HMS K9 was a K class submarine built by Vickers, Barrow-in-Furness. K9 was laid down on 28 June 1915. She was commissioned on 9 May 1917. In 1921, K9 was placed in reserve. K9 was sold in Charlestown on 23 July 1926. It had a complement of fifty-nine crew members and a length of 338 ft.

Design

Like all British K-class submarines, K9 had a displacement of 1800 LT when at the surface and 2600 LT while submerged. It had a total length of 338 ft, a beam of 26 ft, and a draught of 20 ft. The submarine was powered by two oil-fired Yarrow Shipbuilders boilers and one geared Brown-Curtis or Parsons steam turbine; this developed 10,500 ship horsepower (7,800 kW) to drive two 7 ft screws. It also contained four electric motors each producing 350 to 360 hp. It was also fitted with a diesel engine providing 800 hp to be used when steam was being raised, or instead of raising steam. The submarine had a maximum surface speed of 24 kn and a submerged speed of 9 to 9.5 kn. It could operate at depths of 150 ft at 2 kn for 80 nmi. K9 was fitted with a 3 in anti-aircraft gun, ten 18 in torpedo tubes, and two 4 in deck guns. Its torpedo tubes were fitted to the bows, the midship section, and two were mounted on the deck. Its complement was fifty-nine crew members.