Agano-class cruiser

Agano in October 1942, off of Sasebo, Nagasaki
Class overview
Name:	Agano class
Builders:	Sasebo Naval Arsenal, Yokosuka Naval Arsenal
Operators:	Imperial Japanese Navy
Preceded by:	Sendai class
Succeeded by:	Ōyodo class
Completed:	4
Lost:	3
General characteristics
Type:	Light cruiser
Displacement:	6,652 t (6,547 long tons) (standard); 7,590 t (7,470 long tons) (loaded)
Length:	174 m (571 ft)
Beam:	15.2 m (50 ft)
Draught:	5.6 m (18 ft)
Propulsion:	4 shaft Gihon geared turbines 6 Kampon boilers 100,000 shp (75,000 kW)
Speed:	35 knots (65 km/h; 40 mph)
Range:	8,000 nautical miles (15,000 km) at 18 knots (33 km/h)
Complement:	730
Armament:	6 × 152 mm Type 41 guns (3×2) 4 × 76 mm Type 98 DP guns, 32 × 25 mm AA guns 8 × 610 mm torpedo tubes (4 × 2) 16 depth charges
Armour:	Belt 60 mm (2.4 in) Deck 20 mm (0.8 in)
Aircraft carried:	2 × floatplanes
Aviation facilities:	1 aircraft catapult

The four Agano-class cruisers (阿賀野型軽巡洋艦, Agano-gata keijun'yōkan) were light cruisers operated by the Imperial Japanese Navy. All were named after Japanese rivers. Larger than previous Japanese light cruisers, the Agano-class vessels were fast, but with little protection, and were under-gunned for their size. They participated in numerous actions during World War II.

The Agano class was followed by the larger Ōyodo-class cruiser, of which only a single vessel was completed.

Background

The Imperial Japanese Navy had developed a standardized design for light cruisers as flagships for destroyer and submarine squadrons, based on a 5,500 ton displacement, shortly after World War I. However, by the 1930s these vessels were obsolete, as contemporary destroyers were faster, carried more powerful armament, and had greater endurance. As soon as the restrictions of the London Naval Treaty were removed, the Navy General Staff developed a plan within the Fourth Fleet Supplemental Budget to build 13 new 6000 ton cruisers between 1939 and 1945 to replace the Tenryū, Kuma, and Nagara-class cruisers. These vessels were intended to be the flagships for six destroyer squadrons and seven submarine squadrons. The new design was finalized in October 1937; however, construction was delayed due to overloading of the Japanese shipyards. Construction costs came to 16.4 million yen per vessel.

Design

The design for the Agano class was based on technologies developed by aboard the cruiser Yūbari, resulting in a graceful and uncluttered deck line and single smokestack. Unlike most Japanese designs, the Agano class was not overweight, so it exhibited good stability and seaworthiness.

The Agano class was armed with six 152 mm Type 41 guns in three gun turrets. These guns were also used on the Kongō-class battlecruisers, some of these weapons having been removed from the Fusō-class battleships and the Kongō class during their modernizations in the early and late 1930s, respectively. This gun fired a 100 lb (45 kg) projectile 22,970 yards (21,000 m). The Agano class was unique among Japanese cruisers in that its main armament could elevate to 55 degrees, but this was still not enough to make them effective as anti-aircraft weapons. Secondary armament included four 76 mm Type 98 DP guns designed specifically for the class, in two twin turrets amidships. Anti-aircraft weapons included two triple 25 mm AA guns in front of the bridge, and two twin 13 mm mounts near the mast. The class also had two quadruple torpedo launchers for Type 93 torpedoes located below the flight deck, with eight reserve torpedoes. The torpedo tubes were mounted on the centerline, as was more common with destroyers, and had a rapid reload system with eight spare torpedoes. Being mounted on the centerline allowed the twin launchers to fire to either port or starboard, meaning that a full eight-torpedo broadside could be fired, whereas a ship with separate port and starboard launchers can only fire half of its torpedoes at a time. Two depth charge rails and 18 depth charges were also installed aft. The class was also equipped with two Aichi E13A aircraft. The first two vessels in the class (Agano and Noshiro) had a larger flight deck with a 26-foot catapult. The later Yahagi and Sakawa had a shorter 19-meter catapult.

The engines were a quadruple-shaft geared turbine arrangement with six boilers in five boiler rooms, developing 100,000 shp (75,000 kW) for a maximum speed of 35 knots (65 km/h). Like Yūbari, the Agano class had its stacks join into a single funnel.

All of the vessels in the class were updated with additional anti-aircraft weaponry and radar at various points in their service lives.

Ships in class

Four ships were budgeted under the 1939 4th Naval Replenishment Programme, three from the Sasebo Naval Arsenal and one from Yokosuka Naval Arsenal.

Agano

Main article: Japanese cruiser Agano

Completed on 31 October 1942, Agano participated in the battles for Guadalcanal and the Solomon Islands during 1943. Agano was badly damaged in Rabaul harbor by aircraft from the aircraft carriers USS Saratoga and USS Princeton, and in a subsequent attack by aircraft from TF38 on 11 November she received a torpedo hit. Ordered to home waters for repair, she was torpedoed and sunk north of Truk by the US submarine USS Skate (SS-305), on 16 February 1944.

Noshiro

Main article: Japanese cruiser Noshiro

Commissioned on 30 June 1943, Noshiro participated in operations in the Solomon Islands and was damaged during the US carrier aircraft raids on Rabaul on 5 November 1943. She served in the Marianas in the summer of 1944, and was part of Admiral Kurita's force during the Battle of the Philippine Sea. At the Battle of Leyte Gulf in October 1944. She was west of Panay while withdrawing from the Battle off Samar on the morning of 26 October when she was sunk by aircraft from USS Wasp and USS Cowpens.

Yahagi

Main article: Japanese cruiser Yahagi (1942)

Commissioned on 29 December 1943 Yahagi saw action in the Marianas in May/June 1944, during the Battle of the Philippine Sea, and during the Battle of Leyte Gulf. After the US invasion of Okinawa on 1 April 1945, she was ordered to accompany the battleship Yamato on its suicide mission against the American fleet at Okinawa. Yahagi was hit by some seven torpedoes as well as a dozen bombs, and sank on the afternoon of 7 April 1945.

Sakawa

Main article: Japanese cruiser Sakawa

Sakawa was not completed until the end of 1944, by which time there was little fuel available. She survived the war unscratched and was used as a transport to return demilitarized troops from New Guinea and other areas after the war. She was expended in the atom bomb tests at Bikini Atoll in 1946.