280'

2 x direct drive turbines

26'

4

8'

2

770 std

21,500

36

110

3,000 NM @ 15 knots

3

4.7"/45 (12cm)

3 single mounts

17,500 yards @ 33° (9.9 miles)

2

7.7mm (0.303")

single mounts

1,000 yards

4

21" torpedo tubes

2 twin launchers

16,400 yards (9.3 miles)

Armament changes

Units not reclassified during the war had the mine equipment removed and had
4 depth charge launchers and 36 depth charges added.

1939: Units reclassified as Patrol Boats carried 2 x 4.7" and 6 x 25mm and had
the torpedo tubes removed. They also carried up to 60 depth charges.

1940: Units reclassified as training boats carried between 1 and 2 x 4.7"
and 2 x 21" torpedo tubes.

Momi

Kure Navy Yard
Kure, Japan

June 10, 1919

N/A

N/A

Scrapped in 1932.

Kaya

Yokosuka Navy Yard
Yokosuka, Japan

June 10, 1919

N/A

N/A

Scrapped in 1939.

Nashi

Kawasaki Jyuko Co.
Kobe, Japan

Aug. 26, 1919

N/A

N/A

Scrapped in 1939.

Take

Kawasaki Jyuko Co.
Kobe, Japan

Aug. 26, 1919

N/A

N/A

Sunk as breakwater, raised and scrapped in 1947.

Reclassified as training ship in 1940.

Kaki
(later Osu)

Uraga Dock Co.
Tokyo, Japan

Oct. 20, 1919

N/A

N/A

Scrapped in 1947.

*Reclassified as training ship in 1940.
Disarmed in 1944 and had wooden huts built in place of armaments.
Renamed Osu on Feb. 23, 1945.

Nire
(later Tomariura #1)

Kure Navy Yard
Kure, Japan

Dec. 22, 1919

N/A

N/A

Scrapped in 1947.

*Reclassified as training ship in 1940.
Renamed Tomariura #1 in Dec. 1944.

Kuri

Kure Navy Yard
Kure, Japan

Mar. 19, 1920

N/A

N/A

Sunk Oct. 8, 1945 by a left over mine.

Location: Off Korea

Unknown number of casualties or survivors.

Tsuga

Ishikawajima Zosensho
Tokyo, Japan

Apr. 17, 1920

N/A

N/A

Sunk Jan. 15, 1945 by US Aircraft from TF-38.

Location: Makung, Pescadores Islands, Taiwan. (23.33N - 119.33E)

Unknown number of casualties or survivors.

Kiku
(Patrol Boat #31)

Kawasaki Jyuko Co.
Kobe, Japan

Oct. 13, 1920

N/A

N/A

Sunk Mar. 30, 1944 by US Aircraft from TF-38.

Location: Philippine Sea 10 miles N of Koror, Palau. (07.30N - 134.30E)

Unknown number of casualties or survivors.

Hagi
(Patrol Boat #33)

Uraga Dock Co.
Tokyo, Japan.

Oct. 29, 1920

N/A

N/A

Sunk Dec. 22, 1941 by USMC shore guns.

Location: Wake Island. (19.17N - 166.39E)

Unknown number of casualties or survivors.

Aoi
(Patrol Boat #32)

Kawasaki Jyuko Co.
Kobe, Japan

Nov. 9, 1920

N/A

N/A

Sunk Dec. 22, 1941 by USMC shore guns.

Location: Wake Island. (19.17N - 166.39E)

Unknown number of casualties or survivors.

Fuji
(Patrol Boat #36)

Fujinagata Zosensho
Osaka, Japan

Nov. 27, 1920

N/A

N/A

Scrapped in 1947.

*Damaged May 17, 1945 by aircraft from USS Saratoga CV-3 and HMS Illustrious.
Surrendered unrepaired in Aug. 1945. Transferred to The Netherlands in 1946.

Sutsuki
(Patrol Boat #34)

Ishikawajima Zosensho
Tokyo, Japan

Feb. 21, 1921

N/A

N/A

Sunk July 3, 1944 by US Aircraft.
*Had been damaged in a collision with Yakaze on Mar. 6, 1943 and was at
Truk for repairs.

