Koko Kyouwakoku (Republic of Koko)

F-19 Class Minelayer:

he 1930 London Naval Treaty had put limits to the number of ships Koko no Kaigun could have built. In it's effort to circumvent it Koko no Kaigun issued the requirement for a class of large minelayers to be built to cruiser standards like the Hayabusa class seaplane tender. Despite beign scaled back from the original plan, as opposed to the Hayabusa, which grew even more ambitious with each revision, the ship that emerged fromt he drawing board was a 5.449ton standard (6.686t at full load) unit, 155,27m long, 15,9m abeam and with a draft of 6,1m. Like on the Hayabusa the forecastle housed the triple 140mm gun turrets, this time two mounts instead of three, for a total of six guns. Three single 120mm guns, two fitted abeam and one at the stern, made up for the dual purpose battery. Anti-aircaft duties were performed by sixteen 13mm machine guns in four quadruple mounts.
Side armor was thinner, at 30mm, giving effective protection only against Destroyer guns. It was split in two sections one protecting the engines and another one shifted lower into the hull to protect the magaines of the 140mm guns. Below the belt, a 10mm bulkhead acted as the anti-torpedo system. A single deck 20mm thick ran from the forward guns sto the turbine rooms, the gun themselves protected by 50mm face plates, 30mm side and roof and 50mm on the barbettes. Engine-wise, the first draft called for a 30+knot ship but the plan was subsequently revised: three oil-firing boiler generating 33.123shp powered two geared turbines that in turn drived two propellers, enough to push the ship up to 28knots. endurance was 8.000 nautical miles at 14knots.
As for the minelaying gear, no half measures were taken: the planned ships could carry 700 Mk.6-Mod.1 naval mines, or 850 Type88 ones. Up to 44 depth charges could also be carried without reducing the mine complement. Finally, a catapult was fitted at midship, with enough space to carry two Kawanishi E7K floatplanes for reconaissance duties. Three ships were ultimately ordered F-19, F-22 and F-24, the first starting construction at Toumachi Naval Arsenal in 1932.
By the time F-19 was launched, in 1935, the Navy had already started questioning of the effective usefulness of such hybrid ships, even more so as the official policy was now to ignore naval treaties, a thing that made naval construction like the F-19 completely pointless. The two sisters, F-22 and F-24, had already been redesigned as smaller units exclusevly dedicated to minelaying missiones. As for F-19, construction slowed to a near halt while the higher-ups discussed her fate. Instead of the Hayabusa Seaplane Tenders, which could easily act as scout cruisers for the Aircraft Carriers or be converted into CVLs themselves, F-19 lacked both speed and dimensions to be useful for such roles.
Ultimately, it was decided to just finish F-19 as designed, with the only change being the quad 13mm machine guns replaced by triple 25mm mounts, totaling 12 barrels. F-19 was finally commissioned in early 1938.
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After the start of the Pacific War, F-19 sailed with F-22 and F-24 to the Aleutians, before beign detatched to reach Singapore in february 1942, were she was based until late 1943. She then returned to the Aleutians undertake a more active role, exploiting her higher speeds and ordinance capacity to lay minefields against the advancing US forces. While not employed in this manner, she acted as a convoy escort. In this guise she took part in the Battle of the Komandorski Islands on 27 March 1944, were she had the unwelcome privilege to be the first target of the US Battleship Nevada before it switched fire on Yagumo. Luckily, the closest shots were a straddle and F-19 managed to raise steam and escape (something that Yagumo could not...).
