S E C R E T

NAVY DEPARTMENT

OFFICE OF THE CHIEF OF NAVAL OPERATIONS

WASHINGTON

Final Report - G/Serial 28

REPORT ON THE

INTERROGATION OF SURVIVORS FROM U-841

SUNK 17 OCTOBER 1943

AND

U-848 SUNK 5 NOVEMBER 1943

S E C R E T

TABLE OF CONTENTS

				Page
CHAPTER	I.		INTRODUCTION	1
	II.		DETAILS OF U-841	3
	III.		TORPEDOES	17
	IV.		ELECTRONIC GEAR AND PRODCEURE	26
	V.		GUNS AND GUNNERY	34
	VI.		CREW OF U-841	44
	VII.		EARLY HISTORY OF U-841	48
	VIII.		FIRST AND FINAL PATROL OF U-841	56
	IX.		SINKING OF OF U-841	61
	X.		FINAL REPORT ON U-848	66
	XI.		MISCELLANEOUS REMARKS ABOUT U-BOATS	69
	XII.		BASES	77
	XIII.		OTHER U-BOATS	85
ANNEX			CREW LIST OF U-841 AND U.S. EQUIVALENTS OF GERMAN NAVAL RANKS

LIST OF ILLUSTRATIONS

	Facing Page
Plate A	Bridge and Platforms U-841	5
Plate B	R.D.B.	13
Plate C	Wanz G.1, G.S.R.	26
Plate D	Combination Radar and G.S.R. Aerial	27
Plate E	D.F. Gear	28
Plate F	New type G.S.R.	29
Plate G	Radar	30
Plate H	Track Chart U-841	59
Plate I	Bridge and Platforms U-848	67
Plate J	Map of Bergen	77
Plate K	Map of Trondheim	83

CHAPTER I.  INTRODUCTION

        This is a joint report on U-841 and U-848.

        U-841, commanded by Kapitänleutnant Werner Bender, was sunk by H.M.S. BYARD escorting convoy ONS 20 on the afternoon of 17 October, 1943, in position 59 N - 31 W, some 750 miles East of Cape Farewell.

        U-841 was a 750 ton U-boat built at the Deschimag Yards in Bremen.  She had completed her trials at the end of June and was ready to sail on patrol at the time when the U-boat arm was in transition.  Her departure was twice delayed, the first time for a six weeks' return to Bremen, where her second platform was rebuilt and a quadruple mounting 20 mm. added to bring her anti-aircraft armament up to the new standard.  Again in Norway she spent a month awaiting the arrival of the latest search receiver.

        The new equipment could not offset the inexperience of her captain to which the older crew members attributed the sinking of U-841 just 13 days after leaving Trondheim on her first and final patrol.

        One officer, five P.O.'s and 21 ratings were rescued out of a crew of 54.  Preliminary interrogation of all survivors was conducted at the port of arrival.  Seventeen ratings were brought to an interrogation center in the United States for final questioning.

        The crew for the most part had good military bearing and showed evidence of considerable training in security.  The final communicativeness of a number of the men was due to their realization of the hopelessness of the military situation and a growing resentment

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against the Nazi regime for the deception it has practiced on its own supporters.  Some of the more intelligent crew members were willing to go to the limit to help speed the end of the war.

        In Chapter X will be found the report on U-848, commanded by Korvettenkapitän Wilhelm Rollmann, sunk 5 November, 1943, in position 10.09 S. - 18.00 W. by 6 U.S. Army and Navy planes based in Ascension Island.  A sole survivor rescued nearly a month later was interrogated in Recife.  In almost uninterrupted delirium he was not able to cast much light on the history of the boat.   Some details were furnished by the crew of U-841 which was built at Deschimag and worked up at Kiel and in the Baltic at approximately the same time as U-848.

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CHAPTER II.  DETAILS OF U-841

        U-841 was, in general, a standard IX C, 750-ton U-boat.  When no mention is made of any detail of equipment on board it may be assumed to be standard.  The observations below cover a number of points of new or salient interest.  Attention is directed also to Chapter III on Torpedoes, Chapter IV on Electronic Gear and Procedure and Chapter V on Guns and Gunnery.

TONNAGE.

        750 tons.

TYPE.

        IX C, Standard

BUILDING YARD.

        DESCHIMAG, Bremen.

FLOTILLA.

        2nd Flotilla, Lorient.  Temporarily attached to 13th Flotilla in Trondheim.

F.P.N.

        M-49972.

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PATRON.

        None.

INSIGNIA.

        None.

CAMOUFLAGE.

        None.

     

        Welded.

THICKNESS OF PRESSURE HULL PLATING.

        About 25 mm.  amidships, tapering to about 20 mm. at bow and stern.

SPACING OF FRAMES.

        About 75 cm. average.

SPACING BETWEEN PRESSURE HULL AND UPPER DECK.

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on last and only patrol and once previously.  At the time of the attack she dived to 120 meters.

GUN PLATFORMS

        As originally built U-841 had the usual Platform 1 and a small Platform 2.  In Bremen before her first patrol an enlarged Platform 2 was substituted for the original smaller one.  Armored doors between the bridge and Platform 1 were fitted with spring hinges which closed them when a knob on the top of the fairing was struck.

        Plate A. shows the final arrangement of the bridge and platforms on U-841.

GUNS.

        After numerous changes in her armament U-841 finally sailed on her first and final patrol with a 105 mm. on the deck forward, 4 machine guns (MG 15's) on the bridge, two single 20 mm. guns on Platform 1, a shielded quadruple 20 mm. on Platform 2.

        A detailed description of the guns' ammunition and gun platforms will be found in Chapter V, Guns and Gunnery.

TORPEDOES.

        See Chapter III.

SCUTTLING CHARGES.

        Two types of scuttling charges were carried by U-841.

        The larger ones, known as Sprengtopf A, were pot-shaped, about 6 to 8 inches in diameter and 10 to 12 inches in height.  Only

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two of the larger charges were reported, one being placed in the Control Room on the portside, next to the chart table, one by the D.F. Gear, one over Magazine No. 1.

        All charges were reported to be fused with ordinary string type fuses, with 9 minutes burning time.

        No charges had apparently been placed in the usual locations next to the torpedoes under the floor plates in the forward and aft torpedo rooms, in the radio room, or in the conning tower.  The reason given was that at the start of a patrol the boat is too crowded with stores to permit the placing of scuttling charges.

        Only one fuse was actually lit at the time of the sinking and that was extinguished by the Engineer Officer on orders of the Captain, when it was evident that the boat was sinking rapidly.

S.B.T.

      Fitted in after head.  Apparently only chemical projectiles were carried.  A number of projectiles were reported fired at the time of the sinking.

D.C.P.

        Not Fitted.

RUBBER COVERING.

        Never used on U-841.

ENGINES.

        Two M.A.N., 9 cylinder Diesels of 2050 H.P. each, 4 cycle, single acting.

        Bore:  400 mm.

