or coastal defense ship was a type of

naval ship A naval ship is a military ship (or sometimes boat, depending on classification) used by a navy. Naval ships are differentiated from civilian ships by construction and purpose. Generally, naval ships are Damage control, damage resilient a ...

used by the

Imperial Japanese Navy The Imperial Japanese Navy (IJN; Kyūjitai: Shinjitai: ' 'Navy of the Greater Japanese Empire', or ''Nippon Kaigun'', 'Japanese Navy') was the navy of the Empire of Japan from 1868 to 1945, when it was dissolved following Japan's surrender ...

during

World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the World War II by country, vast majority of the world's countries—including all of the great power ...

for escort duty and coastal defense. The term escort ship was used by the

United States Navy The United States Navy (USN) is the maritime service branch of the United States Armed Forces and one of the eight uniformed services of the United States. It is the largest and most powerful navy in the world, with the estimated tonnage ...

to describe this category of Japanese ships.REPORTS OF THE U. S. NAVAL TECHNICAL MISSION TO JAPAN, SERIES S: SHIP AND RELATED TARGETS
JM-200-G, S-01-2. Characteristics of Japanese Naval Vessels-Article 2, Surface Warship Machinery Design. Page 49-52

Description

These ships were the Japanese equivalent to Allied

destroyer escort Destroyer escort (DE) was the United States Navy mid-20th-century classification for a warship designed with the endurance necessary to escort mid-ocean convoys of merchant marine ships. Development of the destroyer escort was promoted by th ...

s and

frigate A frigate () is a type of warship. In different eras, the roles and capabilities of ships classified as frigates have varied somewhat. The name frigate in the 17th to early 18th centuries was given to any full-rigged ship built for speed an ...

s, with all three types of warships being built as a less expensive

anti-submarine warfare Anti-submarine warfare (ASW, or in older form A/S) is a branch of underwater warfare that uses surface warships, aircraft, submarines, or other platforms, to find, track, and deter, damage, or destroy enemy submarines. Such operations are typ ...

alternative to fleet

destroyer In naval terminology, a destroyer is a fast, manoeuvrable, long-endurance warship intended to escort larger vessels in a fleet, convoy or battle group and defend them against powerful short range attackers. They were originally developed ...

s. While similar, destroyer escorts of the US Navy played a slightly different role to that of ''kaibōkan'' within the IJN, namely being that ''kaibōkan'' were diesel engine ships that never carried torpedo tubes, while many examples of Allied destroyer escort classes featured boiler and turbine machinery, and carried torpedoes; as a result of these design differences, ''kaibōkan'' often proved inferior to Allied destroyer escorts when undertaking escort roles. Additionally, because of these features of Allied destroyer escorts, they are more comparable to the Matsu-class, which the IJN considered to be , envisioned as general escorts with less firepower and speed.REPORTS OF THE U. S. NAVAL TECHNICAL MISSION TO JAPAN, SERIES S: SHIP AND RELATED TARGETS
JM-200-G, S-01-4. Characteristics of Japanese Naval Vessels-Article 4, Surface Warship. Page 1 ''Kaibōkan'' had some counterparts among Japan's

Axis An axis (plural ''axes'') is an imaginary line around which an object rotates or is symmetrical. Axis may also refer to: Mathematics * Axis of rotation: see rotation around a fixed axis * Axis (mathematics), a designator for a Cartesian-coordinat ...

allies: the 10 ''

Kriegsmarine The (, ) was the navy of Germany from 1935 to 1945. It superseded the Imperial German Navy of the German Empire (1871–1918) and the inter-war (1919–1935) of the Weimar Republic. The was one of three official branches, along with the a ...

'' escort ships of the F-class, and '' Amiral Murgescu'' of the

Romanian Navy The Romanian Navy ( ro, Forțele Navale Române) is the navy branch of the Romanian Armed Forces; it operates in the Black Sea and on the Danube. It traces its history back to 1860. History The Romanian Navy was founded in 1860 as a river flo ...

. In the course of the war, the design was simplified and scaled down to permit larger numbers of vessels to be built more quickly.

Old definition

Before the onset of World War II, ''kaibōkan'' was the catchall name for various ships, from battleships to sloops, which had become obsolete. For example, the battleship '' Mikasa'' was reclassified as a Kaibokan 1st class in 1921, after 19 years from her commissioning.

Classes

Ships of the first four classes were all named after Japanese islands.

(''Ishigaki'')

*Also known as Type A – multi purpose patrol, escorts or minesweeper. *Main Engine: Diesel X 2, double shaft () *Max Speed: *Range: () *Fuel: Oil X 120t

(''Matsuwa'')

*Modified Type A *Main Engine: Diesel X 2, double shaft () *Max Speed: *Range: () *Fuel: Oil X 120t

(''Chiburi'')

*Also known as Type B *Main Engine: Diesel X 2, double shaft () *Max Speed: *Range: () *Fuel: Oil X 120t

(''Okinawa'')

*Modified Type B *Main Engine: Diesel X 2, double shaft () *Max Speed: *Range: () *Fuel: Oil X 120t

Type C and Type D

Same design with different engines; diesels for Type C and turbines for Type D. More than 120 were mass-produced during the war, employing

modular design Modular design, or modularity in design, is a design principle that subdivides a system into smaller parts called ''modules'' (such as modular process skids), which can be independently created, modified, replaced, or exchanged with other modules ...

method.

Others

In addition, two former Chinese light cruisers were used, renamed '' Ioshima'' and '' Yasoshima''.

Footnotes

References

Notes

Sources

*
Stories and Battle Histories of the IJN's Escorts
9 July 2011 By Bob Hackett, Sander Kingsepp and Peter Cundall *Kimata Jirō (木俣滋郎). ''Military history of Japan's coastal defense ships'' (『日本海防艦戦史』). Toshu Publishing (図書出版社), 1994. p. 299