Derfflinger was struck only once during the battle. At 11.40 a 13.5in shell struck the belt armour 1.15m above the waterline to starboard at frame 181 and detonated without penetrating. Here the belt was 300mm thick. The plate was pushed in approximately 10cm and was left with an indentation 30mm deep and concentric rings for about 2m around the point of impact. The torpedo net and equipment was badly damaged, and the outer skin was bowed-in below the armour. The armour carrier was bent in compartments IX and X. The following compartments flooded: the wing passage and protective bunkers to starboard of compartments VIII, IX and X; some water penetrated into the boiler room but could be removed with pumps.
The near misses to starboard aft caused a leak in the starboard outer shaft tunnel through sprung rivets. Some frames and the outer hull skin bent and seams leaked. The cause of these leaks was only found after Derfflinger went into the floating dock.
On 16 February at 19.15 Derfflinger moved from the floating dock to berth A5 and began coaling and fitting-out work. On 17 February the ship was combat ready and the following day ran out to picket duty in Schillig Roads. This monotonous duty continued uninterrupted and the only event to occur was on 11 March when there was an explosion in the southern roads. The searchlights were illuminated and it was revealed that there had been a boiler explosion aboard torpedo boat S35.
From 21 March to 25 March Derfflinger went into the imperial dockyard at Wilhelmshaven and had supplemental oil firing installed on the coal boilers. On 29–30 March the I AG, Moltke, Derfflinger and von der Tann, took part in the first fleet advance undertaken by the new Flottenchef, Admiral von Pohl.
After that, picket duty continued. At midnight on 4/5 April the unit weighed anchor and went to the Elbe River and from 06.00 to 18.20 made the canal trip to Kiel. From 6–10 April Derfflinger carried out training including torpedo shooting, searchlight practice, sub-calibre and calibre shooting, night shooting, acting as a target for torpedo boats and battle line training. Then at 09.00 on 11 April the canal trip back to the west was begun. 12 April was spent coaling in Brunsbüttel and on 13 April a trip was undertaken to Schillig Roads. The remainder of April was spent on picket duty.
On 17 April Derfflinger participated in War Task 26, in accordance with Operational Order 26, supporting a minelaying operation by Straßburg and Stralsund. At around 18.00 the following day Derfflinger anchored in Schillig Roads. Towards midnight on 21 April she weighed anchor and put to sea in accordance with Operational Order 27, the third fleet advance. After reaching a point 15nm north of Borkum, the fleet turned NW and proceeded to the Dogger Bank. On the morning of 22 April the I AG made a turn and later that afternoon performed evolutions in the German Bight.
From 1 May until 3 May Derfflinger remained in the imperial dockyard undergoing minor repairs. Then on 17 May she participated in the execution of Operational Order 23, supporting small cruisers laying mines on the Dogger Bank. At 21.24 on 18 May she returned to Wilhelmshaven Roads. On 29 May Operational Order 28 was carried out as the I AG ran out into the German Bight to cover the auxiliary cruiser Meteor putting to sea. The following day the cruiser anchored in Wilhelmshaven Roads at 20.18.
The month of June 1915 began quietly for Derfflinger and there were no significant occurrences until 25 June, when the cruiser weighed anchor and went in file with von der Tann to Kiel, arriving there and making fast to buoy A13 at 15.48 on 26 June. On 28 June Derfflinger was once again overtaken by misfortune. As the cruiser manoeuvred to put to sea the bow suddenly swung back, as happened occasionally at low speed. Derfflinger swung close to Kaiser Wilhelm der Große, which was lying moored to buoy D2, whilst at the same time the stern neared buoy C1. Kapitän zur See von Reuter gave the order ‘three times “utmost power” [AK] astern’. As the ship stopped, ‘half astern’ was ordered; however, the starboard low-pressure turbine failed to respond. When the cover of this turbine was lifted it was revealed that the turbine blades and guide vanes of the third, fourth, fifth, sixth and seventh stages had been destroyed. Once again it was believed that vibrations had caused the blades to contact the guide vanes and be damaged. Vizeadmiral Hipper’s report ran in part:
Probably the first blade row of the III Stage turbines began lateral oscillations that matched the vibrations of the ship, so that a resonance was created whereby the oscillations of the blades increased to such an extent that they came into contact with one another and were pushed backwards. So the following IV Stage turbines were hit and these moved further back and so on until the turbine seized. A proper determination of the cause of the damage cannot, unfortunately, be made. However, it can be said with certainty that crew error is not the cause. Therefore, no person of the crew can be blamed.
