank)
Treibölbunker 1		(No. I. Oil Fuel tank)
Treibölbunker 2		(No. II " " " )
Treibölbunker 3		(No. III " " " )
Tauchbunker 3		(No. III main ballast (emergency fuel tank)
Tauchbunker 4		(No. IV " " (emergency fuel tank)
Tauchzelle 5		(No. V main ballast tank)
Regelzelle		(Compensating tank). Capacity 54 m3 (27 m3 each side).
Untertriebzelle		(Quick diving tank). Capacity 16 m3 (8 m3 each side).
Tauchzelle 6		(No. VI main ballast tank). One single cell.
Tauchbunker 7		(No. VII main ballast (emergency fuel tank).
Tauchbunker 8		(No. VIII " " (emergency fuel tank).
Treibölbunker 4		(No. IV oil fuel tank)
Treibölbunker 5		(No. V " " " )
Treibölbunker 6		(No. VI " " " ) )
Tauchzelle 9		(No. IX main ballast tank) ) See plate III.
Wasserdichtes Back		(Bow buoyancy tank) )

All tanks mentioned above are external. The compensating and quick diving tanks, port and starboard, although external, are reinforced and pressure tight and were said to enable the U-boat to maneuvre even if all other tanks were damaged.

There were also a port and starboard trimming tank forward and aft internally, each of 8 m3 capacity.

18 m3 (15.3 tons) of lubricating oil were carried internally. This was considered important for trimming purposes. Consumption by the boat herself was about 4 m3 (3.2 tons) of lubricating oil per 100 m3 (85 tons) of fuel.

(ix) Pumps.

The main bilge pump was two-stage. When in series it delivered 60 tons per hour against 492 ft. head of water; in parallel, 150 tons per hour against 82 ft. head of water. It was fitted on the port side in the control room.

The auxiliary bilge pump was fitted on the starboard side of the control room.

The fuel supply pumps were spindle pumps rated to give 45 m3 (36 tons) per hour at about 2 kg./cm2 (28.4 lbs/sq.in). In practice they never delivered more than 40 m3 (34 tons) per hour.

(x) Oxygen Supply.

Three groups of four bottles, each of 250 litre (9 cu. ft) capacity at 150 atmospheres.

(xi) Klima Equipment.

This is the name given to the air conditioning plant fitted in the control room of all U-boats of this type. It delivered air at about 15⁰ to 18⁰ C. (59⁰ to 64⁰ F) but this did not have much effect on the temperature within the U-boat. Its great virtue was that it removed about 2.2 gallons of water per hour from the air and kept humidity very low. The water could be used for washing purposes.

The plant is manufactured by Linde, of Cologne.

(xii) Potash Cartridges.

It was said that one cartridge could deal with the CO2 from one man for four hours. 650 cartridges were carried.

(xiii) Batteries.

Lead acid type. 13,000 amp./hr. capacity being slightly larger than the batteries of a 500-ton



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	U-boat. Each battery had an overload trip switch.

	(xiv) G.S.R.

	Metox R.800 A type carried for own use. The set had a small green Magic Eye across which a permanent trace was left. This was disturbed when any reception was obtained.

	The new drum-shaped aerial was fitted on the port side of the bridge structure.

	(xv) Radar. Not fitted.

	(xvi) R.D.B.

	Two boxes of R.D.B. stowed in the control room on the last patrol. They were never used. (N.I.D. NOTE: See C.B.04051 (74), Section II.)

	(xvii) Spares Carried for Supply to Other U-boats.

	A number of G.S.R. sets and Southern Cross type aerials.
	2 complete Junkers Free Piston Compressors and five boxes of small parts for these compressors, which are particularly sensitive to depth charge attack.
	1 piston complete with rings and connecting rod for G.W. engines.
	1 piston complete with rings and connecting rod for M.A.N. engines.
	6 exhaust valves for G.W. engines.
	2 exhaust valves for M.A.N. engines.
	Also boxes of other small parts and the usual supplies of grinding paste, cleaning materials, etc.
	A good stock of bar steel and brass was also carried to enable special parts to be made.
	The smaller number of spares carried for M.A.N. engines was accounted for partly by the fact that there are far fewer M.A.N. engines in U-boats than there are G.W. and partly by the fact that M.A.N. are more reliable.

	(xviii) Diving Equipment.

	This was carried for the first two patrols only, but since it proved impossible to carry out underwater repairs at sea with diving gear, this was then discontinued. Every supply U-boat was said to have one or two men on board who had done some diving courses.

	(xix) Diving Performance.

	Before alterations to the gun platform the fastest crash dive to periscope depth achieved by this U-boat was 38 seconds, checked by stop-watch. After the alteration had been made the crash-diving time had been considerably longer, as the lower bandstand created a big drag on the U-boat. One prisoner stated that an additional eight seconds was then required to reach 40 meters (131 ft).

	(xx) Periscopes.

	Prisoners stated that both the attack and search periscopes were inside the conning tower. (N.I.D. NOTE: In supply U-boats attack equipment, normally to be found in the conning towers of operational U-boats is not necessary and hence space becomes available for both periscopes. The positions of the periscopes in U.461 are probably incorrectly shown on Plate I, C.B. 4051(50).)

	(xxi) Rubber Dinghies.

	One 25 ft. dinghy and two 13 ft. dinghies were stowed on the upper deck. Inside the U-boat were stowed at least as many single-man dinghies as there were members of the ship's company. Each dinghy was equipped with brandy and biscuits.

	(xxii) Provisions.

	The greatest load of provisions ever carried was 33 tons. The usual load was 23, 26 or 28 tons.

	(xxiii) Conning Tower Badge. None.

	(xxiv) Field Post Number. M26638.



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III.	SIXTH AND LAST PATROL OF U.461.

	(N.I.D. NOTE: See also C.B. 04051(82), Section III, Interrogation of Survivors from U.462.)

	(i) U.461 Sails from Bordeaux but is Forced to Put Back.

	U.461 first sailed from Bordeaux on 22nd July 1943. It was originally intended that she should sail with U.459 and U.117 (N.I.D. NOTE: See C.B. 04051 (79), Section III.) The three U-boats rendezvoused in the mouth of the Gironde, but U.461 discovered a leak in Diving Tank No. 6 and put back to Bordeaux where defects were made good. The damage had originally been caused by an ocean-going tanker which had fouled U.461 during bad weather when mooring at Bordeaux.

