SM UB-123

	UB-148 at sea, a U-boat similar to UB-123.
History
German Empire
Name	UB-123
Ordered	6 / 8 February 1917
Builder	AG Weser, Bremen
Cost	3,654,000 German Papiermark
Yard number	296
Laid down	13 July 1917
Launched	2 March 1918
Commissioned	6 April 1918
Fate	Sunk 19 October 1918
General characteristics
Class and type	Type UB III submarine
Displacement	512 t (504 long tons) surfaced; 643 t (633 long tons) submerged;
Length	55.85 m (183 ft 3 in) (o/a)
Beam	5.80 m (19 ft)
Draught	3.72 m (12 ft 2 in)
Propulsion	2 × propeller shaft; 2 × Körting four-stroke 6-cylinder diesel engines, 1,050 bhp (780 kW); 2 × Siemens-Schuckert electric motors, 780 shp (580 kW);
Speed	13.9 knots (25.7 km/h; 16.0 mph) surfaced; 7.6 knots (14.1 km/h; 8.7 mph) submerged;
Range	7,280 nmi (13,480 km; 8,380 mi) at 6 knots (11 km/h; 6.9 mph) surfaced; 55 nmi (102 km; 63 mi) at 4 knots (7.4 km/h; 4.6 mph) submerged;
Test depth	50 m (160 ft)
Complement	3 officers, 31 men
Armament	5 × 50 cm (19.7 in) torpedo tubes (4 bow, 1 stern); 10 torpedoes; 1 × 10.5 cm (4.13 in) deck gun;
Service record
Part of:	III Flotilla; 22 June – 19 October 1918;
Commanders:	Oblt.z.S. Robert Ramm; 6 April – 19 October 1918;
Operations:	2 patrols
Victories:	1 merchant ship sunk ; (2,646 GRT); 1 merchant ship damaged ; (4,095 GRT); 3 merchant ships taken as prize ; (3,530 GRT);

SM UB-123 was a German Type UB III submarine or U-boat in the German Imperial Navy (German: Kaiserliche Marine) during World War I. She was commissioned into the German Imperial Navy on 6 April 1918 as SM UB-123.^{[Note 1]}

She torpedoed and sunk Leinster, a vessel operated by the City of Dublin Steam Packet Company on 10 October 1918, shortly after the new parliamentary based German Government under Max von Baden had asked U.S. President Woodrow Wilson to negotiate an armistice.

Leinster went down just outside Dublin Bay. Over 500 people perished in the sinking – the greatest single loss of life in the Irish Sea.

UB-123 struck a mine at the North Sea Mine Barrage on 19 October 1918, all 36 crew members died in the event.^[3]

Construction

She was built by AG Weser of Bremen and following just under a year of construction, launched at Bremen on 2 March 1918. UB-123 was commissioned later the same year under the command of Oblt.z.S. Robert Ramm. Like all Type UB III submarines, UB-123 carried 10 torpedoes and was armed with a 10.5 cm (4.13 in) deck gun. UB-123 would carry a crew of up to 3 officer and 31 men and had a cruising range of 7,280 nautical miles (13,480 km; 8,380 mi). UB-123 had a displacement of 512 t (504 long tons) while surfaced and 643 t (633 long tons) when submerged. Her engines enabled her to travel at 13.9 knots (25.7 km/h; 16.0 mph) when surfaced and 7.6 knots (14.1 km/h; 8.7 mph) when submerged.

Summary of raiding history

Date	Name	Nationality	Tonnage^{[Note 2]}	Fate^[5]
16 July 1918	Anine	Denmark	1,299	Captured as prize
16 July 1918	Constantin	Denmark	831	Captured as prize
16 July 1918	Hjortholm	Denmark	1,400	Captured as prize
10 October 1918	Leinster	United Kingdom	2,646	Sunk
16 October 1918	Caloria	United States	4,095	Damaged

References

Notes

^ "SM" stands for "Seiner Majestät" (English: His Majesty's) and combined with the U for Unterseeboot would be translated as His Majesty's Submarine.
^ Tonnages are in gross register tons

Citations

^ Rössler 1979, p. 55.
^ Helgason, Guðmundur. "WWI U-boats: UB 123". German and Austrian U-boats of World War I - Kaiserliche Marine - Uboat.net. Retrieved 13 February 2009.
^ ^a ^b ^c ^d ^e ^f Gröner, Jung & Maass 1991, pp. 25–30.
^ Helgason, Guðmundur. "WWI U-boat commanders: Robert Ramm". German and Austrian U-boats of World War I - Kaiserliche Marine - Uboat.net. Retrieved 10 March 2015.
^ Helgason, Guðmundur. "Ships hit by UB 123". German and Austrian U-boats of World War I - Kaiserliche Marine - Uboat.net. Retrieved 10 March 2015.

