Agano-class cruiser

The four Agano-class cruisers (阿賀野型軽巡洋艦) were light cruisers operated by the Imperial Japanese Navy. They participated in numerous actions during World War II.

The Agano class was followed by the larger Ōyodo class, of which only one vessel was completed.

Background
The Imperial Japanese Navy had standardized on 5,500 ton displacement light cruisers as flagships for destroyer and submarine squadrons, and numerous vessels constructed shortly after World War I served in this role. The Agano class was conceived in the 1930s as a replacement for the aging Tenryū, Kuma and Nagara classes. Larger than these previous light cruisers, the Agano-class vessels were fast, but with little protection, and were under-gunned for their size.

Originally they were to have eight 6.1-inch guns in four twin mounts but the X turret was eliminated to allow a heavier torpedo armament and to save on costs.

Design
Initial design specifications for the Agano class called for a nominal 5,000 ton displacement hull with six 6.1 in guns and eight 5 in dual purpose guns. Its armor was designed to protect against 6 inch gun and vital parts had additional protections. 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.

The engines were a quadruple-shaft geared turbine arrangement with six boilers, developing 100.000 shp for a maximum speed of 35 kn. Like Yūbari, the Agano class had its stacks join into a single funnel.

As completed, the main armament was the same type of 152 mm (6 inch) gun as used on the Kongō-class battlecruisers, some of these weapons having been removed from the Fusō and Kongō classes during their modernizations in the early and late 1930s, respectively. This gun fired a 100 lb projectile 22970 yd. Secondary armament consisted of four 80 mm HA, which were actually 3-inch (76.2 mm) guns in two twin mountings. These guns fired a 13.2 lb projectile and were of unique size in the Japanese navy. The design was equipped with thirty-two 25 mm AA guns. The torpedo tubes were mounted on the centerline as was more common with destroyers, and had a rapid reload system with eight spare torpedoes. The design included a single catapult forward of the main mast, with stowage for two floatplanes. Depth charge equipment was also fitted.

In subsequent upgrades, the 25 mm anti-aircraft weaponry increased to 46 sets by 1944, and then to 52 sets and finally 61 sets by July 1944 on the surviving ships.

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

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 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, on 16 February 1944.

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 (CV-18) and USS Cowpens (CVL-25).

Yahagi
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 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
Sakawa was not completed until the end of 1944, by which time there was little fuel available. She survived the war unscratched. After the war she was expended in the atom bomb tests at Bikini Atoll in 1946.