Akatsuki-class destroyer (1931)
The was a class of four destroyers of the Imperial Japanese Navy. According to most sources, they are regarded as a sub-class of the , partly because the Imperial Japanese Navy itself kept the improvements made a secret, and did not officially designate these four destroyers as a separate class. Background. After a number of years of operational experience with the "Fubuki" class, the Imperial Japanese Navy General Staff issued requirements for four additional destroyers, with a maximum speed of , range of at , and armed with Type 8 torpedoes. These destroyers were intended to operate with  the new series of fast and powerful cruisers also under consideration as part of a program intended to give the Imperial Japanese Navy a qualitative edge with the world's most modern ships. The new vessels were built from 1931-1933. Design. The main difference in design between the "Akatsuki" vessels and the standard "Fubuki"-class was the use of a new high-pressure boiler, which enabled the number of boilers to be reduced from four to three without a reduction in power. This also enabled the fore smokestack to be made narrower than on standard "Fubuki"-class vessels, and this feature  was the most evident visual recognition feature between the two designs. Other improvements over the "Fubuki" class included a larger bridge structure, with the addition of another level to house improved fire control facilities, and a splinter-proof torpedo launcher/turret, which allowed the torpedo launcher tubes to be reloaded in action. The four ships incorporated many weight-saving measures, and was the first all-welded Japanese ship. However, the "Akatsuki" class shared a number of inherent design problems with the "Fubuki" class. The large amount of armament combined with a smaller hull displacement than in the original design created  issues with stability. After the "Tomozuru" Incident, in which the basic design of many Japanese warships was called into question, additional ballast had to be added. In the Fourth Fleet Incident, during which a typhoon damaged virtually every ship in the Fourth Fleet, issues with the longitudinal strength of the "Akatsuki"-class hull was discovered. As a result, all vessels were reconstructed from 1935-1937. An additional 40 tons of ballast was added, the bridge reduced in size and the height of the smoke stacks was decreased. The number of torpedo reloads were reduced from nine to three (for the center  launcher only), and fewer shells were stored for the guns. The amount of fuel carried was also increased to help lower the center-of-gravity. This increased the displacement to 2050 tons standard tons and over 2400 tons full load. The rebuild reduced the top speed slightly to 34 knots. Armament. The main battery consisted of six Type 3 127 mm 50 caliber naval guns, mounted in pairs in three weather-proof, splinter-proof, gas-tight gun turrets . These guns were dual purpose guns that could be elevated to 75 degrees, making them the world's first destroyers with this  ability. Ammunition was brought up on hoists from magazines located directly underneath each gun turret, which had a far greater rate of fire than those of other contemporary destroyers in which ammunition was typically manually loaded. However, the gun houses were not bullet-proof, and were thus actually still gun mounts, rather than proper turrets. The three triple torpedo launchers used on the standard "Fubuki"-class retained, and originally Type 8 torpedoes were carried. These were later replaced with the famous Type 93 "Long Lance" oxygen-propelled torpedoes during World War II. Anti-aircraft capability was initially two Type 93 13  mm AA Guns mounted in front of the second stack. In 1943, an additional pair of Type 93 guns was mounted in front of the bridge, which was later changed to Type 96 25mm AA Guns on and in January 1944. These vessels also lost one of their aft guns in April 1944 in exchange for two triple Type 96 guns, and another pair of triple Type 96 guns was added between the aft torpedo mounts. "Hibiki" had another 20 single-mount Type 96s added, as well as a Type 22 and Type 13 radar, before the end of  the war. Operational history. Of the four "Akatsuki" class vessels, only "Hibiki" survived the war, and was awarded as a prize of war to the Soviet Navy, and continued to be used a floating barracks ship until retirement in 1953. Eventually, she was used as target-practice in the 1970s, where she was finally sunk. was lost at the Naval Battle of Guadalcanal in November 1942, where she was sunk by American cruiser and destroyer gunfire. "Ikazuchi" was sunk while escorting a convoy 200 miles south-southeast of Guam on April 14, 1944 by the . exploded after being struck by  torpedoes launched by in the Celebes Sea near Tawitawi on 14 May 1944.