Tag Archives: blockade

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

The Naval Blockades: (1) The United Kingdom


During the First World War both the United Kingdom and Germany attempted to carry out naval blockades of the other.

Blockades had been a part of British strategy in its wars with European enemies for many years. In the early 18th century they were mainly strategic, with the intention of giving warning if enemy fleets came out of port. By the end of that century, they also aimed at damaging enemy trade.

The UK had paid little attention to the rights of neutrals during its 18th and early 19th century wars: this was one of the causes of the War of 1812 with the United States of America. In 1856, however, it signed the Declaration of Paris, which stated that belligerents should not interfere with neutral trade. including enemy cargoes carried in neutral ships and neutral cargoes carried in enemy ships.

However, the protection offered to neutral trade did not extend to contraband, which was divided into two categories. Absolute contraband was items useful only to the military. Conditional contraband meant goods with both peaceful and military uses that were clearly destined for the enemy’s armed forces.

Conditional contraband was not defined by the Declaration of Paris. The UK insisted that it did not include food, but other countries disagreed. France, supported by Germany, declared it to be contraband during its 1885 war with China, as did Russia in the 1904-5 Russo-Japanese War.

The UK was the world’s largest shipping carrier, a net importer of food and an exporter of manufactured goods. It had to consider the issue from three viewpoints: as a neutral in other people’s wars; the defensive one of defending its own trade; and the offensive one of blockading the enemy. Defensively, in a war with another country, it could continue to import from the USA in US ships. However, other European countries were less vulnerable to blockade than they had been before the development of railways, provided that they neighboured neutral countries.

In 1909 the Declaration of London attempted to define contraband. Absolute contraband was confined to a small number of purely military items, whilst the list of supplies defined as conditional contraband included food provided that it was for military, not civilian consumption.

The British delegates agreed the terms of the Declaration of London, but the UK never ratified it. There were protests from the public, which focussed mainly on the neutral and defensive angles, and a petition signed by 138 retired admirals.

Sir Edward Grey, the Foreign Secretary, and the Foreign Office accepted the Declaration. They were concerned mainly with the neutral and defensive issues of protecting Britain’s merchant fleet and its wartime food supply.[1]

The Admiralty was planning to conduct economic warfare in the event of a war with Germany, which makes the agreement of its delegates to the London Conference more puzzling. Avner Offer suggests that it may have been ‘partly a matter of muddle and neglect’, but also offer a ‘more Machiavellian interpretation’; Admiral Lord Fisher, the First Sea Lord, may have wanted the UK to have legal protection when a neutral, but expected it to act in its self interests in wartime.[2]

Some contemporary writers, such as Thomas Gibson Bowles, feared that the 1909 Declaration of London would prevent the Royal Navy from exerting the same pressure on a future enemy that they claimed had won past wars. However, Archibald Bell, the Official Historian of the British blockade, argues that Bowles’s claim that past blockades had been decisive was wrong. Bell contends that British leaders of the past ‘had never hoped that a continental enemy could be brought to terms by stopping its commerce.’[3]

Fisher’s immediate successor as First Sea Lord, Admiral Sir Arthur Wilson, was sceptical about the merits of blockade, but he had retired by 1914. By then British strategy was to blockade Germany in wartime. The UK was allied to France and Russia, so the fears that a naval blockade would be circumvented by trade with neighbouring countries no longer applied. Germany was surrounded and her trade with the rest of the world could be stopped if Antwerp and Rotterdam were blockaded.[4]

Just before the start of the war the British decided that the traditional policy of a close blockade of enemy ports was no longer viable because of the threat of attack from torpedo armed enemy vessels on the blockading force. Instead, a distant blockade would be carried out. The Channel Fleet would block the English Channel, whilst a line of cruisers from the Shetland Islands to Norway would close the northern entrance to the North Sea.

There were, however, some difficulties in implementing the blockade when war came. One was the doctrine of continuous voyage. Absolute contraband intended for Germany could be stopped even if it was to be first unloaded in a neutral port such as Rotterdam and then transported by land to Germany. However, the Declaration of London stated that conditional contraband could only be stopped if it was heading directly to an enemy port.

The UK was reluctant to abandon entirely the Declaration of London, partly because Grey did not want to give up his support for neutral rights and international law and partly because it did not want to offend the USA.

However, 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 announced that it would apply continuous voyage to conditional as well as to absolute contraband.

