Yuuka Class Destroyer (Part 1, 1927-1940):
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 the 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 succesful sea-trials led the Naval Staff to choose for placing further orders of ships of that type in order to focus on more advanced designs.
With a planned deadline set for 1925, Koko no Kaigun designers took apart the IJN Mutsuki blueprints, producing a larger ship in the process: the new hull had more lenght, beam, draft and depth while retaining similar lines. The design also called for a similar range and an increased top speed while compared to the Minekaze/Kamikaze/Mutsuki family, torpedo complement was to remain the same, but gun armament was planned to be increased from four to five guns. The resulting project was thus the most ambitious Destroyer design made by KnK since the Sato class. Since the Sato was unanimously considered as 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.
110,6m 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 5 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 beign already under construction by the end of the year. Yuuka herself was commissioned in early 1927.
Despite the more revolutionary Fubuki class was already under full costruction 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, but this not without giving them further upgrades during construction whenever this 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 six 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 beign 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.....
Ships in class: (laid down-launched-commissioned - fate)
yuuka 1925-1926-1927 - ?
mugetsu 1926-1927-1928 - ?
ran 1926-1927-1928 - ?
yuki 1927-1928-1929 - ?
mai 1927-1928-1928 - ?
yumeko 1927-1929-1930 - ?
shinki 1927-1929-1929 - ?
daiyousei 1927-1928-1929 - ?
koakuma 1928-1929-1929 - ?
sakuya 1928-1929-1930 - ?
youmu 1928-1929-1929 - ?
yuyuko 1928-1929-1929 - ?
yukari 1929-1930-1931 - ?
ranko 1929-1930-1930 - ?
gengetsu 1929-1930-1931 - ?
suika 1929-1930-1931 - ?
keine 1929-1930-1931 - ?
tewi 1930-1931-1932 - ?