Japanese aircraft carrier Unryu
Encyclopedia
The Japanese aircraft carrier was a fleet aircraft carrier
of the Imperial Japanese Navy
which served during World War II
. She was commissioned on 6 August 1944 and eventually torpedoed and sunk by US submarine in the East China Sea on 19 December that same year. The name Unryū means literally "cloud dragon" and bears the allusion "Heavenward Bound Dragon Riding the Clouds".
and Taihō class
carriers, making her the ideal candidate and the design was quickly adopted with only a few modifications.
Other ships of the Unryū class
included Katsuragi, Amagi, Kasagi, Ikoma and Aso. A further eleven examples were ordered in 1942 but work on all ships of the class was suspended in 1945 when worsening wartime conditions left even those carriers already completed (Unryū, Katsuragi and Amagi) virtually inoperational due to a lack of aircraft, aircrews and fuel oil.
The carrier's aviation fuel tanks were still made integral with the ship's hull, a standard practice in Japanese carrier design that heightened the risks of fuel fires due to cracks and leaks developing from sudden shocks to the hull, whether from torpedo hits or bomb near-misses. In a concession to later wartime experience, aviation fuel capacity in the Unryū-class carriers was cut from 150,000 gallons to 48,000 gallons as it had been found that most Japanese carriers damaged or sunk during combat had time to use only a small proportion of their available AvGas. The empty air spaces around the aviation fuel tanks were also filled in with concrete as added splinter protection.
The upper hangar measured 175 m (574.1 ft) long by 21 m (68.9 ft) wide while the lower hangar, though of the same width, was appreciably shorter at 130 m (426.5 ft).They featured the standard fireproofed fabric dividing curtains and twin rows of foam-dispensing pipes and nozzles running along the hangar walls and ends as had been installed on earlier Japanese carriers. The curtains served to limit the supply of air to and delay the spread of any fires breaking out on either deck while the foam suppression system worked to extinguish the blaze.
In order to save on building time and materials, only two aircraft elevators were installed fore and aft, the aft elevator being an entirely new design, roughly pentagonal in shape, measuring 14.2 m (46.6 ft) by 14.2 m (46.6 ft). Both elevators had the same load limit of 5000 kilogram as those on the Sōryū-class carriers. The absence of an amidships elevator increased available floor space on the upper and lower hangar decks by 276 m² (330.1 sq yd) but total aircraft capacity remained unchanged due to the fact that Unryū was expected to operate the larger carrier-plane types just coming into service at the time of her completion.
The carrier's starboard-side island was larger than that of Hiryūs but was offset enough that it did not encroach on the width of the flight deck.
Two Type 21 air-warning and control radars with mattress-type antennas were installed, one atop the island and the other on a retractable pillbox on the port side aft edge of the flight deck. Two Type 13 radars were also added, one on the main-mast abaft the island and the other attached to one of the two hinged radio masts on the ship's aft starboard side. The Type 21 radar had a maximum effective range of 80 nmi (148.2 km; 92.1 mi) while the Type 13 had a range of 54 nmi (100 km; 62.1 mi)
armored belt
was 1.8 inches (4.6 cm) thick over her machinery spaced, but this increased to 5.5 inches (14 cm) over her magazine
s. Her deck armor
above the magazines was 25 millimetre (0.984251968503937 in) thick, but the deck above the magazines was 2.2 inches (5.6 cm) thick.
The ship's primary armament consisted of a dozen 40-caliber
12.7 cm Type 89
anti-aircraft
(AA) guns in twin mounts on sponson
s on the ship's sides. Unryū was initially equipped with 16 triple 25 mm Type 96 and three single AA gun mounts, most on sponsons along the sides of the hull. By the end of the war, the ship mounted 22 triple and 23 single mounts. These guns were supplemented by six 28-round AA rocket launchers. For defense against submarines, the carrier was fitted with six depth charge
throwers and carried between six and ten depth charges for them.
Two Type 94 high-angle fire-control directors, one on each side of the ship, were fitted to control the Type 89 guns. Each director mounted a 4.5 metre rangefinder. Six Type 95 directors controlled the 25 mm guns and the 12 cm rocket launchers. Early warning was provided by two Type 2, Mark 2, Model 1 air search radar
s. One of these was mounted on the top of the island while the other retracted into the port side of the flight deck, between the two elevators. In addition, Unryū had two smaller Type 3, Mark 1, Model 3 air search radars, one mounted on the tripod mast on the island and the other on the aft starboard retractable radio mast.
escorted by Shigure
, Hinoki, and Momi
under the overall command of Captain Konishi. Her maiden sea voyage was a vain attempt to reinforce the garrison on the island of Luzon
just prior to the US landings there.