	(ii) U.461 Sails.

	U.461 finally sailed from Bordeaux at noon on 28th July, 1943, in company with U.462 (Oberleutnant zur See der Reserve Bruno Vowe) and one other supply U-boat, thought by prisoners to have been either U.460 (Oberleutnant zur See der Reserve Schnorr), or U.119.

	Escort consisted of between nine and twelve nits, including three Narvik Class destroyers, One Sperrbrecher, and six more minesweepers. Periodically flights of Ju.88 aircraft provided air cover.

	(iii) A U-boat in Company Puts Back; U.504 Joins.

	On the following day the third supply U-boat developed a faulty clutch and put back to Bordeaux. Her place was taken by U.504, a 740 ton U-boat commanded by Kapitänleutnant Luis, who was outward bound from another base.

	Escort remained with the U-boats until 2300 on 29th July. The three U-boats remained together throughout that night. U.461 was the "leader" boat of the formation and either flashed or semaphored action to be taken to the other two.

IV.	SINKING OF U.461.

	(i) Aircraft Sighted: the U-boats Remain Surfaced.

	On the morning of 30th July, 1943, the three U-boats were proceeding on a course of 250⁰T., surfaced and at a speed of about 19 knots.

	According to the Captain of U.461, a Sunderland was sighted at 0950. This aircraft kept at 5,000 yards distance, out of range of A/A fire. It was heard signaling for other aircraft.

	A liberator or Halifax then appeared, followed by what was taken to be another Halifax and another aircraft, until there were eventually five in all.

	(N.I.D. NOTE: Sunderland "U" of 461 Squadron, R.A.A.F., reported sighting three U-boats at 1148 with Halifax "B" of 502 Squadron and a U.S.A. Liberator circling. At this time an attack was being made on U.462 by the Halifax, three A/S bombs falling off the starboard quarter and exploding in one big plume. Sunderland "U" of 461 Squadron then ran in to attack the same U-boat from astern. The three U-boats turned to bring all guns to bear and put up such a heavy barrage that the aircraft was compelled to break away. Sunderland "U" of 461 Squadron then endeavored to get ahead of the U-boats in order to make a bow attack, but the entire pack wheeled inside the aircraft's turning circle, preventing the attack. Halifax "S" of 502 Squadron then made an attack on U.462, dropping a single A/S bomb from 3,000 feet, having approached from dead astern. This was a near miss.

	At noon a Liberator attacked unsuccessfully, but drew the fire from all three boats. Taking advantage of this, Sunderland "U" of 461 Squadron attacked.



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	(ii) U.461 Attacked and Sunk.

	Korvettenkapitän Stiebler said that at the moment of this attack he attempted a turn to port; he was unable to turn to starboard owing to the short distance between him and U.462. Machine gun fire from the Sunderland was very heavy and severely wounded one or two of his officers and killed both the leading members of the 20 mm. quadruple gun, which reduced the effectiveness of A/A action. He thought the aircraft attacked from dead astern. Two bombs or depth charges fell to one side of the U-boat and two to the other. It was two which fell forward of the conning tower and exploded beneath the U-boat which caused the fatal damage. U.461 went down like a stone.

	The gunlayer of the port single 20 mm. gun said that he fired until the aircraft was 60 feet away and then his ammunition ran out.

	The sole survivor to escape from inside the U-boat said that five aircraft were reported one after the other. Suddenly there was a tremendous explosion and a wall of water rushed into the control room from forward. The prisoner thought that the bows had been blown off. He is a strong athletic type and said that it was only with the greatest exertion that he managed to haul himself up through the conning tower hatch, for water was already pouring down it. He was preceded only by a Propaganda Company camera man, a supernumerary on board, who, however, later disappeared. When he arrived on the bridge Stiebler had already ordered everyone to abandon ship.

	(N.I.D. NOTE: Aircraft "U" of 461 Squadron reported running in from port quarter to starboard bow, at 50 degrees to the axis of the U-boat, at 50 feet. The aircraft was free of A/A fire until closing to 1,000 yards. At this range the nose gunner opened fire on the A/A gunners on the rear gun-platform of the U-boat, scoring direct hits. A stick of seven depth charges set to 25 feet, spaced 60 feet, was dropped and straddled the U-boat. All exploded, the center of the stick being just forward of the conning tower. As the aircraft passed over the U-boat, the tail gunner fired 600 rounds, scoring numerous hits. By this time the aircraft was flying into a heavy barrage put up by the other two U-boats, causing the pilot to take such violent evasive action that details of the U-boat attacked could not be fully observed. The navigator, however, observed the U-boat slide forward under the water, with quantities of orange colored froth and scum issuing, apparently from the fore part. When the aircraft completed the circuit up to thirty men were seen swimming in the orange patch of scum still in evidence. The aircraft dropped a dinghy to survivors. It was seen to inflate and several survivors eventually climbed aboard.)

	U.461 sank at approximately 1205 in position 45⁰42'N., 011⁰00'W. For the continuance of this action, which resulted in the destruction of U.462, and the probable destruction of the U-boat commanded by Kapitänleutnant Luis, see C.B. 04051 (82), Section IV.

	Survivors from U.461 were picked up, some five hours after sinking by H.M.S. "WOODPECKER".

V.	GENERAL REMARKS ON U-BOATS.

	(i) U-boat A/A/ Gunnery.

	(a) (1) Training at A/A Gunnery School.

	A survivor from this U-boat was the first Leading Seaman fully qualified in A/A weapons, and carrying out the duties of Gunner's Mate, so far captured.

	He attended the first Flakspeczialist training course at a new school at Nest near Berlin. This course lasted six months, from March to September, 1942. 200 to 220 men were under training. They were divided into three troops, (Züge), each troop being divided into five groups of 12 to 15 men.

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Each man fired about 24,500 rounds during the six months. (N.I.D. NOTE: The course is a very long one and the ammunition allowance generous, which may account for the results claimed below in categories fired day and night:

Type and Calibre Gun	No. of Rounds
	Day	Night
Madsen* 40 mm. (1.57")	200	-
U-boat 37 mm. (1.46")	3000/5000	-
Quadruple 20 mm. (.79")	500	-
Oerlikon	3000	-
C.38 - 20 mm.	15000/17000	800/1000

*Madsen is of Danish manufacture.