The UK also decided the treat food as contraband after it received reports that all food distribution in Germany was to be taken over by the government. The reports were actually an exaggeration of a plan to control food prices, but the British went ahead. However, the early British efforts at blockade did not have the desired effect. There was a reluctance to take measures that would offend neutrals who also supplied the UK.[5]

The naval force carrying out the blockade was also weak. Eric Osborne describes Rear Admiral Dudley De Chair as ‘an excellent choice for the job’ of commanding the 10th Cruiser Squadron, responsible for closing the northern approaches to the North Sea.[6] However, he initially had only six Edgar and two Royal Arthur class cruisers, launched in 1890-92. They were too slow to catch blockade runners and struggled in the harsh weather of their patrol area. they also had to take part in sweeps of the North Sea by the Grand Fleet. On 15 October one of them, HMS Hawke, was sunk by U9.

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. A number of Scandinavian shipping companies agreed that their ships would call at Kirkwall for inspection in return for being allowed to use the northern route.

The blockade was also strengthened in December by the replacement of the 10th Cruiser Squadron’s old ships with 23 armed merchant cruisers, merchant liners requisitioned by the navy and armed. They were both more numerous and more suitable for their role than the old warships initially assigned to it.[7]

The British blockade was not as successful in 1914 as its planners had hoped. It later tightened because the UK signed agreements with neutral countries, but only one of these, with the Netherlands on 23 November, was concluded in 1914. The UK had to move slowly because it could not afford to offend neutrals, especially the USA.[8]

The greatest British success in destroying German trade in 1914 was in sweeping the German merchant fleet from the seas, causing major economic problems for Germany. In November there were 221 German merchant ships were laid up in German ports and 1,059 in neutral ports, with another 245 having been interned in Allied ports.[9]

Osborne argues that:

‘The official reports on Germany’s economic conditions for November and December revealed hardship, but not sufficient to cripple the German war effort…The greatest achievement of British negotiations in 1914 was not the practical results achieved but the establishment of a foundation for future tightening of the blockade…The deadlock on the Western Front meant that economic pressure was vital to the success of the Allied cause and measures to date were not satisfactory.’[10]

The development of the British blockade was an example of the way in which a breach of international law by one side would be used by the other to justify a further breach, leading towards total war. The next escalation would be made by the Germans, when they used the British declaration that the North Sea was a war zone to justify the implementation of unrestricted submarine warfare.


[1] A. Offer, The First World War: An Agrarian Interpretation (Oxford: Clarendon, 1989), pp. 271-77.

[2] Ibid., pp. 278-79.

[3] A. C. Bell, A History of the Blockade of Germany and of the Countries Associated with Her in the Great War – Austria-Hungary, Bulgaria, and Turkey, 1914-1918 (London: HMSO, 1961), p. 18.

[4] Offer, First, pp. 285-99.

[5] E. W. Osborne, Britain’s Economic Blockade of Germany, 1914-1919 (London: Frank Cass, 2004), pp. 58-65.

[6] Ibid., p. 59.

[7] Ibid., pp. 72-73.

[8] Ibid., pp. 76-78.

[9] Ibid., p. 61.

[10] Ibid., p. 79.


Filed under War History

Pre WWI British Naval War Plans

As in previous wars, Britain intended to blockade its Continental enemies in order to prevent them from trading with the rest of the world. In 1908 Admiral Sir John ‘Jacky’ Fisher, the First Sea Lord, decided that the traditional close blockade was no longer viable because of the threat from torpedo armed vessels. He therefore ordered that the blockade ships should withdraw 170 miles at night.

In 1911 Admiral Sir Arthur Wilson, his successor, reinstated the plan for a close blockade. However, as well as being very risky, it required twice as many destroyers as the Royal Navy (RN) possessed, since one would be in port refuelling and one on the way to or from the port for each one on duty.

In mid-1912, the Admiralty considered replacing the close blockade with an observational one across the North Sea in the middle of 1912. This was rejected because it was still vulnerable to German attack and needed too many ships. Admiral Prince Louis Battenberg, who was appointed First Sea Lord in December 1912, called this idea ‘plain stupid.’[1]

A policy of distant blockade was introduced in July 1914. The Channel Fleet would block access to the English Channel. A line of cruisers from the Shetlands to Norway would prevent German trade with the rest of the world. They would be safe from the enemy because the Grand Fleet, the RN’s strongest force, including most of its dreadnoughts and battlecruisers, would frequently patrol the North Sea from its base at Scapa Flow in the Orkneys.