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        Diameter of pistons:  399.70 mm.

        Stroke:  460 mm.

        Rotation:  Starboard, clockwise, forward.

                       Port, counterclockwise, forward.

        Engine Numbers:  Starboard 730 - 740

                                    Port         730 - 750.

        Nicknames of engines were "Hein" and "Fitsche" - Hamburg comedians.

        The pistons in the M.A.N. engines were made of light alloys, two-thirds lighter than gray iron.  Piston heads were oil cooled.  Wrist pins were rigidly mounted in steel bushings hot pressed into pistons.  Connecting rods and crankshafts were forged.  Bearings were babbit.  Cylinder heads were gray iron.  The upper half of the connecting rod bearings were bronze; the lower half was babbit.

        The capacity of the reciprocating cooling water pumps was 92 cubic meters per hour for each pump.

        The M.A.N. vibration dampers on forward end of crankshafts each contained 14 springs.

        The reversing gear longitudinally displaced the camshaft 38 mm and required 70 atmospheres of pressure and 4 to 5 seconds for operation.  Each flask in the reversing gear contained 4 liters of oil.

SUPERCHARGERS.

        A supercharger drive of a new type was fitted.  In place of the conventional large ring gear on the camshaft directly driving a

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small pinion on the impeller shaft, a pinion on the crankshaft drove a ring gear on a countershaft, on which was mounted a hydraulically controlled conical friction clutch and vibration damper unit similar to that on the crankshaft.  It consisted of two main parts, essentially discs, one of which was keyed or otherwise fastened to the countershaft and which could be considered as the hub of the unit.  Four radial members extended outward.  The other part was free to revolve upon the shaft; it could be considered as the felloe of the unit.  Four radial members projected inward between the members of the hub part.  Eight compression springs were placed between the members, held in place by cups and bolts.  Guides and retainers made up the remainder of the unit.  The remainder of the drive consisted of other gearing of conventional design.  Gears were cut from Krupp V2a steel, stated to be hard and non-corrosive by sea water.

        The blower itself was of the simple centrifugal type, with vanes about 2.0 to 2.5 cm. wide and an impeller diameter of 1.30 meters, turning at 1500 R.P.M., with a crankshaft speed of 480 to 500 R.P.M., at which speed the pressure was stated to be 0.2 atmosphere (2.94 P.S.I.).

        The drive and blower were said to be noiseless in operation and that the 11-1/4 degree play between the parts of the damper prevented the stripping of gears.  A further preventive was the calculated slipping of the clutch when first engaged.  The drive was also said to be similar to that of the Kaspelgebläse (Root's type).  The entire unit was of M.A.N. manufacture.

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MAIN CLUTCHES.

        The main clutches were of the conical friction type, made by BAMAG.  They were lined.  They were designed to slip until the last moment when a spring actuated stud made positive contact.

ENGINE SPEED TABLE.

Telegraph Speeds	Surface Speed
K.F. (Dead Slow)	10 knots
L.F. (Slow)	12 knots - without supercharging
H.F. (Half Speed)	14 knots
2x H.F. (3/5 Speed)	(seldom used)
G.F. (3/4 Speed)	16  knots
2x G.F. (Full Speed)	(Seldom used) - with supercharging
A.K. (Flank Speed)	18 knots, possible 20

        Critical speed of engines:  190 R.P.M.

        If motors/generators were operated in tandem with Diesels at A.K. speed would be 22 knots, but this procedure was never used on U-841.

NOTES ON FUEL CONSUMPTION.  (Taken verbatim from notebook of Chief Warrant Machinist)

        (O.N.I. Note:  No attempt has been made to reconcile the discrepancies.)

                Consumption at 460 R.P.M.  A.K.

                        100 liters in 4 minutes

                        300 liters in 19 minutes

                        500 liters in 35.5 minutes

                        656 liters in 8 hours

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                Hourly consumption at A.K. - 410 liters.

                        Port                - 392 liters per hour

                        Starboard       - 424    "     "      "

	Port	462.1 R.P.M.	392 liters per hour
			329 kg.     "      "
	Starboard	463.7 R.P.M.	424 liters   "      "
			356 kg.     "      "
	Port	406 R.P.M.	262 liters per hour
			220 kg.     "      "
	Starboard	409 R.P.M.	280 liters   "      "
			235 kg.     "      "
	Both engines	320 R.P.M.	252 liters   "      "
	Both engines	240 R.P.M.	149 liters   "      "

NOTES ON TANK CAPACITIES OR CONTENT.  (Taken verbatim from notebook of Chief Warrant Machinist.)

Tank	Contents or Capacity
	cubic meters (?)
Diving Tank 2	17.80 Port
	17.80 Starboard
Diving Tank 3	25.80 Port
	25.80 Starboard
Diving Tank 4	32.66 Port
	32.66 Starboard
Diving Tank 6	34.26 Port
	34.26 Starboard
Diving Tank 7	32.60 Port
	32.60 Starboard
	_____
	286.24 (243.30 T.)

        (O.N.I. Note:  Apparently these figures are contents of, or capacity of, tanks used for fuel oil, as they are immediately followed by

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meter readings on tanker barge and aboard.)

Sump Port	400 liters
Sump Starboard	400 liters
Port-aft		9.7 cubic meters
Port-forward		8.7    "        "
Starboard-aft		8.4    "        "
Starboard-forward		7.3    "        "

LUBRICATING OIL SUPPLY.

        1 April, 1943 - 6849 liters.

        Additional contents or capacities:

		O.N.I. Comments
	46.74	Quick diving tank (?)
	5.36	(?)
	20.00	Diving tank 2 (?)
	25.80	Diving tank 3 port or starboard
	32.66	"         "     4   "    "        "
	34.26	"         "     6   "    "        "
	32.60	"         "     7    "    "        "
	____
	197.42	Apparently total capacity, in cubic meters, tanks on one side

BATTERIES.

        Usual lead-acid type, hard rubber cases, no inner flexible lining.

        Eleven of 20 cells checked after depth charging were ruptured.

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MOTORS/GENERATORS.

        2 units of 500 H.P. each.

PUMPS.

        1 main ballast, double impeller, could be used at single stage or in series.

        1 auxiliary ballast, reciprocating.

PERISCOPES.

        1 observation.

        1 attack.

COMPRESSORS.

        1 electric.

        1 junkers crankless Diesel.

        The junkers crankless Diesel compressor operated at a constant speed of 180 to 200 strokes per minute.  The pressure of the stages  was as follows:

1st stage	4.5 Kg. per Sq. Cm.
2nd stage	25.0   "      "     "      "
3rd stage	45.0   "      "     "      "
4th stage	205.0   "      "     "      "

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was also installed, and operated when pressure exceeded the setting.

        In starting the compressor, starting air was admitted into several stages, particularly the second, to equalize pressures and thus prevent a piston from going through a head.  A soft copper stud on the inner surface of a head was an added protection for several unequalized starts, until it had been flattened against the head.

