Tag Archives: unrestricted submarine warfare

U-boats, the Zimmermann Telegram and the US Entry into the War

On 22 December 1916 Admiral Henning von Holtzendorff, the Chief of the Admiralty Staff of the Imperial German Navy, sent Field Marshal Paul von Hindenburg, the Chief of the General Staff, the last of a series of memos advocating that Germany adopt unrestricted submarine warfare.[1] Unrestricted submarine warfare meant sinking merchant ships without warning. German U-boats were then surfacing in order to check the nationality of merchant ships before opening fire. This was done largely to avoid the problems that would ensue if US citizens were killed.[2]

Holtzendorff argued that Germany had to win the war by autumn 1917 or else it would finish with the exhaustion of all the belligerents, which would mean disaster for Germany. The Italian and French economies had been so weakened by the war that they were able to continue to fight only with British support. The Germans had to break the British economy in order to win the war, and the way to do this was to attack the British merchant fleet. Extra demands were being placed on it because Britain imported much of its food and the 1916 global grain harvest had been poor. This meant that Britain would have to replace imports from Canada and the USA with grain from Argentina, India and especially Australia.[3]

Holtzendorff thought that a destruction of 600,000 tons of merchant shipping per month would reduce British trade ‘by 39% within five months. This would not be bearable’.[4] He admitted that he could not ‘guarantee that a campaign of unrestricted submarine warfare’ would force a British surrender within five months.[5] However, acting in accordance with cruiser rules would mean sinking only 400,000 tons per month, reducing British trade by only 18%, which was not enough. Holtzendorff claimed that this was the actual rate achieved over the two previous weeks.[6] The actual losses, shown in the table below, were a little lower.

The British, however, were concerned even at the level of losses of late 1916. In October, Admiral Sir John Jellicoe, who replaced Admiral Sir Henry Jackson as First Sea Lord, the professional head of the Royal Navy, in late November, warned the Admiralty that the losses of British and neutral merchant ships might by the summer of 1917 reduce imports of food and other necessities to a level that would force the Allies to accept worse peace terms than were justified by the European military situation. Admiral Sir David Beatty, who succeeded Jellicoe as C.-in-C. of the Grand Fleet, said that the danger was ‘jeopardising the fate of the nation and seriously interfering with the successful prosecution of the war.’[7]

Holtzendorff  wanted to avoid war with the USA if possible but argued that the risk of it happening should not stop Germany ‘from making use at the decisive moment of a weapon that promises victory.’[8] He thought that the USA would not be able to replace the lost merchant shipping and that there would be insufficient transports to take US troops to Europe. He expected that the USA would make peace when Britain as it would not be able to do as much damage to Germany as U-boats did to its commerce and would want an early return to economic prosperity.[9]

The decision to launch unrestricted submarine warfare from 1 February 1917 was made at a meeting held on 9 January. Chancellor Theobald von Bethman-Hollweg, who had until then opposed unrestricted submarine warfare, finally agreed to it, commenting it that it was ‘the last card.’[10]

On 1 February 1917 the Germans had 105 U-boats available, with new construction taking their strength to 129 by 1 June. They had at least 120 for the remainder of 1917 and 124 at the end of the year. [11]

The U-boat campaign was a military success, as shown by the following table:

British tonnage sunk (excludes fishing vessels) World tonnage sunk (includes British and foreign fishing vessels
October 1916 176,248 353,660
November 1916 168,809 311,508
December 1916 182,292 355,139
January  1917 153,666 368,521
February 1917 313,486 540,006
March 1917 353,478 593,841
April 1917 545,282 881,027

Source: C. E. Fayle, Seaborne Trade, 3 vols (London: HMSO, 1920), vol. iii, p. 465.

However, it resulted in US President Woodrow Wilson breaking off diplomatic relations with Germany on 3 February.[12] He, Congress and the US public were not yet ready to enter the war.

On 16 January Arthur Zimmermann, the German Foreign Minister, sent a telegram to Count Bernstorff, the German ambassador in Washington that he was to forward to Heinrich von Eckhardt, the German minister in Mexico City. Von Eckhardt was to offer the Mexican government an alliance if war broke out between Germany and the USA. The Germans would provide financial aid to Mexico, which would regain the territory that it had lost to the USA in the Mexican-American War of 1846-48 after a victorious war. The Mexicans were also to attempt to persuade Japan to change sides.[13]

The British had destroyed the German cable communications with the rest of the world early in the war. The Germans, however, had access to two neutral cables to the USA: a Swedish one that they had been allowed to use since early in the war; and a US one that Wilson had allowed them to use when he was attempting to mediate between them and the Allies. Both passed through Britain, which could therefore intercept them. The simplicity of American codes and cyphers enabled the British code breakers of Room 40 to break them. They also had a copy of the German diplomatic code book that was captured when Wilhelm Wassmuss, a German agent in Persia, was forced to flee without his baggage.[14] The British and Russians had captured German naval code books in 1914.