Not more than 150 rounds were fired by any one man in one day or night shoot.

A typical day's programme was as follows:

0700		Call the hands
0800-1000		Theoretical instruction
1000-1100		Range estimation
1100-1130		Either theoretical or practical gun drill.
1200-1400		Dinner
1400-1700		Gun drill and/or practice shoots at fixed or towed targets (up to 150 rounds per man

On about ten occasions a night shoot replaced the afternoon shoot. Practices were carried out against targets towed in the moonlight and against sleeve targets towed with a small searchlight inside the sleeve and with searchlights on the ground trying to dazzle the gunners. The prisoner claimed to have achieved five hits out of 20 rounds under those conditions.

Theoretical instruction included names and functions of parts, types of ammunition, theory of sighting and use of 70 cm. and 1.5 metre range finders.

(a) (2) Passing Out Test.

The final passing out test lasted three days. It consisted of:

Day 1:	Theoretical written examination. Six hours in all.

Day 2:	Practical gun drill including stripping and assembly, clearance of stoppage and range estimation.

Day 3:	Practical firing tests. 30 rounds on the 37 mm. gun (the prisoner claimed 9 hits); 60 rounds on 20 mm. gun (prisoner claimed 15/20 hits. Range was between 1,000 and 2,000 metres; height 800 to 1,000 metres. (1 metre = 1.09 yards)
	(N.I.D. NOTE: The prisoner would seem to have reached a high degree of proficiency.)



	- 11 -

	(b) Range Finding and Fire Control in Practice.

	The same prisoner said that the commanding officer, or the officer of the watch, found the range on the 70 cm. range finder type E.34 and so controlled the gun or guns on the bridge and bandstands. Type E.34 was accurate for ranges from 500 metres to 4,000 metres. It could be used down to 150 metres. (N.I.D. NOTE: The 70 cm. type is a portable coincidence range finder in strict contradistinction to other German range finders, all of which work on the stereoscopic principle. Two types exist, the "E-Mesageerät 14" and the "E-34".)

	The prisoners said that the 1.5 metre range finder was normally for use against stationary targets, but it could also be used for A/A purposes. It was not, however, much used in U-boats because it was clumsy to handle in a confined space.

	The gunlayer of the forward 37 mm. gun, when mounted, had to find his own range without the assistance of a range finder. The gunlayer of the 20 mm. quadruple mounting also controlled his own fire, but might have the help of "artillery glasses" accurate from 1,000 to 3/4,000 meters. (See N.I.D. NOTE Section II(v)).

	Fire might be opened with the 37 mm. gun at 3,000 metres, but in no case should any of the 20 mm. guns open fire before the target was at 1,000 metres or even less. (N.I.D. NOTE: The open fire range of 3000 metres for the 37 mm. gun appears high).

	(c) Barrage Fire.

	A type of barrage fire might be used against single aircraft. In U.461 the two single 20 mm. guns on the bandstand were instructed to form sides of a cone of fire 100 metres broad. The quadruple gun would then fill in the interval between these two points. Barrage fire would be opened at a maximum range of 2,000 metres and continued down to the range of 1,000 metres and occasionally down to as low as 500 metres, at which range independent fire would begin.

	(d) Independent Fire.

	If the aircraft maintained a direct attack the order would be given to change over from barrage fire to independent fire.

	The prisoner said that he would normally fire his first sighting burst with tracer when the target was 500/1,000 metres away. He would fire his first burst slightly above the aircraft and his second slightly below, expecting to be dead on target with his third burst. (N.I.D. NOTE: This technique does not appear likely to achieve early hitting and might encourage missing astern). He would then maintain continuous flow of fire, correcting his aim as required.

	Independent fire was more likely to be used against a circling aircraft, unless it was circling beyond 1,000 meters' range.

	(e) Vertical Barrage.

	Should an aircraft attack from low down dead ahead and guns could not be brought to bear, the quadruple gun at least would be elevated to fire a vertical barrage, as the aircraft would have to pass over the U-boat. The new quadruple mounting greatly facilitated this drill.

	The moment at which an aircraft flew directly over a U-boat was the moment at which the quadruple gun's crew felt the most exposed, as they then had no armour protection and were vulnerable to the rear gunner's fire.

	(f) Point of Aim.

	(1) Against Aircraft: U-boat gunners aimed at the pilot's cabin in the hope of disabling the pilot or nose-gunner or both. Four-engined aircraft were not considered very vulnerable to fire directed against their engines.



	- 12 -

	(2) Against Searchlight Aircraft: Fire was invariably across the searchlight beam so that the bullets would leave from the upper edge of the beam and enter the aircraft's cabin.

	(g) Ammunition.

	Except for size, precisely the same natures of ammunition were used in the 37 mm. and 20 mm. guns. Filling sequences varied from U-boat to U-boat. The prisoner favored a sequence of three HE/AP to one tracer. The 20 mm. H.E. had both contact fuses and self-destroying fuses set for 2-1/2 to 3 seconds. Tracer burnt out at 2,000 metres and HE/AP was self destroying at a maximum of 2,900 metres. Splinters would carry 10 metres and might inflict personnel casualties at that range.

	The HE/AP ammunition was colored black with a red annulus. The tracer was colored yellow. The prisoner had heard that 20 mm. incendiary tracer ammunition was to be introduced.

	(h) Practice Shoots.

	U.461 held practice shoots two or three times a week when past 30⁰ West. (N.I.D. NOTE: It seems probable that these were more in the nature of functioning trials.)

	(i) Mimizan A/A Course.

	The A/A course for ordinary U-boat A/A gunners at Mimizan has been extended to one month instead of the previous five days. Those who passed the course wore the flying shell A/A badge, but not the chevron beneath it which was the badge of a 'Flakspezialist' such as the prisoner.

	(j) Development of U-boat A/A Fire.

	The Captain said that he considered U-boat A/A armament the answer to A/S aircraft as "a diving U-boat is the airman's delight, like a sitting bird." He was, however, of the opinion that they must introduce bolt-fed guns in order to meet aircraft attack effectively. His deduction was that A/A fire failed because it was cannon-fed and needed leaders, whereas a bolt-fed gun would still continue to be served, even if only one man was left.

	(k) Manning of the 20 mm. Quadruple Gun.

