SMS Mainz

SMS Mainz was a Kolberg-class cruiser light cruiser of the German Kaiserliche Marine (Imperial Navy) during the First World War. She had three sister ships, SMS Kolberg, SMS Cöln (1909), and SMS Augsburg. She was built by the AG Vulcan shipyard in Stettin; her hull was laid down in 1908 and she was launched in January 1909. She was commissioned into the High Seas Fleet in October 1909. She was armed with a main battery of twelve 10.5 cm SK L/45 guns and had a top speed of 25.5 kn.

After her commissioning, she served with the II Scouting Group, part of the reconnaissance forces of the High Seas Fleet. She was assigned to patrols off the island of Heligoland at the outbreak of World War I in early August 1914. At the Battle of Heligoland Bight on 28 August 1914, the German patrol forces were attacked by superior British forces, including five battlecruisers and several light cruisers. Mainz was initially stationed in support of the forces on the patrol line. She attempted to reinforce the beleaguered German forces, and encountered a much stronger force of British cruisers and destroyers. They scored several damaging hits with gunfire and a torpedo that disabled Mainz and prompted her commander to abandon ship. The British rescued 348 men from the crew before the ship rolled over and sank. Eighty-nine men were killed in the battle, including her commanding officer.

Design
Mainz was ordered under the contract name Ersatz SMS Jagd and was laid down in 1907 at the AG Vulcan shipyard in Stettin. She was launched on 23 January 1909 and christened by the mayor of Mainz, Karl Emil Göttelmann, after which fitting-out work commenced. She was commissioned into the High Seas Fleet on 1 October 1909. The ship was 130.5 m long overall and had a beam of 14 m and a draft of 5.58 m forward. She displaced 4915 MT at full combat load. Her propulsion system consisted of two sets of AEG-Curtiss steam turbines driving two 3.45 m propellers. They were designed to give 19000 shp. These were powered by fifteen coal-fired Marine water-tube boilers. These gave the ship a top speed of 26 kn. Mainz carried 1010 MT of coal that gave her a range of approximately 3630 nmi at 14 kn. Mainz had a crew of eighteen officers and 349 enlisted men.

The ship was armed with twelve 10.5 cm SK L/45 guns guns in single pedestal mounts. Two were placed side by side forward on the forecastle, eight were located amidships, four on either side, and two were side by side aft. She also carried four 5.2 cm SK L/55 anti-aircraft guns. She was also equipped with a pair of 45 cm torpedo tubes submerged in the hull. She could also carry 100 mines. The conning tower had 100 mm thick sides, and the deck was covered with up to 40 mm thick armor plate.

Service history
After her commissioning in 1909, Mainz served with the reconnaissance forces of the German fleet. Her first commander was Fregattenkapitän (commander) Friedrich Tiesmeyer, the uncle of Ernst Lindemann; he held the command until January 1910. She was assigned to the II Scouting Group, which screened for the battlecruisers of the I Scouting Group. After the outbreak of World War I at the beginning of August 1914, she and several other cruisers were tasked with patrol duties in the Heligoland Bight. The cruisers were divided with the torpedo boat flotillas, and assigned to rotate through nightly patrols into the North Sea. As part of this operation, Mainz conducted a patrol on the night of 16 August with the VIII Torpedo-boat Flotilla, without incident.

At the same time, British submarines began reconnoitering the German patrol lines. On 23 August, several British commanders submitted a plan to attack the patrol line with the light cruisers and destroyers of the Harwich Force, commanded by Commodore Reginald Tyrwhitt. These ships would be supported by submarines and Vice Admiral David Beatty's battlecruisers and associated light forces. The plan was approved and set for 28 August. The British forces began to leave port on the evening of 26 August, beginning with the submarines assigned to the operation. Most of the surface forces went to sea early on the following morning; the 7th Cruiser Squadron, which had been added to provide further support to the Harwich Force, left port later in the day.

On the morning of 28 August, Mainz was at anchor in the mouth of the Ems; her sister SMS Cöln (1909), the flagship of Rear Admiral Leberecht Maass was re-coaling in Wilhelmshaven, SMS Ariadne lay in the entrance to the Weser. These three cruisers were assigned to support the cruisers SMS Stettin and SMS Frauenlob, and the aviso SMS Hela, which were stationed on the patrol line that morning. At 07:57, the Harwich Force encountered the outer German torpedo boats, which fled back to the German cruisers. In the ensuing Battle of Heligoland Bight, Stettin engaged the British force first, and was quickly reinforced by Frauenlob. At 09:47, Mainz was ordered to steam out behind the British to cut off their line of retreat. She got under way by 10:00, and operated in conjunction with a floatplane used for reconnaissance.

At around 12:30, Mainz encountered the British cruiser HMS Arethusa (1913) and several destroyers. The ships engaged each other for the next forty-five minutes. Fifteen minutes into the engagement, three British cruisers appeared ; Mainz broke off the engagement and attempted to escape from the superior British forces. The pursuing British cruisers scored several hits, but by 12:55, Mainz had escaped under cover of a dense smoke screen. Another British cruiser, HMS Fearless (1912), and six destroyers, appeared on Mainz's port side, however, and attacked the fleeing German ship. Mainz quickly scored hits on the destroyers HMS Laurel (1913), HMS Liberty (1913) and HMS Laertes (1913); Laurel was damaged and forced to withdraw and Laertes was disabled by a salvo that hit her engine room.

A shell from one of the British cruisers hit Mainz at around 13:00, which jammed her rudder at ten degrees to starboard. Her crew shut off the port engine in an attempt to correct the ship's course, but she continued to turn to starboard. By 13:20, the majority of the ship's guns had been disabled and the ship's superstructure had been shot to pieces. Her center and aft funnel collapsed after suffering several hits. A torpedo from the destroyer HMS Lydiard (1914) then hit the ship on her port side, amidships; this prompted the ship's commander to order the crew to abandon the stricken cruiser. He then left the conning tower with the navigation officer, both of whom were immediately killed by a shell hit. The ship's communication system was out of service, and so the order to abandon ship did not reach the entire crew. The ship's executive officer then reached the bridge, and reiterated the order to abandon the crippled ship at 13:35.

Mainz was by now completely disabled. Her engines were stopped and her guns had ceased firing. Shortly before 14:00, HMS Lurcher (1912) came alongside and took off the wounded German sailors. At 14:10, Mainz rolled over to port and quickly sank at the position 53°58' N and 6°42' W; the survivors now in the water gave three cheers for their ship. The British rescued 348 survivors; 89 men, including the ship's commander, were killed in the battle. Among the survivors was Oberleutnant zur See (Sub-Lieutenant) Wolfgang von Tirpitz, the son of Admiral Alfred von Tirpitz, the architect of the German fleet. Winston Churchill, then the First Lord of the Admiralty, informed Tirpitz via the US embassy in Berlin that his son survived the battle. In the course of the engagement, the British sank two more German cruisers: Mainz's sister Cöln and Ariadne, with minimal losses to themselves.