On the morning of 17 January Captain Reginald ‘Blinker’ Hall, the Director of Naval Intelligence, was handed a partial translation of the intercepted cable.[15] The code was in a variant of the one captured from Wassmuss and the parts that could not be decoded included details of the terms offered by Germany to Mexico. Showing it to the Americans risked revealing to them that the British were intercepting neutral diplomatic traffic and to the Germans that their diplomatic codes had been broken. Hall, perhaps hoping that the USA might enter the war anyway, sat on the telegram until 5 February, when he showed it to the Foreign Office.

By 10 February British agents had obtained a copy of it from the Mexico City telegraph office. The German legation there used a simpler code than the one used between Berlin and Washington, and the British were able to fully decode it. It could now be passed to the Americans without them realising that the British were intercepting Swedish and US diplomatic cables. The telegram, available online at the Great War Primary Document Archive, read:

Berlin, January 19, 1917

On the first of February we intend to begin submarine warfare unrestricted. In spite of this, it is our intention to endeavor to keep neutral the United States of America.

If this attempt is not successful, we propose an alliance on the following basis with Mexico: That we shall make war together and together make peace. We shall give general financial support, and it is understood that Mexico is to reconquer the lost territory in New Mexico, Texas, and Arizona. The details are left to you for settlement….

You are instructed to inform the President of Mexico of the above in the greatest confidence as soon as it is certain that there will be an outbreak of war with the United States and suggest that the President of Mexico, on his own initiative, should communicate with Japan suggesting adherence at once to this plan; at the same time, offer to mediate between Germany and Japan.

Please call to the attention of the President of Mexico that the employment of ruthless submarine warfare now promises to compel England to make peace in a few months.

(Secretary of State)

Arthur Balfour, the British Foreign Secretary, handed it to Walter Page, the US ambassador to London on 23 February. It was published in the USA on 1 March. A minority of Americans argued that it was a forgery. Hall took steps to prove to that it was genuine, but these proved unnecessary when Zimmermann admitted on 3 March that he had sent it.[16]

Wilson had already decided to ask Congress for permission to arm US merchant ships, which would have almost certainly have resulted in an incident that led to war. The measure was passed overwhelmingly by the House of Representatives but was filibustered out of the Senate. Wilson decided to go ahead anyway. On 20 March, after a number of US merchant ships were sunk by U-boats, he obtained the unanimous consent of his cabinet for a declaration of war. [17] On 2 April the House of Representatives voted 373 to 50 in favour of war, with the formal declaration coming on 6 April.[18]

The Germans thought that they would have starved Britain into surrender before the USA, which in April 1917 had an army of 213,557 men and 55 aircraft, 51 of them obsolete, could make a decisive difference. However, by the end of the war 1.97 million US troops had been sent to the Western Front, with no troopships being sunk on the way from the USA to Europe. By the summer of 1918 the USA was sending 536,000 tons of supplies per month to France, with a troop or cargo ship leaving every five hours. The USN committed 68 destroyers and 121 submarine chasers to the battle against the U-boats.[19]

This link, to a new exhibit at Arlington National Cemetery marking the 100th anniversary of American involvement in World War I, was kindly pointed out to me by G.P. Cox, writer of the excellent Pacific Paratrooper blog.


[1] D. Steffen, ‘The Holtzendorff Memorandum of 22 December 1916 and Germany’s Declaration of Unrestricted U-Boat Warfare’, Journal of Military History 68, no. 1 (2004), pp. 215-16.

[2] A. J. Marder, From the Dreadnought to Scapa Flow; the Royal Navy in the Fisher Era, 1904-1919, 5 vols (London: Oxford University Press, 1961-70). vol. iv, p. 51.

[3] Steffen, ‘Holtzendorff’, pp. 219-20.

[4] Ibid., p. 221. This and subsequent quotations are from Holtzendorff’s memo, which is reproduced in Steffen’s paper.

[5] Ibid., pp. 220-21.

[6] Ibid., p. 222.

[7] J. S. Corbett, H. Newbolt, Naval Operations, 5 vols (London: HMSO, 1938). vol. iv, pp. 324-25.

[8] Steffen, ‘Holtzendorff’, p. 222.

[9] Ibid.