On 19 December 1944, Unryū was torpedoed and sunk by the submarine USS Redfish
. Redfish fired four bow torpedoes, one of which hit directly under the carrier's bridge on the starboard side at 16:35, stopping the vessel dead in the water. Unryū engaged with all her starboard side guns. A second torpedo struck at 16:50 on the starboard side abreast the forward elevator, just as the carrier was managing to get under way again. The resulting explosion set off the Ohka suicide planes stored on the lower hangar deck as well as the highly volatile aviation fuel underneath.
Once the boiler rooms flooded, the ship listed to 30 degrees and the order to abandon ship was given. With a 90 degree list, the ship sank to the bed of the East China Sea
in just seven minutes at position 29°59′N 124°03′E. Casualties were great: Captain Kaname Konishi and 1,238 officers and men lost their lives. Only one officer and 146 men survived and were rescued by the escort destroyer Shigure, which returned to Sasebo, Nagasaki
on 22 December.
Aircraft carrier
An aircraft carrier is a warship designed with a primary mission of deploying and recovering aircraft, acting as a seagoing airbase. Aircraft carriers thus allow a naval force to project air power worldwide without having to depend on local bases for staging aircraft operations...
of the Imperial Japanese Navy
Imperial Japanese Navy
The Imperial Japanese Navy was the navy of the Empire of Japan from 1869 until 1947, when it was dissolved following Japan's constitutional renunciation of the use of force as a means of settling international disputes...
which served during World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
. She was commissioned on 6 August 1944 and eventually torpedoed and sunk by US submarine in the East China Sea on 19 December that same year. The name Unryū means literally "cloud dragon" and bears the allusion "Heavenward Bound Dragon Riding the Clouds".
Design
Unryū was one of six fleet carriers laid down by the Imperial Japanese Navy in 1942-43 as part of the Navy's War Construction Program. In order to expedite building of the new carriers, a standard design was chosen based on ease of manufacture and availability of materials. The Hiryū, with her high speed, good seakeeping and relatively large air group, required far less armor plate and use of special machinery than needed for the Shōkaku classJapanese aircraft carrier Shokaku
Shōkaku was an aircraft carrier of the Imperial Japanese Navy, the lead ship of her class. Along with her sister ship , she took part in several key naval battles during the Pacific War, including the attack on Pearl Harbor, the Battle of the Coral Sea and the Battle of the Santa Cruz Islands...
and Taihō class
Japanese aircraft carrier Taiho
was an aircraft carrier of the Imperial Japanese Navy during World War II. With a heavily armored hull and flight deck , she represented a major departure in Japanese carrier design and was expected to not only survive multiple bomb, torpedo or shell hits but also continue fighting effectively...
carriers, making her the ideal candidate and the design was quickly adopted with only a few modifications.
Other ships of the Unryū class
Unryu class aircraft carriers
The were World War II Japanese aircraft carriers. 16 carriers were planned under the Maru Kyū Programme and the Kai-Maru 5 Programme . However, only 3 carriers were completed.-Design:...
included Katsuragi, Amagi, Kasagi, Ikoma and Aso. A further eleven examples were ordered in 1942 but work on all ships of the class was suspended in 1945 when worsening wartime conditions left even those carriers already completed (Unryū, Katsuragi and Amagi) virtually inoperational due to a lack of aircraft, aircrews and fuel oil.
Hull
Unryūs hull form was virtually identical to that of Hiryū with the exception that, since the carrier's island was now located on the starboard side of the flight deck, the width of the hull on her port side was increased in order to balance the transfer of weight. As in Hiryū, the hull was not bulged and the only anti-torpedo defense was the 150 mm (5.9 in) waterline belt armor abreast the machinery and magazines, tapering down to 90 mm (3.5 in) where the aviation fuel tanks were located at either end of the ship. The partial 20 mm (0.78740157480315 in) internal anti-splinter bulkhead was also retained. Deck armor was again limited to 25 mm (0.984251968503937 in) over the machinery spaces and 55 mm (2.2 in) over the fore and aft ordnance magazines and AvGas tanks, giving the carrier scant protection from plunging shellfire or armor-piercing bombs.The carrier's aviation fuel tanks were still made integral with the ship's hull, a standard practice in Japanese carrier design that heightened the risks of fuel fires due to cracks and leaks developing from sudden shocks to the hull, whether from torpedo hits or bomb near-misses. In a concession to later wartime experience, aviation fuel capacity in the Unryū-class carriers was cut from 150,000 gallons to 48,000 gallons as it had been found that most Japanese carriers damaged or sunk during combat had time to use only a small proportion of their available AvGas. The empty air spaces around the aviation fuel tanks were also filled in with concrete as added splinter protection.
