U-23 - 5th War Patrol

Translation by Jerry Mason with help from Andi Forster

Departed	Date	Arrived	Date	Days at Sea
Kiel	5 December 1939	Kiel	15 December 1939	11

 

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Ships Hit
Date	KTB Time	Position	Ship	Tons	Nationality	Convoy
8 Dec 39	00.04	57°31'N, 2°17'W	SCOTIA	2,400	Danish
			Total = 2,400
Note:  The positions in the table above and in the Google Earth patrol summary are derived from the KTB and in many cases do not match those set forth in authoritative references such as Jürgen Rohwer, Axis Submarine Successes of World War Two or the Uboat.net website.  The goal here is to present the picture relative to the U-boat and not the absolute position that the ship was attacked or sank.

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				K  r  i  e  g  s  t  a  g  e  b  u  c  h    "  U  2  3  "
				-----------------------------------------------
				from 5.XII. to 15.XII.1939.
				© U-boat Archive 2025 - all rights reserved

Click the flag to view the above page from the original German KTB

	- 1 -
		05.12.39
		22.00		Cast off Kiel Tirpitz Mole.
		06.12.39
		06.19	SSW 1	Put to sea from Brunsbüttel.
		12.51	NW 1-2	Passed Elbe I
		16.00	L 2632 lower-center	Own mine search formation comes from starboard on course 300° crossed own course ahead at a distance of 5000 meters (own course 341°) and stoped in the left half of square L 2838.
		20.00	L 2787 center-left edge
		20.05	06.-07.12. 12 hours 210 nm
				Kapitänleutnant and Kommandant
		07.12.39	NW 1-3
		00.00	L 2943 lower-center edge
		04.00	L 2950 upper-left
		07.50 - 13.40		Dived for empty neutral steamer course 90° at the northern edge of the warning area.  With that carried out deep dive to depth 60 meters.  At depth 40 meters leak in the main exhaust gas valve, later already at 20 meters.
		16.00	E 2529 center
		17.10	E 2351 upper-center edge	4 smoke clouds in 350°T, apparently on the Skagerrak-North Scotland steamer track.  Because the bearing shifted a little ahead increased speed on intercept course.
		20.00	E 2114 center-left 7. - 8.12. 12 hours 231 nm	The lights of the steamers are in sight.  Afterwards maneuvered ahead at AK, up front a fishing trawler.  Steamer No. 2 shows clear well illuminated Danish markings.  Steamer No. 3 was black and showed no neutral markings.  Steamer No. 4 was a fishing trawler.
		2326		Attack on steamer No. 3, miss.  Second maneuver ahead.  2nd shot hit forward.  Steamer sunk (about 5000 tons).  Steamer No. 2 comes to provide assistance.
				Kapitänleutnant and Kommandant
		08.12.39
		00.04	S 4-5, Sea 3
			E 1837 lower-right
		04.00	E 1340 lower-right
		08.00	E 1102 upper-right
		09.21		Dived to load the reserve torpedo.
		12.00	E 984 center	Surfaced.  Transit to the Orkney's.  Because in the prevailing stiff SE wind Holm Sound is not in question as an anchorage,  I decide I'll be the first into Inganess Bay,
		17.07	E 1104 upper-left corner
		20.00	E 926 upper-left corner
			SE 6-8, Sea 5-6

	Sun and Moon Data 05.12.39
	Sun and Moon Data 06.12.39
	Sun and Moon Data 07.12.39
	Sun and Moon Data 08.12.39

	- 2 -
		09.12.39		which offers good protection even from SE winds.  Entering the Stronsay Firth at slack tide at 04.00 hours; there would be enough time until dawn at 08.00 hours to finish the operation in Inganess Bay.  The flood tide would then be advantageous for departure. This plan could not be carried out because the first islands only came in sight at 03.00 hours and were in the immediate vicinity.  As it later turned out, it was Auskerry to port and Stronsay to starboard. The ship's location was shown by the glow of the North Ronaldsay light, which bore 10°T and burned from 04.00 hours until the morning.  East of Auskerry sighted 2 illuminated and several unilluminated patrol vessels.  The entrance to Kirkwall was not found at first, until at 07.00 hours a dimmed fishing trawler went between the islets and apparently to Kirkwall. At first I ran behind on the surface, from 08.00 when it got light, submerged.  In the exit of the Stronsay Firth the was a huge swell, which was strengthened by the flood tide.
		00.00	E 629 center-right
			SE 6-7
		04.00	E 451 upper-right
		08.00	E 450 upper-center
		12.00	E 390 center-right	Steering at periscope depth was difficult to achieve. The strong flood current pushed the boat into the rapids of the Mull of Deerness and onto cliffs from which I could only escape at AK.  Having now taken a survey of the entrance to Shapinsay Sound, I headed east underwater to re-enter at dusk.
			SE 6-7, Vis. medium, Sea 5, strong rip current
		17.10	Vis. changing, later always bad (down to 400 meters), rain squalls	Surfaced.  The SE wind had freshened again, so there was a strong swell off Stronsay Firth.
				When attempting to run in, the boat came close to land at Copinsay. It was not possible to find Auskerry on a northerly course. In the end, in the darkness and visibility (500 meters) made very difficult by gusts of rain, and because lookout was made difficult by the oncoming seas, neither an island nor an entrance could be made out.  Therefore, I decided to postpone entering Inganess Bay until weather conditions were more favorable and take advantage of this easterly weather for operation on the west coast of the Shetlands.
		09.15		Began the transit through the Fair Isle Passage to the north.
				Kapitänleutnant and Kommandant

