Germany announced on 4 February 1915 that it would conduct unrestricted submarine warfare in the waters round the United Kingdom from 18 February. It justified this on the grounds that the British blockade of Germany contravened international law. This led to heavy losses in Allied shipping, most infamously the sinking of the liner Lusitania on 7 May with the loss of 1,201 lives including 128 Americans.
A number of incidents involving submarines that occurred between 18 and 21 August led to both Germany and the UK accusing the other of being guilty of atrocities.
The first of these took place in the early hours of 18 August. The submarines HMS E8 and E13 were on their way to the Baltic to join their sister boats E1 and E9 when E13 suffered problems with her magnetic compass. She went off course and ran aground in Danish waters. At 5:00 am a Danish torpedo boat arrived, informing Lieutenant-Commander Geoffrey Layton, E13’s captain, that he had the normal 24 hours to get his boat underway, but that no help would be given.
At 9:00 am, by when another Danish torpedo boat had arrived, two German destroyers appeared. One of them, SMS G132, fired a torpedo at E13 from a range of 300 yards and opened fire with all her guns, although the submarine was in neutral waters. She was soon in flames and her crew abandoned ship. The Germans fired on them in the water until one of the Danish torpedo boats put herself between the German ships and the swimming survivors. Fifteen men were killed and the others picked up by the Danes. They were interned, but Layton escaped after three months. He rose to the rank of Admiral, holding commands in the Mediterranean and Far East during the Second World War.
The next two incidents both took place on 19 August. The website uboat.net lists seven British and one Spanish merchant ships as having been sunk that day by U24, U27 and U38, which were operating between Ushant and St George’s Channel. A Norwegian ship was also sunk by U25 in the North Sea. Two days earlier U-boats had sunk 11 merchantmen, but they were on average smaller, with a total tonnage of 15,733 tons versus 38,434 tons for the nine sunk on 19 August. The largest ship sunk on 19 August, the 15,801 ton British liner SS Arabic was bigger than all the ships sunk on 17 August combined.
Kapitänleutnant Rudolf Schneider’s U24 was in the process of sinking the 4,930 ton merchant ship Dunsley by gunfire when she observed the Arabic, which was on her way to the USA, approaching. Earlier that day, U24 had survived attempts to ram her by the armed yacht Valiant II and the unarmed trawler Majestic and had been fired on by the defensively armed liner City of Exeter. Schneider was therefore wary of the Arabic and mistook her zigzag course for an attempt to ram his boat. U-boats had been ordered not to sink passenger liners without warning unless the liner was attacking them. Schneider thought that the Arabic was attacking him, so fired a single torpedo which hit her. She sank about ten minutes later.
There is some doubt about the number of people on board the Arabic and the number of dead, with the three British Official Histories giving different figures: Naval Operations says 40 dead out of 428 onboard; The Merchant Navy gives 39 killed out of 429; and Seaborne Trade states that 44 died. The Naval Staff Monograph, an internal Admiralty document written in 1926, says that she was carrying 429 people, 181 passengers and 248 crew, of whom 40, 18 passengers and 22 crew, were killed. A document later published by the British government in response to German accusations that the British Q-ship HMS Baralong had murdered members of U27’s crew claimed 47 dead, a number that was increased to 49 in a later note. Paul Halpern says that 44 died, including two or three US citizens.
Baralong was one of a number of merchantmen given concealed armament and RN volunteer crews in order to act as decoy ships that could trap and destroy U-boats. She was a 4,000 ton ship, capable of carrying 3,000 tons of coal in four holds, that had been requisitioned as a supply ship by the RN. She was given three 12 pounder guns, two of which were concealed by dummy life belt lockers and the other by a sheep pen. Two of her holds were used for coal and the other two were filled with empty barrels that would help to keep her afloat if torpedoed. She was captained by Lieutenant-Commander Godfrey Herbert RN, a submariner, with Sub-Lieutenant Gordon Steele RNR as first lieutenant. Her maximum speed was 12 knots ‘on a good day.’