	In this U-boat there were always four men and often the Captain on look-out on the bridge during passage through the Bay of Biscay. A complete quadruple gun's crew was closed up the entire time. Their primary duty was general A/A lookout and particularly in the sun sector.

	(1) 37 mm. (1.46") Gun.

	A prisoner said that muzzle velocity was 300 metres/second (984.3 ft/sec). (N.I.D. NOTE: This is considered very low). Rate of fire was up to 80 rounds per minute. The range at which it was most effective was 2,000 metres (with a maximum of 3,000 to 3,500 metres.). Both single shot and automatic fire with clips of five was possible. The crew consisted of gunlayer, breech worker, who was also responsible for clearing stoppages, loading number and three supply numbers.

	37 mm. H.E. ammunition was self-destroying at 3,400 to 3,500 metres, and tracer burnt out 3,000 metres. Personnel casualties might be caused by 37 mm. H.E. up to 20 to 30 metres. (1 metre = 1.09 yards)

	(ii) Fuel Transfer.

	The method of fuel transfer employed by U.461 differed from that of U.459. (N.I.D. NOTE: See C.B. 04051 (79), Section V.)

	(a) Procedure.

	The U-boat being supplied took station about 90 to 100 yards astern. The hose, which was of 90 mm. (3.5") diameter, was connected in U.461, inflated, and veered back to the other U-boat.



	- 13 -

	Fuel was supplied under pressure of 2 Kg/cm2 (28.4 lbs/sq.in). Average rate of supply was between 25 and 40 m3 (21 and 34 tons) per hour. During the supply the two U-boats proceeded ahead at about 1 knot.

	(b) Supply.

	U.461 supplied fuel pumping by seawater under 0.8 Kg/cm2 (11.3 lbs/sq.in) pressure into the bottom of her fuel tanks, using the diesel auxiliary cooling water pump. (She once burst a tank by increasing pressure beyond this point). Fuel was led off from a pipe in the top of the tank to a spindle pump which delivered into the transfer hose under a pressure of 2 Kg./cm2 (28.4 lbs/sq.in). The amount of fuel left in a tank was ascertained by a test-cock connected to a small pipe at the top of the tank but having its exit slightly below that of the pipe leading from tank to spindle pump. When this cock ejected sea water, it showed that the tank was nearly empty of oil.

	In the event of an emergency the hose was cast off and the fuel supply shut off from within the U-boat.

	(c) Supply in heavy sea.

	A C.E.R.A. said that U.461 had never in a heavy sea pumped oil into the bilges of another U-boat through a hose leading from conning tower to conning tower. This method had been employed in rough weather by non-supply U-boats, but it was extremely laborious, as the oil had to be pumped out of the bilges into tanks by hand-pump, after the slow supply provided by the Diesel auxiliary cooling water pump (see below).

	(d) Fuel Supply between two Operational U-boats.

	This was extremely slow and averaged about 2 m3 (1.7 tons)/hour, as there were no special supply pumps. The only pressure available was 11.3 lbs/sq.in at which pressure sea water was pumped into the fuel tanks by the diesel auxiliary cooling water pump. In consequences, the slightest rolling or pitching of either U-boat generally interrupted the supply.

	(iii) U-boat with E-boat Engines.

	A C.E.R.A. said that a friend of his had been in a U-boat with E-boat Diesel engines in a French port. New engines had to be fitted after each patrol. He understood that the Engineer Officer had had a lot of trouble due to the fact that the natural period of vibration of the U-boat corresponded with certain of the E-boat engine speeds. He believed that the U-boat had six E-boat engines for propulsive purposes and two for charging batteries and driving the compressors. He believed that the maximum speed was 22 knots. (N.I.D. NOTE: See also C.B.'s 04051 (60) Page 15 and 04051 (82) Section V (ix)).

	(iv) Japanese Technicians in Germany.

	A prisoner said that at the end of June, 1943, a U-boat docked at Bordeaux with three Japanese on board. (N.I.D. NOTE: See also C.B. 04051 (82), Section V.) These men were bringing with them new radio-location apparatus. They had been transferred with their inventions from a Japanese submarine, near Madagascar. The U-boat bringing them to Bordeaux was escorted into harbor by two destroyers. Allied aircraft had been sighted. The prisoner was given particulars concerning the Japanese technicians by a friend who was on board. All were in a very bad state of health on their arrival.

	The prisoner also stated that when he was returning from leave on 1st June, 1943, two Japanese in civilian clothes, escorted by a German Commander, boarded his train at Metz. They alighted with him at Bordeaux. He later saw the same pair in naval uniform when they appeared to welcome the Japanese who had arrived in the U-boat.



	- 14 -

	(v) Damage to an Italian U-boat at Bordeaux.

	A prisoner stated that when a large Italian U-boat was about to leave Bordeaux at the end of June, 1943, a scuttling charge exploded on board. The U-boat could not sail and was unloaded preparatory to docking.

	(vi) Glider-Carrying U-boats.

	A prisoner said that all 1200-ton U-boats carry gliders. (N.I.D. NOTE: See also C.B. 04051 (70), Page 5 which referred to a 1200-ton U-boat being adapted to carry a seaplane.)

	(vii) Radio Listening.

	The Captain confirmed that listening to wireless programmes had been forbidden for all U-boats at sea. It was thought that the sets, when in operation, could be D/F'd.

	(viii) Western Limit for Night Diving in the Bay of Biscay.

	A prisoner said that beyond 18⁰W. U-boats ceased to dive at night. Longitude 10 to 13⁰ W. was considered by U-boats to be the most dangerous area in the Bay. (N.I.D. NOTE: It is probable that 18⁰W. is regarded as the Western boundary of the area in which particular care is to be taken against air attack, but diving routines are frequently changed.)

	(ix) Torpedo-Carrying Supply U-boats.

	This type of U-boat was said to be built at Bremen. (N.I.D. Note: No known type of Supply U-boat is being built at Bremen. There is no confirmation that U-boats there are specially designed or modified as torpedo carrying Supply boats.)

	(x) U-boat with Underwater Camera.

	A prisoner said that U.404, commanded by Korvettenkapitän von Bülow, had had a camera for taking underwater moving pictures built into the side of the conning tower in a pressure tight compartment. The camera had pressure-proof lenses. Successful pictures had been taken.

