The Battle of Dogger Bank 

The Battle of Dogger Bank was a naval engagement on 24 January 1915, near the Dogger Bank in the North Sea, during the First World War, between squadrons of the British Grand Fleet and the German High Seas Fleet.

The British had intercepted and decoded German wireless transmissions, gaining advance knowledge that a German raiding squadron was heading for Dogger Bank and ships of the Grand Fleet sailed to intercept the raiders.

The British surprised the smaller and slower German squadron, which fled for home. During a stern chase lasting several hours, the British caught up with the Germans and engaged them with long-range gunfire.

The British disabled Blücher, the rearmost German ship, and the Germans put the British flagship HMS Lion out of action.

Due to inadequate signalling, the remaining British ships stopped the pursuit to sink Blücher; by the time the ship had been sunk, the rest of the German squadron had escaped.

The German squadron returned to harbour, with some ships in need of extensive repairs. Lion made it back to port but was out of action for several months.

The British had lost no ships and suffered few casualties; the Germans had lost Blücher and most of its crew, so the action was considered a British victory.

Both navies replaced officers who were thought to have shown poor judgement and made changes to equipment and procedures, to remedy failings observed during the battle.

Before 1914, international communication was conducted via undersea cables laid along shipping lanes, most of which were under British control.

Hours after the British ultimatum to Germany in August 1914, they cut German cables. German messages could be passed only by wireless, using cyphers to disguise their content. The Signalbuch der Kaiserlichen Marine (SKM) was captured from the German light cruiser SMS Magdeburg after it ran aground in the Baltic on 26 August 1914.

The German-Australian steamer Hobart was seized near Melbourne, Australia on 11 August and the Handelsverkehrsbuch (HVB) codebook, used by the German navy to communicate with merchant ships and within the High Seas Fleet, was captured. A copy of the book was sent to England by the fastest steamer, arriving at the end of October.

During the Battle off Texel (17 October), the commander of the German destroyer SMS S119 threw overboard his secret papers in a lead lined chest as the ship sank but on 30 November, a British trawler dragged up the chest. Room 40 gained a copy of the Verkehrsbuch (VB) codebook, normally used by Flag officers of the Kaiserliche Marine.

The Director of the Intelligence Division of the Admiralty, Rear-Admiral Henry Oliver, established a code breaking organisation to decipher German signals, using cryptographers from academic backgrounds and making use of the windfalls taken from the German ships.

At first, the inexperience of the cryptanalysts in naval matters led to errors in the understanding of the material and this lack of naval experience caused Oliver to make personal decisions about the information to be passed to other departments, many of which, particularly the Operations Department, had reservations about the value of Room 40.

The transfer of an experienced naval officer, Commander W. W. Hope, remedied most of the deficiencies of the civilians' understanding.

On 14 October, Oliver became Chief of the Naval War Staff, but continued to treat Room 40 more as a fiefdom and a source for the informal group of officers around the First Lord of the Admiralty, Winston Churchill, which received decoded messages but had insufficient authority to use them to best advantage.

German ships had to report their position every night by wireless and British listening posts along the east coast took cross-bearings to find the positions of the ships when they transmitted.

This signals intelligence meant that the British did not need wasteful defensive standing patrols and sweeps of the North Sea but could economise on fuel and use the time for training and maintenance.

The Admiralty also uncovered the German order of battle and tracked the deployment of ships, which gave them an offensive advantage. The lack of a proper war staff at the Admiralty and poor liaison between Room 40, Oliver and the operations staff, meant that the advantage was poorly exploited in 1915. (It was not until 1917 that this was remedied.)

When German ships sailed, information from Room 40 needed to be passed on quickly but Oliver found it hard to delegate and would not routinely supply all decrypts; commanders at sea were supplied only with what the Admiralty thought they needed.

Information could reach the Grand Fleet late, incomplete or mistakenly interpreted. When Jellicoe asked for a decryption section to take to sea, he was refused on security grounds.

German raid Main article: Raid on Scarborough, Hartlepool and Whitby With the German High Seas Fleet (HSF) confined to port after the British success at the Battle of Heligoland Bight in 1914, Admiral Friedrich von Ingenohl, the Commander-in-Chief of the HSF planned a raid on Scarborough, Hartlepool and Whitby on the east coast of England, with the I Scouting Group (Admiral Franz von Hipper), a battlecruiser squadron of three battlecruisers and a large armoured cruiser, supported by light cruisers and destroyers.

Hipper opened fire at 08:00 on 16 December 1914, eventually killing 108 and wounding 525 civilians.

British public and political opinion was outraged that German warships could sail so close to the British coast, shelling coastal towns with impunity; British naval forces had failed to prevent the attacks and also failed to intercept the raiding squadron.

The British fleet had sailed but the German ships escaped in stormy seas and low visibility, assisted by British communication failures.

The Germans had made the first successful attack on Britain since the 17th century and suffered no losses but Ingenohl was unjustly blamed for missing an opportunity to inflict a defeat on the Royal Navy, despite him creating the chance by his offensive-mindedness.

British counter-action The British had let the raid occur and appeared to the public to have been surprised (having been forewarned by decoded wireless messages) and then to have failed to sink the German raiding force on its way back to Germany. In 1921, the official historian Julian Corbett wrote, Two of the most efficient and powerful British squadrons...knowing approximately what to expect...had failed to bring to action an enemy who was acting in close conformity with our appreciation and with whose advanced screen contact had been established. — Strachan

The British had escaped a potential disaster, because the British 1st Battlecruiser Squadron (Vice-Admiral Sir David Beatty) was unsupported by the 2nd Battle Squadron (Vice-Admiral Sir George Warrender), when it failed to make contact with the raiding force.

The worst British failure was in the exploitation of the intelligence provided by the code breakers at Room 40 (Sir Alfred Ewing), that had given the British notice of the raid.

Some intercepts decoded during the action had taken two hours to reach British commanders at sea, by when they were out of date or misleading.

News of the sailing of the HSF was delivered so late that the British commanders thought that the Germans were on the way, when they were returning. At sea, Beatty had sent ambiguous signals and some commanders had not used their initiative. On 30 December, the commander of the Home Fleet, Admiral Sir John Jellicoe, gave orders that when in contact with German ships, officers were to treat orders from those ignorant of local conditions as instructions only but he refused Admiralty suggestions to loosen ship formations, for fear of decentralising tactical command too far.