The two were the first
light cruiser
A light cruiser is a type of small or medium-sized warship. The term is a shortening of the phrase "light armored cruiser", describing a small ship that carried armor in the same way as an armored cruiser: a protective belt and deck. Prior to th ...
s operated 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 surrend ...
. They participated in numerous actions 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 vast majority of the world's countries—including all of the great powers—forming two opposing ...
.
The ''Tenryū'' class was followed by the larger and more versatile .
Background
The ''Tenryū'' class was designed to act as flagships for destroyer flotillas. The design represented an intermediate class between the light cruiser (e.g.
''Chikuma'' class of 5,000 t) and the destroyer (e.g.
''Kawakaze''-class destroyers of 1,300 t), which had few counterparts in other navies of the time, although it was inspired by a similar concept to the
Royal Navy
The Royal Navy (RN) is the United Kingdom's naval warfare force. Although warships were used by English and Scottish kings from the early medieval period, the first major maritime engagements were fought in the Hundred Years' War against ...
''Arethusa'' class and s.
[Gardner, ''Conway's All the World's Fighting Ships 1906–1921'', p. 237.] The Imperial Japanese Navy and Japanese shipbuilding industry were still closely associated with the British due to the
Anglo-Japanese Alliance, and were able to improve on the British experience.
Plans for the small cruisers were developed in 1915, with orders placed in the 1916 fiscal year. The cost of construction was approximately 4.55 million
yen
The is the official currency of Japan. It is the third-most traded currency in the foreign exchange market, after the United States dollar (US$) and the euro. It is also widely used as a third reserve currency after the US dollar and the e ...
.
Soon after completion, the drawbacks of the small design became apparent to the
Imperial Japanese Navy General Staff
The was the highest organ within the Imperial Japanese Navy. In charge of planning and operations, it was headed by an Admiral headquartered in Tokyo.
History
Created in 1893, the Navy General Staff took over operational (as opposed to adminis ...
. Newer Japanese destroyers, such as the had a design speed of 39 knots, much higher than that of the '' Tenryū''. Newer American cruisers, such as the also exceeded it in firepower.
[Stille, ''Imperial Japanese Navy Light Cruisers 1941-45'', pp. 12-15.] Plans for an additional six ships were later abandoned in favor of a series of medium-sized (5500 ton class) cruisers, based on an enlarged version of the ''Tenryū'' design.
From 1935-1936, plans were considered to convert the class into a dedicated anti-aircraft / anti-submarine platforms, using eight 127 mm guns in dual turrets, eight 25-mm guns, and four
depth charge launchers with 36 depth charges. The redesign would also have involved combining the smokestacks into a single stack. Funding was approved for fiscal 1937, but the plan was cancelled due to an overload in the capacity of Japanese shipyards.
[ The plan was floated again in 1938-1939 using eight Type 98 76.2 mm guns, but eventually abandoned in favor of the s.
]
Design
The ''Tenryū''-class vessels, termed "small-model" (or "3,500-Ton") cruisers, were designed as fast flotilla leaders for the Imperial Navy's new first- and second-class destroyers.[Lacroix and Wells, ''Japanese Cruisers of the Pacific War'', p. 18.] With improvements in oil-fired turbine engine technology and the use of Brown Curtiss geared turbine engines, the ''Tenryū'' class had more than twice the horsepower of the previous , and were capable of .[ Three sets of turbines were used, with ten boilers fitted into three boiler rooms. Two of the boilers were mixed-firing, using a combination of oil and coal, but were converted to oil firing before the start of World War II.][
However, in terms of weaponry, the ''Tenryū'' class was weaker than any other contemporary cruiser. The ]main battery
A main battery is the primary weapon or group of weapons around which a warship is designed. As such, a main battery was historically a gun or group of guns, as in the broadsides of cannon on a ship of the line. Later, this came to be turreted ...
for the ''Tenryū'' class consisted of four 14 cm/50 3rd Year Type naval gun
The 14 cm/50 3rd Year Type naval gun was a Japanese low-angle weapon introduced during World War I.
