HMS G7

HMS G7

Company type	G-class submarine
Industry	Naval military vessel
Founded	1916
Headquarters	United Kingdom
Products	Submarines

HMS G7 was a British G-class submarine constructed for the Royal Navy during the period of World War I.

Description

The G-class submarines originated from the Admiralty's initiative, prompted by intelligence suggesting that Germany was developing double-hulled submarines designed for extended overseas missions. These vessels measured 187 feet 1 inch (57.0 m) in overall length, had a beam of 22 feet 8 inches (6.9 m), and a mean draft of 13 feet 4 inches (4.1 m). Their displacement was 703 long tons (714 t) when surfaced and increased to 837 long tons (850 t) while submerged. Each submarine accommodated a complement of 30 personnel, including officers and ratings, and featured a partial double hull design.

For propulsion on the surface, the submarines were equipped with two 800-brake-horsepower (597 kW) Vickers two-stroke diesel engines, each connected to an individual propeller shaft. When operating underwater, propulsion was provided by two electric motors rated at 420-horsepower (313 kW) each. These submarines were capable of achieving speeds up to 14.25 knots (26.39 km/h; 16.40 mph) on the surface and 9 knots (17 km/h; 10 mph) submerged. Their surfaced cruising range extended to approximately 2,400 nautical miles (4,400 km; 2,800 mi) at a speed of 16 knots (30 km/h; 18 mph).

Originally, the armament plan included one 21-inch (53.3 cm) torpedo tube positioned at the bow and two 18-inch (45 cm) tubes mounted on the sides. However, during construction, this arrangement was altered: the 21-inch tube was relocated to the stern, and two extra 18-inch tubes were installed in the bow section. Consequently, these submarines carried a total of two 21-inch torpedoes alongside eight 18-inch torpedoes. Additionally, they were outfitted with a single 3-inch (7.6 cm) deck gun for surface combat.

Career

As with her sister vessels, the primary mission of G7 involved patrolling designated sectors of the North Sea to detect and engage German U-boats. On 15 April 1917, while operating between Lerwick and Bergen, G7 encountered the German submarine U-30. Upon sighting U-30, G7 launched a torpedo and engaged in a brief gun duel, after which the German submarine submerged and escaped. Despite U-30 avoiding damage, G7 successfully disrupted its attack on two Norwegian merchant vessels. One of these, Svanfos, which still carried a boarding party from U-30, managed to sail back to Bergen under its own power. The other vessel, the Borgila, had been abandoned by her crew. To secure the ship, G7 placed a salvage team aboard until the arrival of the Norwegian destroyer Draug, which then assumed control.

In October 1918, while conducting patrols in the North Sea, G7 lost all communications on 23 October and was officially declared missing as of 1 November.

References

• Template:Cite Colledge2006
• Gardiner, Robert & Gray, Randal, eds. (1985). Conway's All the World's Fighting Ships 1906–1921. Annapolis, Maryland: Naval Institute Press. ISBN 0-85177-245-5.
• McCartney, Innes (2008). British Submarines of World War I. New Vanguard. Vol. 145. Oxford, UK: Osprey. ISBN 978-1-84603-334-6.
• Monograph No. 34: Home Waters—Part VIII.: From February to July 1915 (PDF). Naval Staff Monographs (Historical). Vol. XVIII. The Naval Staff, Training and Staff Duties Division. 1933.