[10] Marder, From. vol. iv, p. 51.

[11] P. G. Halpern, A Naval History of World War I (London: UCL Press, 1994), pp. 338-39.

[12] Ibid., p. 340.

[13] D. Stevenson, 1914-1918: The History of the First World War (London: Allen Lane, 2004), p. 313.

[14] C. M. Andrew, Secret Service: The Making of the British Intelligence Community (London: Heinemann, 1985), pp. 107-8.

[15] Hall was promoted Rear Admiral on 27 April 1917. His nickname resulted from a chronic facial twitch.

[16] Andrew, Secret, pp. 110-13.

[17] Stevenson, 1914-1918, p. 317.

[18] H. H. Herwig, The First World War : Germany and Austria-Hungary, 1914-1918 (London: Arnold, 1997), p. 320.

[19] Ibid.


Filed under Political History, War History

Allegations of War Crimes at Sea in 1915

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.[1] 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.[2]

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.[3] 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.[4] 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.[5] Paul Halpern says that 44 died, including two or three US citizens.[6]

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.’[7]

Baralong received the Arabic’s SOS, but arrived too late to help.[8] 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.[9]

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.[10] 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.[11]

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. [12]

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.’[13] 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.’[14]

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.[15]

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.[16]

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.’[17]

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.[18] Palen, however, was born in Canada.[19]

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.[20] The first raid on London by an airship took place on 31 May, killing five people and injuring 35.[21]

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.[22]

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.[23] Tirpitz was told that he would no longer be needed at ‘consultations on naval questions connected with foreign politics.’[24]

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.[25]

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.[26] 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.[27] 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.[28]

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.[29]

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.[30] 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.[31]

Five U-boats were lost in 1914, two in January 1915 and 15 from March to September 1915.[32] 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.[33]

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.

[1] The last two paragraphs are based on J. S. Corbett, H. Newbolt, Naval Operations, 5 vols. (London: HMSO, 1938). vol. iii, pp. 135-36.

[2] Ibid., p. 131.

[3] 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.

[4] Naval Staff Monograph (Historical) 1926 vol. xiv, Home Waters part v, July 1915 to October 1915. pp. 81-82.

[5] 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.

[6] P. G. Halpern, A Naval History of World War I (London: UCL Press, 1994), p. 301.

[7] 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.

[8] Ibid., p. 23.

[9] Naval Staff vol. Xiv. ‘Appendix N, Report from M.F.A. Baralong’, p. 229,

[10] Bridgland, Sea Killers, pp. 24-27.

[11] Naval Staff vol. Xiv. pp. 229-30.

[12] PP, Cd. 8144. pp. 1-4.

[13] Ibid., p. 11.

[14] Ibid., p. 8.

[15] Bridgland, Sea Killers, p. 37.

[16] Hurd, Merchant. vol. ii, pp. 33-34.

[17] PP, Cd. 8176.

[18] Bridgland, Sea Killers, pp. 26, 36.

[19] PP, Cd. 8144. p. 6.

[20] H. H. Herwig, The First World War: Germany and Austria-Hungary, 1914-1918 (London: Arnold, 1997), pp. 135, 168-69.

[21] 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.

[22] Naval Staff vol. Xiv. p. 173.

[23] Corbett, Newbolt, Naval. vol. iii, p. 141

[24] Naval Staff vol. Xiv. p. 173.

[25] Halpern, Naval, p. 302.

[26] Naval Staff vol. Xiv. p. 175.

[27] Ibid., pp. 176-77.

[28] Bridgland, Sea Killers, pp. 51-54.

[29] Halpern, Naval, p. 385.

[30] V. E. Tarrant, The U-Boat Offensive, 1914-1945 (London: Arms and Armour, 1989), pp. 152-53.

[31] Halpern, Naval, p. 303.

[32] Tarrant, U-Boat, p. 24.

[33] R. H. Gibson, M. Prendergast, The German Submarine War, 1914-1918. (London: Constable, 1931), pp. 63-64.