History
It served as the secondary armament in a number of Japanese dreadnoughts and as the main armament in light cruisers and some auxiliar ...
s, which were also utilized as the secondary battery on the s. However, the guns were situated in single mounts on the centerline, with only a limited angle of fire, and could fire only one gun at a target immediately in front or aft of the vessel. Ammunition handling was entirely manual. There were 2 magazines at the lowest deck level (4 decks below the guns), one between mounts 1 and 2 below the bridge, one below mount 3, reachable by bucket chain hoists. Loading and training was all manual as well. A Type 13 fire-control director was mounted above the bridge and two 2.5m range finders were used, one mounted on the compass bridge, the other just ahead of gun mount 3.[Lacroix/Wells p. 25]
A further weakness was the lack of room for anti-aircraft guns. Despite awareness increasing about the growing threat of aircraft to surface ships, the secondary battery of the ''Tenryū'' class consisted of only a single dual-purpose 8 cm/40 3rd Year Type naval gun, plus two 6.5 mm machine guns. The class also was the first to use triple torpedo launchers, with two centerline-mounted Type 6 21-inch launchers. No reloads were carried.[
The hull design resembled enlarged destroyers, with a high ratio of length to width (11.28:1) and a raised bow deck. The No.1 ]gun turret
A gun turret (or simply turret) is a mounting platform from which weapons can be fired that affords protection, visibility and ability to turn and aim. A modern gun turret is generally a rotatable weapon mount that houses the crew or mechani ...
was situated on the foredeck, followed by a short three-story tower superstructure with the mast, and the No.2 gun turret to the rear. This was followed by a stepped hull, housing a triple torpedo launcher on the centerline, followed by a narrow amidships superstructure forming the base for three relatively low smokestacks. This was followed by the aft triple torpedo launcher and the No.3 and No.4 gun turrets. The armor protection for the hull was weak, designed primarily against the 102 mm weapons used on contemporary 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 ...
destroyers.[
]
In service modifications
In 1930 (''Tenryū'') and in 1933 (''Tatsuta''), the ships were renovated with a modified bow superstructure, replacing the canvas sides of the bridge with steel plate, and lowering the mast for increased stability. In 1936, the bridge was further reinforced with steel plate as protection against shrapnel
Shrapnel may refer to:
Military
* Shrapnel shell, explosive artillery munitions, generally for anti-personnel use
* Shrapnel (fragment), a hard loose material
Popular culture
* ''Shrapnel'' (Radical Comics)
* ''Shrapnel'', a game by Adam C ...
. In July 1937, two Type 93 13 mm AA machine guns in single mounts were added on platforms near the first smokestack. These were replaced in 1940 with two twin-mount Type 96 25 mm AA guns; the 8 cm/40 3rd Year Type naval gun was removed at this time.
Since both vessels were regarded as second-line units by the time of World War II, wartime modifications were minor. An additional two Type 96 25-mm twin mounts were added while at Truk in February 1942. ''Tatsuta'' received a fifth Type 96 twin mount in an August 1943 refit.[
]
Ships in Class
Two vessels were built in the ''Tenryū'' class, neither of which survived the Pacific War.
; (天龍)
''Tenryū'' was laid down on 7 May 1917 and completed on 20 November 1919, at the Yokosuka Naval Arsenal
was one of four principal naval shipyards owned and operated by the Imperial Japanese Navy, and was located at Yokosuka, Kanagawa prefecture on Tokyo Bay, south of Yokohama.
History
In 1866, the Tokugawa shogunate government established the ...
. Prior to 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 vast majority of the world's countries—including all of the great powers—forming two opposing ...
, she participated in the Siberian Intervention
The Siberian intervention or Siberian expedition of 1918–1922 was the dispatch of troops of the Entente powers to the Russian Maritime Provinces as part of a larger effort by the western powers, Japan, and China to support White Russian f ...