VI.	SURFACE SHIPS.

	(1) "Narvik" and "Seetier" Class Destroyers.

	(N.I.D.: NOTE: These destroyers were previously referred to by prisoners of war in C.B. 4051 (51) pages 22 and 23. Prisoners then stated that the destroyers numbered Z23 and Z32 were "Narvik" class and that Z33 was the first of the new "Seetier" class.

	The latest type with twin mounting forward will now be known as "Seetier class in C.B. 1815.)

	(a) General.

	A prisoner who had served in the destroyer Z.23 was of the opinion that at least ten destroyers of the Narvik class, Nos. Z.23 to Z.32, have been built by Deschimag, Bremen. Z.37 and Z.38 of the same class were built by Germania in Kiel. The intervening numbers may also have been built in Kiel, but Z.38 was the first one to have been put into service at this time.

	On 17 December, 1941, Z.23 took part in an engagement with Russian destroyers off the North of Norway. It was claimed that one Russian was sunk by gunfire after firing only 55 rounds, and one by torpedo. The Germans were undamaged.

	Z.23, Z.24. Z.25, Z.28 and Z.29 were in the Arctic Ocean in May, 1942.



	- 15 -

	In June, 1942, Z.23 lay in Wesermünde undergoing overhaul, the rest of the flotilla moving between different Scandinavian harbours. Z.26 has been sunk.

	From June to August, 1942, Z.23 was doing machinery trials in the Baltic. She was then in Narvik and Trondheim and in early 1943 was at Kiel for a fortnight.

	Z.23, Z.24, Z.32 and Z.37 are now based at Bordeaux. The four destroyers sailed from Kiel in March, 1943, and proceeded through the English Channel to Bordeaux. Z.23 met the other three ships in the North Sea. They had left Kiel two days previously. They proceeded through the Channel at an average speed of 23 knots, and although attacked by M.G.B's and aircraft, suffered no damage.

	(b) Details of Z.23. (See Plate I)

	(N.I.D. NOTE: The following details refer to Z.23 only, but the prisoner stated that the other destroyers are identical.)

	(i) Dimensions: The prisoner had no exact knowledge of Z.23's dimensions, but estimated extreme length at about 125 meters (410 ft), extreme breadth at about 12 meters (39.4 ft), and draft at about 3-1/2 metres (11.5 ft). (N.I.D. NOTE: A report graded B.2. gave (at full load?) the standard displacement as 2,400 tons).

	(ii) Complement: About 300 officers and men.

	(iii) Speeds: Cruising speed 27 knots; maximum speed 36/37 knots. Economical speed stated to be 23 knots. Endurance at 27 knots stated to be 7 days (4536 miles). (N.I.D. NOTE: A report graded B.2, gives the maximum speed as 39.2 knots and the endurance at 25 knots as 2640 miles. The endurance at 27 knots, given above, is considered excessive; 2500 miles is more likely).

	(iv) Armament - Guns: Five 150 mm. (5.9") guns;
	Two twin 37 mm. (1.46") guns;
	Three 20 mm. (.79") guns;
	One 20 mm. quadruple gun;
	Twelve or fifteen Mark C.34 machine gun positions.

	Two of the 150 mm. guns are mounted in an enclosed turret on the forecastle. The turret guns have an elevation limit of 90⁰. The other three are in single mountings with open shields; two mounted on the raised after superstructure forming the officer's living quarters and one on the quarterdeck. Those guns have protective armour in front, on top, and at the sides, but are unprotected in the rear. Their elevation limit is about 65. All 150 mm. guns are fitted with R.P.C., which gear was installed in 1942. (N.I.D. NOTE: It is thought that the latest German destroyers are armed with 130 mm. (5.1") guns and not 150 mm. (5.9")).

	The single 150 mm. gun has a nominal crew of eight, and the twin turret a crew of fifteen. (N.I.D. NOTE: The size of these crews supports the view that these guns are only 130 mm).

	The 20 mm. quadruple gun is mounted between the two 150 mm. guns on the after superstructure.

	The two twin 37 mm. guns are mounted, one each side, on the fore end of the midship superstructure, abreast the after funnel.

	One 20 mm. gun is mounted each side on the after end of the superstructure. Another 20 mm. gun is mounted on a platform about 6 ft. above the deck and projecting from the fore side of the bridge. This gun was due to be replaced by a 20 mm. quadruple gun.

	There are four machine gun mountings on the bridge and "several" others on different parts of the upper deck. The Mark C.34 machine guns were to be replaced by Mark M.G.81's.



	- 16 -

	(v) Armament - Torpedoes: One set of quadruple torpedo tubes is mounted between the two funnels and another set of four between the midship and after superstructures.

	Eight torpedoes are carried. They are all 21" air torpedoes. No spare torpedoes are carried.

	(vi) Minesweeping Gear: Z.23 carried two paravanes forward with bows operation. Paravanes were about 6 ft. in length. There was also a large winch for minesweeping gear right aft and the prisoner described the gear as an "Otter-gerät".

	(vii) Depth-Charge Throwers: The prisoner stated that Narvik class destroyers carried six depth-charge throwers. Two were mounted abaft the forward torpedo tubes one each side and four abaft the after 150 mm. gun, two each side. As far as he knew depth-charges were always fired and none were carried in slips aft.

	(viii) Mines: There were two mine rails on the upper deck extending from right aft to just forward of the after torpedo tubes, one each side. About 15-20 mines could be stowed each side. Prisoner had never seen them used during the period he served in Z.23.

	In November, 1941, Z.23 transported fifty mines from Kiel to Kirkones in Norway. These were stacked along the upper deck and unloaded immediately upon arrival.

	(ix) Smoke Floats: Z.23 carried smoke-making gear aft. There were two large vents in the stern, but prisoner was not certain whether these were enclosed slips for smoke canisters, or whether they were merely vents for a fixed smoke-making apparatus.

	(x) Engines: Prisoner did not know who had made Z.23's engines, but said that he had no reason to suppose that they were not made by Deschimag, the builders. He thought that the boilers operated at 70 atmospheres (about 1000 lbs/sq. in) and might have been supplied by another firm, but was not at all clear on the latter point. He had heard that the engines were rated at 70,000 H.P. (N.I.D. NOTE: A report graded B.2, confirms both boiler pressure and horsepower).