COMPRESSED AIR SUPPLY.

        8 groups of 8 flasks each.

OXYGEN SUPPLY.

        Oxygen was carried in liquid state and fed into circulating blower system through a simple pressure reduction valve.

RUDDER CONTROLS.

        Electric remote and emergency hand controls.  Remote control station on bridge was in pressure proof container.

GERMAN ASDIC.

        Not fitted.

RADAR.

        Fitted.  (See Chapter IV)

R.D.B.

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        It was stated that the box in which balloon was kept acted as the anchor.

        The types shown in figures 2 and 3 were not carried by U-841 but were observed by a member of the crew during trials in Kiel.

G.S.R.

        Fitted.  Wanz G.1 installed just before U-841 left on patrol.  Both Runddipol and radar aerial used.  (See Chapter IV.)

D.F. GEAR.

        Fitted.  Loop aerial (No. 1 on Plate A), retractable into the forward portside fairing of the bridge, was connected to long wave receiver.

COMMUNICATIONS.

        (For detailed account see Chapter IV.)

        Transmitters.

        1.  200 W. Telefunken short wave.

        2.  40-70 W. Station Lorenz short wave.

        3.  Telefunken long wave.

        Receivers.

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HYDROPHONES.

        G.H.G.  Fitted.

        K.D.B.  Not fitted.

ECHO SOUNDER.

        "Atlaslot" fitted

ELEKTROLOT.

        Fitted.

GYROS.

        Anschütz.  1 Master, 4 repeaters, one of which was in pressure proof container on bridge.

DEPTH GAUGES.

        Gauges registering to 200 meters in the Control Room, Forward and Aft Torpedo Compartments.  Gauge registering to 25 meters in the Control Room.  Depths over 200 meters had to be taken from the water pressure gauge in the Control Room which will give readings to 30 Kilos per sq. cm.  The equivalent of about 300 meters depth.

OIL TESTING APPARATUS.

        The "Jentzche Gerät" in U-841 was an apparatus used for determining such as flash point, viscosity, etc.

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RUBBER BOAT.

        Carried.  Not used at sinking.

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CHAPTER III.  TORPEDOES

TORPEDOES.

        According to statements of torpedo-room personnel, U-841 carried 14 torpedoes, of which 6 were air-drived FAT's (FAT-1) and 8 were electric torpedoes with impact-magnetic firing (T-3).  Stowage of these torpedoes was as follows:

        In forward torpedo compartment:

                Tube 1:  T-3

                Tube 2:  T-3

                Tube 3:  FAT-1

                Tube 4:  T-3

                Under floor-plates:  one T-3 and three FAT-1

                On floor-plates:  two T-3.

        In stern compartment:

                Tube 5:  T-3

                Tube 6:  FAT-1

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        The air-driven FAT's were fitted with impact firing pistols (AZ) only.  The electric torpedoes were provided with MZ/AZ pistols, i.e., combination magnetic and impact firing.  One spare MZ/AZ pistol was carried.

        No torpedoes were carried in upper-deck containers, these having been removed during final overhaul in Stettin.

        No acoustic torpedoes were carried, nor any of the circling torpedoes (Kreisläufer or Kreisaale) reported recently on other U-boats.  It is interesting to note that torpedo-room personnel under interrogation claimed to have received no instruction of any sort on acoustic torpedoes; one, in fact, stated that he had never even heard of any except English ones.

        Prisoners had likewise never taken any course of instruction in FATs and had only vague knowledge of details of course, length of run, mechanism, etc.

        Prisoners were familiar with the following terms and their meaning as indicated:

                T-1:  air driven torpedo.  Ato.  G7a.

                T-2:  electric torpedo.  Eto.  G7e.

                T-3:  electric with combination magnetic and impact firing.  Et0 with MZ/AZ.

                FAT-1:  air driven FAT.  Ato FAT.

        T-4, T-5, FAT-2, FAT-x were unknown to prisoners,

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as were the terms Pi-1 to Pi-5.  Pistols were referred to and described as follows:

PiG7h:	Impact firing (AZ).  Short pistol with four whiskers
MZ/AZ	Combination impact and magnetic firing.  Long pistol with four whiskers.  A torpedo with magnetic firing is set for a depth of two meters greater than the draught of the target ship; it detonates under the ship, exerting explosive force upwards.
Arming distance for both pistols was given as 300 meters.  It was stated that neither pistol could be used in a sea force greater than 5.  Electric torpedoes had one speed, 30 knots.

        The FAT's were all set for a speed of 30 knots, though the other two usual settings of 40 and 44 knots were not blocked off.

        The rudder-lock setting (Rudersperrung) in operation as the torpedo leaves the tube was stated to be 30 for air torpedoes and 40 for electric (see Final Report U-664, G/serial 27, pages 56-58).

        The usual procedure of servicing electric torpedoes (airing daily, filling and charging every four or five days) was followed on board U-841.  One prisoner

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volunteered the information that the electric torpedo has two batteries of 28 cells each.  The life of these batteries was said to be two years.

        U-841 fired no torpedoes during her sole war patrol.

Additional Torpedo Information.

        The coxswain of U-841, who had attended Torpedo Fire Control School in Flensburg from 9 May 1943 to 12 June 1943, proved to be an unexpected source of further information on torpedoes.  While most of his instruction was concerned solely with computation of firing data (it is emphasized that he is not a torpedoman), the following newer torpedo types were more or less completely explained to him in Flensburg.

        Anti-destroyer Circling Torpedo  (O.N.I. Note:  This torpedo was called FAT-2 by the prisoner.  Although the description does not agree with that given under FAT-2 in Final Report U-664 G/serial 27, pages 51 and 52, it must not be assumed that the following is necessarily inaccurate.  Reports from other sources confirm the use of the term to describe a circling torpedo steered by FAT apparatus.  In certain details, however, inaccuracies may occur.)

                Propulsion:  Air-driven.

                Depth setting:  Same as in other torpedoes.

                Arming run:  150 meters.

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                Speed:  30 or 40 knots, probably always set at 40 knots.

                Stowage:  Can be shot from bow tubes or from stern tube(s).

                Pistol:  Impact.

                Maximum run:  Same as for ordinary air torpedo.

                Description of run:  The initial straight run is set to coincide with distance to target.  On reaching the end of the initial straight run, the torpedo turns left and describes a circle with a constant radius.  It will continue to describe this circle until it hits the target or is exhausted.  The diameter of the circle is pre-set and bears some relation to the length of the target, the smaller the target, the smaller the diameter of the circle).

                                                             

        The torpedo always turns left, and the circle remains on the same spot.

        Setting gear:  Although this torpedo differs radically from FAT-1, the same setting spindle (see Final

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        Steering:  The prisoner stated there was no acoustic mechanism and no magnetic mechanism in this torpedo.  FAT settings alone control path of torpedo.

        Effectiveness:  The prisoner was never on a boat carrying this type of torpedo and has no first-hand knowledge of its use and effectiveness.