Bibliography

Bendert, Harald (2000). Die UB-Boote der Kaiserlichen Marine, 1914–1918. Einsätze, Erfolge, Schicksal (in German). Hamburg: Verlag E.S. Mittler & Sohn GmbH. ISBN 3-8132-0713-7.
Gröner, Erich; Jung, Dieter; Maass, Martin (1991). German Warships 1815–1945, U-boats and Mine Warfare Vessels. Vol. 2. Translated by Thomas, Keith; Magowan, Rachel. London: Conway Maritime Press. ISBN 0-85177-593-4.
Rössler, Eberhard (1979). Die deutschen U-Boote und ihre Werften: eine Bilddokumentation über den deutschen U-Bootbau; in zwei Bänden (in German). Vol. I. Munich: Bernard & Graefe. ISBN 3-7637-5213-7.

[5] "SM" stands for "Seiner Majestät" (English: His Majesty's) and combined with the U for Unterseeboot would be translated as His Majesty's Submarine.

[tonnage-6] Tonnages are in gross register tons

[FOOTNOTERössler197955-1] Rössler 1979, p. 55.

[UB-123-2] Helgason, Guðmundur. "WWI U-boats: UB 123". German and Austrian U-boats of World War I - Kaiserliche Marine - Uboat.net. Retrieved 13 February 2009.

[FOOTNOTEGrönerJungMaass199125–30-3] ^ ^a ^b ^c ^d ^e ^f Gröner, Jung & Maass 1991, pp. 25–30.

[4] Helgason, Guðmundur. "WWI U-boat commanders: Robert Ramm". German and Austrian U-boats of World War I - Kaiserliche Marine - Uboat.net. Retrieved 10 March 2015.

[7] Helgason, Guðmundur. "Ships hit by UB 123". German and Austrian U-boats of World War I - Kaiserliche Marine - Uboat.net. Retrieved 10 March 2015.

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[2]

[3]

[4]

[Note 1]

[Note 2]

[5]

v t e Type UB III submarines
SM UB-48 SM UB-49 SM UB-50 SM UB-51 SM UB-52 SM UB-53 SM UB-54 SM UB-55 SM UB-56 SM UB-57 SM UB-58 SM UB-59 SM UB-60 SM UB-61 SM UB-62 SM UB-63 SM UB-64 SM UB-65 SM UB-66 SM UB-67 SM UB-68 SM UB-69 SM UB-70 SM UB-71 SM UB-72 SM UB-73 SM UB-74 SM UB-75 SM UB-76 SM UB-77 SM UB-78 SM UB-79 SM UB-80 SM UB-81 SM UB-82 SM UB-83 SM UB-84 SM UB-85 SM UB-86 SM UB-87 SM UB-88 SM UB-89 SM UB-90 SM UB-91 SM UB-92 SM UB-93 SM UB-94 SM UB-95 SM UB-96 SM UB-97 SM UB-98 SM UB-99 SM UB-100 SM UB-101 SM UB-102 SM UB-103 SM UB-104 SM UB-105 SM UB-106 SM UB-107 SM UB-108 SM UB-109 SM UB-110 SM UB-111 SM UB-112 SM UB-113 SM UB-114 SM UB-115 SM UB-116 SM UB-117 SM UB-118 SM UB-119 SM UB-120 SM UB-121 SM UB-122 SM UB-123 SM UB-124 SM UB-125 SM UB-126 SM UB-127 SM UB-128 SM UB-129 SM UB-130 SM UB-131 SM UB-132 SM UB-133 SM UB-136 SM UB-142 SM UB-143 SM UB-144 SM UB-145 SM UB-148 SM UB-149 SM UB-150 SM UB-154 SM UB-155
Preceded by: Type UB II Followed by: Type VII (World War II)
List of U-boats of Germany

v t e Shipwrecks and maritime incidents in October 1918
Shipwrecks	2 Oct: Keltier 3 Oct: Burutu, SMS G41 4 Oct: HMS L10, SM UB-68, Oceania 5 Oct: USS Mary Alice, SM UB-10, SM UB-40, SM UB-59, SM UC-4 6 Oct: HMS C12, HMS Otranto 7 Oct: USS West Gate 10 Oct: Leinster, Senator Schröder 15 Oct: HMS J6 16 Oct: Dumaru, SM UB-90 19 Oct: HMS Plumpton, SM UB-123 20 Oct: HMS M21 21 Oct: USS Cero, SM UB-89 23 Oct: HMS D1 25 Oct: Princess Sophia 27 Oct: SM U-78 28 Oct: USS Tarantula, SM U-47, SM U-65, SM UB-48, SM UB-116, SM UC-25, SM UC-53, SM UC-54 30 Oct: HMCS Galiano, SM U-73, SM UC-34 31 Oct: SM UB-129 Unknown date: SMS Brugge, HMS G7, SM U-34
Other incidents	2 Oct: Aquitania, USS Shaw 3 Oct: USS George G. Henry 5 Oct: USS O-13 6 Oct: HMS Kashmir 7 Oct: USS American 12 Oct: USAT Amphion 15 Oct: HMS Cymric 18 Oct: Voltaire 20 Oct: USS Berwyn 21 Oct: SMS Frankfurt
1917 1918 1919 September 1918 November 1918