more updated and completed destroyer classes
Yuuka Class Destroyer:
In 1923, as soon as the first Shion and Okaze class Destroyers were entering service, Koko no Kaigun's Naval Staff was already contemplating a new class of ships to be put into service once production lines of the earlier classes had been exausted. At first a simple repetition of the Japanese Mutsuki (also in planning stage at the time) was considered, but Okaze successful sea-trials led the Naval Staff to place further orders of that class in order to focus on developing a more advanced design.
With a planned deadline set for 1925, Koko no Kaigun designers started by taking apart the blueprints for the IJN Mutsuki, producing a larger ship in the process: the new hull had more length, beam, draft and depth, stronger keel and larger rudder. The design also called for a similar range and an increased top speed compared to the Minekaze/Kamikaze/Mutsuki family. Torpedo armament was to remain the same, but the number of guns was to be increased from four to five. The resulting project quickly became the most ambitious Destroyer design made by KnK since the Sato class. As the Sato was unanimously considered a failure the Naval Staff initally ordered a single ship to be built and evaluated before proceeding with a full scale construction. Thus the first, and at the time only, ship of the new class was laid down at Toumachi Naval Arsenal in 1925. Named Yuuka, the ship was launched in 1926, starting a long stint of pre-commissioning trials by the second half of the year.
110,6 meters long, 9,8 abeam and drafting 3 the new destroyer displaced 1.535T at standard load, over 16% more than a Mutsuki from which it derived. It had an armament of five 120mm/45 guns in single shielded mounts, six 610mm torpedo launchers in two triple sets with reloads and two 7.7mm/94 machine guns. Unlike those of the Sato, Yuuka's trials were a success: the four boilers, powering two geared turbines with 44.000shp propelled the ship with ease at speeds between 37,6 and 37,8 knots, above than the planned 37,5. Endurance was 3.900 nautical miles at 14 knots, this too higher than the initial requirements by 300 miles.
Pleased by the unexpected success, the Navy immediately placed order for another 17 units, five to be built at Toumachi Naval Arsenal, 8 at Kousaten and 4 at Hoshiguma.The first two already under construction by the end of the year. Yuuka herself was commissioned in early 1927.
Despite the more revolutionary Fubuki class was under costruction in large numbers in Japan by the time Yuuka's first sisters were entering service, Koko no Kaigun choose to stick with their latest home-designed destroyer for the full lenght of its planned building run. This not without giving them further upgrades during construction whenever it was possible: Starting with Koakuma, in 1929, the ships sported a redesigned, fully enclosed bridge structure. An RDF installation was fitted at midship, just forward of the second funnel. Both smokestacks were also raised to keep smoke away from the decks.
Tewi, the last ship to be commissioned in 1932, recieved splinter-proof torpedo launcher-turrets like the Japanese Akatsukis, which allowed the torpedo launcher tubes to be reloaded in action and protected crew and equipment from rough seas.
The 18 Yuuka Class ships formed five Kuchikutais, operating under three Suirai Sentai units for all the 30's. During the second half of the decade all were refitted, recieving the enclosed bridge and enclosed torpedo launchers the late units had since commissioning. In addition to that the RDF equipment was replaced and relocated near the searchlight platform, and the two 7.7mm machine guns were replaced by two single 25mm ones, fitted abaft the new RDF room.
Despite being the final evolution of a design first concieved in 1917 (as the Japanese Minekaze), the Yuuka Class ships proved to be reliable and capable vessels during their peacetime service, so Koko no Kaigun still considered them suitable for frontline duties, as war was already raging in Europe, and seemingly coming closer in the Pacific Ocean too. As a last small refit before the start of the hostilities, all units were fitted with two single 13mm machine guns abreast the bridge and an hydrophone.
In December 1941 the entire class recieved black and white arctic camouflage and, after war broke out on the 7th, supported the Kokoan invasion of the western Aleutians, taking part in the Battle off Turf Point on december 16 that preceded the occupation of Adak, Tanaga and Kanaga islands.
