In the first decade of the 20th century, the Imperial German Navy had generally ordered twelve large torpedo boats (Große Torpedoboote) as part of each year's construction programme, with a gradual evolution of design in each year's orders, with speed, range and seaworthiness improving year-on-year. These changes resulted in the ships becoming larger, and concerns grew that the torpedo boats were becoming too big to manoeuvre in and out of the battle fleet. For the 1911 fiscal year's orders, it was decided to revert to a smaller design, with the numbering system for torpedo boats restarting as a consequence.^[2] As was normal practice, that year's order was split between two shipyards, with six (V1–V6) to be built by AG Vulcan and six (G7–G12) by Germaniawerft, with detailed design differing between the two shipyards.^[3]

Germaniawerft's design was 71.5 metres (234 ft 7 in) long overall and 71.0 metres (232 ft 11 in) between perpendiculars, with a beam of 7.56 metres (24 ft 10 in) and a draught of 3.09 metres (10 ft 2 in). Displacement was 573 tonnes (564 long tons) design and 719 tonnes (708 long tons) full load.^[4]

Three coal-fired and one oil-fired water-tube boiler fed steam at a pressure of 18 standard atmospheres (260 psi) to two sets of direct-drive steam turbines. The ship's machinery was rated at 16,000 PS (16,000 shp; 12,000 kW) giving a design speed of 32 knots (37 mph; 59 km/h).^[4] 110 tons of coal and 80 tons of oil fuel were carried, giving an endurance of 1,150 nautical miles (1,320 mi; 2,130 km) at 17 knots (20 mph; 31 km/h).^[5]

The ship was armed with two 8.8 cm SK L/30 naval guns, (replaced by 8.8 cm SK L/45 naval guns in 1916),^[4] one on the forecastle and one aft. Four single 50 cm (19.7 in) torpedo tubes were fitted, with two on the ship's beam in the gap between the forecastle and the ship's bridge which were capable of firing straight ahead, and two on the ship's centreline aft of the funnels.^[5][6] 18 mines could be carried.^[4] The ship had a crew of 74 officers and men.^[5]

G9 was laid down at Germaniawerft's Kiel shipyard as yard number 172, was launched on 31 January 1912 and completed on 25 September 1912.^[7]

On commissioning, G9 joined the 10th Half Flotilla of the 5th Torpedo boat flotilla, and remained in that flotilla in April 1914.^[8][9]

G9 was a member of the 10th Half-flotilla of the 5th Torpedo boat flotilla of the German High Seas Fleet on the outbreak of war.^[10] On 28 August 1914, the British Harwich Force, supported by light cruisers and battlecruisers of the Grand Fleet, carried out a raid towards Heligoland with the intention of destroying patrolling German torpedo boats.^[11] The German defensive patrols around Heligoland consisted of one flotilla (I Torpedo Flotilla) of 12 modern torpedo boats forming an outer patrol line about 25 nautical miles (29 mi; 46 km) North and West of Heligoland, with an inner line of older torpedo boats of the 3rd Minesweeping Division at about 12 nautical miles (14 mi; 22 km). The 5th Torpedo boat flotilla, including G9, together with four German light cruisers waited near Heligoland,^[12] and was ordered from Heligoland to investigate sightings of British submarines. G9, at the head of the flotilla, sighted several ships ahead and the flash of guns, but uncertain whether the ships were friendly or enemies, continued to close until the unknown ships could be clearly identified as British destroyers, when she opened fire and turned away to escape the trap, as did the rest of the flotilla. The torpedo boat V1, which along with S13 could not make full speed and lagged behind the rest of the flotilla, was hit by British shells before the arrival of the German cruiser Stettin allowed the 5th Flotilla to escape.^[13][14][15] The torpedo boat V187 of the outer screen did not manage to evade the British force and was sunk. The intervention of the supporting British forces resulted in the sinking of the German cruisers Mainz, Cöln and Ariadne. The British light cruiser Arethusa and destroyers Laurel, Laertes and Liberty were badly damaged but safely returned to base.^[16] G9 was undamaged.^[17]

On 23 January 1915, a German force of Battlecruisers and light cruisers, escorted by torpedo boats, and commanded by Admiral Franz von Hipper, made a sortie to attack British fishing boats on the Dogger Bank.^[18] G9, part of the 10th Half-Flotilla, formed part of the escort for Hipper's force.^[19][20] British Naval Intelligence was warned of the raid by radio messages decoded by Room 40, and sent out the Battlecruiser Force from Rosyth, commanded by Admiral Beatty aboard Lion and the Harwich Force of light cruisers and destroyers, to intercept the German force.^[21] The British and German Forces met on the morning of 24 January in the Battle of Dogger Bank. On sighting the British, Hipper ordered his ships to head south-east to escape the British, who set off in pursuit.^[22] The armoured cruiser Blücher was disabled by British shells and was sunk, but the rest of the German force escaped, with the German battlecruiser Seydlitz and the British battlecruiser Lion badly damaged.^[23] On 3 February 1915, G9 as part of the 5th Torpedo boat Flotilla and together with the cruisers Strassburg, Graudenz, Stralsund and Rostock, accompanied minesweepers as they searched for British minefields West of the Amrun Bank. G9 and the torpedo boat V4 destroyed two British mines.^[24][25]