	Z.23 was regarded as the most efficient vessel in the flotilla. She had never had any engine trouble, and had never been in dock for engine repairs, apart from the usual recurrent boiler cleaning. Prisoner had not heard that Narvik-Class destroyers were noted for frequent engine breakdowns, and said that this was certainly not the case with the four boats based at Bordeaux.

	(xi) General Arrangement: (See Plate 1). Narvik Class Destroyers have the flared bow characteristic of German warships and a stern construction which is referred to as a "spieglheck" and which overhangs slightly aft and is somewhat tapered. There is a breakwater about 2 feet high on the forecastle fitted before the twin gun turret. The bridge is of fairly massive design. The enclosed navigating bridge, chart house and captain's sea cabin form a square structure with an open gangway about six foot wide on each side and aft.

	The main fire control position with a rangefinder (base about 12 feet) is above the chart house. A small Radar cabin, mounting a mattress type aerial, is fitted on the after side of the control position. Prisoners thought that the Radar was only used for ranging.

	The foremast is stepped immediately abaft the chart house structure and the forward funnel in just abaft the foremast.

	The headroom, between forecastle and main deck, is about 6'9".

	The height of the superstructure above the upper deck is about 7'6" and only 3 feet where the torpedo tubes are mounted.



	- 17 -

	(xii) Accommodation: Officers are accommodated in the superstructure aft which mounts two 150 mm. guns above. There are also officers' cabins on the deck below. C.P.O.'s are accommodated immediately abaft these lower officers' cabins, and there is a large seaman's mess deck right aft.

	The forecastle deck accommodates torpedo-men, seamen, stokers, W/T operators, seaman P.O.'s and signal ratings. It also contains washrooms, heads, the galley, canteen and sick bay.

	The main deck compartments, reading from the bow are: Store Rooms, W/T operators' mess, E.R.A's and torpedo-men's messes, boiler room No. 3, boiler room No. 2, boiler room No. 1, turbine room No. 2, turbine room No. 1, officers' cabins, C.P.O.'s mess deck and after seaman's mess. The W/T room is on the bridge structure.

	(c) Z.23's Commanding Officers.

	Z.23 was commanded by Fregattenkapitän Böhme until about June, 1942, when he relinquished command owing to heart trouble. At the time of the Narvik battle he was Town Major of Narvik.

	He was succeeded in Command of Z.23, who was Flotilla leader, by Korvettenkapitän Wittich.

	Since August, 1942, Kapitän zur See Hans Erdmonger, (Captain (D)) had flown his pennant in Z.23 and his staff had been accommodated on board. When the prisoner left the ship in April, 1943, Kapitän zur See Erdmenger was due to leave Z.23. She was then to carry twenty-three midshipmen for training.

	(2) "ALSTERUFER". (2,700 tons).

	The following information was given by a prisoner, still under interrogation, who was captured from the blockade runner "PORTLAND". (N.I.D. NOTE: See C.B. 04051 (73).)

	"ALSTERUFER" sailed from Bordeaux in late March, 1943. She left on a secret mission and it was not known whether she was to act as raider, supply ship or blockade runner. Her armament was unorthodox for all of those categories. She was said to be fitted with torpedo tubes; two 150 mm. (5.9") guns, one forward and one aft; four 37 mm. (1.46") guns, two on the bridge and two amidships; six twin 20 mm. (.79") guns, two forward, two on the bridge and two aft. She was believed to be fitted with Radar. She was known to be carrying torpedoes. Her complement was sixty naval personnel and seventy merchant seamen.

	(3) "BATAVIA III". (2,637 tons).

	The prisoner from "PORTLAND" also gave the following information. "BATAVIA III" had been used by the Germans as a rescue ship off the Norwegian coast. Her duty was to pick up survivors from sunken ships or shot down aircraft. In August, 1942, "BATAVIA III" was herself sunk, by acoustic mine, off Anlborg. The wrecks of three transports, all sunk by the same type of mine, were now lying near her. The ship's company of "BATAVIA III", were picked up by a patrol ship.

	(4) 600-ton Torpedo Boats.

	It was stated that the new 600-ton torpedo boats now being built in Germany are exceptionally fast, and that one of them recently made the passage from Bergen to Wilhelmshaven at a sustained speed of 33 knots. (N.I.D. NOTE: Prisoner may have been referring to the T.1-T.20 class completed 1938/40 with a designed speed of 36 knots).

VI.	BASES.

	Bordeaux.

	The headquarters and administrative offices of the 12th U-boat Flotilla are at Bacalan, a few miles north of Bordeaux. They are about half an hour's walk from the shelters. In January, 1943, only a skeleton staff of the Flotilla had joined as there were then no U-boats or personnel there.



	- 18 -

	At present there were two guard platoons at the base, each of about forty men. These supplied guards for the base and fatigue parties for the base and shelters. Each was commanded by a Petty Officer.

	The Personnel Reserve was about thirty strong in July, 1943.

APPENDIX "A"

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BUILDING AND WORKING UP OF U. 461.

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(i) Building.

U.461 was built by Deutsche Werke, Kiel, one of the series U.459 to U.464. It is not known when she was laid down or launched but prisoners were drafted to her, to stand by the final stages of building in November and December, 1941.

The first Commanding Officer, prior to commissioning, was Oberleutnant zur See BERNBECK. He was succeeded upon commissioning by Korvettenkapitän STIEBLER.

(ii) Commissioning: U.461 is frozen in.

U.461 was commissioned on 30th January, 1942. She was immediately frozen in at her berth for five to six weeks.

(iii) Working Up.

U.461 began working up in March, 1942. In turn she visited Kiel (U-boat Acceptance Command), Danzig (tactical exercises) and Hela Peninsula (Agru front). She returned to Kiel for final adjustments in mid-April. Adjustments took about six weeks.

APPENDIX "B"

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PREVIOUS PATROLS OF U.461.

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(i) First Patrol.

Officers:	Captain:	Korvettenkapitän STIEBLER
	First Lieutenant:	Oberleutnant zur See HYRONIMUS
	Second Lieutenant:	Leutnant zur See MÖHRSTEDT
	Engineer Officer:	Oberleutnant (Ing) MANKOPF
	Junior Engineer Officer:	Leutnant (Ing) BURCHERT

U.461 sails.