Filed under War History

The Sinking of the Lusitania 7 May 1915

On 1 May 1915 the Cunard Liner RMS Lusitania, captained by Captain William Turner, left New York for Liverpool. The German Embassy to the USA took out advertisements in US newspapers warning passengers that the waters round the British Isles were a war zone in which merchant ships were liable to be sunk without warning. The German ad did not specifically mention the Lusitania or Cunard, but the most commonly reproduced version shows it to be placed below Cunard’s announcement of the departure times of its services to Liverpool.[1]170px-Lusitania_warning

The day before the Lusitania sailed, the German U-boat U-20 departed from Germany. Her captain, Kapitänleutnant Walther Schweiger, had orders to attack transports off Liverpool.[2] He had been in command when U20 sank three British merchants hips off Le Havre on 30 January, before the German declaration of unrestricted submarine warfare. He had also unsuccessfully tried the sink the hospital ship Asturias, claiming that he thought that she was a troopship and could not in any case have been carrying wounded as she was heading from the United Kingdom.[3]

Schweiger sank the schooner Earl of Lathom (132 tons), carrying bacon, eggs and potatoes to Liverpool, by gunfire on 5 May off the Old Head of Kinsale on the south coast of Ireland after giving her crew time to abandon ship. Later that day he fired a torpedo at a 3,000 ton steamer but missed.

The next day he made a surface attack on the steamer Candidate (6,000 tons) in the St George’s Channel. She was heading for Jamaica with a cargo of hardware and groceries. She tried to flee into fog banks, but was eventually forced to stop by gunfire. Schweiger fired a torpedo at her after the crew had abandoned ship, but she would not sink, so U20 had to finish her off by gunfire.

Later that day, after being unable to get into position to torpedo the 16,000 ton passenger liner Arabic, Schweiger fired a torpedo at the steamer Centurion (6,000 tons), en route to Durban. She did not sink, and he finished her off with another torpedo after the crew had abandoned ship. This left him with only three torpedoes; his standing orders said that he was to keep a minimum of two for the return journey.[4]

The large number of patrol ships in the area meant that U-20 would have to proceed to Liverpool submerged, which would be difficult because fog restricted visibility using the submarine’s periscope. Consequently, Schweiger decided to remain in the entrance to the Bristol Channel.

On 7 May he spotted the cruiser HMS Juno, which he followed in the hope of an opportunity to torpedo her. However, she headed for the Queenstown (now Cobh) on the south coast of Ireland. Schweiger, not wanting to approach a well defended naval base, turned away to the west.

Soon afterwards Schweiger spotted a four funnelled liner off the Old Head of Kinsale. It did not appear that he could get his boat into an attacking position until the liner, which was the Lusitania, turned towards U20. Schweiger fired a torpedo at 2:10 pm at a range of 700 metres. It struck just astern of the bridge, producing a large explosion and causing the ship to stop and list.

Schweiger, realising that the Lusitania was doomed, left the scene. He fired a torpedo that suffered a mechanical failure at another Cunarder later the same day.

An SOS signal from the Lusitania was received at 2:11 pm. HMS Juno was ordered to go to her aid, in contravention of Admiralty orders that the old ships of Cruiser Force E at Queenstown should not be put at risk of submarine attack. All available tugs, small craft and patrol vessels were also sent. At 2:33 pm a signal reporting that the Lusitania had sunk was received. Juno was then recalled.[5]

The Lusitania was capable of only 21 knots rather than her full speed of 24 knots. This was because of a commercial decision by Cunard to use only 18 of her 24 boilers in order to make it economic to run her when passenger traffic was reduced in wartime: she was capable of carrying 2,350 passengers and had a crew of 750 in peacetime.[6] Because of the fog Turner had reduced her speed to 15 knots, but had increased it to 18 knots by the time of the sinking as visibility had improved.[7]

U20 returned to Wilhemshaven on 13 May with ‘only 19 tons of oil left’, according to the British Naval Staff Monograph, written in 1925 for internal Royal Navy use only.[8] This phrase makes it sound as if his tanks were almost dry, but U20’s fuel capacity was only 77 tons:[9] presumably 1925 RN officers would have been expected have at least a rough idea of this number.

A total of 1,201 people were killed when the Lusitania sank: 785 out of 1,257 passengers, including 128 Americans, 413 of the 702 strong crew and three stowaways. Some sources quote 1,198, omitting the stowaways. [10] They were German speakers, so were suspected of being spies or saboteurs and held in confinement below decks.[11] Only six out of 48 lifeboats reached Queenstown intact.[12]

Many of the survivors were rescued by small craft from Queenstown, including the Indian Prince and the Flying Fox, and by fishing vessels such as the Peel 12 and the Bluebell.[13]

The Lusitania’s cargo included a number of cases of munitions: 4,200 each containing about 1,000 rifle cartridges, 1,250 of 3.3 inch shrapnel shells and 18 of percussion fuses. The shells and fuses were stated in the official manifest to be without explosives. it was also carrying material for military uniforms and leather equipment.[14]

These items were all classed as contraband under the rules of cruiser warfare. These rules entitled Schweiger to stop and search Lusitania and, on finding the contraband, to require the crew and passengers to take to the lifeboats before he sank the liner and her cargo. They did not allow him to sink her without warning. However, he would have been putting his boat at severe risk by acting in accordance with the rules so close to the British base at Queenstown.

