Background to the Battle of Heligoland Bight

HMS Arethusa, flagship of the Harwich Force commanded by Commodore Tyrwhitt.  She was the first of a new class of 'light armoured cruiser', later re-classified to light cruiser, designed to work with destroyers.  Arethusa had only been in service a couple of days before the Battle of Heligoland Bight but despite the risk of teething problems she was so much faster, better armed and protected than Tyrwhitt's previous flagship, HMS Amethyst, that he took the risk.

British submarine patrols in the Heligoland Bight region in August 1914 had noticed that German torpedo boats patrolled this area supported by light cruisers in two shifts of a day and night group. Roger Keyes Commodore (S), commander of British submarines, formulated a plan to raid these patrols using the Harwich Force of light cruisers and destroyers under Reginald Tyrwhitt Commodore (T).

The plan was for the Harwich force to drive the German patrol away from the German coast at dawn with British submarine split into two groups, one to intercept any German reinforcements and the other to act as a decoy to keep the German torpedo boats offshore. Further offshore would be some heavier units to support the Harwich Force against any German reinforcements and ideally the Grand Fleet would be in distant support.

Keyes approached the Admiralty for approval of the plan on August 23 1914 but the War Staff were too busy to consider the plan. Keyes, rather than giving up, went direct to the First Lord of the Admiralty, Winston Churchill.

Churchill was impressed by the idea and called a meeting the following day with Tyrwhitt (who had to be recalled form sea), Price Louis of Battenburg (the 1st Sea Lord), Vice Admiral Sturdee (Chief off the Admiralty War Staff) and Vice Admiral Sir Fredrick Hamilton (2nd Sea Lord).

Sturdee decided that is was not necessary to send the Grand Fleet in support and so the plan was changed to reduce the support to Cruisers Force C of five old armoured cruisers and Cruiser Force K with the Battlecruisers Invincible and New Zealand. He also changed the direction of the attack.

Eight British submarines were involved with an inner line of E4, E5 and E9 north and south of Heligoland to attack any reinforcing or retreating German ships. An outer line of E6, E7 and E8 was formed 40 miles further out and were intended to try and lure the German destroyers further out to sea. Finally D2 and D8 were stationed off Ems to attack any reinforcements coming from that direction.

The sweep was to take place on the 28 August with Keyes and Tyrwhitt putting to sea on the 26 and 27 August respectively. Unfortunately it was not until the 26 August that the Admiralty informed Admiral John Jellicoe (C-in-C Grand Fleet) that a major operation was planned in the North Sea, and even when they did inform him the information they sent was limited and vague.

Jellicoe was concerned by the lack of support for an operation so close to German bases and so requested that he bring the Grand Fleet out in support. Sturdee told Jellicoe that this was not necessary but if he wanted he could send additional battlecruisers. Jellicoe took this opportunity and he informed the Admiralty that he would be sending Beatty with the First Battlecruiser Squadron and Commodore Goodenough with the First Light Cruiser Squadron to reinforce the covering force. Keyes and Tyrwhitt had already sailed and the Admiralty failed to inform them of the additional British units involved in the operation.

This lack of communication from the Admiralty nearly led to disaster when before dawn the Harwich force encountered the First Light Cruiser Squadron. Fortunately it was established the cruisers were friendly. Tyrwhitt was then informed of the reinforcements but it was too late to inform the British submarine of the new units.

Facing the British raid the German Navy had two patrol lines. The outer line, 25 miles west of Heligoland, consisted of nine modern destroyers of the I torpedo Boat Flotilla. Twelve miles nearer Heligoland were vessels of the III Minesweeping Division. Supporting these lines were the light cruisers SMS Hela, Ariadne, Frauenlob and Stettin. SMS Mainz was waiting off the Ems to the south but the other seven light cruisers allocated to the patrols were all in either Brunsbuttel or Wilhelmshaven. Unfortunately for the German light forces any heavier ships that might be used to reinforce the patrols were limited in the times they could leave the Jade by tides.

SMS Ariadne was a Gazelle class light cruiser.  They were Germany's first true light cruisers and set the pattern from which all German light cruisers were based until after World War 1.  Ariadne was in had been in reserve for several years before the outbreak of war but was brought back into service although by then she was small and outclassed by modern light cruisers.