U.461 left Kiel for her first patrol early in June 1942, accompanied by U.458. The two U-boats put into Kristiansand S. for a few hours. U.461 did not top up with fuel.

U.461 carries out a special mission.

U.461 continued to the North Atlantic. According to a prisoner she patrolled between the Iceland area and the Azores and on one occasion was possibly as far south as 20⁰N. On board as supernumeraries were a Sub-Lieutenant, specialized in Telegraphy, and two Chief Petty Officer Telegraphists. None of them were U-boat men. The prisoner said that although not authorized to enter the W/T cabin, he used to watch the three men marking a small map of the U.S.A. on which the main features were certain American radio stations with which they were presumably in touch. He also believed that the men were tapping British aircraft R/T, as they used to report messages from them.

U-boats supplied.

Among about sixteen U-boats supplied on this patrol was U.552 (Korvettenkapitän Erich TOPP), and U.202 (Kapitänleutnant LINDER). (N.I.D. NOTE: See C.B. 04051 (72), Appendix B). U.461 put back to St. Nazaire where she arrived in August, 1942. The radio specialists left the U-boat and returned to a radio station at Neumünster.

(ii) Second Patrol.

Officers:	Captain:	Korvettenkapitän STIEBLER
	First Lieutenant:	Oberleutnant zur See HYRONIMUS
	Second Lieutenant:	Leutnant zur See MÖHRSTEDT
	Engineer Officer:	Oberleutnant (Ing) MANKOPF
	Junior Engineer Officer:	Leutnant (Ing) BURCHERT

U.461 sails: 10 U-boats refueled.

U.461 left St. Nazaire in August, 1942, and proceeded to the South Atlantic. About 10 refuelings were carried out. These included U-boats commanded by Oberleutnant zur See WALKERLING, Kapitänleutnant WITTE, Oberleutnant zur See LASSEN (LASSAN and WITTE both boarded U.461), Kapitänleutnant Ernst MENGERSEN, (N.I.D. NOTE: See C.B. 04051 (74), Appendix B), Korvettenkapitän ACHILLES, Korvettenkapitän Erich TOPP, Korvettenkapitän von BUELOW, Kapitänleutnant PFEFFER and Korvettenkapitän Otto FECHNER. (N.I.D. NOTE: U.164, commanded by a Fregattenkapitän was also supplied, off the South American coast. This U-boat had been damaged by bombs in the South Atlantic.

On this patrol U.461 suffered a heavy depth charge attack by a Sunderland. Deckboards were torn to shreds, instrument glasses broken, lights extinguished and depth gauges smashed. U.461 dived to nearly 600 feet. One of the bilge pumps was out of commission and considerable confusion reigned in the ship. U.461 returned to St. Nazaire on 18th October, 1942.

(iii) Third Patrol.

Officers:	Captain:	Korvettenkapitän STIEBLER
	First Lieutenant:	Oberleutnant zur See ASENDORF
	Second Lieutenant:	Leutnant zur See MÖHRSTEDT
	Third Lieutenant:	Leutnant zur See FALK
	Engineer Officer:	Oberleutnant (Ing) MANKOPF

Oberleutnant zur See HYRONIMUS had left U.461 to attend a Commanding Officers' course and later to take over a Hamburg-built U-boat, and Leutnant (Ing) BURCHERT had entered hospital to undergo an operation.

U.461 takes over a British Master.

U.461 left St. Nazaire in November, 1942, and proceeded to the south Atlantic. On passage she supplied U.505, commanded by Kapitänleutnant LOEWE. She later rendezvoused with a 740 ton U-boat from Lorient commanded by a Korvettenkapitän, and received from her a British Master named Captain Lorains, whose ship had been sunk not far off the African coast. This rendezvous occurred in latitude about 10⁰N. (N.I.D. NOTE: "THESBANK", 5,136 tons, was torpedoed on 5th December, 1942, in position 3⁰33'N. 29⁰35'W. The Master, Captain Lorains, is known to have been taken prisoner).

At the same time a sick Stoker was transferred to U.461 by the 740-tonner and one of U.461's Stokers named Zander took his place. Zander later rejoined U.461.

A convoy encountered.

On Christmas Eve, when between Gibraltar and the Azores, U.461 by error found herself in the midst of a huge convoy. She dived

immediately and cleared S.B.T. for action, but did not use it, as no attack developed.

U.461 returned to St. Nazaire on 5th January, 1943.

(iv) Fourth Patrol.

Officers:	Captain:	Korvettenkapitän STIEBLER
	First Lieutenant:	Oberleutnant zur See ASENDORF
	Second Lieutenant:	Oberleutnant zur See LUDEWIG
	Third Lieutenant:	Leutnant zur See FALK
	Engineer Officer:	Oberleutnant (Ing) MANKOPF

Leutnant zur See MÖRSTEDT had left U.461 after the third patrol, having been pronounced unfit for further service in U-boats.

A second British Master taken on board.

U.461 left St. Nazaire in February, 1943, and proceeded to the South Atlantic. On this patrol she met a 740-ton U-boat and took off a Captain Davis, who they were told was a Master of a 6,000-ton ship sunk between Trinidad and the Azores. (N.I.D. NOTE: "SAINT MARGARET" 4,312 tons, routed independently, was torpedoed and sunk at 1256 on 27th February, 1943, in position 27⁰38'N., 43⁰23'W. Captain D.M.S. Davis was taken prisoner). Prisoners said that the 740-ton U-boat came from Lorient and had as conning tower badge the hand of a man in profile with a finger laid alongside the nose. (N.I.D. NOTE: See C.B. 04051 (78), Section II. This conning-tower badge was that of U.558 (Kapitänleutnant Günther KRECH), sunk on 20th July, 1943. U.558 was, however, a 500-ton U-boat and was based at Brest).

Captain Davis was popular whilst aboard U.461. He related that following the torpedoing of his ship the survivors in the life-boats had been provisioned by the U-boat. He calculated that it would take them about 18 days to make the South America coast. One life-boat had an engine with fuel for eight days, and all boats were well provisioned. Among the survivors were a Polish woman and her daughter, and an Englishwoman. Captain Davis asked all members of the ship's company to try to communicate with his wife, who lived at Liverpool, should they ever reach land.

U-boats supplied.