        Tactics:  This torpedo is primarily a defense weapon to be used against escort vessels ("Zerstorer-Abwehr-Torpedo").  When the U-boat realizes that it has been detected or sighted by the escort vessel, whatever the relative bearings, the U-boat will turn away and try to put the escort vessel astern, bearing roughly 180 degrees relative, target angle as near zero degrees as possible (prisoner said that ten degrees variation on either side of these bearings would not affect chances of a successful shot, but greater variation probably would).  (NOTE:  Torpedo can be fired when target bears zero degrees or 180 degrees from U-boat and U-boat bears zero degrees or 180 degrees relative from the target, ten degrees variation on either said causing no lessening of the effectiveness of the shot.)

        Distance to the target is estimated and the initial straight run set to correspond with this distance.

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        The prisoner definitely stated that any ship moving at speeds 5 to 38 knots would certainly be trapped.  At speed less than 5 knots, the target would remain within the circle unharmed;  at a speed greater than 38 knots the target could escape from the circle.

        Prisoner had no exact knowledge as to whether this torpedo would be slightly angled so as to put the target in the exact center of the circle, but admitted that this was possibly the case.

         Firing Data and settings:

                1.  Torpedo depth setting and torpedo speed.

                2.  Speed of target.

                3.  Distance to target and initial straight run.

                4.  Length of target.

        Miscellaneous:  Prisoner does not know how long the circling torpedo has been in use.  He never heard of the circling torpedo being fired in spread, nor does he now of the term FAT-x.

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                Speed:  20 knots, electrically driven.

                Tactics:  Shot at a departing target, target angle being 180 degrees.  Used against merchant vessels, not against escort vessels.  Can be fired from bow or stern tubes.  Hits target in stern.

                Path of Torpedo:  A straight run, then zig-zags thus:

                                                                   

                Prisoner did not know whether this torpedo has or has not acoustic or magnetic apparatus.  The torpedo was not in operational use, June 1943.

        REG or RECK (?):  Stated to be the cover-name of a new torpedo that describes "peculiar convolutions."  It is not yet operational.

        TORPEDO COMPUTER.

        A coxswain stated that all boats have recently been equipped with a new torpedo computer (Vorhaltrechner) with an extra switch was not on the older type carried

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CHAPTER IV.  NEW ELECTRONIC GEAR AND PROCEDURES

WANZ G.1 G.S.R.

        U-841 was said to be the second U-boat fitted with Wanz G.1 G.S.R. also said to be known under the name of Hagenuck.  The installation was made in Trondheim.  So much importance was attached to the apparatus that U-841 postponed her sailing at least three weeks awaiting its arrival.

Attached Plate C illustrates the Wanz G.1 (prisoner believes this means Wellenanzeigerät No. 1).  The apparatus is fitted with a cathode ray tube graduated for wavelength from 120 to 180 cm.  On this cathode ray tube a green trace appears when in operation.  The trace has a pulse of 25 to the second, operated by a motor-driven automatic scanner.  Operation is as follows:  

 

        1.  Set is switched on.

        2.  Knob is turned to automatic scanning (4 on sketch).

        3.  The button (2 on sketch) revolves and the trace then travels on the tube.

        4.  When a blip appears on the screen the knob is turned to hand tuning (5 on sketch).

        5.  Operator puts on head-phones and used the button (2 on sketch) for fine tuning.

        6.  If a bearing is desired, this can be obtained by plugging into the antenna socket (3 on sketch) a plug connected to the radar aerial which is rotated until a

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        On U-841 the Wanz had been to some extent re-wired and a telegraph key fitted to the upper earphone connection.  With this key connected in the circuit the tube heater could be turned on independently while the set would not actually operate unless the telegraph key were pressed.  Prisoners stated that it was a policy to press this key and therefore operate the set for only 10 seconds out of every minute.  Prisoners believed that continuous use of the set would have set up radiations which could have been D/F'd by the enemy.

        The G.S.R. was fitted with the conventional fixed basket type antenna, the radar antenna being used as described above when a bearing was wanted.

COMBINED RADAR AND G.S.R. ANTENNA.

        Plate D gives full details of the combined radar and G.S.R. antenna, which was mounted on U-841.  The antenna was encased in a recess on the port side of the conning tower fairing (No. 9 on Plate A).  When in use it was elevated on a central shaft by compressed air to a height of 1 meter to 1.5 meters (approximately 3 to 5 feet) above the fairing.  The shaft and leads entered the pressure hull through the water-tight glands.  The antenna was rotatable in 360⁰ by means of a hand wheel located in the control room, where the radar set was also kept.  If it was desired to use this antenna

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D.F. GEAR.

        Plate E shows the arrangement of dials on the D/F gear.  The circular antenna was retractable into the forward starboard side of the bridge fairing.  Signals on LF (Langwellen) 250-2500 meters and VL/F (Längstwellen) 10,000 meters and up were received.

        Radiomen from U-841 supplementing and confirming statements made by radiomen from U-664 gave the following outline of procedure for the sending of homing signals by a contact keeper:

        Such homing signals are given on long wave - it was said between 500 and 1000 meters.

        When a U-boat sights a convoy she reports to control, who then instructs her to transfer to the convoy wavelength (Geleitzugschaltung).  The contact keeper must then issue a signal,

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        Should one of the boats that is attempting to join the contact keeper request a beacon signal, control will instruct the contact keeper to make this signal.  This consists of a VVV, or a similar group like RRR, followed by the signature transmitted very slowly.  Intervals of repetition of the beacon signal are determined by the date and the time of day and are set out in the same book in which the convoy frequencies, above mentioned, are listed.

NEW TYPE G.S.R.

        Two radiomen from U-841, when at the G.S.R. school at Le Touqet in early August 1943, were shown a small and very primitive G.S.R. set which was apparently at the time used only for demonstration purposes.  Plate F shows this set.  Prisoners were positive that there were no dials of any kind on the box, but are quite definite that the antenna is exactly as shown.  The insulation (at 5 on the plate) was said to be of plexiglass and they stated that they had noticed that the dipole inside the plexiglass was reduced to almost half its diameter, i.e., to about 4 mm.  Prisoners are not clear about the purposes of the slotted rubber disc, illustrated at 2 on the plate.

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(O.N.I. Note:  The equipment here described is evidently the Naxos G.S.R. subsequently reported in operational use on U-boats.)

RADAR.

        Plate G illustrates the three units of radar apparatus carried on U-841.  A prisoner from this boat, with a limited knowledge of the subject, gave the following directions for use of radar and its operation:

        Current is supplied by a 6 KVA transformer.  After the 6 KVA transformer had been turned on, the main switch on the radar is turned to "on".  After a pause of two minutes (for pre-heating the apparatus, otherwise there is danger of overload), the high voltage is adjusted by means of the high voltage regulator up to the red mark which is indicated on the scale.  The X-apparatus is next carefully adjusted, that is, the two amplitudes which the tube shows must be turned on full.  Then the constant amplitude of the main radar apparatus is in turn regulated with the help of the adjusting knob.