Location: Truk Lagoon.

Unknown number of casualties or survivors.

Tsuta
(Patrol Boat #35)

Kawasaki Jyuko Co.
Kobe, Japan

May 9, 1921

N/A

N/A

Sunk Sept. 2, 1943 by USAAF Aircraft.

Location: Huon Gulf, Lae Harbor, Papua New Guinea. (06.43S - 146.59E)

Unknown number of casualties or survivors.

Hishi
(Patrol Boat #37)

Uraga Dock Co.
Tokyo, Japan

May 19, 1921

N/A

N/A

Sunk Jan. 24, 1942 by USS Pope DD-225 and USS Parrott DD-219. (gunfire)
*Raised and scrapped.

Location: Balikpanpan, Borneo. (01.24S - 117.12E)

Unknown number of casualties or survivors.

Ashi
(Tomariura #2)

Kawasaki Jyuko Co.
Kobe, Japan

Sept. 3, 1921

N/A

N/A

Scrapped in 1947.

*Reclassified as training ship in 1940.
Renamed Tomariura #2 in Dec. 1944.

Warabi

Fujinagata Zosensho
Osaka, Japan

Sept. 28, 1921

N/A

N/A

Sunk Aug. 25, 1927 after being rammed by Jintsu.

Location: Cape Miho, Japan.

Unknown number of casualties or survivors.

Hasu

Uraga Dock Co.
Tokyo, Japan

Dec. 8, 1921

N/A

N/A

Scrapped in 1947.

*Damaged Jan. 16, 1945 by US Aircraft from TF-38 at Hong Kong,
surrendered unrepaired in Aug. 1945.

Sumire
(Mitaka)

Ishikawajima Zosensho
Tokyo, Japan

Dec. 14, 1921

N/A

N/A

Scrapped in 1948.

*Reclassified as training ship in 1940.
Disarmed in 1944 and had wooden huts built in place of armaments.
Renamed Mitaka in Feb. 1945.

Yomogi
(Patrol Boat #38)

Ishikawajima Zosensho
Tokyo, Japan

Mar. 14, 1922

N/A

N/A

Sunk Nov. 25, 1944 by USS Atule SS-403. (torpedo)

Location: North Pacific 3 miles south of Sabtang Island, Philippines.
(20.12N - 121.51E)

Unknown number of casualties or survivors.

Tade
(Patrol Boat #39)

Fujinagata Zosensho
Osaka, Japan

Mar. 15, 1922

N/A

N/A

Sunk Apr. 23, 1943 by USS Seawolf SS-197. (torpedo)

Location: North Pacific 75 miles E of Hua-lien, Taiwan.
(23.45N - 122.45E)

Unknown number of casualties or survivors.

This was the first class to carry the 21" torpedo tubes.

1939:

9 units reclassified as Patrol Boats.
(Kiku, Aoi, Hagi, Sutsuki, Tsuta, Fuji, Hishi, Yomogi and Tade)
One boiler removed reducing HP to 12,000 and reducing speed to 31.5 knots.
Extra ballast added increasing the standard tonnage to 935 tons.
Armaments changed. (see above)

1940:

5 units reclassified as training ships.
(Ashi, Kaki, Nire, Sumire and Take)
Two boilers removed reducing HP to 9,000 and reducing speed to 14 knots.
Armaments changed. (see above)

1941:

All Patrol Boats except PB-31 were modified in the stern to carry and launch
1 Daihatsu landing craft and 150 troops.
When used in this roll only 18 depth charges were carried.
Some units also had the second funnel removed.

1942:

PB-31 had 2 additional 25mm AA guns added.

Class Statistics

21 in class

10 sunk

11 scrapped

*Of the 11 scrapped 2 had been damaged in combat and were unreapired
and 2 had been sunk in combat but raised and scrapped.

* 2 of the units sunk were accidents, 1 collision and 1 by a mine after the war.