During this patrol U.461 supplied about 14 U-boats. One of these was the U-boat commanded by Kapitänleutnant Klaus POPP, who took about 10 tons of fuel. Returning to her base U.461 was attacked at about 0300 during a night at the beginning of April, by a searchlight aircraft. This attack took place at about 18⁰W. No serious damage was sustained.

U.461 reached St. Nazaire early in April.

(v) Fifth Patrol.

Officers:	Captain:	Korvettenkapitän STIEBLER
	First Lieutenant:	Oberleutnant zur See ASENDORF
	Second Lieutenant:	Oberleutnant zur See LUDEWIG
	Third Lieutenant:	Leutnant zur See FALK
	Engineer Officer:	Oberleutnant (Ing) MAHNKOPF
	Junior Engineer Officer	Leutnant (Ing) STEINERT

U-boats supplied.

U.461 left St. Nazaire at the end of April and operated just south of the Azores, refueling about 22 U-boats in all. One of these was a 500-ton minelayer carrying a Swordfish flotilla sign as badge. (N.I.D. NOTE: Device of the 9th flotilla based on Brest). It was said that this U-boat had previously laid mines in the St. George's Channel. This U-boat's First Lieutenant was sick or injured and Oberleutnant zur see ASENDORF was transferred to take his place.



	U.461 attacked by a Sunderland.

	About four weeks out U.461 was attacked ineffectively by a Sunderland aircraft.

	A rendezvous with U.463 fails to take place.

	On returning to the Bay of Biscay U.461 should have rendezvoused with U.463, commanded by Korvettenkapitän der Reserve WOLFBAUER, whose mission was to supply spare Southern Cross G.S.R. aerials to other U-boats. The rendezvous was not kept and U.461 finally received orders from Control to proceed to Bordeaux.

	She arrived on, or about, 31st May.

	After this patrol Leutnant (Ing) STEINERT left U.461 to join another supply U-boat. Oberleutnant zur See ASENDORF did not return and Oberleutnant zur See LUDEWIG took his place as First Lieutenant.

	U.461 received additional A.A. armament.

	U.461 was docked and considerable modifications were then made to her bridge structure and her new A.A. armament was mounted.

APPENDIX "C"

xxxxxxxxxxxxxx

Nominal Roll of U.461.

(i) Survivors:

Name.	Rank.	English Equivalent.	Born.

STIEBLER, Wolf	Korvettenkapitän	Lieutenant-Commander	4. 8.07.
LUDEWIG, Herbert	Oberleutnant zur See	Sub-Lieutennant	9.11.04.
SCHRÖCK, Carston	Oberfähnrich zur See	Midshipman	24. 4.23.
LENZ, Joseph	Obermaschinist	Chief Stoker & E.R.A. 1st Class	14. 1.14.
WEIDEMANN, Alfred	Verwaltungsobermaat	Acting (Supply) P.O.	12. 6.18.
MAASS, Hubert	Bootsmannsmaat	Leading Seaman	1. 1.21.
MOMPER, Alois	do.	do.	13. 5.20.
ROCHINSKI, Helmut	Matrosenobergefreiter	Able Seaman	1. 1.21.
ANGER, Erich	do.	do.	23. 3.24.
MÖESENEDER, Hermann	do.	do.	11. 3.24.
MEIER, Wilhelm	do.	do.	19.12.21
ALEX, Franz	do.	do.	6. 9.23.
HÖFFKEN, Wilhelm	Sanitat obergefreiter	S.B.A.	25.11.19.
SCHMERSE, Hans	Matrosengefreiter	Able Seaman	2. 7.22.
KORBJUHN, Gerhardt	do.	do.	28. 6.24.

Officers:	3
Chief & Petty Officers:	2
Men:	10
	15

(ii) Casualties:

Name.	Rank.	English Equivalent.

GERD,	Stabsaust Dr.	Surgeon Lieutenant
MANKOPF,	Oberleutnant (Ing.)	Sub-Lieutenant (E)
FALK,	Leutnant zur See	Junior Sub-Lieutenant
?	Leutnant (Ing.)	Junior Sub-Lieutenant (E)
KLIMASZEWSKI,	Obersteuermann	C.P.O. (Navigation)
WEBER,	Obermaschinist	Chief Stoker & E.R.A. 1st Class
HAMDORF,	do.	do.
GRYGIER	Bootsmann	Petty Officer
REH,	Maschinist	Stoker P.O. & E.R.A. 3rd Class
FLEMMING,	do.	do.
JAHN,	Oberfunkmaat	Acting P.O. Telegraphist
LÖSECKE,	do.	do.
SCHLEMMER,	P.K. Maat (M.A.)	Propaganda Company P.O. (Marine Artillery)
WIESSNER,	Bootsmannsmaat	Leading Seaman (Seaman's Branch)
LACHZINSKI,	do.	do.
ASSMANN,	Maschinenmaat	Leading Stoker & E.R.A. 5th Class
ZIEGENHORN,	do.	do.
FORSTER,	do.	do.
HERNDORF,	do.	do.
BORDES,	do.	do.
KOCH,	do.	do.
DAHMS,	do.	do.
RAUH,	Matrosenobergefreiter	Able Seaman
MEYER,	Maschinenobergefreiter	Stoker, 1st Class
HUNGER,	do.	do.
MANZ,	do.	do.
FREYER,	do.	do.
HANSEN,	do.	do.
RÖMER	Funkobergefreiter	Telegraphist
SCHAAF,	do.	do.
BRÜGER,	Mechanikerobergefreiter	Able Seaman (S.T.)

(ii) Casualties (continued)

Name.	Rank.	English Equivalent.

BÖLLING,	Matrosengefreiter	Able Seaman
HÄNSCH,	do.	do.
AUFSCHLÄGER,	do.	do.
THÖNNISSEN,	Maschinengefreiter	Stoker, 1st Class
MUSCHNICK,	do.	do.
HEINRICHS,	do.	do.
WILHELM	do.	do.
BUHMANN	do.	do.
BÄNDER,	Matrose I	Ordinary Seaman
SANDER,	do.	do.
TOMMILIN,	do.	do.
NEUMANN,	Matrose II	Stoker, 2nd Class
STOCK	do.	do.
LEHNEN,	do.	do.

Officers:	4
Chief & Petty Officers:	9
Men:	32
	45

(iii) Total Crew:

Officers:	7
Chief & Petty Officers:	11
Men:	42
	60

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