Koko Kyouwakoku (Republic of Koko)

again updating of one the earlier Destroyer classes and adding WWII service.

Okaze Class Destroyer:

To supplement the 15 smaller Shion class Destroyers the naval staff reordered the last 6 ships of the canceled Sato class to a larger design: the Okaze Class. As for the Shions, in order to have the new units in service as soon as possible Okaze and her sisters were modified Kamikaze class Destroyers. Modifications included the addition of walkways that linked the bridge with the middle gun and searchlight platform, and a different bridge structure. Armament consisted of four Type3 120mm/45 guns in single mounts, six 533mm torpedo tubes in three sets of double launchers and two 7.7mm machine guns. The ships were equipped to carry up to 20 mines if needed. Four Kampon boilers powered two-shaft geared turbines at 38,500 shp, giving the ships a top speed of 37knots and an endurance of 3.600 natical miles at 14 knots.
The lead ship, Okaze, was laid down in august 1922 and commissioned by fall 1923. Her perfomance was considered so satisfactory that another twelve units were immediately ordered, bringing the class to 18 ships. At the cost of 47 more tons in displacement when compared tot he Sato class (and 73 to the Kuchikukan 14 units), the Ozake sported the same armament but enyoyed 1,5 times more range and a nearly 3-knots higher top speed, all in a shorter and sturdier hull, more suited to blue water operations.
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All ships were built between 1922 and 1929: 7 At Kumoi Arsenal, 4 at Toumachi Naval Arsenal, 3 at Kousaten Navy Yard, 2 at Hoshiguma Navy Yard and one at Yamatogawa Shipyards. Finally, one last unit, Mima, was ordered abroad in Japan as all available domestic shipyards were occupied with ship construction. Mima was laid down at Yokosuka in september 1923, but was destroyed during the Great Kanto Earthquake and had to be laid down again, she was ultimately commissioned in 1926.
Six units, Meira, Kana, Rikako, Chiyuri, Yumemi and Kurumi, recieved the newer 120mm/45 Type10 guns, which having a maximum elevation of 70°, effectively served as both surface and AA duties. Also, they sported depth charges instead of the mine-laying gear of the earlier sisters.
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Ruukoto, the las unit to be commissioned, in 1929, recieved some more modifications, being given a larger bridge and an expanded searchlight/rangefinder platform. RDF equipment was added at midship and the bridge rangefinder replaced with a newer model.
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The ships formed 5 Kuchikutai units (three 4-unit and two 3-unit) up to the mid 30's. Then, starting in 1936, they entered the yards for their pre-war refit: All had a late-model RDF equipment fitted, the bridge wings enclosed and two single 25mm machine guns fitted. Both funnels were increased in height to improve smoke-clearing issues. The depth charge complement was also notably increased and an hydrophone installed.
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Despite being of the same age of the Shion class, the Okaze were still considered capable enough to be rated as first-rate ships. Their role in an eventual war according to Koko no Kaigun strategy was to operate as anti-submarine units close to home waters or in support of larger naval operations.
At the start of the Pacific War Okaze, Tsumujikaze, Norio and Sacho took part in the invasion of the Aleutians. All other members of the class supported the operations around Midway and its subsequent occupation, they were then sent to support operation in the Dutch East Indies where they took part in the naval battle of Balikpapan agaist British and Recerhean units and the subsequent invasion of the Indonesian archipelago. Next were the Japanese carrier operations in the Indian Ocean and the battle of Bay of Bengal. Back to Koko they saw involvement in the AL/MI operation (invasion of the eastern Aleutians and ambush of the American carrier fleet), but like all other Japanese and Kokoan surface fleets took no part in the -disatrous- carrier battle.
With the first four ships still deployed north, all others descended south instead, supporting the joint Kokoan-Japanese defence of Guadalcanal and other operations in the Solomon Islands. Rika and Yumemi were both sunk there in July 1943, the first hit by air attack and the other by a Submarine. After an uneventful involvement in the battle off the Frigate Shoals (also known as battle off Gardner) Kawatake, Yoshikaze, Mima, Kikuri, Kana, Rikako and Chiyuri got redeployed in the Aleutians, joining their sister that had been deployed there since the first days of the conflict. On December 19th, during the Naval battle of Unalaska, Norio and Chiyuri were Sunk. The same fate befell on Meira a few days later, bombed by US airplanes while escorting a convoy bound for Atka island.
Split again between the Aleutians, the western Hawaiian island chain and the Solomons, the surviving Okaze class ships recieved their first major wartime refit. During works a sonar was added, a Type13 air-search radar installed, the birdge given a steel roof, the RDF equpment upgraded, depth charge stowage increased and augmented with the addition of a pair of rails at the stern. Armament-wise the aftmost 120mm gun mount was removed and a triple and two twin 25mm machine guns were added, increasing the light anti-air suite to nine barrels. Finally most portholes on the hull were sealed to inprove watertight integrity.
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The modifications did little to stop the class from bleeding out ships. Tsumujikaze, Sachio, Yoshizake, Kikuri, Konngara and Kurumi were lost in 1944 alone.
Early 1945 saw most of the units still serving in the Solomons to leave the area and concentrate on Midway and the Aleutians. During a second refit they landed another 120mm gun and one of the twin torpedo tubes in exchange for eight more 25mm machine guns (two triple and two single mounts) and were painted blue overall.
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Kana and Kawatake were sunk on May 11th 1945 during the Naval battle of Adak. The five survivors, still operating between Koko and the Aleutians, were refitted once again between August and September 1945. All torpedo tubes and one more 120mm gun were landed, leaving the single bow-mounted piece as the main armament. Another two triple 25mm machine guns were added, further increasing the light anti-air suite to twenty-three barrels. A 28-barrel rocket anti-air rocket launcher was also added. The number of depth charge throwers was doubled and a Type22 surface-search radar was added. The camouflage pattern was modified with the addition of a green stripe on the hull with a false bow wave.
When Koko uprisings started in November of that year all ships but Okaze, whose crew had remained loyal to Morimoto, joined the rebels.
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With the exception of Okaze herself, Sunk in January 1946 near Daigo island by US aircrafts, all other ships survived the war. Only to be decommissioned shortly after and being scrapped in the next few years.