Still on station during the invasion of Atka and Amila in May 1942, they later joined the northern fleet in June of the same year during operation AL/MI for the planned invasion of Umnak, Unalaska and Unimak. Plans were eventually aborted after the Kido Butai got decimated by US carriers off Midway one June 4th.
With the waters around Guadalcanals heating up during late summer and fall half of the class was recalled home, repainted gray and sent to Truk with the bulk of the fleet. During one of the subsequent operations, the night between november 21 and 22 1942, Yuki was sunk in the third naval battle of guadalcanal, becoming the first unit of the class, and first Kokoan destroyer overall, to be lost in action during the war. As the class was still split between the Aleutians and the Solomons, and later Aleutians and Western Hawaiian islands, 1943 saw Mai and Shinki sunk in northern waters, while Yuyuko suffered the same fate in the waters around New Georgia.
1944 ended up being much kinder, with no losses, and also saw all ship recieve their first wartime refit. During works a Type22 surface-search and Type13 air-search radar were fitted. The aftmost 120mm gun mount was removed and replaced with a triple 25mm machine gun mount. Two more twin pieces were also added on platforms abreast the bridge, replacing the outdated 13mm singles fitted there. Depth charge stowage was increased, the rack and thrower set doubled and augmented by two rails as well. A sonar was installed and most portholes were sealed to improve watertight integrity.
With the wartime situation deteriorating and the ship getting damaged repeatedly another refit was implement in early 1945. Both Type22 and Type13 radars were replace by more advanced Type33-kai and TypeR2FA ones. Anti air-defences were strengthened with the addition of two triple and two single 25mm mounts, for a total of seventeen barrels. All ships were given a blue-black dazzle camouflage, which in many cases just meant that the white of their arctic-camo was replaced by a new coat of blue paint.
Little could be done by that point however. Yumeko, Daiyousei and Sakuya were all lost in the Aleutians, the first torpedoed by submarine off Amchitka, the second sunk by enemy gunfire on May 11 during the Naval Battle of Adak and the last by US land based planes near Tanaga. Yuuka was torpoedoed east of Midway by a submarine in September, her crew mamaged to control damage and get the destroyer underway again, only for a squadron of B-25s to intercept and sink her with bombs and torpedoes.
Yukari disappeared with all hands in mysterious circumstances on October 20 1945 while on patrol roughly 170 miles northwest of Midway island. No distress call were made and no floating debris were spotted by recon planes. Her wreck has not been found to this day despite searches had been made in three different occasions in the over 70 years that elapsed since her sinking. According to official records there were no US submarines lurking around where she disappeared. It is believed that Yukari probably hit US air-dropped mines (among the first being laid by the Americans so close to the Kokoan home islands) and exploded after either her magazine or depth charges detonated.
Suika was lost in early 1946 durig Koko uprisings, so In the end seven of the initial eighteen ships survived the war. All were decomissioned by the end of 1946 and scrapped over the course of the next few years.
Ships in class: (laid down-launched-commissioned - fate)
Yuuka 1925-1926-1927 - Sunk 1945
Mugetsu 1926-1927-1928 - Decommissioned 1946
Ran 1926-1927-1928 - Decommissioned 1946
Yuki 1927-1928-1929 - Sunk 1942
Mai 1927-1928-1928 - Sunk 1943
Yumeko 1927-1929-1930 - Sunk 1945
Shinki 1927-1929-1929 - Sunk 1943
Daiyousei 1927-1928-1929 - Sunk 1945
Koakuma 1928-1929-1929 - Decommissioned 1946
Sakuya 1928-1929-1930 - Sunk 1945
Youmu 1928-1929-1929 - Decommissioned 1946
Yuyuko 1928-1929-1929 - Sunk 1943
Yukari 1929-1930-1931 - Sunk 1945
Ranko 1929-1930-1930 - Decommissioned 1946
Gengetsu 1929-1930-1931 - Decommissioned 1946
Suika 1929-1930-1931 - Sunk 1946
Keine 1929-1930-1931 - Sunk 1945
Tewi 1930-1931-1932 - Decommissioned 1946