        When in operation, the cathode tube gives a horizontal and vertical base.  The horizontal base runs across the entire surface of the tube-screen, while the vertical base takes in only the upper diametrical half.  The constant amplitude comprises three-quarters of the height of the vertical base, and

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        Besides the constant amplitude and the base, the cathode tube also shows tube disturbances.  These are called "grass".  Tube disturbances jump up steeply and fall back in narrow, rounded-off curves on the screen.  Because these impulses cover 89⁰, a strong illumination is produced on the screen, and thus every indication of direction can be recognized immediately with great certainty.

        The apparatus has a high voltage of 15,000 volts.  The plate current has about 5,000 to 6,000 volts.

        The radar has, among other tubes, RV12P2000, RV12P2001, AD101, RS291, in considerable number.

        The radar carried by U-841 was designed for use exclusively against surface craft.  It was not intended for use against aircraft and had no elevation indicator.  Actually U-841 had never made any operational use whatever of its radar as her

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COVER NUMBERS FOR U-BOATS IN BALTIC.

        A radioman from U-841 states that the cover numbers for U-boats on trials in the Baltic for communication purposes are always the U-boat's number plus 600.  So for example, the cover number which control used to call U-841 all through her trials was 1441.  (O.N.I. Note:  While this prisoner has stated that this is a standard practice it should be borne in mind that his experience in this respect is limited to the trials of U-841 alone, which took place from February to May 1943.

GOLIATH TRANSMITTER.

        Radiomen from U-664 and U-841 state that since the construction of the new 1,000 K.W. "GOLIATH" transmitter known to them as "Paris I", and which operates on extremely long wave, around 15,000 meters, it is possible for U-boats to receive transmissions on such wave lengths when submerged to a depth up to 30 meters, under favorable conditions.  Before the construction of this transmitter the maximum depth at which U-boats could receive was 13 to 15 meters.

VH/F GEAR:

        Prisoners state that the the "Tornistergerät" is used for both telegraph and voice traffic.  It is used exclusively

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MISCELLANEOUS INFORMATION.

        Prisoners state that there is an area of notably bad reception (Todtpunk) off the coast of Newfoundland.  A radioman from U-841 states that he was told that the enemy practiced deception on "Kurzsignale" which messages begin with the symbol Beta twice repeated followed by a three letter group then two or three four-letter groups and a signature consisting of a three letter group.

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CHAPTER V.  GUNS AND GUNNERY

ARMAMENT.

        As indicated above, U-841 had a 105 mm. gun on her forward deck, demountable machine guns (M.G. 15) on the bridge, 2 single 20 mm. guns on platform I, one quadruple 20 mm. gun on Platform II.

        When first built, she had the 105 mm. forward, the demountable machine guns, no guns on Platform I, one single 20 mm. gun on a small Platform II and one 37 mm. gun on her after deck.  This state of armament remained until the final overhaul in Stettin when the 37 mm. was removed and a single 20 mm. gun was mounted on Platform I.  It was with this armament that she expected to go on patrol from Kiel late June or early July, 1943.

        However, the remodeling of the Conning Tower structure in Bremen during July again changed the picture.  Platform II was removed and a pre-fabricated, larger and stronger Platform II was added.  On this new platform, a quadruple 20 mm A/A gun was mounted.  A second single 20 mm gun was added to Platform I, and the two 20 mm.'s were placed symmetrically to port and starboard.

        A well, about 150 mm. (6 inches) in diameter was located in the deck of Platform II between the quadruple 20 mm. and Platform I.  Sea water was kept in this well which was to be used to immerse the barrels of the quadruple 20 mm. if and when they became hot.  This cooler was not used on the patrol.

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        The 105 mm. gun was adapted for A/A use by means of a special mount that permitted elevation to 70⁰ and depression to 10⁰.  One turn of the elevation hand wheel was claimed to have elevated or depressed the gun 10⁰.  It had a traverse of 120⁰ to port and to starboard (one prisoner insisted it was only 110⁰ to starboard).  One turn of the traversing hand wheel was claimed to have trained the gun 10⁰ right or left.  The rifling was said to have 3-1/2 turns and 32 lands.  This gun had no splinter shield or armor of any kind.

        The sighting gear seems to have been conventional.  There was a telescopic sight both right and left, which consisted of two eyepieces set at right angles.  Number 1 looked into the side eyepiece, Number 2 used the other.  Instead of crossed hairs, the telescopic sight had four small arrows which did not quite meet in the center.  One prisoner stated there was an open sight inboard of the telescopic sight, which consisted of a rear sight and a bead front sight.  The Azimuth gear and range dial were located on the left side of the gun on the recoil housing and were manned by Number 3.

        The rate of fire was claimed as high as 25 rounds per minute, but a prisoner who had taken both the gunnery courses and an A/A course stated that 6 or 7 per minute was the rate of fire per minute in combat from a surface vessel, and even up

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        The crew of the 105 mm. consisted of six men and an extra passer:  Number 1 was the pointer and fired when ready; Number 2 was the trainer; Number 3 was the sight setter; Number 4 was the plug man; Number 5 was the loader and called "ready!" when the breach had been closed.  Numbers 6 and 7 were passers.

20 MM. QUADRUPLE GUN.

        The quadruple 20 mm. gun was mounted on Platform II.  It was actually 4 single 20 mm. guns (C-38's) on a single mounting (C-41 or C-42) with splinter shield through which the 4 barrels projected and which had a hinged armored wing on each side.

        This quadruple 20 mm. could be elevated 90⁰ and depressed 10⁰.  It had a traverse of 360⁰, with an automatic stop that forced elevation to clear the conning tower structure forward of Platform II and prevented depression that would damage the after decking.  Both these stops could be disengaged at will.

        Prisoners asserted that their quadruple 20 mm. was the same as the land gun, except for the mounting.  (O.N.I. Note:  This land gun has been described in detail in APG, Aberdeen, Md. Project # FMAR-213, 5 Oct, 1943.)  The rate of fire was 4 times that of a single 20 mm. gun or about 600 rounds per minute.  The crew of the quadruple gun comprised 4 men:  Number 1, trainer who

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        The magazines were not fully loaded, but one or 2 shells were left out in order to save the springs.

        The center section of the splinter shield of the quadruple gun was about 15 mm. thick, with openings for the four barrels.  The wings were hinged and kept folded parallel to the keel line when not in action.  They could be opened out to form an angle of about 150⁰ with the center section.  These wings were reinforced in the center with armor plating about 20 mm. thick.  The dimensions of the armor plates were variously stated but seem to have been different on the two sides.

SINGLE 20 MM. GUNS.

        There were 2 of the C-38 model, single barrel 20 mm. guns on Platform I.  These well known guns were served by 2 men.  Their rate of fire was given as high as 250 rounds per minute.  Sights for these guns were described as follows:  a front sight of 2 concentric circles with crossed lines through both and lines at 45⁰ intervals between the crossed lines from the outer to the inner circle.  The rear sight was of V-type.  There was no protection of any kind on these guns.

