SMS Lützow[a] was the second Derfflinger-class battlecruiser built by the German Kaiserliche Marine (Imperial Navy) before World War I.

She was named in honor of the Prussian general Ludwig Adolf Wilhelm von Lützow who fought in the Napoleonic Wars.

Lützow was commissioned on 8 August 1915, but did not join I Scouting Group until 20 March due to engine damage during trials.

The Derfflinger class was authorized for the 1911 fiscal year as part of the 1906 naval law; design work had begun in early 1910.

To keep costs from growing too quickly, the number of guns was reduced from ten to eight, compared to the earlier Seydlitz, but a more efficient superfiring arrangement was adopted.

Lützow's powerplant was rated at 63,000 metric horsepower (62,138 shp; 46,336 kW), which generated a top speed of 26.4 knots (48.9 km/h; 30.4 mph).

Her secondary armament consisted of fourteen 15 cm SK L/45 guns mounted in casemates at main deck level.

On 24 April, Lützow and the battlecruisers Seydlitz and Moltke made a brief sortie into the North Sea, cruising to the eastern end of the Amrun Bank, since British destroyers had been reported to have been in the area.

Konteradmiral (Rear Admiral) Friedrich Boedicker, the deputy commander of I Scouting Group, temporarily raised his flag aboard the ship from 29 March to 11 April.

Seydlitz, the flagship, followed by Derfflinger, Lützow, Moltke, and Von der Tann left the Jade Estuary at 10:55 on 24 April, and were supported by a screening force of six light cruisers and two torpedo boat flotillas.

[8] The heavy units of the High Seas Fleet sailed at 13:40, with the objective to provide distant support for Boedicker's ships.

Due to reports of British submarines and torpedo attacks, Boedicker broke off the chase and turned back east towards the High Seas Fleet.

[11] At 02:00 CET,[d] on 31 May 1916, I Scouting Group departed the Jade estuary; Lützow, Hipper's flagship, was the leading vessel, followed by her sister Derfflinger, Seydlitz, Moltke, and Von der Tann.

The ships were accompanied by II Scouting Group, under the command of Rear Admiral Boedicker, composed of the four light cruisers Frankfurt, Wiesbaden, Pillau, and Elbing.

The reconnaissance force was screened by 30 torpedo boats of II, VI, and IX Flotillas, directed by the cruiser Regensburg.

[19] Eight minutes later, Lion scored the first hit on Lützow; a salvo from the British ship struck the battlecruiser on her forecastle, but no major damage was done.

In the course of the first nineteen minutes of the battle, Lützow had fired thirty-one salvos at Lion, scoring six hits, forcing the latter to sheer out of line temporarily.

[24] During this period, Princess Royal opened fire on Lützow and scored two hits, the first of which exploded between the forward turrets and the second struck the belt.

Witnesses reported at least five shells from two salvos hit the ship, which caused an intense explosion that ripped the Queen Mary in half.

[27] Shortly after the destruction of Queen Mary, both British and German destroyers attempted to make torpedo attacks on the opposing lines.

[33] During the engagements between the combined German fleet and the British 1st Battlecruiser and 5th Battle Squadrons, Lützow had both of her wireless transmitters damaged; after that point, the only method of communication between ships was via signal lamp.

[40][g] While Lützow and the rest of the fleet were concentrating on Defence, Lion scored two hits on Hipper's flagship, causing a serious fire.

[42] From this point onward, Lützow came under no further fire from the British battlecruisers, though she was flooding badly from two of the hits from Invincible that had struck below the waterline.

This development made it impossible for Scheer to retreat, for doing so would have sacrificed the slower pre-dreadnought battleships of II Battle Squadron.

[45] Instead, Scheer ordered his ships to turn 16 points to starboard,[h] which would bring the pre-dreadnoughts to the relative safety of the disengaged side of the German battle line.

[48] Shortly before, at 19:50, Kommodore Andreas Michelsen, aboard the cruiser Rostock, dispatched the torpedo boats of I Half-Flotilla to assist Lützow.

V45 and G37 began laying a smoke screen between the battered ship and the British line, but at 20:15, before it was finished, Lützow was struck in quick succession by four heavy-caliber shells.

[58] The crew attempted to reverse direction and steam backwards, but this had to be abandoned when the bow became so submerged that the propellers were pulled partially out of the water; forward draft had increased to over 17 metres (56 ft).

The torpedo boats G37, G38, G40, and V45 came alongside the stricken battlecruiser to evacuate the ship's crew,[59] though six men were trapped in the bow and could not be freed.

Echo took sonar images of the wreck, which her commander stated would "ensure the ship's final resting place is properly recognised as a war grave.