HMS K7

History
United Kingdom
NameHMS K7
BuilderHM Dockyard Devonport
Laid down8 November 1915
Launched31 May 1916
CommissionedJuly 1917
FateSold, 9 September 1921
General characteristics
Class and typeK-class submarine
Displacement
  • 1,980 long tons (2,010 t) surfaced
  • 2,566 long tons (2,607 t) submerged
Length339 ft (103 m)
Beam26 ft 6 in (8.08 m)
Draught20 ft 11 in (6.38 m)
Propulsion
Speed
  • 24 knots (44 km/h; 28 mph) surfaced
  • 8 knots (15 km/h; 9.2 mph) submerged
Range
  • Surfaced :
  • 800 nmi (1,500 km; 920 mi) at 24 kn (44 km/h; 28 mph)
  • 12,500 nmi (23,200 km; 14,400 mi) at 10 kn (19 km/h; 12 mph)
  • Submerged :
  • 8 nmi (15 km; 9.2 mi) at 8 kn (15 km/h; 9.2 mph)
  • 40 nmi (46 mi; 74 km) at 4 kn (4.6 mph; 7.4 km/h)
Complement59 (6 officers and 53 ratings)
Armament

HMS K7 was a K class submarine built by HM Dockyard, Devonport. She was laid down on 8 November 1915 and commissioned in July 1917.

K7 was the only one of the disastrous K class to engage with an enemy; on 16 June 1917 she fired a salvo of torpedoes at the U-boat U-95 and scored a direct hit. However, the torpedo failed to explode with what has been described as typical "K" luck; K-7 escaped retaliation by steaming away at speed.[1]

K7 was involved in an accident with the 4th Light Cruiser Squadron. She was also involved in the catastrophic series of accidents during a night exercise that came to be known sarcastically as the Battle of May Island; K7 was damaged by running over the sinking K4. K7 was sold on 9 September 1921 at Sunderland.

Design

K7 displaced 1,800 long tons (1,800 t) when at the surface and 2,600 long tons (2,600 t) while submerged.[2] It had a total length of 338 feet (103 m), a beam of 26 feet 6 inches (8.08 m), and a draught of 20 ft 11 in (6.38 m).[3] The submarine was powered by two oil-fired Yarrow Shipbuilders boilers supplying one geared Brown-Curtis or Parsons steam turbine that developed 10,500 ship horsepower (7,800 kW) to drive two 7 ft 6 in (2.29 m) screws. Submerged power came from four electric motors each producing 350 to 360 horsepower (260 to 270 kW).[3] It also had an 800 hp (600 kW) diesel engine to be used when steam was being raised, or instead of raising steam.[4]

The submarine had a maximum surface speed of 24 kn (44 km/h) and a submerged speed of 9 to 9.5 kn (16.7 to 17.6 km/h).[3][5] It could operate at depths of 150 ft (46 m) at 2 kn (3.7 km/h) for 80 nmi (150 km).[2] K7 was armed with ten 18-inch (460 mm) torpedo tubes, two 4-inch (100 mm) deck guns, and a 3-inch (76 mm) anti-aircraft gun.[3] Its torpedo tubes were fitted to the bows, the midship section, and two were mounted on the deck.[2] Its complement was fifty-nine crew members.[5]

References

  1. ^ Edwyn Gray (31 January 2016). British Submarines at War: 1914–1918. Pen and Sword. pp. 220–221. ISBN 978-1-4738-5348-5.
  2. ^ a b c "K for Katastophe". Undersea Warfare Magazine. Archived from the original on 24 September 2015. Retrieved 20 August 2015.
  3. ^ a b c d Colledge, J. J.; Warlow, Ben (2006) [1969]. Ships of the Royal Navy: The Complete Record of all Fighting Ships of the Royal Navy (Rev. ed.). London: Chatham Publishing. ISBN 978-1-86176-281-8.
  4. ^ Anthony Bruce; William Cogar (27 January 2014). Encyclopedia of Naval History. Routledge. p. 356. ISBN 978-1-135-93534-4.
  5. ^ a b Julian Holland (1 May 2012). Amazing & Extraordinary Facts Steam Age. David & Charles. p. 145. ISBN 978-1-4463-5619-7.

Bibliography

  • Hutchinson, Robert. Submarines, War Beneath The Waves, from 1776 to the Present Day.