Returned to Koko, F-19 was refitted with a newer hydrophone, a full radar suite and a new airwing made up by Nakajima E8N. Anti-aircraft suitee was augmented by the addition of 8 triple and 20 single 25mm machine guns, bringing the total count to 56 barrels. Depth charge inventory was increased and a green camouflage pattern painted. She continued to operatee as a minelayer or a convoy escort as requirements dictated for most of 1945.
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By mid 1945 F-19 had become one of the first non major-combatant ships in Koko no kaigun to be fitted with Thiarian designed (and Kokoan license-built) fire-control radars, qith an R4CA for the DP-gun director and an R5CD for her main guns. Integration between Japanese and Thiarian systems was deemed satisfactory, with F-19 proving it herself when she managed to shot down three Avengers and two Hellcats during and American raid on Attu, while F-30, wich had yet to recieve the systems, failed to score a single hit on the attacking planes and was sunk during the engagement.
At the start of Koko uprisings F-19 was still stationed in the Aleutians. Except of one of her E8N wich was shot down, she fell almost undamaged in US hands when the armistice was signed, in March 1946. F-19 then joined the Kokoan co-belligerent fleet and was painted in the standard USN Measure-22 style camouflage. A kokoan flag and the ship name were also painted on each side.
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The ship was temporarily interned to Midway, then steamed to Okinawa by mid-June 1946 to support the later stages of the operations, the Kokoan flag on her side was painted over for this occasion as to not make her a clear, reconizable, target for Japanese Kamikazes.
At the end of the war F-19 operated as a repatriation ship, she was then renamed Seisei, entering service with the reorganized Koko Kaijou in May 1947. After two-and-a-half years of service, the ship was decommissioned and laid up. Most of her weapons and the aircraft facilities were removed, the mainmast was also cut down. Seisei was slated to be scrapped when the korean war borke out on June 25 1950. In order to allow for larger ship to support the USN and JMSDF* off Korea and retain an acceptable degree of patrol force to operate as Soviet deterrence the ship was recalled to active duty.
Recommissioning works were as fast as possible, a twin and a quadruple 40mm Bofors were fitted, augmented by two twin 20mm Oerlikons, the aft deckhouse was explanded and turned into a landing spot for a single Sikorsky H-5 helicopter, two depth charge racks and six throwers were fitted at the stern. A new crane was installed for boat handling and some electronics were replaced with USN ones, creating an unusual mix of Kokoan, Thiarian and USN systems, the latter of which was not so well integrated as the other two, leading to a complex shakedown in order to achieve satisfactory performances. Despite that, conflict between her eterogeneous and far-fetched radar suite kept hampering herfor the remainder of her service life.
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In August 1953, a little less than a month after the end of the Korean War and after three years of service based at Teshigawa, Tenji island, Seisei was decommissioned for a second time. After a brief period spent in the mothball fleet she was scrapped by the end of 1954.