On 29 June Derfflinger moved into the imperial dockyard and work was begun on the port and starboard low-pressure turbines. Repairs would take a considerable time and would include further measures to prevent the third stage blades vibrating. When the port low-pressure turbine was inspected, no damage was found; but work on the starboard low-pressure turbine continued until 26 August 1915.
During the stay in Kiel trials were undertaken shipping a floatplane. On 28 August Derfflinger went to sea for a trials trip followed by torpedo shooting, which continued the following day along with artillery sub-calibre shooting. These activities were cut short by bad weather, but on 30 August a calibre shoot was carried out before the canal trip back to the Jade was undertaken. After arriving in Wilhelmshaven Roads on 31 August, picket duty was resumed in Schillig Roads the following day. On 3 September Kapitän zur See Heinrich took command of Derfflinger. He wrote:
About 9.30am the dispatch boat lay alongside Derfflinger. My predecessor, Kapitän zur See von Reuter, welcomed me. After a brief handover I took over the ship and crew, when it is usual to address the ship’s company. For my predecessor, who had been appointed Leader of the IV AG, leaving the ship and his Offizier Korps was very difficult. The sorrow of separation, however, was mutual for a beloved commander was departing. This inspired in me the intention to depart the ship under similar circumstances.
On 5 September Derfflinger set out for manoeuvres with the 6 Division of battleships. On 11 September she put to sea with the I AG in accordance with Operational Order 30, in the support of the II AG minelaying operation on the Swarte Bank, returning at 20.46 on the evening of 12 September. The usual routine of picket duty followed, interrupted by fleet manoeuvres on 9 October. On 16 October Derfflinger and the torpedo boat V30 carried out a trial, with the cruiser transferring oil to V30 whilst underway. Then the cruiser participated in the fleet advance on 23–24 October in accordance with Operational Order 31.
On 7 November Derfflinger made the trip through the Kaiser Wilhelm Canal to Kiel, picking up buoy A17 the following day. On 10 November she made a trial passage of the Aarö Sound, leading to the Kleinen Belt passage. Torpedo-firing practice followed the next day, before, on 13 November, she returned to the Jade, arriving in Wilhelmshaven Roads and anchoring at 16.30. Another trip to the Baltic began on 23 November. This time it was not without incident and on 24 November Derfflinger stuck fast for a short time near Kilometre 29, before arriving in Kiel later that day. A period of training followed, including exercises with torpedo boats, artillery firing and torpedo shooting for the Torpedo Trials Commission. The cruiser returned to the Jade on 5 December. On 16 December Derfflinger ran into Wilhelmshaven Dockyard and the following day entered the floating dock for the conclusion of work and adjustment of the RW equipment (direction indicator equipment for the artillery). This work continued until 15 January 1916, when the ship moved out of the dock. From 19–26 January firing trials were carried out.
The year 1916 brought increased activity for the High Sea Fleet, as Vizeadmiral Scheer had taken over command of the fleet and the High Command had determined on a more active policy to bring the enemy to battle. On 2 February Derfflinger ran out with von der Tann for a short advance into the North Sea in a search for the missing airship L19, but she had anchored again by 16.25. Early on the morning of 11 February the I AG put to sea to support the II TBF, which was engaged with British forces. Practice in the battle line followed on 28 February.
Early on 4 March Derfflinger was one of the units that put to sea to welcome home the commerce raider Möve; however, because of thick fog, a rendezvous could not be made. Only at 09.48 was Möve made out to starboard ahead, and she was then escorted back to the Jade. The following day, 5 March, Derfflinger weighed anchor and steered to the west for an operation into the Hoofden. The operation off Holland continued until 7 March, when at 12.45 Derfflinger once again anchored in Schillig Roads.
On 16 March Derfflinger cast off from the quay in Wilhelmshaven for the trip to Kiel; however, one of the port propellers became tangled and the cruiser had to go into the floating dock, where the prop was cleared. The next day she left the dock, but now thick fog delayed the departure so that the canal trip took place on 18 March – and only at 00.30 on 19 March did she make fast to buoy A17 in Kiel. From 20–23 March training was undertaken without any significant occurrences.