Baralong received the Arabic’s SOS, but arrived too late to help. At 3:00 pm she spotted that a steamer 9 miles away had changed her course significantly. She then received a radio message from the steamer, which was the Nicosian, saying that she was being chased by a submarine. Herbert headed for Nicosian, hoisting the signal for ‘Save life’ when 3 miles away.
The Nicosian was a 6,250 ton ship of the Leyland Line, carrying a cargo of cotton, timber, steel rods and tinned meat plus mules for the British Army from New Orleans to Liverpool. She was unarmed, but carried a dummy gun on her stern. She was British but most of the 48 muleteers who tended to the mules were Americans. Baralong then flying the US flag and also had boards along her sides indicating that she was a US ship. Sailing under false colours was legitimate under the rules of war, provided that the ship lowered and replaced them by her true ones before opening fire.
The submarine, which was U27, was firing on the Nicosian, whose crew had taken to her boats, from 1,000 yards. Baralong passed behind the merchantman, meaning that she was out of sight of the U-boat, dropped her neutral colours, raised the White Ensign and opened fire at 600 yards range once U27 was in sight. Several of the German deck gun crew were hit before they could fire on Baralong. She scored 34 hits with her 12 pounder guns and U27 sank, with the surviving members of her crew jumping into the sea and swimming for the Nicosian. Herbert claimed in her after action report that he was worried that they might try to scuttle or set fire to the ship in order destroying her and her cargo. He consequently ordered his crew to fire on them. Six succeeded in getting on board, so Herbert sent a party of marines across, warning them to be careful in case the Germans found the rifles that were in the Nicosian’s charthouse. According to Herbert, the six Germans who made it on board the Nicosian all ‘succumbed to the injuries they had received from lyddite shell.
The German government issued a memorandum to the British government via the US government that accused ‘Captain William McBride’, a pseudonym adopted by Herbert as part of the pretence that Baralong was a merchant ship, of murder. They produced affidavits sworn by six of the American muleteers made to US public notaries. The witnesses were either on or in the process of boarding Baralong when she fired on the Germans in the water. They agreed that U27’s captain, Kapitänleutnant Bernd Wegener, was shot in the water after raising his hands in surrender. 
One of them, James J. Curran, claimed that Baralong had opened fire before she lowered her US colours. He also stated that Herbert said to his crew ‘Boys, we’ll shoot those poor wounded devils in the water’ and then told the men that he sent aboard the Nicosian ‘Get them all, take no prisoners.’ Another American muleteer, Bud Emerson Palen, said that he heard Herbert tell one of the boarding party that ‘My orders are to take no prisoners.’
The testimony of a seventh American can be disregarded. Larrimore Holland had joined the RN, claiming to be a Canadian. He said that he had been a member of Baralong’s crew, but in fact never went to sea during his four months in the RN. He admitted to being American on 11 August and was discharged from the RN on 24 August.
The British responded to the German demand that ‘McBride’ be charged with murder by suggesting that an impartial court of investigation, perhaps comprising United States Navy officers, should be set up to investigate the alleged incidents in four sinkings that occurred close together: E13 on 18 August, the Arabic and U27 on 19 August and the SS Ruel on 21 August.
The 4,029 ton collier Ruel was attacked by a surfaced submarine whilst returning from Gibraltar to Barry Roads in ballast. After a chase lasting an hour and half Ruel’s crew abandoned ship once the U-boat was a mile away. It then fired on her lifeboats, killing one man and wounding eight. The Ruel sank just as the armed trawler Dewsland and the drifter Campania appeared, chasing off the U-boat.
The Germans said in reply to this that they had already investigated the three incidents in which accusations had been made against their navy. They claimed that that E13 was sunk in the final stage of an engagement and noted that British ships had attacked German ships in neutral waters, that Schneider thought that the Arabic was attacking U24 and that the attack on Ruel was in line with the policies that they had introduced in retaliation to the British blockade. They reiterated their demand that the British take action against ‘McBride.’
The British awarded Herbert the Distinguished Service Order but did not say why, a normal security measure when decorations were given to Q-ship crews.
E13 was certainly attacked whilst helpless in neutral waters. The light cruiser SMS Dresden was sunk by the British in Chilean waters, but she had stayed there longer than allowed by international law, which E13 had not.