Machinery
The same cruiser-type machinery as had been used in Sōryū and Hiryū was installed on Unryū. The four sets of geared turbines had an output of 152000 shp and were connected to four separate shafts, giving Unryu a top speed of 34 kn (66.6 km/h; 41.4 mph) during sea trials. Steam was generated from eight oil-fired Kampon boilers. Unryūs standard fuel oil capacity of 3670 tons gave her a radius of 8000 nautical miles (14,816 km) at 18 knots (9.8 m/s).Flight Deck & Hangars
Unryūs wooden-planked flight deck was 217 m (711.9 ft) long by 27 m (88.6 ft) wide and retained the standard arrangement of nine hydraulically-controlled Type 3 arrester wires as used on Hiryū, three forward and six aft. These were capable of stopping a 6000 kilogram aircraft at speeds of 60-78 knots. The three forward wires allowed Unryū to recover aircraft over the bows while steaming astern in the event the after end of the flight deck was rendered unusable due to bomb damage or during periods of excessively high winds.The upper hangar measured 175 m (574.1 ft) long by 21 m (68.9 ft) wide while the lower hangar, though of the same width, was appreciably shorter at 130 m (426.5 ft).They featured the standard fireproofed fabric dividing curtains and twin rows of foam-dispensing pipes and nozzles running along the hangar walls and ends as had been installed on earlier Japanese carriers. The curtains served to limit the supply of air to and delay the spread of any fires breaking out on either deck while the foam suppression system worked to extinguish the blaze.
In order to save on building time and materials, only two aircraft elevators were installed fore and aft, the aft elevator being an entirely new design, roughly pentagonal in shape, measuring 14.2 m (46.6 ft) by 14.2 m (46.6 ft). Both elevators had the same load limit of 5000 kilogram as those on the Sōryū-class carriers. The absence of an amidships elevator increased available floor space on the upper and lower hangar decks by 276 m² (330.1 sq yd) but total aircraft capacity remained unchanged due to the fact that Unryū was expected to operate the larger carrier-plane types just coming into service at the time of her completion.
The carrier's starboard-side island was larger than that of Hiryūs but was offset enough that it did not encroach on the width of the flight deck.
Two Type 21 air-warning and control radars with mattress-type antennas were installed, one atop the island and the other on a retractable pillbox on the port side aft edge of the flight deck. Two Type 13 radars were also added, one on the main-mast abaft the island and the other attached to one of the two hinged radio masts on the ship's aft starboard side. The Type 21 radar had a maximum effective range of 80 nmi (148.2 km; 92.1 mi) while the Type 13 had a range of 54 nmi (100 km; 62.1 mi)
Armor, armament and sensors
Unryūs waterlineWaterline
The term "waterline" generally refers to the line where the hull of a ship meets the water surface. It is also the name of a special marking, also known as the national Load Line or Plimsoll Line, to be positioned amidships, that indicates the draft of the ship and the legal limit to which a ship...
armored belt
Belt armor
Belt armor is a layer of heavy metal armor plated on to or within outer hulls of warships, typically on battleships, battlecruisers and cruisers, and on aircraft carriers converted from those types of ships....
was 1.8 inches (4.6 cm) thick over her machinery spaced, but this increased to 5.5 inches (14 cm) over her magazine
Magazine (artillery)
Magazine is the name for an item or place within which ammunition is stored. It is taken from the Arabic word "makahazin" meaning "warehouse".-Ammunition storage areas:...
s. Her deck armor
Deck (ship)
A deck is a permanent covering over a compartment or a hull of a ship. On a boat or ship, the primary deck is the horizontal structure which forms the 'roof' for the hull, which both strengthens the hull and serves as the primary working surface...
above the magazines was 25 millimetre (0.984251968503937 in) thick, but the deck above the magazines was 2.2 inches (5.6 cm) thick.
The ship's primary armament consisted of a dozen 40-caliber
Caliber (artillery)
In artillery, caliber or calibredifference in British English and American English spelling is the internal diameter of a gun barrel, or by extension a relative measure of the length....
12.7 cm Type 89
12.7 cm/40 Type 89 naval gun
The 12.7 cm/40 Type 89 naval gun was a Japanese anti-aircraft gun introduced before World War II. It was the Imperial Japanese Navy's standard heavy AA gun during the war.-External links:*...
anti-aircraft
Anti-aircraft warfare
NATO defines air defence as "all measures designed to nullify or reduce the effectiveness of hostile air action." They include ground and air based weapon systems, associated sensor systems, command and control arrangements and passive measures. It may be to protect naval, ground and air forces...