MACHINE GUNS.

        Four demountable M/G 15's were carried aboard U-841.  They were not used on the patrol.  They were kept in the Conning

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        These M/G's were drum fed.  The drums contained 35 to 40 rounds.  Some were kept in the Conning Tower.

AMMUNITION STOWAGE.

        The main Magazine on U-841 was below the deck of the Control Room.  The decking opened just beneath the ladder to the Conning Tower.  In the Magazine was stowed the greater part of the 20 mm. ammunition and about half the 105 mm. shells on board.  The 20 mm. shells were stowed in chests of 100 rounds each;  the 105 mm. shells were stowed in their individual containers.  Two chests of 20 mm shells were carried on this patrol in the Control Room, since the magazine was too full.

        Abaft the 105 mm gun there was a deck well with a partition on the keel line and a hatch which opened in 4 sections.  In this well 60 shells, as ready ammunition, were stowed in pressure proof containers set on end at an angle of about 30⁰ in 6 rows of 5 shells each on either side of the partition.

        Pressure-proof containers for ready use 20 mm. magazines were located on Platforms I and II.  The former had only one, on the keel line abaft the 2 guns; the latter had 4 such containers, 2 on each side of the quadruple gun.  These containers held 12 to 15 magazines each.  The first 4 were placed vertically in the containers, the rest lay flat.  A removable framework held the magazines in the containers which extended as foot or more above the deck level and were about 20 inches in diameter.  (O.N.I. Note:

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AMMUNITION PASSING.

        The problem of getting ammunition on deck from the magazines and distributing it was solved as follows:

        A man in the Magazine passed shells or loaded magazines to another in the Control Room.  He in turn relayed the ammunition to a man on the ladder to the Conning Tower who handed it to one sitting in the Conning Tower hatch.  This man gave it to another standing in the Conning Tower who passed it to a man sitting in the bridge hatch.

        If this man was passed a 105 mm. shell, he put it into either the port or starboard opening in the forward Bridge fairing, through which it slid down a short steep (ca. 50⁰) chute to Number 7 of the 105 mm. gun crew on the forward deck.  The latter passed it to Number 6 who in turn passed the shell to Number 5 who loaded the gun.

        If a 20 mm. magazine reached the Bridge, it was handed to a passer to Port or Starboard who would then give the magazine to Number 2 of the 20 mm. gun crew.  More were passed to the man to starboard, since he also had to feed magazines into the chute from the Bridge to Platform II for the quadruple 20 mm. gun.  This chute is unique with U-841.  It was put on at Klt. Bender's personal insistence.  Some claim he invented it himself.  Its success was not agreed upon by prisoners, but it is certain that

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105 MM. AMMUNITION.

        There was but one type of 105 mm. ammunition taken on the sole patrol by U-841, namely A/A shells.  These could be set to any desired range by turning the head with a key on the order of a wrench.  For practical reasons, the ready ammunition was set in advance at 3,000 m. and 1,500 m.  The former was marked with a white "W" meaning "weit" (distance), and the latter with a white "N", meaning "nahe" (near).  These settings could be changed at will, and would be, if these H.E. shells were to be turned against surface targets.  They could be set either by seconds or on contact.

        The muzzle velocity of 105 mm. shells was given as 1,200 m.p.s.  (O.N.I. Note:  This seems most unlikely; the stated muzzle velocity of 105 mm. shells in British reports of 2,132 ft. per second is more probably that of the 105 mm. projectiles carried by U-841.)

        The color of the 105 mm. A/A ammunition was red; some informants claimed red and white stripes while another source insisted the white was merely polished, unpainted metal.  The letters "W" and "N" indicating the zone setting were painted on the shell containers as well as on the projectiles themselves.

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20 MM. AMMUNITION.

        There were 184 boxes of 20 mm. ammunition on board, each box containing 100 rounds; 182 boxes were in the Magazine and 2 in the Control Room.

        The types of 20 mm. ammunition on board were reported to be as follows:

        Armor piercing delayed explosion - Blue, pointed.

        Armor piercing                             - Black, flat nose.

        Incendiary                                    - Yellow, flat nose.

        These were all said to come with or without tracer.  There was no agreement on loading order of these types.  Also, there was a great divergency of opinion on the types and color markings of 20 mm. ammunition, and the above is to be treated with the greatest reserve.

        It was generally reported that all the 20 mm. ammunition was self destroying at 2,100 m.  Thus these guns were not used until the attacking plane was within that range.  The muzzle velocity of the 20 mm. shells was stated to be 900 m. per second.

GUNNERY NOTES.

        The setting of the 105 mm. ammunition determined the

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        Since the 20 mm. shells were self-destroying at 2,100 m.  this was the opening range for the quadruple or single guns.  The practice with these guns was to lead the nose of the plane.

        The practice of firing alternate barrels of the quadruple gun seems to have been disregarded on U-841.  Any barrel could be fired separately or any number of the 4 barrels together.  It was not considered too awkward to feed magazines to two barrels at almost the same time.

        One of the differences between the C-30 and C-38 is that the C-30 has a handle cocking device whereas the C-38 has a chain device.

        It was claimed that the most common cause of jamming of the C-30 was breach trouble.  This lead to its discontinuance.  If loaded magazines for the C-38 were not serviced every two weeks, the gun was very likely to jam.  Otherwise it was much more reliable than the C-30.

        The C-41 of the German Army has a higher rate of fire, but is said to be not adaptable for U-boat use.

        Although the four barrels of the quadruple 20 mm.

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        Remote fire control was not used on U-841, nor did any of her crew know of its use in the U-boat Service.

        The first few shots were said to be aimed with the ring sight and then the tracer was relied on for aiming.

GUNNERY OPINIONS ON U-841.

        It was felt that the 105 mm. was not satisfactory as an A/A/ gun and would be discarded as the 88 mm. has.  Its slow practical rate of fire and its size which tends to increase the diving time are bringing it into disfavor.

        The quadruple 20 mm. gun is considered a disappointment.  It is too complicated and bulky, too easily damaged by the force of the water, as was the one on U-841, to be reliable.

        There is a double-barreled 20 mm. gun which is not 2 separate guns which is planned for use on U-boats.

        Opinion varied on the practicability of the twin 37 mm. gun.  Its increased fire power was admired, but it was held to be too bulky for use on a U-boat.

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CHAPTER VI.  CREW OF U-841

        The Commander and all officers, except the Executive, were lost with U-841.

        Kapitänleutnant Werner Bender, Captain of U-841, entered the Navy in 1936 and made his midshipman cruise on the Schleswig-Holstein in 1938.  He sailed on two patrols as First Watch Officer under Korvettenkapitän Albrecht (Ajax) Achilles.  (O.N.I. Note:  This was probably in U-161).  He was 27 years old.

