W-1-class minesweeper

W-3 in 1923
Class overview
Name	W-1-class minesweeper
Builders	Sasebo Naval Arsenal Harima Zōsen Mitsui Bussan Ōsaka Iron Works
Operators	Imperial Japanese Navy
Succeeded by	W-13 class
Subclasses	W-1 class (Project Number I1) W-5 class (Project Number I2)
Cost	700,000 JPY (in 1920)
Built	1922–1929
In commission	1923–1946
Planned	6
Completed	6
Lost	5
Scrapped	1
General characteristics W-1-class
Type	Minesweeper
Displacement	600 long tons (610 t) standard
Length	76.20 m (250 ft 0 in) overall
Beam	8.03 m (26 ft 4 in)
Draught	2.29 m (7 ft 6 in)
Installed power	3 × Kampon coal-fired boilers 4,000 shp (3,000 kW)
Propulsion	2 shafts, 2 × triple-expansion steam engines
Speed	20.0 knots (37.0 km/h; 23.0 mph)
Range	2,000 nmi (3,700 km; 2,300 mi) at 10 knots (19 km/h; 12 mph)
Complement	97
Armament	2 × 120 mm (4.7 in) L/45 naval guns 1 × 76.2 mm (3.00 in) L/40 AA gun 18 × depth charges 2 × Type 81 depth charge projectors 1 × paravane or 50 × Mk.5 naval mines
General characteristics W-5-class (differences only)
Displacement	620 long tons (630 t) standard
Length	77.00 m (252 ft 7 in) overall
Beam	8.25 m (27 ft 1 in)
Draught	2.25 m (7 ft 5 in)
Complement	91
Armament	2 × paravanes or 50 × Mk.5 naval mines

The W1 class minesweeper (第一号型掃海艇,, Dai Ichi Gō-gata Sōkaitei) was a class of minesweepers of the Imperial Japanese Navy (IJN), serving during the 1930s and World War II. 6 vessels were built in 1922–29 under the Eight-eight fleet plan. They have two sub-classes, this article handles them collectively.