Some media sources, including The Guardian and The Daily Telegraph, have suggested that the British government admitted only recently that the Lusitania was carrying munitions after some Foreign Office documents from 1982 were made public. They dealt with concerns that salvage operations then proposed might reveal the presence of explosives. However, the fact that she was carrying munitions was revealed by the 1918 Mayer hearing into lawsuits against Cunard, although allegations that there were more explosives on board than then admitted persist.[15]

There are several mysteries about the sinking of the Lusitania. One is when Schweiger realised which ship he had sunk. The Naval Staff Monograph, sourcing the German Official Naval History, says that it was not until he saw her name painted on her bows in gold letters, but notes that Lusitania’s captain says that this had been painted over.[16]

German U-boats carried a pilot, a merchant navy officer intended to help with ship identification. Simpson says that U20’s pilot identified the liner as being either the Lusitania or her sister the Mauretania before firing.[17]

Preston argues that there were only five four funnelled British liners and that the Germans knew that the Lusitania was the only one of them that could be inbound on 7 May. She contends that Schweiger’s war diary was later altered to conceal the fact that he knew exactly what ship he was torpedoing.[18]

A major issue is that there were two explosions. The British Official History of The Merchant Navy claims that Schweiger fired two torpedoes, whilst quoting a German source that says that he did not.[19] It is now accepted that he fired only one.

Colin Simpson argues that Schweiger’s torpedo flooded the starboard coal bunkers and cased a 15 degree list, but that it was the second explosion that sank the Lusitania, which he believes was caused by the explosion of contraband. He argues that this is supported by the fact that relevant Admiralty papers, including those of Captain Reginald Hall, Director of Naval Intelligence, and Captain Guy Gaunt, Naval Attaché in Washington, were unavailable when he researched his 1972 book.[20] Some of Hall’s papers are now available at Churchill College, Cambridge, but they do not appear to include any from May 1915.

Diana Preston goes through a number of theories to explain the second explosion:[21]

  1. The munitions that were known to be carried. The shells would have remained inert even if they, contrary to the manifest, contained their powder and propellant charges because they would still have lacked their fuses, a standard procedure during transport. The rifle cartridges would not have exploded, as shown by an example in 1972 when a railway wagon full of United States Navy bullets caught fire but did not explode.
  2. Detonation of less stable explosives that it has been rumoured but never proven were secretly on board. The Scientific American concluded soon after the sinking that such as explosion would have blown the Lusitania’s bows off. A survey of the wreck by the oceanographer and underwater archaeologist Robert Ballard showed no such damage.
  3. Aluminium powder that the manifest showed was being transported to the Woolwich Arsenal. This is highly volatile and can ignite spontaneously in air. However, it would also have created a much larger explosion and greater damage than actually occurred. Some of the crew from the cargo area survived, which they would not have done in this case.
  4. Coal dust explosion. This can ignite if exposed to a spark or flame in the right conditions. However, seepage of sea water into the hull, moist air from the boilers and sea water from the flooding that followed the torpedo hit mean that the conditions were not right.
  5. A boiler explosion. This is the only explanation that would have produced the steam reported by survivors. The sound would have been carried up through the funnels and vents, explaining why the explosion sounded loudest to those on deck. The main flaw is that some of the boiler room personnel survived, which would not have been the case if the boilers exploded immediately. However, a delay of a minute or two would have allowed a few men to get out.
  6. Failure of the steamlines that carried high-pressure superheated steam from the boilers to the turbines. The effect of this fits the reports of survivors.

Preston argues convincingly that ‘steamline explosions are easily the most likely source of the second explosion’, quoting Captain Turner as telling the Mayer hearing that ‘The torpedo burst the steampipe and put the engines out of commission.’[22]

However, Preston’s conclusion is that there were probably a number of explosions, and that the main cause of the sinking of the Lusitania was that she was not designed to survive a torpedo hit in a vital area.[23]

It may seem strange that Lusitania, a ship displacing more than 30,000 tons sank about 20 minutes after being hit by a single torpedo. However, three months later the Arabic went down nine minutes after being hit by a torpedo. HMS Aboukir, an armoured cruiser, albeit an elderly one with weak underwater protection, took only nine minutes to sink after being hit by a single torpedo.[24] The old Ottoman battleship Mesudiye also sank after being hit by only one torpedo from HMS B11.

