SMS Mainz was a light cruiser of the Kolberg class in the Imperial German Navy

Kaiserliche Marine

The Imperial German Navy was the German Navy created at the time of the formation of the German Empire. It existed between 1871 and 1919, growing out of the small Prussian Navy and Norddeutsche Bundesmarine, which primarily had the mission of coastal defense. Kaiser Wilhelm II greatly expanded...

, launched in 1909, with 4,400 tons displacement. She was armed with twelve 10.5 cm guns and had a top speed of 27 knots. Within weeks of the outbreak of World War I

World War I

World War I , which was predominantly called the World War or the Great War from its occurrence until 1939, and the First World War or World War I thereafter, was a major war centred in Europe that began on 28 July 1914 and lasted until 11 November 1918...

, she was sunk, along with her sistership Köln and the light cruiser Ariadne

SMS Ariadne

SMS Ariadne was a light cruiser of the Gazelle class in the Imperial German Navy, with 2,700 tons displacement and 10 × 10.5 cm guns...

, in the first Battle of Heligoland Bight on 28 August 1914.

Battle of Heligoland Bight

The British Harwich Force of two light cruisers and 31 destroyers under Commodore Reginald Tyrwhitt

Reginald Tyrwhitt

Admiral of the Fleet Sir Reginald Yorke Tyrwhitt, 1st Baronet, GCB, DSO was a senior officer of the Royal Navy in World War I who commanded light forces stationed at Harwich on the east coast of England during the first part of the war.-Naval career:Tyrwhitt entered the Navy as a cadet in July, 1885...

 made a raid upon the German patrols west of the German naval base on the island of Heligoland

Heligoland

Heligoland is a small German archipelago in the North Sea.Formerly Danish and British possessions, the islands are located in the Heligoland Bight in the south-eastern corner of the North Sea...

. Providing cover was the First Battle Cruiser Squadron under Vice Admiral David Beatty

David Beatty, 1st Earl Beatty

Admiral of the Fleet David Richard Beatty, 1st Earl Beatty, GCB, OM, GCVO, DSO was an admiral in the Royal Navy...

 with five battlecruisers.

In the early morning hours on 28 August, the Harwich Force encountered the first German destroyers west of Heligoland. Not entirely surprised by the attack, the Germans hastily deployed the two light cruisers SMS Frauenlob

SMS Frauenlob

SMS Frauenlob was a Gazelle-class light cruiser in the German Imperial Navy. She was the second ship of that name, after a schooner launched in 1853.-History:Frauenlob was built at A.G. Weser in Bremen...

 and SMS Stettin

SMS Stettin

SMS Stettin was a Königsberg class light cruiser of the Kaiserliche Marine. Laid down at AG Vulcan Stettin shipyard in 1906, she was launched on 7 March 1907, and commissioned on 29 July 1907. The ship served in European waters during World War I, participating in the Battle of Heligoland Bight in...

, joined shortly afterwards by four more light cruisers steaming from Wilhelmshaven

Wilhelmshaven

Wilhelmshaven is a coastal town in Lower Saxony, Germany. It is situated on the western side of the Jade Bight, a bay of the North Sea.-History:...

 and Emden

Emden

Emden is a city and seaport in the northwest of Germany, on the river Ems. It is the main city of the region of East Frisia; in 2006, the city had a total population of 51,692.-History:...

, including SMS Mainz. Due to low water, the German battlecruisers in Wilhelmshaven were unable to leave harbour in time to provide support.

Outgunned and with his flagship, the light cruiser HMS Arethusa

HMS Arethusa (1913)

HMS Arethusa was the name ship of the Arethusa class of light cruisers. She was laid down at Chatham Dockyard in October 1912, launched on 25 October 1913, and commissioned in August 1914 as flotilla leader for the Harwich Destroyer flotillas....

, heavily damaged by Frauenlob, Tyrwhitt received initial support from Commodore William Goodenough's squadron of six modern light cruisers of the Southampton-class

HMS Southampton (1912)

HMS Southampton was a Royal Navy warship that served in the First World War.Southampton was one of the third batch of "Town" class light cruisers, her sister ships were Dublin and Chatham...

. Frauenlob suffered severe damage herself and retreated to Heligoland.
Mainz, arriving on the battlefield from Emden, initially encountered several British destroyers, but soon found herself facing Goodenough's cruisers. As Mainz turned away, she steamed directly into the path of Tyrwhitt's two cruisers, HMS Arethusa and Fearless

HMS Fearless (1912)

HMS Fearless was an Active-class scout cruiser of the Royal Navy. She was built at Pembroke Dockyard and launched on 12 June 1912.On commissioning she was assigned to the Harwich Force with her sisters, and was the leader of the 1st Destroyer Flotilla...

, and 31 destroyers. A hit from Fearless damaged the steering gear of Mainz; unable to escape, she was severely pounded in a bruising battle that left three British destroyers damaged. At 12:25 Tyrwhitt's ships ceased fire and began to rescue survivors from the doomed German ship. Some 200 were saved, including a son of Admiral Tirpitz

Alfred von Tirpitz

Alfred von Tirpitz was a German Admiral, Secretary of State of the German Imperial Naval Office, the powerful administrative branch of the German Imperial Navy from 1897 until 1916. Prussia never had a major navy, nor did the other German states before the German Empire was formed in 1871...

; 89 perished. About 40 minutes later Mainz sank.