INS Jamuna (U21)

History
India
Name	Jumna
Namesake	Yamuna River
Ordered	8 September 1939
Builder	William Denny and Brothers
Laid down	20 February 1940
Launched	16 November 1940
Commissioned	13 May 1941
Decommissioned	31 December 1980
Fate	Broken up 1981
General characteristics
Class and type	Black Swan-class sloop
Displacement	1,250 tons original 1,350 tons modified
Length	299 ft 6 in (91.29 m)
Beam	37 ft 6 in (11.43 m) original 38 ft 6 in (11.73 m) modified
Draught	11 ft (3.4 m)
Propulsion	Geared turbines, 2 shafts: 3,600 hp (2,700 kW) (original) 4,300 hp (3,200 kW) (3.21 MW) (modified)
Speed	19 knots (35 km/h) (original) 20 knots (37 km/h) (modified)
Range	7,500 nmi (13,900 km) at 12 kn (22 km/h)
Complement	180 (original) 192 (modified)
Armament	6 × QF 4 in (102 mm) Mk XVI AA guns (3 × 2) 4 × 2-pounder AA pom-pom 4 × 0.5-inch (12.7 mm) AA machine guns (original) 12 × 20 mm Oerlikon AA (6 × 2) (modified)

HMIS Jumna (U21) was a Black Swan-class sloop, which served in the Royal Indian Navy (RIN) during World War II.

After India became a republic on 26 January 1950, the vessel was renamed as the Indian Navy's INS Jamuna.