G9 was still a member of the 10th Half-flotilla of the 5th Torpedo Boat Flotilla at the Battle of Jutland on 31 May – 1 June 1916. The 5th Flotilla supported the main force of the German High Seas Fleet.^[26] G9 picked up some of the survivors from the British destroyers Nomad and Nestor, which had previously been disabled and then sunk by fire from German battleships at about 18:30–18:35 CET (17:30–17:35 GMT).^[27] From about 20:15 CET, the German torpedo boat flotillas launched a series of torpedo attacks against the British battle line in order to cover the German fleet's turn away from the British. First to attack were the 6th and 9th Flotillas, followed by the 3rd Flotilla. At 20:38, the 5th Flotilla started an attack run, but it was unable to find the British battleline due to poor visibility caused by fog and smoke, and the attack was aborted.^[28][29] During the night action, the 5th Flotilla was ordered to search for and attack the British fleet, but failed to encounter the British battleships. While G9 and sister ship G10 did spot a "four-funneled cruiser" at about 01:00 on 1 June, they did not engage as they were not certain whether the ship was British or German.^[30] G9 was undamaged during the battle.^[31] G9 was part of the 5th Torpedo Boat Flotilla during the inconclusive Action of 19 August 1916, when the German High Seas Fleet sailed to cover a sortie of the battlecruisers of the 1st Scouting Group.^[32]

By late April 1917, the torpedo boats of the 5th Torpedo Boat Flotilla had been fitted for minesweeping and their crews trained in that task, and became increasingly dedicated to minesweeping.^[33] On 3 May 1918, G9 was sunk by a mine in the North Sea at 55°14′N 6°19′E / 55.233°N 6.317°E / 55.233; 6.317. 31 of her crew were killed.^[7]

• Campbell, John (1998). Jutland: An Analysis of the Fighting. London: Conway Maritime Press. ISBN 0-85177-750-3.
• Fock, Harald (1989). Z-Vor! Internationale Entwicklung und Kriegseinsätze von Zerstörern und Torpedobooten 1914 bis 1939 (in German). Herford, Germany: Koehlers Verlagsgesellschaft mBH. ISBN 3-7822-0207-4.
• Gardiner, Robert; Gray, Randal, eds. (1985). Conway's All The World's Fighting Ships 1906–1921. London: Conway Maritime Press. ISBN 0-85177-245-5.
• Gröner, Erich; Jung, Dieter; Maass, Martin (1983). Die deutschen Kriegsschiffe 1815–1945: Band 2: Torpedoboote, Zerstörer, Schnellboote, Minensuchboote, Minenräumboote (in German). Koblenz: Bernard & Graef Verlag. ISBN 3-7637-4801-6.
• Groos, O. (1920). Der Krieg in der Nordsee: Erster Band: Von Kreigsbeginn bis Anfang September 1914. Der Krieg zur See: 1914–1918 (in German). Berlin: Verlag von E. S. Mittler und Sohn – via National Library of Estonia.
• Groos, O. (1923). Der Krieg in der Nordsee: Dritter Band: Von Ende November 1914 bis Unfang Februar 1915. Der Krieg zur See: 1914–1918. Berlin: Verlag von E. S. Mittler und Sohn – via National Library of Estonia.
• Massie, Robert K. (2007). Castles of Steel: Britain, Germany and the Winning of the Great War at Sea. London: Vintage Books. ISBN 978-0-099-52378-9.
• Monograph No. 11: Heligoland Bight—The Action of August 28, 1914 (PDF). Naval Staff Monographs (Historical). Vol. III. The Naval Staff, Training and Staff Duties Division. 1921. pp. 110–166. OCLC 220734221.
• Monograph No. 12: The Action of Dogger Bank, January 24th, 1915 (PDF). Naval Staff Monographs (Historical). Vol. III. Naval Staff, Training and Staff Duties Division. 1921. pp. 209–226.
• Monograph No. 33: Home Waters: Part VII: From June 1916 to November 1916 (PDF). Naval Staff Monographs (Historical). Vol. XVII. Naval Staff, Training and Staff Duties Division. 1927.
• Moore, John (1990). Jane's Fighting Ships of World War I. London: Studio. ISBN 1-85170-378-0.