The Germans subsequently claimed that the Lusitania was a Royal Navy auxiliary cruiser. Her construction and that of the Mauretania had been financed by a cheap loan from the British government, which was concerned that Cunard was struggling to compete with its German and US rivals. In return, they were to be built to the Admiralty’s specifications and were to be taken out of passenger service and converted into armed merchant cruisers if hostilities threatened. A set proportion of their crews must be members of the Royal Naval Reserve. In 1913 the Lusitania was refitted to allow her to carry 12 6 inch guns.[25]

However, the Lusitania was never actually fitted with guns. The Admiralty considered doing so at the start of the war, but decided that she was too expensive to fuel relative to her value as a warship. Inspections by US customs officials and film of her leaving New York on her last voyage showed no sign of any armament.[26] Most of the naval reservists on board the Lusitania in 1914 had by May 1915 been called up by the RN, leaving her with an inexperienced crew.[27]

The Germans also alleged that the Lusitania was carrying Canadian troops across the Atlantic. If they were travelling as an armed and organised unit, rather than as individuals, this would have made her a troopship liable to be sunk without warning. There is no evidence in archives or the accounts of survivors to support this claim. One of the dead passengers, Robert Matthews, was a Lieutenant in the 60th Rifles of Canada, a militia unit. However, he had not attended any drills in the winter of 1914-15, had been rejected for a commission in the Canadian Expeditionary Force and was travelling with his mistress.[28]

The other main conspiracy theory is that the British deliberately put the Lusitania in danger in the hope that she would be sunk, bringing the USA into the war on the Allied side. However, the British in 1915 were happy to have the USA as a friendly neutral munitions supplier rather than as an ally that would want to impose its views on a peace settlement.[29]

As with most conspiracy theories, there is no archival evidence to support it, but the proponents of conspiracy theories always argue that the absence of evidence is itself part of the conspiracy. There are some gaps in British government correspondence during the period in question, notably from Winston Churchill, the First Lord of the Admiralty and Admiral Lord Fisher, the First Sea Lord.

However, the two were then mainly pre-occupied with their dispute over the Dardanelles, Churchill was in France at the time of the sinking and Fisher was close to a nervous breakdown. Their by then poor relations make it unlikely that they would have co-operated in a conspiracy or that either would have kept quiet if the other had been responsible for one. The other contender was Hall, but if he did conspire, it is more likely to have been by omission than commission by not passing on intelligence about U-boat movements.[30]

A conspiracy to have the Lusitania sunk left a lot of things to chance. U20 might not have been in the right place to meet her. The Lusitania might not have approached at an angle that gave Schweiger such a good chance. He might not have aimed so well. His torpedo might have suffered a technical failure, as did the one that he fired the next day. One torpedo might not have been enough, although an unsuccessful attempt to sink the Lusitania might have achieved the objective of the alleged conspirators without serious loss of life.

Like Preston, I have a preference for the cock up theory over the conspiracy one.[31] The Lusitania was not warned that U-boats were operating in the area because the Admiralty was then lax in issuing warnings. Initiative was discouraged and information shared even less widely than security dictated. The Lusitania did not have an escort because it was thought that her speed made her safe. The Admiralty’s anti-submarine strategy was then to patrol waters where there was a risk of U-boat attack rather than to escort merchant ships.

Even in the Second World War, when merchant ships normally sailed in escorted convoys, fast liners such as the Queen Elizabeth and Queen Mary carried large number of Canadian and Us troops across the Atlantic unescorted, depending on their high speed to avoid U-boat attack.

The sinking of the Lusitania caused great damage to US-German relations. President Woodrow Wilson wrote a note that stated that:

‘Manifestly, submarines cannot be used against merchantmen…without an inevitable violation of many sacred principles of justice and humanity.’[32]

This comment formed part of a note that was sent to Germany despite the protests of Secretary of State William Jennings Bryan that it was too pro-British. It arrived on 15 May, by when Kaiser Wilhelm had already ordered his U-boats to cease sinking neutral ships. The navy ignored this order, and Wilhelm reiterated it on 1 June, this time adding that enemy passenger liners should also be spared. Admirals Gustav Bachmann, Chief of the Admiralty Staff, and Alfred von Tirpitz, State Secretary of the Imperial Naval Office, both thought that by doing so Germany was admitting that the sinking of the Lusitania had been illegal and was giving up its best weapon against the UK.[33]

Unrestricted U-boat warfare did bring the USA into the war, but not for nearly two years. From a US point of view, the crucial difference between the British blockade and German unrestricted submarine warfare was that the British only interfered with US trade and property, whilst the Germans additionally killed Americans. The German problem in 1915 was that they did not enough U-boats to win the war by submarine warfare, but trying to do so would damage their relations with the USA.

