" 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).
	(c)  Details of "Narvik" and "Seetier" Class destroyers.  (Section VI).
	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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	(c)  Tank Arrangement (See Plate II)  Tanks from stern to stem, both port and starboard were:
	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