I-121-class submarine

I-121 (as I-21) in 1930.
Class overview
Name	I-121 class submarine
Builders	Kawasaki Corporation
Operators	Imperial Japanese Navy
Built	1924–1928
In commission	1927–1945
Planned	6
Completed	4
Cancelled	2
Lost	3
Retired	1
General characteristics
Type	Minelaying submarine
Displacement	1,142 long tons (1,160 t) surfaced 1,768 long tons (1,796 t) submerged
Length	85.20 m (279 ft 6 in) overall
Beam	7.52 m (24 ft 8 in)
Draft	4.42 m (14 ft 6 in)
Propulsion	2 × Rauschenbach Mk.1 diesels 2,400 bhp surfaced 1,100 shp submerged 2 shafts
Speed	14.9 knots (27.6 km/h) surfaced 6.5 knots (12.0 km/h) submerged
Range	10,500 nmi (19,400 km) at 8 knots (15 km/h) surfaced 40 nmi (74 km) at 4.5 knots (8.3 km/h) submerged
Test depth	75 m (246 ft)
Complement	51
Armament	2 × 533 mm (21 in) torpedo tubes 12 × 6th Year Type torpedoes 1 × 14 cm/40 11th Year Type naval gun[1] 42 × naval mines

The I-121-class submarine (伊百二十一型潜水艦, I-hyaku-ni-jū-ichi-gata sensuikan) was a class of minelayer submarine in the Imperial Japanese Navy (IJN), serving from the 1920s to World War II. The IJN classed it as a Kiraisen type submarine (機雷潜型潜水艦, Kiraisen-gata sensuikan). The type name, was shortened from Kirai Fusetsu Sensuikan (機雷敷設潜水艦, Minelaying submarine).