A good performance by submarines in the 1913 fleet manoeuvres led to suggestions that the close blockade might be reinstated using submarines. Nicholas Lambert notes that ‘[s]ufficient evidence has survived…to contradict widespread assertions of myopia among British naval officers with regard to the submarine.’[2] Admiral Sir John Jellicoe wrote that submarines ‘can undoubtedly carry out a blockade of the enemy’s coast in the old sense of the word.’[3]

There were not enough submarines to adopt such a policy in 1914, but it was intended to increase submarine construction in later years. The Naval Estimates had risen from £31.3 million in 1907-8 to £48.7 million in 1913-14. It could be reduced by replacing a planned battleship with a number of submarines. Winston Churchill, then First Lord of the Admiralty, wrote in the first draft of The World Crisis, his history of the First World War, that the margin of 60 per cent over Germany could be maintained by regarding dreadnoughts ‘not as capital ships, but as units of power which could, if desirable, be expressed in any other form.’[4]

The British switch to a distant blockade ruined German plans to whittle down the RN by attacks on British ships carrying out a close blockade. Admiral Alfred von Tirpitz, the Secretary of State for the Imperial Navy Office, asked Admiral Friedrich von Ingenohl, the commander of the High Seas Fleet, Germany’s main naval force, in May 1914 ‘[w]hat will you do if they do not come [into the Heligoland Bight]’?[5] Neither appeared to have an answer to this question.

Lambert argues in a recent book, Planning Armageddon, that the Admiralty planned to conduct economic warfare against Germany in a huge scale.[6] Britain would use its effective monopolies in banking, communications and shipping to disrupt the global economy and paralyse Germany. The plan was not carried out because of fears about the impact on Britain and neutral countries, especially the USA.

In the Mediterranean Austria-Hungary and Italy, although both members of the Triple Alliance with Germany, each regarded the other as its principal naval rival. They were building against each other, but their alliance meant that the Admiralty had to allow for the possibility that they would combine against Britain and France.

After a period of neglect of its navy, France laid down its first dreadnoughts in 1910. A new naval programme was announced in 1912, with 16 dreadnoughts planned, although the need to prioritise the army during the war meant that only seven were completed, plus another that was converted to an aircraft carrier.

Britain and France had undertaken a series of naval conversations, but were not formally allied. Britain, which had to match the threat from Germany in the North Sea, reduced its Mediterranean fleet. France, which could not match Germany on its own, moved most of its fleet to the Mediterranean.

Churchill was wary that the Anglo-French naval conversations had restricted British freedom of choice. He argued that both parties would have made the same dispositions of their fleets even without the talks as they were the logical  measures to take:

‘the French…are not strong enough to face Germany alone, still less to maintain themselves in two theatres. They therefore rightly concentrate their Navy in the Mediterranean where it can be safe and superior and can assure their African communications. Neither is it true that we are relying on France to maintain our position in the Mediterranean.’[7]

The Cabinet decided that Britain would deploy a Mediterranean fleet of a one power standard excluding France in 1915 when enough ships would be available, meaning a fleet of six dreadnoughts and the two newest pre-dreadnoughts. In the interval, the Mediterranean fleet would be made up of enough battlecruisers and armoured cruisers to ensure that Anglo-French strength exceeded the combined Triple Alliance fleet, including the German Mediterranean squadron of a battlecruiser and a light cruiser.

Despite the absence of a formal alliance between Britain and France Sir Edward Grey, the British Foreign Secretary, told the House of Commons on 3 August, the day before Britain declared war, that the naval conversations gave Britain a moral obligation to France:

‘the Northern and Western Coasts of France are absolutely undefended…The French fleet is in the Mediterranean, and has for some years been concentrated there because of the feeling of confidence and friendship which has existed between the two countries.’[8]

RN ships in the rest of the world were mostly old, with the exception of the battlecruiser HMAS Australia, the flagship of the Royal Australian Navy. Their wartime role would be to protect trade and hunt down the German cruisers that were stationed overseas.


[1] Quoted in H. Strachan, The First World War: Vol. 1, to Arms (Oxford: Oxford University Press, 2001), p. 395.

[2] N. A. Lambert, Sir John Fisher’s Naval Revolution (Columbia, SC: University of South Carolina Press, 1999), p. 290.

[3] Quoted in Ibid., p. 289.

[4] Quoted in Ibid., p. 299.

[5] Quoted in P. G. Halpern, A Naval History of World War I (London: UCL Press, 1994), p. 23.

[6] N. A. Lambert, Planning Armageddon: British Economic Warfare and the First World War (Cambridge, MA; London: Harvard University Press, 2012).

[7] Quoted in 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. v, p. 306

[8] Quoted in C. M. Clark, The Sleepwalkers: How Europe Went to War in 1914 (London: Penguin, 2013), p. 544.


Filed under War History