        The more experienced members of the crew looked upon Bender as representative of the young officers now being given command of U-boats.  U-841 was Bender's first command.  He joined the boat during her first stages of construction in Bremen.  During her trials in the Baltic he made a brilliant record.  A strict disciplinarian, he was generally well liked and respected, looked upon as a spirited and promising officer.  Lack of experience, however, led him into a fatal mistake and the loss of his boat.

        The executive Officer was Leutnant zur See Herman Knaup, 23, of the December 1939 Naval Term.

        After the fall of France Knaup was a member os a party of 100 sent to La Pallice to requisition boats and arms and organize a mine sweeper flotilla.  Following service with this flotilla, he was Executive officer on a training U-boat of the 24th Flotilla at Memel.

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        Leutnant zur See Ernst Huffmann of the October 1940 Naval Term served as Second Watch Officer with U-841 from her commissioning until just before her sailing from Trondheim.  He was said to be the son of a Major General now serving on the Russian Front.  Before joining U-841 he had been a platoon commander in the 3rd company of the U-boat Training Detachment at Neustadt.

        Huffmann was held in very high esteem by all his subordinates.  His captain, who did not share the crew's enthusiasm for this young officer, found him forgetful, immature, and given to too much familiarity with the men.  In Swinemünde Huffmann discovered that he had left the key to the code machine in Stettin.  One of the radio ratings volunteered to retrieve it, and after a night of almost unbelievably picaresque adventures returned with the missing key before its loss had become known.

        In Bergen Huffmann's memory played a far more serious trick.  After a night of drinking he left a number of secret documents in a hotel room.  It was stated that some

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        Huffmann was succeeded as Second Watch Officer by Oberfähnrich zur See Nahrgang, 23, of the May 1941 Naval Term.  From all accounts Nahrgang was an excellent young officer, firm, competent, and considerate.  His previous experience included two patrols in the Mediterranean under Kapitänleutnant Koenenkamp in the Summer of 1942.  (O.N.I. Note:  This was probably in U-375, at that time based on La Spezia).  He was a member of the Personnel Reserve at Trondheim when he was assigned to U-841.

        The Engineer Officer of U-841, Oberleutnant (Ing.) Max Hörig, joined the Navy in October 1937.  He is said to have had better connections and to have had a more firmly established reputation with the high command than his captain had.  The German Navy list does not show him as a lower deck promotion but he was so regarded on board.  The men in general felt that, having to come up through the ranks, he had more insight with their problems.  The respected his leadership.

        U-841 carried a doctor, Marinestabsarzt Dr. Rudolf Brautigam who joined the Navy in 1940.  He spent a good deal

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        A midshipman left U-841 at Hela where two other midshipmen joined her.  It was at first expected that they would go on active patrol with U-841 but after remaining on board during the Active Service Training Group Exercises at Hela and the torpedo firing practice in the Gulf of danzig, they were unexpectedly sent to Watch Officers Training School.  One of these midshipmen was said to be Oberfähnrich Hentzling.  (Not in G.N.L.)

        Some of the older petty officers were men of judgment and experience, having sailed with such U-boat captains as Endrass, Achilies, Hardegen and Moehle.  The crew on the whole, however, were young and immature.

        Two men serving in the Merchant Marine were caught abroad at the outbreak of war, one successfully ran the blockade; the other was sunk in the Bay of Biscay and spent a brief period in a French prison camp.

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CHAPTER VII.  EARLY HISTORY OF U-841

        U-841 was launched in the latter part of November 1942 at the Deschimag yard in Bremen.  Her crew gradually collected during the final stages of construction and stayed with her, with a few exceptions, until the sinking.

        The commissioning took place 6 February 1943, at which time the boat was assigned to the 4th Flotilla at Stettin.  She remained attached to this Flotilla until her final overhaul was completed.  She was then transferred to the 2nd Flotilla at Lorient.

        After taking on supplies and otherwise getting shipshape, U-841 put out from Bremen on the morning of 13 February 1943.  She proceeded only as far as Bremerhaven that day and put up overnight in the destroyer basin by the old locks.  The crew slept in the Destroyer barracks.  The next morning, she set out with one escort vessel and arrived at Hamburg-Trollerort at 2300 hours.  There part of the crew stayed aboard the depot ship Veendam.  The morning of 15 February, tests were made with the radar which lasted some 5 or 6 hours.  U-841 moved on to Brünsbüttel directly after these tests and spent the night there, since boats are not allowed to use the Kiel Canal after dark.  Most of the crew slept ashore in barracks.

        On the morning of 16 February at 0600, U-841 set out from Brünsbüttel and made the passage of the canal in 9 hours, arriving in Kiel-Wik where she tied up at the Albatros

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        One episode during the U.A.K. period deserves note.  U-841 did not undergo the silent running tests at Rönne, Bornholm Island, as had been routine in the past, but proceeded to Sonderburg, Denmark for these tests.  Leaving Kiel one morning, the boat arrived at Sonderburg in the afternoon and immediately made the prescribed runs.  Then she tied up for the night, and the crew were given 5 Kroner with which to make 4 hours liberty a pleasant memory.  It was claimed by some of the crew that the sustained A.K. speed trial was run on the say to Sonderburg, but this statement was emphatically denied by reliable prisoners who insisted that this test was

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        During the first few days of March, U-841 cleared Kiel for Hela, Gotenhafen and Danzig.  She put into Swinemünde that evening and tied up for the night.  The next two days were spent in A/A exercises, theoretical and practical.

One half the crew went out each day for drill in firing the 20 mm. guns and the 37 mm. gun.  Each man on board, including the cook and the doctor fired 15 rounds from the 37 mm., and an unstated quantity of 20 mm. ammunition.  Approximately 2,000 rounds of the latter were fired in the two days.  It was claimed that 30 rounds each day were fired from the 105 mm. also but this was denied by some.  Part of the crew lived on a small steamer serving as depot ship there.

       Early in the morning of the third day the boat put out from Swinemünde and ran up to Stettin where she unloaded further extra equipment.  Part of the crew spent the night aboard the depot ship Usambara.  The next morning U-841 set out for Danzig.

        She lay over at Danzig for about a week.  Most of the crew lived aboard the depot ship Iberia, near which their boat was berthed.  At this time the U.A.G. (U-boat Acceptance Group) trials including the measured mile run, were carried out.  The day after their arrival, the crew was ordered by Bender to paint all top and side surfaces very light gray.  It was insisted that this was entirely on Bender's initiative; no one seemed to know why it was ordered.  The T.E.K. (Torpedo Testing Command trials were held in Neufahwasser where water

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        Upon completion of U.A.G. and T.E.K., U-841 sailed over to Gotenhafen where provisions were shipped.  It was necessary to wait over a second day for canteen supplies.

        After this brief first Gotenhafen visit, the boat moved across the bay to Hela where the approximately 4-week Agru-Front was held.  The depot ship used by the men while they were in port there was an old, small, river vessel named Preussen.  In the midst of this phase of the trials, 5 days of so-called "Vortaktische Uebungen" (Pre-Tactical Exercises) occurred in which U-841 exercised with about seven other boats.  The crews  stayed aboard the entire time.  There were conflicting statements about staying out or running in late each night.

