SM U-30^{[Note 1]} was one of 329 U-boat submarines serving in the Imperial German Navy in World War I. She engaged in commerce warfare as part of the First Battle of the Atlantic. U-30 is significant for the torpedoing of the US tanker Gulflight on 1 May 1915 20 nautical miles (37 km; 23 mi) west of Scilly.^[3]

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History
German Empire
Name	U-30
Ordered	19 February 1912
Builder	Kaiserliche Werft Danzig
Yard number	20
Launched	15 November 1913
Commissioned	26 August 1914
Fate	Surrendered 22 November 1918. Broken up at Blyth in 1919-20.
General characteristics [1]
Class and type	German Type U 27 submarine
Displacement	675 t (664 long tons) surfaced 878 t (864 long tons) submerged
Length	64.70 m (212 ft 3 in) (o/a)
Beam	6.32 m (20 ft 9 in)
Draught	3.48 m (11 ft 5 in)
Speed	16.7 knots (30.9 km/h; 19.2 mph) surfaced 9.8 knots (18.1 km/h; 11.3 mph) submerged
Range	9,770 nmi (18,090 km; 11,240 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	50 m (164 ft)
Complement	4 officers, 31 enlisted
Armament	4 × 50 cm (19.7 in) torpedo tubes 1 × 8.8 cm (3.5 in) SK L/30 deck gun
Service record
Part of:	IV Flotilla Unknown start – 19 November 1917 Training Flotilla 19 November 1917 – 11 November 1918
Commanders:	Kptlt. Erich von Rosenberg-Grusczyski 25 September 1914 – 22 June 1915 Kptlt. Franz Grünert 1 May 1916 – 20 November 1917
Operations:	6 patrols
Victories:	27 merchant ships sunk (48,060 GRT) 1 merchant ship damaged (5,189 GRT)[2]

Close

The particular mission when Gulflight was attacked commenced 24 April 1915. On 28 April U-30 intercepted the 1,905 GRT collier Mobile which she sank by gunfire after allowing the crew to escape. On 29 April she similarly sank the 3,220 GRT Cherbury. 30 April she ordered the steamer Fulgent to halt, but when the ship failed to do so fired a shot into the ship's bridge, which killed the captain and quartermaster. The ship stopped and the rest of the crew were allowed to escape before the ship was sunk by explosive charges placed inside. That afternoon, the 3,102 GRT Svorno was stopped and sunk. On 1 May the grain carrier Edale and French ship Europe were sunk. A Dutch ship was stopped and, as a neutral, permitted to continue at a point some 45 nautical miles (83 km; 52 mi) north west of the Scilly Isles, but the submarine was spotted at this point by a steam drifter, Clara Alice which reported her position to a naval patrol.^[4]

The patrol ships HMS Iago and Filey started to hunt for the submarine, but succeeded only in intercepting the US-flagged Gulflight, which they took under escort. The escort proved something of a disadvantage to Gulflight because she was obliged to slow down for the patrol and then, under international law, as a ship escorted by armed vessels became a legitimate target for attack. U-30 spotted the convoy and fired one torpedo at Gulflight, before noticing that she was flying an American flag. The submarine then broke off the attack in accordance with her instructions not to attack neutral vessels.

Gulflight survived the attack, although two members of the crew drowned while evacuating the ship and the master Captain Gunter died later that night from a heart attack. The ship was towed to Crow Bay and later repaired. News of the event would be overshadowed a few days later by the sinking of RMS Lusitania but the incident, together with the attack on Lusitania and another ship, Cushing, formed the basis of a formal complaint from the US government to Germany. Although the United States remained officially neutral in the ongoing hostilities, it reached agreement with the German government that further attacks by submarine would be strictly in accordance with "cruiser Rules" as defined by international law.