(AA) guns in twin mounts on sponson
Sponson
Sponsons are projections from the sides of a watercraft, for protection, stability, or the mounting of equipment such as armaments or lifeboats, etc...
s on the ship's sides. Unryū was initially equipped with 16 triple 25 mm Type 96 and three single AA gun mounts, most on sponsons along the sides of the hull. By the end of the war, the ship mounted 22 triple and 23 single mounts. These guns were supplemented by six 28-round AA rocket launchers. For defense against submarines, the carrier was fitted with six depth charge
Depth charge
A depth charge is an anti-submarine warfare weapon intended to destroy or cripple a target submarine by the shock of exploding near it. Most use explosives and a fuze set to go off at a preselected depth in the ocean. Depth charges can be dropped by either surface ships, patrol aircraft, or from...
throwers and carried between six and ten depth charges for them.
Two Type 94 high-angle fire-control directors, one on each side of the ship, were fitted to control the Type 89 guns. Each director mounted a 4.5 metre rangefinder. Six Type 95 directors controlled the 25 mm guns and the 12 cm rocket launchers. Early warning was provided by two Type 2, Mark 2, Model 1 air search radar
Radar
Radar is an object-detection system which uses radio waves to determine the range, altitude, direction, or speed of objects. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, weather formations, and terrain. The radar dish or antenna transmits pulses of radio...
s. One of these was mounted on the top of the island while the other retracted into the port side of the flight deck, between the two elevators. In addition, Unryū had two smaller Type 3, Mark 1, Model 3 air search radars, one mounted on the tripod mast on the island and the other on the aft starboard retractable radio mast.
Final voyage
On 13 December 1944, thirty "Ōhka" suicide rockets of the Thunder-Gods Corps were loaded aboard Unryū for transport to the port city of Manila in the Philippines. Four days later, on 17 December 1944, Unryū departed Kure, HiroshimaKure, Hiroshima
is a city in Hiroshima prefecture, Japan.As of October 1, 2010, the city has an estimated population of 240,820 and a population density of 681 persons per km². The total area is 353.74 km².- History :...
escorted by Shigure
Japanese destroyer Shigure
was the second of ten s, and the first to be built for the Imperial Japanese Navy under the Circle One Program . Along with the destroyer , she developed a reputation within the Imperial Japanese Navy for being "lucky" or "unsinkable", emerging as the sole surviving Japanese warship from numerous...
, Hinoki, and Momi
Japanese destroyer Momi
was a of the Imperial Japanese Navy, sunk on January 5, 1945 by an American air attack west of Manila, in the South China Sea.-Operational history:...
under the overall command of Captain Konishi. Her maiden sea voyage was a vain attempt to reinforce the garrison on the island of Luzon
Luzon
Luzon is the largest island in the Philippines. It is located in the northernmost region of the archipelago, and is also the name for one of the three primary island groups in the country centered on the Island of Luzon...
just prior to the US landings there.
On 19 December 1944, Unryū was torpedoed and sunk by the submarine USS Redfish
USS Redfish (SS-395)
USS Redfish , a Balao-class submarine, was the first ship of the United States Navy to be named for the redfish, a variety of salmon also called blueback, sawqui, red salmon, and nerka. Her keel was laid down on 9 September 1943 by the Portsmouth Navy Yard of Kittery, Maine...
. Redfish fired four bow torpedoes, one of which hit directly under the carrier's bridge on the starboard side at 16:35, stopping the vessel dead in the water. Unryū engaged with all her starboard side guns. A second torpedo struck at 16:50 on the starboard side abreast the forward elevator, just as the carrier was managing to get under way again. The resulting explosion set off the Ohka suicide planes stored on the lower hangar deck as well as the highly volatile aviation fuel underneath.
Once the boiler rooms flooded, the ship listed to 30 degrees and the order to abandon ship was given. With a 90 degree list, the ship sank to the bed of the East China Sea
East China Sea
The East China Sea is a marginal sea east of China. It is a part of the Pacific Ocean and covers an area of 1,249,000 km² or 750,000 square miles.-Geography:...
in just seven minutes at position 29°59′N 124°03′E. Casualties were great: Captain Kaname Konishi and 1,238 officers and men lost their lives. Only one officer and 146 men survived and were rescued by the escort destroyer Shigure, which returned to Sasebo, Nagasaki
Sasebo, Nagasaki
is a city located in Nagasaki Prefecture, Japan. As of 2011, the city has an estimated population of 259,800 and the density of 609 persons per km². The total area is 426.47 km². The locality is famed for its scenic beauty. The city includes a part of Saikai National Park...
on 22 December.