This website contains a great deal of information about Lusitania and her passengers and crew.


[1] D. Preston, Wilful Murder: The Sinking of the Lusitania, Special Centenary edition. ed. (London: Doubleday, 2015 edition, first published 2002), p. xii; C. Simpson, Lusitania (London: Longman, 1972). Frontispiece.

[2] Naval Staff Monograph (Historical) 1925 vol. xiii, Home Waters part iv, February 1915 to July 1915. p. 169.

[3] Preston, Wilful, pp. 152-53.

[4] Ibid., pp. 162-67.

[5] Naval Staff vol. Xiii. pp. 169-72.

[6] A. S. Hurd, The Merchant Navy, 3 vols. (London: HMSO, 1921). vol. i, pp. 411, 413.

[7] R. K. Massie, Castles of Steel: Britain, Germany, and the Winning of the Great War at Sea (London: Jonathan Cape, 2004), p. 531.

[8] Naval Staff vol. Xiii. p. 172.

[9] R. Gray, Conway’s All the World’s Fighting Ships, 1906-1921 (London: Conway Maritime Press, 1985), p. 176.

[10] Preston, Wilful, p. 299.

[11] Ibid., pp. 131-2, 208.

[12] Simpson, Lusitania, p. 165.

[13] Hurd, Merchant. vol. i, pp. 420-24.

[14] Preston, Wilful, p. 394.

[15] Hurd, Merchant. vol. i, p. 414.

[16] Naval Staff vol. Xiii. pp. 171-2. pp. 171-72 and footnote 1 on p. 172.

[17] Simpson, Lusitania, p. 147.

[18] Preston, Wilful, pp. 423-25.

[19] Hurd, Merchant. vol. i, p. 418

[20] Simpson, Lusitania, p. 151.

[21] Preston, Wilful, pp. 436-44.

[22] Ibid., p. 444.

[23] Ibid.

[24] Ibid., p. 432.

[25] Simpson, Lusitania, pp. 20-32.

[26] Preston, Wilful, pp. 391-92.

[27] Ibid., p. 108.

[28] Ibid., pp. 393-94.

[29] Ibid., p. 401.

[30] Ibid., pp. 402-3.

[31] Ibid., pp. 389-90.

[32] Quoted in Massie, Castles, p. 537.

[33] Ibid., pp. 539-40.



Filed under War History

The Naval Blockades: (2) Germany

During the First World War both the United Kingdom and Germany attempted to carry out naval blockades of the other. Each country used actions by the other to justify escalations by the other. The Germans laid unanchored, floating mines in the North Sea early in the war. International law said that such mines had to become inoperable after an hour. It was not feasible to do so, but this gave the UK an opportunity to argue that it was Germany that had first broken international law.

The UK then tightened its blockade beyond what was permitted by the 1909 Declaration of London. On 5 November the Admiralty announced that the whole of the North Sea was a war zone, warning that ships entering from the north would do so at their own risk. The official reason for this was the German minefields, but the real one was to force neutral ships heading into the North Sea to go through the English Channel, making it easier to search them for contraband.

On 4 February 1915 Germany announced that the waters round the United Kingdom of Great Britain and Ireland would be a war zone from 18 February. It justified this by reference to the British declaration of 5 November. All hostile merchant ships in this area would be destroyed without warning. The safety of neutral ships could not be guaranteed because British ships had been flying neutral colours. U-boat captains were ordered that their first duty was the safety of their boat, so they should not take risks to find out if a ship was really neutral.[1]

In 1914 the most important successes of German U-boats had been against warships. This continued in 1915, with U24 sinking the pre-dreadnought battleship HMS Formidable in the early hours of the year.

It was extremely difficult for submarines to comply with the rules of cruiser warfare, which required raiders to stop and search enemy merchant ships. Merchant ships could be sunk or captured only if their cargoes contained either war materials (absolute contraband) or items such as food or fuel that had peaceful uses but were intended for the enemy’s military (conditional contraband).

The safety of the crews of merchant ships that were sunk had to be ensured. Submarines had no space for prisoners and no spare men to act as prize crews for captured ships, so could comply with this only if the sinking occurred close to land.