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

F-19 1932-1935-1938 - Renamed Seisei 1947, Decommisisoned 1949, Recommissioned 1950, Decommissioned 1953
F-22 /-/-/ - reordered as F-22 design, 1934
F-24 /-/-/ - reordered as F-22 design, 1934

(*) no, it's not an error, in this timeline the JMSDF is established much earlier.

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MS State Guard - 08 March 2014 - 28 January 2023

The Official IJN Ships & Planes List

#FJB

I've been observing this thread for a long time now and I can only say that this is an excellent AU. [ img ]

I like the post-war fit on the Seisei.

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>"Emotions are prohibited." —YoRHa No. 2, Type B ("2B"), NieR: Automata
>"Wow, if I wasn't a hardened killing machine, that mightta hurt..." —SSgt. John Lugo (1st SFOD-D), Spec Ops: The Line

really nice design, well tought and executed

A short history update (some more might come in the next days) while I keep working on the next Ship entry, whixch might end up beign pretty huge...

11.Storm over the pacific (1941-1942)
On the morning of December the 7th 1941 bombs had been falling on Pearl Harbor for a little more than 30 minutes when Koko no Kaigun attacked Midway Island and Attu. The American garrison on Attu put up a fierce resistance but was eventually overwhelmed by the disparity of forces between them and the Rikugun troops. The last fighting dying by December 9th evening. Clashes around midway were the busiest, with the Kokoan carrier fleet engaging USS Lexington's planes in the first carrier-battle of the war. Despite suffering losses, the still green air-crews managed to damage the American carrier and sink a destroyer, forcing TF-12 to retreat. Midway eventually fell the next day after fierce bombardments when Rikugun tropps landed on the island. On December 11th another landing was made on the Island of Kiska, in the Aleutians. With the royal Navy losing two capital ships by the hands of Japanese planes near Singapore, the US navy quickly built up a task-force around the USS Saratoga to strengthen the Aleutian fleet and prevent more offensive movements from Koko. Luckily for Koko, Saratoga had just left Pearl Harbor one day before when Koko no Kaigun and TF-8 met off Sequamis Island on December 16th. Aided only marginally by their respective land-based air forces the two fleet faced each other in the Battle off Turf Point, during which the light cruiser Trenton was sunk, again for negligible losses for Koko no Kaigun. The invasion of Adak started the same day.
Kokoan engineers quickly worked to built an operating airfield on Adak, providing air cover against US planes based on Dutch Harbor while troops from bot KnR and IJA occupied most of the other islands between Attu and Adak. KnK Koku Sentai (carrier division) started patrolling the waters around Midway, with most of the surface fleet split between them and the Aleutian waters. Submarines were deployed to hit merchants and any American warship that would have been spotted. As fiery as it had been during the first two weeks, the Aleutian theatre soon saw action dying down, reduced to sporadic bombing runs by Kokoans against Dutch Harbor and Americans against Adak, which in turn waned into dogfights between fighters and a handful of inconclusive skirmishes between light units, the most serious ones usually requiring a few days of repairs on either side Destroyers.
With the eastern front Against the United States temporarily motionless, Koko's attention shifted towards Supporting the Japanese invasion of the Philippines and Indonesia. KnK sent the Battleshp Amagi, Sentai 5 (a cruiser division) and a few Suirai Sentai (destroyer squadrons) to join the IJN ranks. During the night of January 25th 1942, part of this task force engaged the British Battlecruiser Irresistible and her escort in the Naval battle of Balikpapan. Despite no ships were sunk, both side inflicted heavy damage to it's opponent, with Irresistible ultimately forced to withdraw after being hit by two torpedoes fired by the heavy cruiser Fujiwara. After the battle, Amagi returned to Koko for repairs, but was back within two months, backed by the Battleships Kii and Owari. The rest of Koko no Kaigun group was supplemented by auxiliary units and marginally involved in the subsequent battles, which saw the ABDACOM fleet being defeated in the battles of Makassar, Badung, Sunda and Java. In early April the three Kokoan battleships, accompanied by two destroyer squadrons joined the Kido Butai as escorts during the Indian Ocean Raids. Here, an accursed report from a British recon plane which inexplicably mistook the three ships for the Japanese Cruiser Kumano, Suzuya and the destroyer Shirakumo, led tot he loss of the Battleship Marlborough sunk by Amagi herself. Warspite, the other British battleship engaged, managed to retreat with minor damage after a gunnery duel with Kii.
By mid April 1942, Koko and Japan had managed to hold half of the Aleutians, Midway, Wake, the Philippines, Indonesia and much of Indochina while still advancing towards India and in New Guinea. All with a string of naval victories in which they had never lost anything larger than a destroyer. Japanese and Kokoan submarines patrolled the Pacific Ocean targeting warships and merchants, with the USS Saratoga torpedoed by I-6 on January 11th 1942 and the battlecruiser Constitution hit and almost sunk by Ki-32 on April 5th of the same year. With the Axis on the loose in Europe too, and Thiaria seemingly one step from defeating Brazil, victory appeared on sight, as Morimoto's government propaganda never failed to echo. Still, the Americans had not threw in the towel yet. On April 2nd a USN carrier task force had left Alameda, and was now slipping undetected south of Koko on her way to Japan.....

I've also updated the flags of Koko on the first page. No major changes were made, i've just deleted some black outlines, and I think they look better this way.

Interesting addition to backstory.

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MS State Guard - 08 March 2014 - 28 January 2023

The Official IJN Ships & Planes List

#FJB

another history update, it can be foun on the first page with the rest of Koko's history too...