Ships in class: (laid down-launched-commissioned - fate)

Okaze 1922-1923-1923 - Sunk 1946
Tsumujikaze 1922-1923-1923 - Sunk 1944
Norio 1923-1924-1924 - Sunk 1943
Sachio 1923-1924-1925 - Sunk 1944
Kawatake 1923-1924-1924 - Sunk 1945
Yoshizake 1923-1924-1925 - Sunk 1944
Mima 1923-1926-1926 - Decommissioned 1946
Kikuri 1923-1924-1925 - Sunk 1944
Konngara 1924-1925-1926 - Sunk 1944
Genjii 1924-1925-1926 - Decommissioned 1946
Rika 1924-1925-1926 - Sunk 1943
Meira 1925-1926-1927 - Sunk 1943
Kana 1925-1926-1927 - Sunk 1945
Rikako 1925-1927-1927 - Decommissioned 1946
Chiyuri 1925-1927-1927 - Sunk 1943
Yumemi 1926-1927-1928 - Sunk 1943
Ruukoto 1926-1928-1929 - Decommissioned 1946
Kurumi 1926-1927-1928 - Sunk 1944

_________________
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MS State Guard - 08 March 2014 - 28 January 2023

The Official IJN Ships & Planes List

#FJB

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.
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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.
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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.
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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.
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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.
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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.
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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.
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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

Lovely additions, good to see more added to this AU.

_________________
Hood's Worklist
English Electric Canberra FD
Interwar RN Capital Ships
Super-Darings
Never-Were British Aircraft

Awesome work, my friend! These types of DDs make me very much look forward to the IJN DDs of similar designs!

_________________
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MS State Guard - 08 March 2014 - 28 January 2023

The Official IJN Ships & Planes List

#FJB

same stuff, different destroyer class

Reisen Class Destroyer:

In late 1929, with the Yuuka Class close to the end of its planned construction run, Koko no Kaigun naval staff started to focus on a successor ship to further suplement the fleet, expanding ranks and replacing older units if and when needed. Design time was extremely short, as common practice Kokoan ships shared an high degree of commonality with japanese ones. Since the Destroyer class built in Japan at the time was also the most advanced ship of its kind there was few that Kokoan designers could have bettered. Thus the new units were essentually Fubuki Class Destroyers of the Ayanami-Type with minor modifications made to the bridge and armament.
Named Reisen, the first ship of the class was laid down at Toumachi Naval Arsenal in early 1930, the ship differed from a standard Ayanami-Type thanks to her capped funnels and enclosed torpedo launchers. She also sported 40mm machine guns and early RDF equipment. The stern structure sported further modifications, with a straight internal deck -noticeable by the absence of the typical swaying in the portholes row- and an enlarged rudder. Finally, a sharp-eye would have noticed slight differencies in the fire-control room and director size and layout.
The Naval staff planned to build at least eighteen vessels of the class, with another seven units built to Ayanami-Type standards to be laid down by 1932, followed by at least ten more built to Akatsuki-Type specifications. Yet, the signing of the London Naval Treaty in late 1930 made this all but impossible. Owing to treaty restrictions the planned units were cut to four, with Reisen herself already under construction this meant only three more would be built. All ships were built at Toumachi Naval arsenal. The lead ship, Reisen, was launched in 1931 and commissioned in 1932, a second ship, Eirin, was laid down after Reisen's launch, she was commissioned in 1933.
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The third ship, Kaguya, was laid down in 1932, launched in early 1934 and commissioned in 1935. She differed for her two earlier sisters because she was fitted with a new RDF set, sporting it's own dedicated room aft of the searchlight platform. A quadruple 13mm machine gun mount replaced the two 40mm single ones fitted on Reisen and Eirin. The fourth ship, Aya, was laid down in 1934 and launched in a record time by the end of the same year, ultimately being commissioned in 1936.
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Meanwhile, starting in late 1931, a new class of Destroyers, purposedly designed in order to skirt treaty limitations, was beign bult as the Shizuka Class. When in 1936, under the second reamament bill, Koko decided that it was time to completely ingore the treaties, the decision was made to revert to full-sized Destroyer construction. As a stop-gap measure before a new class would have entered production, a fifth and last Reisen was ordered. As plans were already made years earlier, taking dust in the Naval Staff archives, the new ship was started almost immediately. Laid down in early 1937 at Kumoi arsenal and named Shikieiki, that fifth Destroyer was built to Akatsuki-Type standard, sporting just three boilers but with a smaller aft-funnel instead. Newer turrets were fitted, as it was for an updater RDF fit and an hdrophone set in the bow. Anti-aircraft armament was further increased to four 25mm machine guns in two twin mounts and two 13mm in single ones. The bridge was modified and enlarged in order to fit the most advanced equipment available, the fire-control room was redesigned as the ship was fitted with an and integrated director-rangefinder unit, this way the bridge structure even turned out to be lower, relieving top-heavy issues. Shikieiki was launched and commissioned during the year 1939.
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Shikieiki was assigned to Kuchikutai 2, joining her sisters in Suirai Sentai 1 under Light Cruiser Onozuka. Before the start of the war all recieved the same hydrophone, RDF and anti-air fit Shikieiki was built with. All five had a degaussing cable installed as well. All five eventually saw their entire wartime service spent in Aleutian waters, and were thus among the very few kokoan Kokoan ships that retained their arctic-camo, or variants of it, up to the end of the war.
As their first wartime refit, between January and August 1943, all ships recieved a triple 25mm maching un on a platform forward of the bridge structure. Later on the seme year, on October and late December, Eirin and Reisen were lost to enemy aircrafts as the Americans started their counteroffensive.
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Another refit followed for the three remaining sisters in 1944. The two 13mm singles were removed and two triple and six single 25mm machine guns fitted to improve the anti-air armament. A sonar was added and the depth charge armement was improved with the addition of two extra throwers. Type22 surface-search, Type2RFA air-search and TypeR4CA fire-control radars were installed. Mosto of the portholes were sealed as well.
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Further modifications were made in 1945: more advanced Type33-Kai surface-search and TypeR12CAD fire-control radars were fitted and the anti-air suite increased to five triple, two twin and ten single 25mm machine guns (totaling 29 barrels). An IFF set was added as well and a stripe of blue paint added on the hull.
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In the subsequent Aleutian onslaught that started with a new US offensive in the spring of 1945 and escalated until the Kokoan uprisings of November 1945 two more ships, Kaguya and Shikieiki, were lost, leaving only Aya to survive to the end of the war.
Aya would be decommissioned shortly after and scrapped under surrender and peace terms like many other Kokoan ships.

Ships in class: (laid down-launched-commissioned - fate)

Reisen 1930-1931-1932 - Sunk 1943
Eirin 1931-1932-1933 - Sunk 1943
Kaguya 1932-1934-1935 - Sunk 1945
Aya 1934-1934 1936 - Decommissioned 1946
Shikieki 1937-1939-1939 - Sunk 1945

_________________
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MS State Guard - 08 March 2014 - 28 January 2023

The Official IJN Ships & Planes List

#FJB

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