It is unlikely that the Arabic was trying to ram U24, but Schneider may well have genuinely believed that she was trying to do so.
The Germans may have intended to scuttle the Nicosian. However, Herbert’s claim that all the Germans who managed to swim from U27 to the Nicosian and haul themselves onboard her by ropes were so badly wounded that they soon died is impossible to believe, suggesting that he had something to hide. There are two witnesses that he told his marines to take no prisoners. Curran was an Irish-American who may have been prejudiced against the British. Palen, however, was born in Canada.
There was no justification for the Germans continuing to fire on the crew of the Ruel after they had abandoned ship.
The allegations made by both UK and Germany against the other would therefore appear to be justified, but there was little hope of either side admitting to this in the midst of a war in which the level of violence and ruthlessness was increasing. The first successful use of poison gas was by the Germans at Ypres on 22 April: the French had earlier made limited use of tear gas and a German attempt to use gas on the Eastern Front in January had failed because it did not work in temperatures below zero. The first raid on London by an airship took place on 31 May, killing five people and injuring 35.
The blockades imposed by Germany and the UK both aimed to starve the enemy. Diplomatically, the big difference Germans was that killed Americans as well as British.
The USA sent Germany a series of strong diplomatic notes after the sinkings of the Lusitania and the Arabic. On 27 August Kaiser Wilhelm II accepted the view of his Chancellor, Theodore von Bethman-Hollweg, that passenger ships, even enemy ones, should not be sunk without warning. Three days later the order was amended to included ‘small passenger steamers’, without defining what this meant.
The naval high command objected, Grosse Admiral Alfred von Tirpitz, the State Secretary of the Imperial Naval Office, and Admiral Hugo von Pohl, Commander-in-Chief of the High Seas Fleet, both offered their resignations, which were rejected. Pohl argued that the 30 August order meant that U-boats would have to examine ships before attacking them in case they carried passengers, making it impossible to conduct submarine warfare against commerce. Tirpitz was told that he would no longer be needed at ‘consultations on naval questions connected with foreign politics.’
Vize Admiral Gustav von Bachmann was removed as Chief of the Naval staff. On 18 September his replacement, Admiral Henning von Holtzendorf, announced that U-boats would be withdrawn from the west coast of the UK and the English Channel. The minelaying UC-boats based in Flanders and some U-boats continued to operate in the North Sea, but the latter were required to follow prize rules . Others were sent to the Mediterranean, where they could attack Allied commerce and communications with much less risk of sinking American ships or killing Americans. The transfer of boats to the Mediterranean and the need to repair others meant that only four would have been available for use west of the UK.
On the night of 4 September the passenger liner Hesperian, bound from Liverpool to Canada, suffered an explosion 125 miles south west of Queenstown. The Germans insisted that she had struck a mine, but fragments of a torpedo were found on Hesperian before she sank. Kapitänleutnant Walter Schweiger’s U20, which had sunk the Lusitania, was in the area. It is unlikely that the Germans would have mined an area in which their submarines were operating..
The last U-boat patrol to the south west of the UK was carried out by U41, which sailed on 14 September. She sank three British ships on 23 September. The next day she stopped and sank the liner Urbino. Another ship then appeared, which U41 approached and ordered to stop. She was HMS Baralong, now captained by Lieutenant-Commander A. Wilmot-Smith. She opened fire and quickly sank U41, before picking up the crew of the Urbino and the two survivors from the U-boat. One of them, Oberleutnant Iwan Crompton, was later repatriated to Germany because of the severity of his wounds. He claimed that Baralong had been flying the US flag when she opened fire, which the British denied.
The switch of U-boats to the Mediterranean did not prevent them killing Americans. On 7 November U38, a German boat that was flying Austro-Hungarian colours because Germany and Italy were not yet at war, sank the Italian liner Ancona off Bizerte, killing over 200 people, including about 20 Americans.