From 25–26 March Derfflinger took part in the counter-thrust against British light forces, which had approached the coast. At dawn on 25 March the seaplane-carrier Vindex launched five seaplanes against the airship base, which was believed to be at Hoyer, but was actually at Tondern. Vindex was escorted by the Harwich forces. During a German seaplane attack the destroyers Laverock and Medusa collided, and as the weather deteriorated Medusa was abandoned. The light cruiser Cleopatra rammed and sank G194, but was in turn rammed by Undaunted. Although the High Sea Fleet put out to sea on 26 March, it missed an opportunity to inflict a defeat on the scattered British forces.
Derfflinger resumed picket duty and on 16 April made a brief advance to the west of Helgoland. The following day she and the new Lützow ran out and searched for aircraft 505 before returning to Schillig Roads and anchoring at 21.54. Early on the morning of 21 April at 01.00 she weighed anchor and proceeded to the north, leading Moltke, to welcome the IX TBF home. At 04.45 a turn was made at the latitude of Amrum Bank and at 09.23 Derfflinger anchored in Wilhelmshaven Roads. On 22 April she belatedly advanced to join the I AG, which had advanced to intercept a suspected British attack.
At 10.45 on 24 April the I AG weighed anchor and put to sea in accordance with Operational Order 5, the attack on Great Yarmouth and Lowestoft. At about 15.53 Seydlitz struck a mine and I AG received orders from the BdA, Kontreadmiral Boedicker, to retrace its previous course. The ships formed up in the line of Derfflinger, Lützow, von der Tann and Moltke. The Flottenchef, Vizeadmiral Scheer, ordered the operation to continue, taking a course along the East Frisian coast. At 17.30 the I AG, without Seydlitz, took a westerly course at 22kts. Early on the morning of 25 April shore targets were taken under fire along with the light cruisers of the Harwich Force. By 19.30 on 25 April the I AG had returned to the Jade. During the next three days, 26, 27 and 28 April, Derfflinger made short forays out into the North Sea.
On 3 May she briefly put to sea to support returning airships. The following day Derfflinger and Lützow ran out to counter reported enemy forces, another British operation to mount an aerial attack on Tondern. At 05.00 on 5 May the Panzerkreuzers made a turn and ran in. A period in dockyard hands followed from 22–26 May. Picket duty followed.
The Skagerrak Battle
At 03.00 on 31 May 1916 Derfflinger weighed anchor and ran out as part of the unit of the I AG. She was under the command of recently appointed Kapitän zur See Hartog and ran as tactical number 2, behind the new flagship Lützow. The day passed without incident until the afternoon, when enemy forces were reported. The I AG went onto a course to the west at high speed towards the reported enemy. Towards 16.20 enemy battlecruisers came in sight.
At 16.48 Derfflinger opened fire on the second ship from the left in the enemy line, Princess Royal. The range was 140hm, bearing 86°. Initially, Derfflinger overestimated the range, but soon found it and hit Princess Royal at least eight times during the first part of the battle. During this time Derfflinger was not fired upon. By 17.16 the leading British battlecruiser had sheered out of line and was out of range, so Derfflinger changed target to the right, the third in line, Queen Mary. From 17.23 rapid salvos straddled the enemy ship. At 17.26 and 10secs Queen Mary exploded and disappeared in a giant cloud of smoke. The I Artillerie Offizier of Derfflinger, Korvettenkapitän Hase, wrote:
First of all a vivid red flame shot up from her forepart. Then came an explosion forward which was followed by a much heavier explosion amidships; black debris from the ship flew into the air, and immediately afterwards the whole ship blew up with a terrific explosion. A gigantic cloud of smoke rose, the masts collapsed inwards, the smoke-cloud hid everything, and rose higher and higher. Finally, nothing but a thick, black cloud of smoke remained where the ship had been.
At 17.47 it was observed from Derfflinger that the enemy battlecruisers had made a turn, apparently in front of the German main body. At 17.53 the I AG turned onto a northerly course ahead of the main body of the High Sea Fleet. After the turn north the battle was resumed against the British 1 and 2 Battlecruiser Squadrons (BCS); however, it is believed that Derfflinger was actually firing on Barham at this time and made four telling hits. By 18.10 the British battlecruisers were outside effective gun range and so the I AG changed target to the battleships of the 5 Battle Squadron and Derfflinger fired on Valiant from 18.16 with explosive shells. During the first part of the battle Derfflinger was not fired on, and even after the ship was targeted she remained unscathed. Only at 18.19 was she hit on the hull forward, with two further hits occurring at 18.30. Then at 18.55 a hit detached two 100mm armoured plates far forward in the bows. This led to some flooding.
