SM U-24 was one of 329 submarines serving in the Imperial German Navy in World War I. She was engaged in commerce warfare during the First Battle of the Atlantic.

History
German Empire
Name	U-24
Ordered	18 March 1911
Builder	Germaniawerft, Kiel
Yard number	178
Laid down	5 February 1912
Launched	24 May 1913
Commissioned	6 December 1913
Fate	Surrendered, 22 November 1918 Broken up, 1922
General characteristics
Class and type	German Type U 23 submarine
Displacement	669 t (658 long tons) surfaced 864 t (850 long tons) submerged
Length	64.70 m (212.3 ft)
Beam	6.32 m (20 ft 9 in)
Draught	3.45 m (11 ft 4 in)
Propulsion	2 shafts 2 × Germania 6-cylinder two stroke diesel motors with 1,800 PS (1,320 kW; 1,780 shp) 2 × SSW double Motordynamos with 1,200 PS (880 kW; 1,180 shp) 450rpm surfaced 330 rpm submerged
Speed	16.7 knots (30.9 km/h; 19.2 mph) surfaced 10.3 knots (19.1 km/h; 11.9 mph) submerged
Range	9,910 nmi (18,350 km; 11,400 mi) at 8 knots (15 km/h; 9.2 mph) surfaced 85 nmi (157 km; 98 mi) at 5 knots (9.3 km/h; 5.8 mph) submerged
Test depth	about 50 m (160 ft)
Boats & landing craft carried	1 dingi
Complement	4 officers, 31 men
Armament	4 × 50 cm (19.7 in) torpedo tubes (2 each bow and stern) 6 torpedoes 1 × 8.8 cm (3.5 in) SK L/30 gun
Service record
Part of:	III Flotilla 1 August 1914 – 11 August 1917 Training Flotilla 24 August 1917 – 11 November 1918
Commanders:	Kptlt. Rudolf Schneider[1] 6 December 1913 – 3 June 1916 Kptlt. Walter Remy[2] 4 June 1916 – 10 July 1917 Kptlt. Otto von Schubert[3] 11 July – 1 August 1917
Operations:	7 patrols
Victories:	33 merchant ships sunk (105,948 GRT) 1 warship sunk (15,000 tons) 1 auxiliary warship sunk (174 GRT) 3 merchant ships damaged (14,318 GRT) 1 merchant ship taken as prize (1,925 GRT)

In seven patrols, U-24 sank a total of 33 merchant ships and 1 auxiliary warship totalling 106,122 GRT and one warship for 15,000 tons, damaged three merchant ships for 14,318 GRT, and took one merchant ship as prize of 1,925 GRT.^[4]

Her second kill was the most significant. The victim was HMS Formidable, torpedoed 30 nautical miles (56 km; 35 mi) south of Lyme Regis, at 50°13′N 03°04′W / 50.217°N 3.067°W / 50.217; -3.067. She was hit in the number one boiler room on the port side. Out of a crew of approximately 711 men, 547 died as a result. This was one of the largest ships sunk by U-boats during the war.^[5]

In 1915, U-24 claimed another noted victim, the passenger steamer Arabic, causing 44 deaths, including three Americans. Arabic sank in 10 minutes. This escalated the U-boat fear in the U.S. and caused a diplomatic incident which resulted in the suspension of torpedoing non-military ships without notice.^[6]