One man had predicted before the war that submarines would sink merchant ships without warning. This was the British Admiral Lord Fisher, who by February 1915 was in his second spell as First Sea Lord. In late 1913 he had written a paper arguing that the invention of the submarine meant that the main threat to the UK was having its food and oil supplies cut off by submarine attacks on its merchant shipping

Winston Churchill, the First Lord of the Admiralty, and Admiral Prince Louis Battenberg, then the First Sea Lord, both refused to believe that any country would use its submarines in such a way. They thought that Fisher’s view that it would be done weakened his arguments about the risk of submarine attack on the UK’s food and oil supplies.[2]

Only four British merchant vessels had been sunk by U-boats before 30 January. In each case the Germans had given the crew time to abandon ship and no lives were lost.[3]

The most controversial incident had come on 26 October when Kapitänleutnant Rudolf Schneider’s U24 torpedoed but did not sink the 4,590 ton French steamer Amiral Ganteaume. She was carrying 2,500 Belgian refugees, 40 of whom were killed. However, Schneider may have thought that she was a troop ship. Whether he did or not, the incident showed the potential political and diplomatic implications of submarine warfare against merchant shipping.[4]

In the Irish Sea on 30 January U21, which had sunk the cruiser HMS Pathfinder in September, the first moving warship ever to be sunk by a submarine, stopped, searched and sank three British merchantmen after allowing their crews time to take to their boats. On the same day, however,  U20 torpedoed and sank three British merchant ships off Le Havre without warning. The crews of the Tokomaru and Ikaria all survived, but all that was found of the 21 man crew of the Oriole was two lifebuoys discovered near Rye on 6 February.[5]

Before the war Kapitänleutnant Ulrich Blum of the Kaiserliche Marine, the German navy, had estimated that 222 U-boats would be needed to successfully carry out a war against British commerce under international law, far more than Germany possessed in early 1915.[6]

The KM began the war with 24 operational U-boats, plus four older ones that were used for training and 16 under construction. By 22 February 13 more had been completed, but one of the new boats and six of the pre-war ones had been lost. Seven newly completed boats were under sea trials, leaving the KM theoretically with 23 to attack British trade. The need to refit, repair and resupply meant that there was an average of 5.6 and a maximum of 12 boats at sea on any one day between March and May 1915.

After the German capture of the Belgian coast gave them bases much closer to the UK, they had begun to build smaller UB and UC coastal submarines. The latter were minelayers, which initially were armed only with mines, although later ones also had torpedo tubes and guns. They were supposed to take four months to build compared with 18 for an ocean going boat, but UB1 was constructed in 75 days. By mid July 1915 17 UBs and 15 UCs had been completed, but the first six UBs were not operational until the latter part of April and UC1 not until early June. [7]

The U-boat war against British trade would eventually cause great problems for the UK, but Germany had too few submarines when it first launched its offensive. However, British counter-measures were also inadequate at first.

The Germans had lost a high proportion of their submarines so far in the war, but two had been rammed by warships whilst on the surface, four had struck mines and the seventh had been sunk by another U-boat on the surface after failing to respond to a challenge. The method that British warships possessed of sinking submerged submarines was the towing of explosive sweeps.

The British had laid a minefield across the Dover Straits in an attempt to stop U-boats entering the English Channel, but 4,000 out of just over 7,000 mines laid between 2 October 1914 and 16 February 1915 drifted or sank to the bottom because the weights holding them in position were too light.[8] The British also laid nets and organised patrols of small, armed ships, but the U-boats were able to pass through the Dover Straits.

The orders issued to U-boat captains on 18 February were that they should attack all hostile ships except hospital ships, unless clearly acting as troopships, and Belgian Relief ships. Neutrals should be spared. However, they were told that ‘if, in spite of the exercise of great care , mistakes should be made, the commanding officers will not be held responsible.’[9]

However, the first ship to be attacked in the new campaign was the Norwegian Belridge, which was carrying a cargo of oil from New Orleans to Amsterdam for the Dutch government. She was torpedoed on 19 February, but managed to make a British port. The Germans apologised and paid compensation.[10]


[1] P. G. Halpern, A Naval History of World War I (London: UCL Press, 1994), pp. 293-94.

[2] R. H. Gibson, M. Prendergast, The German Submarine War, 1914-1918. (London: Constable, 1931), p. 24.

[3] C. E. Fayle, Seaborne Trade., 3 vols. (London: HMSO, 1920). vol. i, pp.358, 365-66.

[4] Halpern, Naval, p. 292.

[5] Fayle, Seaborne. vol. i, pp. 366-68.

[6] Halpern, Naval, p. 291.

[7] V. E. Tarrant, The U-Boat Offensive, 1914-1945 (London: Arms and Armour, 1989), p. 7.

[8] Ibid., p. 17.

[9] Gibson, Prendergast, German, p. 31.

[10] Fayle, Seaborne. vol. ii, p. 12


Filed under War History