From 18.55, the I AG, including Derfflinger, came under increasingly heavy fire from the British 1 and 2 Battle Cruiser Squadrons, and then the 3 Battlecruiser Squadron in the NE, but because of the poor visibility was unable to respond. To the north numerous cruisers and destroyers were spotted, apparently manoeuvring for a torpedo attack, and so at 19.05 the I AG turned to the south and then SW. Shortly afterwards, from 19.10, the I AG turned to starboard back onto a NE course, and immediately enemy cruisers came into sight. Whilst Lützow did not hesitate to open fire on Defence, aboard Derfflinger they were uncertain as to the identity of the ship and delayed opening fire. In the meantime Defence was hit and blew up after a short time. From 19.25 Derfflinger engaged targets thought to be battleships to port at 60hm range.
Now Derfflinger came under effective fire from the British 3 Battlecruiser Squadron and at 19.28 her heavy artillery opened fire on Invincible at 90–88hm and was firing on that target when she exploded at 19.31. At 19.35 the I AG altered course to the west to extricate itself from the effective fire of the 3 Battlecruiser Squadron and at 19.38 Derfflinger ceased fire as there were no longer any targets in view.
At 19.55 the I AG began a turn to starboard back towards the enemy and whilst in the turn Derfflinger was hit again at 20.04. As Lützow had been forced out of action, Kapitän zur See Hartog now had command of the I AG until Vizeadmiral Hipper could board another ship and resume leadership of his unit. Nevertheless, around this time Derfflinger had to be stopped whilst the turret crews from C and D turrets resecured the port side torpedo nets, which were hanging down and threatening to foul the propellers.
Now the German ships were advancing directly towards the centre of the British Grand Fleet and, to extricate himself from this unfavourable position, at 20.13 Vizeadmiral Scheer ordered the Panzerkreuzers to attack the enemy, but just one minute later amended this order instructing them to operate against the head of the enemy line. Nevertheless, during this critical time Derfflinger, as the leading German ship, came under effective fire and was hit a total of fourteen times. Two turrets – C and D – were disabled, turret A barbette was hit, and the conning tower and bridge were hit. There were various other hits on the belt armour, decks and through the funnels, but damage was only made to light structures. Even the hit on the conning tower, at about 20.22, resulted in no more than a shock vibration. Korvettenkapitän Hase wrote:
Suddenly we seemed to hear the crack of doom. A terrific roar, a tremendous explosion and then darkness, in which we felt a colossal blow.
The whole conning tower seemed to be hurled into the air as though by the hands of some menacing giant, and then shook itself into its former position. A heavy shell had struck the fore-control about 50cm in front of me. The shell exploded but failed to pierce the thick armour … The terrific blow had burst open the heavy armoured door, which now stood wide open. Two men strove in vain to force it back, but it was jammed too tight … once more we heard the colossal roar and crash and with the noise of a bursting thunderbolt a 38cm shell exploded under the bridge … An extraordinary thing happened: the terrific concussion of the bursting shell shut the armoured door of the fore-control.
During this time the I AG was unable to make an effective reply because smoke obscured the range, and visibility was poor.
Derfflinger and the I AG gradually swung onto a WSW course and at 20.50 turned onto a southerly course abeam their fleet. Only at 21.20 was contact with the enemy renewed and Derfflinger suffered her final damage when turret A was struck again, at 21.28. The I AG turned away from the enemy and at 21.31 Derfflinger fired the last shot in her battle. At 21.57 Vizeadmiral Hipper boarded the Panzerkreuzer Moltke and took the lead of the I AG, with Derfflinger now as tactical number 2, albeit with just four heavy guns remaining serviceable. However, when Vizeadmiral Hipper set off for the head of the German line, Derfflinger and von der Tann were unable to keep up and positioned themselves at the rear of the battle line on the orders of Vizeadmiral Scheer. The only event of the night occurred at 03.40 when the next ship ahead, von der Tann, had to manoeuvre abruptly to avoid a torpedo. During the remainder of the night Derfflinger followed the line south.
At 15.40 on 1 June 1916 she anchored in Wilhelmshaven Roads.