12.Stalemate and rebound (1942-1943)
The Doolittle Raid was a great embarrassment for Japan, but it was even more for Koko and it's Navy, as Hornet task group had managed to sail undetected through waters patrolled by KnK crafts. To add insult to injury, despite sailing en-masse after news of the attack reached Toumachi, Koko no Kaigun failed to locate the American fleet for three days. The carriers Umineko, Ahodori and Fukuro gave chase but failed to achieve something too. Attempting to attack with submarines resulted in the sinking of Ki-20. This utter failure caused great abashment within Morimoto's government, leading him to personally require the dispatch of more IJA troops to supplement the Rikugun ranks in the Aleutians fearing a possible imminent American offensive. Something that didn't help to mitigate the bitter rivalry that was breeding between the two arimes. Admiral Kensuke Kaneda, Koko no Kaigun Commander in chief, stepped down after taking the blame of having relaxed the fleet too much after the initial successes. His successor, Genzaburo Karasawa immediately crafted a new, more offensive, plan to be implemented together with Operation Mo, the Japanese invasion of Port Moresby. Departing from Toumachi on May 3rd Koko no Kaigun carrier force bombed and destroyed US installations on Tern Island (French frigate shoals) on May 6th, then steamed north to launch another raid against Dutch Harbor three days later. Success of the two raids was reappraised when the Umineko was torpedoed and damaged by the Submarine Pompano during the return leg, forcing the carrier to underwent a month of repairs.
Failure by the Japanese to land troops at Port Moresby thanks to US carrier interference led the joint Kokan-Japanese command to speed up operation AL/MI. The plan, developed by IJN CiC Isoroku Yamamoto, called for a large IJN and KnK carrier and surface fleet to attack Dutch Harbor, Akutan, Unimak, Cold bay, King Cove and other key settlements on Alaska Peninsula in advance of a large invasion force. This was supposed to lure out the American carrier fleet, which would have been ambushed and disposed by another IJN/KnK combined fleet centered around the Kido Butai, which would have been waiting off Midway Island. Unknown to either the Japanese and Kokoans, US intelligence had managed to discover about AL/MI in due time. On june 4th, 1942, while the light carriers Ryujo, Junyo, Ahodori and Fukuro were making the second attack run against Dutch Harbor, a force of three American carriers ambushed and sank Kaga, Akagi, Hiryuu and Soryuu during the Battle off Midway, while only losing Yorktown in the process.
Suddenly, with Umineko and Shokaku undergoing repairs the joint Japanese and Kokoan fleet found themselves with just a single operational Fleet Carrier: Zuikaku. The invasion of Dutch Harbor was canceled as attention was diverted into strengthening the positions on the Solomon Islands, in anticipation of a possible attack against the Fiji Islands. Despite this, most of Koko no Kaigun fleet, including the carriers was left in northern water under pressures from Morimoto, who feared a possible American counterattack, despite Admiral Karasawa strongly protested as he was not of the same opinion.
The Americans still took the initiative, landing troops on Guadalcanal on August 7th before the Japanese could complete an airfield on the island. To counter it, a fleet consisting of seven heavy cruisers (five IJN two KnK), two light cruisers and a destroyer was assembled and quickly departed from Rabaul. Just after midnight, on august 9th, the Kokoan-Japanese fleet Sank the cruisers Canberra, Quincy, Astoria, Vincennes and Hobart, also damaging the Australia (seriously), Chicago, San Juan and three destroyers in the process. However, US troop transports were spared a disastrous fate when Admiral Mikawa ordered the fleet to turn back fearing attacks from USN carriers, only to have Kako sunk by USS S-44 on her way home.
Not involved in the Battle of the Eastern Solomons Kokoan ships returned into action during the Battle of Cape Esperance, with the cruisers Saimei and Nanto involved in the sinking of the American cruiser Boise and Destroyer McCalla. Other ships lost were the USS Duncan, and the IJN Furutaka and Fubuki. Saimei herself was also damaged. Still left to patrol Midway and Aleutian waters, guarding against a possible attack from USN TF8 based on Anchorage, Koko no Kaigun carrier fleet also missed the battle of Santa Cruz.
Finally Realizing that an American offensive in the Aleutians was not materializing, and that the Guadalcanal theatre was in dire need of new ships (especially carriers), Morimoto finally allowed Karasawa to deploy his ships. Koko no Kaigun combined fleet finally started to sail for southern waters, with battleships Amagi and Owari, escorting the Umineko and the brand new Tanchozoru beign the first to depart. The bulk of the fleet followed shortly after, centered around the light carriers Tobuio, Ajisashi, Ahodori and Fukuro.