From the outbreak of war to the start of unrestricted submarine warfare on 28 February 1915 U-boats sank 13 merchant ships with a total tonnage of 23,490 tons. From March to September they sank 431 ships of 677,184 tons. New construction and seizure of enemy shipping meant that the British merchant fleet actually increased in size in the first year of the war. Construction, however, began to fall as shipyards switched to naval construction and repair work and shipyard workers joined the armed forces. At the same time, overseas campaigns increased the demand for shipping.
Five U-boats were lost in 1914, two in January 1915 and 15 from March to September 1915. New construction, meant that Germany had 46 boats at the end of September, but 15 of them were UB coastal boats and 14 were UC coastal minelayers. Only 17 were ocean going, compared with all 26 available at the start of the year. These figures exclude U25, which had been damaged too badly to return to active service, the obsolete U1-4 and U66-70, built in Germany, originally for Austria-Hungary, and then undergoing trials.
The U-boats had shown that they were a potentially deadly weapon. The numbers available in 1915 could not, however, do enough damage to Allied shipping to balance the harm that they did to German relations with the USA.
 The last two paragraphs are based on J. S. Corbett, H. Newbolt, Naval Operations, 5 vols. (London: HMSO, 1938). vol. iii, pp. 135-36.
 Ibid., p. 131.
 Ibid; C. E. Fayle, Seaborne Trade., 3 vols. (London: HMSO, 1920). vol. ii, p. 103; A. S. Hurd, The Merchant Navy, 3 vols. (London: HMSO, 1921). vol. ii, p. 25.
 Naval Staff Monograph (Historical) 1926 vol. xiv, Home Waters part v, July 1915 to October 1915. pp. 81-82.
 PP, Further Correspondence with the German Government Respecting the Incidents Alleged to Have Attended the Sinking of a German Submarine and Its Crew by His Majesty’s Auxillary Cruiser “Baralong” on August 19, 1915, HMSO 1916 [Cd. 8176]. p. 4; Memorandum of the German Government in Regard to Incidents Alleged to Have Attended the Destruction of a German Submarine and Its Crew by His Majesty’s Auxiliary Cruiser “Baralong” on August 19th, 1915 and Reply of His Majesty’s Government Thereto’, January 1916, HMSO 1916 [Cd. 8144]. p. 16.
 P. G. Halpern, A Naval History of World War I (London: UCL Press, 1994), p. 301.
 T. Bridgland, Sea Killers in Disguise: The Story of the Q Ships and Decoy Ships in the First World War (London: Leo Cooper, 1999), pp. 21-22.
 Ibid., p. 23.
 Naval Staff vol. Xiv. ‘Appendix N, Report from M.F.A. Baralong’, p. 229,
 Bridgland, Sea Killers, pp. 24-27.
 Naval Staff vol. Xiv. pp. 229-30.
 PP, Cd. 8144. pp. 1-4.
 Ibid., p. 11.
 Ibid., p. 8.
 Bridgland, Sea Killers, p. 37.
 Hurd, Merchant. vol. ii, pp. 33-34.
 PP, Cd. 8176.
 Bridgland, Sea Killers, pp. 26, 36.
 PP, Cd. 8144. p. 6.
 H. H. Herwig, The First World War: Germany and Austria-Hungary, 1914-1918 (London: Arnold, 1997), pp. 135, 168-69.
 W. A. Raleigh, H. A. Jones, The War in the Air: Being the Story of the Part Played in the Great War by the Royal Air Force, 7 vols. (Oxford: Clarendon Press, 1922). vol. iii, pp. 97-98.
 Naval Staff vol. Xiv. p. 173.
 Corbett, Newbolt, Naval. vol. iii, p. 141
 Naval Staff vol. Xiv. p. 173.
 Halpern, Naval, p. 302.
 Naval Staff vol. Xiv. p. 175.
 Ibid., pp. 176-77.
 Bridgland, Sea Killers, pp. 51-54.
 Halpern, Naval, p. 385.
 V. E. Tarrant, The U-Boat Offensive, 1914-1945 (London: Arms and Armour, 1989), pp. 152-53.
 Halpern, Naval, p. 303.
 Tarrant, U-Boat, p. 24.
 R. H. Gibson, M. Prendergast, The German Submarine War, 1914-1918. (London: Constable, 1931), pp. 63-64.