Sun and Moon Data 09.12.39

	- 3 -
		10.12.39	E 517 lower-right
		03.00	09.-10.12. 12 hours 155 nm	Passed a patrol vessel west of Fair Isle at 200 meters.
		04.00		Course change towards the coast.  Land in sight, dived 3 nm west of Muckle Ossa and ran into St. Magnus Bay submerged.
		18.09		Surfaced.  With the islands completely darkened, St. Magnus Bay is easily recognized by the large number of patrol vessels, almost all of whom carry lights.  The patrol vessels are mainly concentrated on the southeast corner (entrance to Swarbacks Minn) and the NE corner (entrance to Ura Firth).  Anchored warships were not found in the bay.
				Kapitänleutnant and Kommandant
		11.12.39	SE 2-4
		08.00	Sea 1-2	Ran into the Ura Firth at 08.00 hours on the surface.  Sighted no warships.  A patrol vessel lay at anchor in the eastward diverging Hamar Voe.  It seems to be the main base for the patrol vessels.  Dived due to oncoming lightness and went out submerged.
		08.48
		12.30		Ran into Swarbacks Minn submerged.  Penetrated into Busta Voe; saw no warships there.   Also there were no ships in Olna Firth.
		15.30		Penetrated into Aith Voe; no warships were there.
		17.24		Left Swarbacks Minn again and surfaced.  Afterwards ran to the north to Yell Sound and around the Ramna Stacks, to penetrate Sullum Voe tonight.
		21.30 -		Waited for still water at the NW coast of Yell Island at Gerharda, then ran into Yell Sound on the west side.  Outside 2 patrol vessels and between the Ramna Stacks and in Yell Sound one vessel.  Identified a shielded light buoy with a fixed white beacon at φ = 60°40.5'N, λ = 1°14.5'W.  While entering along the western shore of Yell Sound, North Holm was mistaken for a large warship at anchor and two torpedoes were fired at it at 02.08 hours, one of which exploded.  Because there were no more torpedoes on board, came about to the north out of Yell Sound and around North Unst.  Began return transit
		12.12.39
		00.45	SE 4-5, Vis. changing, rain squalls
		02.08	11.-12.12. 12 hours 131 nm
		05.00	SE 4-5	Muckle Flugga abeam to starboard.
		12.00	E 1362 center
		16.00	E 1419 center-right edge
		20.00	E 1595 lower-left
				Kapitänleutnant and Kommandant

	Sun and Moon Data 10.12.39
	Sun and Moon Data 11.12.39
	Sun and Moon Data 12.12.39

	- 4 -
		13.12.39
		00.00	E 1771 lower-center
		04.00	E 2009 upper-left
		08.00	E 2240 lower-center edge
		09.40 - 09.46	SE 2-3, Vis. good	Dived for aircraft (Do 18 on NW course).
		11.06		Do 18 on SE course to starboard.
		11.35 - 11.47		Dived for aircraft (apparently enemy E-course).
		12.00	E 2533 upper-left corner	In the SW sighted 2 aircraft moving back and forth (Do 18), probably belong to the reported own U-boat hunt formation.
		13.00	12.-13.12. 12 hours 238 nm
				From 14.00 hours steered zigzag course due to U-boat danger.
		16.00	E 2709 upper-right
		19.30		Entered Route blau.
			13.-14.12 12 hours 243 nm	Kapitänleutnant and Kommandant
		14.12.39		Due to U-boat danger on the east route turned to the north and with zigzag courses proceeded through the inner Deutsche Bucht.  In so doing Recognition Signals exchanged with patrol vessels, Signal Station Helgoland and signal traffic with minesweepers.
		14.14	L 2481 center-left edge
		14.46	L 2482 center-left edge	4 German fighters (Me 109) sighted over Helgoland, course W.
		16.50		Passed Elbe I objective buoy.
		15.12.39
		07.35		Made fast Kiel, Tirpitz Mole.
				Kapitänleutnant and Kommandant
			Special Experiences: 1.) All light beacons of the Orkney's, Fair Isle and the Shetland's are continually extinguished.  North Ronaldsay burned on 9 December at 04.00 until morning. 2.) The entrances to harbors can be recognized by the illuminated patrol vessels. 3.) An especially large number of patrol vessels (fishing trawlers) were found in St. Magnus Bay. 4.) In the entrance into Yell Sound lies a shielded light buoy with a fixed white beacon at φ = 60°40.5'N, λ = 1°14.5'W.  A patrol vessel moves back and forth in the vicinity. 5.) The current information in the Nautical Handbook provides good guidance and is generally correct.  The distinctive rocks and cliffs of the Shetland's are, after having recognized their shape by day, good as navigational points of reference for night operations, especially since they are usually in deep water. 6.) I believe a further operation in this sea area could be carried out easily, taking advantage of appropriate weather conditions.
				Kapitänleutnant and Kommandant

	Sun and Moon Data 13.12.39
	Sun and Moon Data 14.12.39
	Sun and Moon Data 15.12.39

 

	Enclosures to U-23's KTB - click on the text at left to proceed to the document
ChartA	Track chart of entire patrol
ChartB	Track chart of period in the operations area 10-12 December
Torpedo	Torpedo firing reports

 

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