The fleet arrived too late to help Hiroaki Abe mission to bombard Henderson Field during the First naval battle of Guadalcanal, but just day after planes from Umineko and Tanchozoru gave the IJN enough air cover to save Kinugasa form air attacks. Ten out of eleven of the reinforcement transports led by Raizo Tanaka also managed to escape destruction. On the night of November 14-15th Owari and Amagi, backed by a Suirai Sentai (Desron), joined Nobutake Kondo's fleet led by the battleship Kirishima. Together the three capital ships managed to force the USS Washington into retreat after suffering heavy damage despite Admiral Lee brilliant fight. The USS South Dakota was also crippled and left in sinking condition. Tanaka's convoy started landing troops and supplies during the night. After another day of airstrikes against each other, both fleets retreated on November 16th evening. During the course of the next days, while ground troops fought for Henderson Field, both sides mustered as much ships they could, as the Japanese also hastly prepared a new invasion force to reinforce the Guadalcanal contingent. On november 21st Kokoan carrier-based planes attacked Henderson field, then engaged in combat those launched by the USS Enterprise and Saratoga. That night Japanese/Kokoan a fleet made by six battleships, six heavy cruisers, three light cruisers and numerous destroyers met with an USN fleet composed by five battleships, three battlecruisers, three heavy cruisers, four light cruisers and many destroyers. The fierce battle that ensued, known as the Third naval battle of Guadalcanal saw the Japanese side prevail. Losing to enemy fire the destroyers IJN Teruzuki and KnK Yuki, they managed to sink the battleship New Mexico, the battlecruiser Constellation and the light cruisers Concord and San diego, also inflicting heavy damage on the USS Alabama, scoring hits on many of the other units. The US fleet regrouped and fell back to assit the damaged battleships, allowing the enemy to shell the airfields.
Anyhouw, the IJN/KnK fleet had not escaped damage either, with many ships suffering various levels of damage -battleship Suruga being the most battered one- so that their fleet withdrew too as dawn approached. With the new day carrier-borne attacks resumed from both sides, followed by a nightime bombardment of Henderson field by IJN Kongo and Haruna non the night of November 23rd. The next day, at dawn, the Japanese convoy started to unload it's troops, with IJN Hiyo and Junyo joining the Kokoan carriers against Enterprise and Saratoga, which also got CVEs Nassau and Altamaha in support. In the ensuing skirmishes USS enterprise suffered damage despite her CAP shot down many of the attacking aircrafts. At the end of the battle the IJA and KnR garrison on Guadalcanal had been strengthened enough to go on the offensive. Americans attempts to open a secure route for supplies failed when the USS Northampton was sunk and three other CAs were heavily damaged during the Battle of Tassafaronga on November 30th. A further attempt was fended off by Umineko and Tanchozoru, whose planes sank the USS Chicago and USS DeHaven during the Battle of Rennel island on January 30th 1943. Ultimately, the US troops were forced to evacuate Guadalcanal starting on February 7th.
With the initiative regained once again, Admirals Yamamoto and Karasawa planned the next offensive against the allied forces. In order to cut off Australia and New Guinea from American supply runs Japanese and Kokoan troops were to occupy the new Hebrides and, later, the Fiji. To fend off any American opposition, a large fleet led by three fleet carriers (Zuikaku, Tanchozoru and Umineko) and seven light carriers took the seaf rom Truk in early March 1943, followed by a massive surface fleet led by the Battleship Yamato, the invasion force convoys shadowing them. To stand before it were two veterans of the south Pacific, US carriers Enterprise and Saratoga, aided by six escort carriers, everything the USN could assemble at the time. In the subsequent Battle of Torres island surface units on both sides played marginal roles. The Kokoan/Japanese carrier fleet managed to damage Enterprise (but failed to sink her once again, much to their dismay) and sink three of the escort carriers while losing the light carrier Ajisashi.
Despite inflicting more damage on the enemy the joint fleet failed to destroy the two most important targets, the two American fleet carriers, also suffering heavy loses in their air-crews to the growing experienced USN pilots. Failure to achieve air superiority negated the possibility for the surface fleet to open a path for the transports, so ultimately the Kokoan/Japanese combined fleet regrouped and returned to Truk.
Here it was planned to launch a new offensive the next month, as this time the fleet would have relied on two more fleet carriers, the Shokaku returning from japan and the brand new Inuwashi, which had just ended her post-shakedown trials, to replace the lost Ajisashi.
Still, once again American intelligence works would have changed the table, this time in an even more unexpected and shocking way...

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MS State Guard - 08 March 2014 - 28 January 2023

The Official IJN Ships & Planes List

#FJB

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