, Yangtze River
The Yangtze or Yangzi ( or ; ) is the longest list of rivers of Asia, river in Asia, the list of rivers by length, third-longest in the world, and the longest in the world to flow entirely within one country. It rises at Jari Hill in th ...
patrols and supported the landings of Japanese troops along the China coast. During the early stages of the Pacific War, she participated in the Battle of Wake Island
The Battle of Wake Island was a battle of the Pacific campaign of World War II, fought on Wake Island. The assault began simultaneously with the attack on Pearl Harbor naval and air bases in Hawaii on the morning of 8 December 1941 (7 December ...
and the invasions of the Solomon Islands
Solomon Islands is an island country consisting of six major islands and over 900 smaller islands in Oceania, to the east of Papua New Guinea and north-west of Vanuatu. It has a land area of , and a population of approx. 700,000. Its capit ...
, New Guinea
New Guinea (; Hiri Motu: ''Niu Gini''; id, Papua, or , historically ) is the world's second-largest island with an area of . Located in Oceania in the southwestern Pacific Ocean, the island is separated from Australia by the wide Torr ...
, Tulagi
Tulagi, less commonly known as Tulaghi, is a small island——in Solomon Islands, just off the south coast of Ngella Sule. The town of the same name on the island (pop. 1,750) was the capital of the British Solomon Islands Protectorate from 1 ...
, and the Battle of Savo Island
The Battle of Savo Island, also known as the First Battle of Savo Island and, in Japanese sources, as the , and colloquially among Allied Guadalcanal veterans as the Battle of the Five Sitting Ducks, was a naval battle of the Solomon Islands cam ...
. Two of her torpedoes are credited with sinking . She was sunk after the Naval Battle of Guadalcanal
The Naval Battle of Guadalcanal, sometimes referred to as the Third and Fourth Battles of Savo Island, the Battle of the Solomons, the Battle of Friday the 13th, or, in Japanese sources, the , took place from 12 to 15 November 1942, and was t ...
by , and struck on 20 January 1943.
''Tenryu Tabular Record of Movement'';
; (龍田)
''Tatsuta'' was laid down on 24 July 1917 and completed at the Sasebo Naval Arsenal on 31 March 1919. Prior to World War II, she participated in the Siberian Intervention
The Siberian intervention or Siberian expedition of 1918–1922 was the dispatch of troops of the Entente powers to the Russian Maritime Provinces as part of a larger effort by the western powers, Japan, and China to support White Russian f ...
, and supported the landings of Japanese troops along the China coast. During the Pacific War, she participated in the Battle of Wake Island
The Battle of Wake Island was a battle of the Pacific campaign of World War II, fought on Wake Island. The assault began simultaneously with the attack on Pearl Harbor naval and air bases in Hawaii on the morning of 8 December 1941 (7 December ...
and the invasions of the Solomon Islands
Solomon Islands is an island country consisting of six major islands and over 900 smaller islands in Oceania, to the east of Papua New Guinea and north-west of Vanuatu. It has a land area of , and a population of approx. 700,000. Its capit ...
, New Guinea
New Guinea (; Hiri Motu: ''Niu Gini''; id, Papua, or , historically ) is the world's second-largest island with an area of . Located in Oceania in the southwestern Pacific Ocean, the island is separated from Australia by the wide Torr ...
, Tulagi
Tulagi, less commonly known as Tulaghi, is a small island——in Solomon Islands, just off the south coast of Ngella Sule. The town of the same name on the island (pop. 1,750) was the capital of the British Solomon Islands Protectorate from 1 ...
. She was retained in Japanese home waters for most of 1943 on training duties. She was sunk while bound for Saipan by , NNE of Hachijōjima on 13 March 1944. ''Tatsuta'' was struck on 10 May 1944.
''Tatsuta Tabular Record of Movement'';
References
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External links
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Notes
{{DEFAULTSORT:Tenryu-class cruiser
Tenryū-class cruisers,