        During the Hela visit, a tragedy occurred which delayed U-841 in her training about half a day.  A 500-ton boat, which could not be identified by number or commanding officer, signaled an emergency dive while her Commander, Executive Officer, and one other man were on deck inspecting a gun.  They jumped into the Conning Tower but could not close the hatch to the bridge and, as the boat submerged, water started to pour into her.  A boatswain's mate secured the control room hatch to the Conning Tower and thus saved the boat.  She was checked in her dive at 20 meters depth and immediately surfaced.  However an estimated half hour to one hour was required to pump the Conning Tower dry, and the three trapped men were dead.  Klt. Bender was ordered to take the boat over to Gotenhafen and

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        Because she was not clear for her tactical exercises when such a group was beginning, U-841 went from the Agru-Front at Hela to the torpedo-firing exercises in Danzig.  These exercises lasted 10 days and were ended 24 April.  The boat lay over in Danzig over Easter, for the convenience of the crew.

        During this second visit to Danzig, U-841 lay in the U-basin, and the crew lived aboard the depot ship Deutschland.  Sea targets were fired at with "everything on deck" from which it must be concluded that the 105 mm., 37 mm., 20 mm., and M.G. 15's were used.  Klt. Bender was said to have been very skillful in the torpedo-firing exercises, and great hopes were raised for a successful career for U-841.

        The tactical exercises lasted from 1 May to 10 May 1943 and were the reason for the second Gotenhafen visit.  It was stated that 8 other boats took part in these exercises.  Submerged attacks were made by day and surface attacks were practiced at night.  U-841 made a navigational error at one time during the tactical exercises and lost the convoy.  She regained it again by the use of her Fu.M.G.  The convoy comprised some 5 Merchant Ships and at least 8 "Destroyers"), some of which were old French and Belgian gunboats, the others were converted fishing vessels.  Klt. Ernst Bauer, K.C.I.C. was in charge of the tactical exercises which he directed from Wilhelm Bauer.

        A second tragedy to another boat occurred at

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        From Gotenhafen U-841 made for Stettin where final adjustments and an overhaul were carried out a the Oderwerke.  This procedure lasted from 12 May to 24 June, in the course of which:  all ten pressure-proof deck containers for torpedoes were removed; the 37 mm. gun was removed; a 20 mm. single barrel gun was mounted on Platform I; the U-boat was again painted gray.  Beyond these items, only usual, routine repairs and adjustments were made, since the boat had suffered no damage to date.  The crew were stated to have lived in barracks and received leaves from 10 to 16 days in length.  Torpedoes and all kinds of supplies were taken on before leaving Stettin in anticipation of setting out soon from Kiel on patrol.  Upon leaving Stettin, U-841 was transferred from the 4th Flotilla to the 2nd Flotilla, at Lorient.  Subsequent changes in plans placed her in an unusual if not anomalous relation to her Flotilla.

        On the way from Stettin to Kiel, U-841 stopped for 2 days at Swinemünde for her second visit. A/A exercises were carried out in which some 1500 to 2,000 rounds of 20 mm. ammunition

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        On June 27 1943, U-841 returned to Kiel in expectation of an early departure.  The crew lived aboard St. Louis.  A G.S.R. was expected at this time, but not received.  Four hours before their supposed sailing, a signal was received ordering the Commander to report to the 5th Flotilla Headquarters aboard the St. Louis at once.  Upon his return, he announced the cancellation of their sailing orders and the fact that they were to proceed to Bremen.  Torpedoes and other supplies were again unloaded in Wik at #17 Tirpitz Mole.  They sailed for Bremen via the Kaiser Wilhelm Kanal 5 July 1943 and spent that night in Brünsbüttel.

        At 1800, 6 July, U-841 arrived at Deschimag yard, Bremen, and the one month task of remodeling the Conning Tower structure got started.  Platform II was removed and a new, larger one was built on in its place.  A quadruple 20 mm. A/A gun was mounted on this stronger structure with its 4 pressure-proof ready ammunition containers built around the gun mount.  A second 20 mm. single barrel A/A gun was mounted on Platform I.  The crew were housed in barracks ashore and given 10 day leaves in 2 shifts.

        U-841 put out again 4 or 5 August from Bremen.  She lay overnight at Bremerhaven and arrived at Brünsbüttel the next day.  There she tied up for the night and made the

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        The 3rd Kiel visit lasted only about 3 days.  U-841 then proceeded to Swinemünde for her 3rd visit there.  This time bad weather interfered with the smooth execution of the A/A exercises and prolonged the stay one day.  Between 3,000 and 3,500 rounds of 20 mm. ammunition were fired and the new quadruple 20 mm. A/A gun was proof fired.  It was again claimed that 10 rounds were fired from the 105 mm. although this was again denied by some.

        U-841 reached Stettin from Swinemünde 15 August 1943 in the late afternoon or early evening and 14 torpedoes were taken aboard that night.  This 3rd Stettin visit lasted a day and a half, and then the U-boat cleared for Kiel, arriving there 18 August.

        This last visit to the port of Kiel - U-841's fourth - was spent in awaiting sailing orders, taking on some supplies, and running outside two nights to avoid possible air raid damage.  Finally at 0800, Thursday, 26 August 1943, she put out from Kiel on her first patrol, which was to be also her final patrol.

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CHAPTER VIII.  FIRST AND FINAL PATROL OF U-841

        The departure of U-841 from Kiel was preceded by an address by Kapitänleutnant Metzler acting in the place of Korvettenkapitän Möhle who was on leave (O.N.I. Note:  Kapitänleutnant Metzler is of the 1931 naval term; he was with the 5th Flotilla, at Kiel having been transferred from command of U-847 because of illness.)  At 0800, 26 August 1943, in company with a 1600-ton combination minelayer and supply U-boat commanded by Korvettenkapitän Burghagen and two 500-ton U-boats, one of which was U-643 commanded by Kapitänleutnant Hans Harald Speigel (O.N.I. Note:  U-643 was sunk 8 October 1943 near 56⁰N., 8⁰W. by 2 Liberators while a member of "Gruppe Rossbach" attacking a convoy, presumably the same against which U-841 was proceeding at the time of her sinking.  Kapitänleutnant Speidel is a P/W.)  U-841 put out from Kiel escorted by a mine destructor vessel and another, smaller vessel.  These latter ships were relieved at different points en route.  They could make only 10-12 knots and thus slowed the uninterrupted run to Kristiansand which was reached between 2200 and 2300, 28 August.

FIRST PATROL TASK.

        The next morning at 0400, the same 4 U-boats put out and ran along the Norwegian coast to Haugesund where they arrived that evening.  There U-841, U-643, and the second 500-tonner were ordered to put about and proceed to Skaggerak.

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