F-22 Class Minelayer:
In it's effort to circumvent the London Naval Treaty Koko no Kaigun issued the requirement for another class treaty-skirting ships like the Hayabusa class seaplane tenders. The resulting class was to be the Minelayer class Fusetsukan-19, whose three ships were rodered for construction in late 1931, with the first starting construction in 1932. Later on, because of the shfting policies of the new Morimoto's government, it was decided to reorder the last two units, F-22 and F-24 to a smaller design.
The newly designed ships were loosely based on the Japanese Okinoshima, but to a more careful eye there were more differencies than affinities. The hull, while retaining similar overall dimensions, had a decidedly different underwater section and a completely redesigned stern. The ventilation system for the engire room was also modified. The searchlight platforms were different, both in appearance and positioning, the same applied to the RDF room. The layout of the bridge deckhouses was revised too. Overall, the ship was armed with four 140mm guns in two twin mounts, fitted in shielded positions, one forward, one aft. two single 76mm guns and two twin 13mm machine guns made up the anti-aircraft armament. Up to 500 naval mines and 22 depth charges could be carried. Top speed was 20knots and endurance 9.000nm at 10knots. Crew was 445 officers and men. Like the Japanese large minelayers a catapult was fitted at midship to operate a single Kawanishi E7K floatplane.
Fusetsukan-22, the first of the two ships, was laid down in 1934, launched in 1935 and commissioned in 1936.
The second ship, Fusetsukan-24, was laid down in January 1936, launched in 1937 and commissioned in record-time by the end of the year. She could be told apart from her sister because she had the fog horn pipes routed on the starboard side (F-22 had it on port) and because she sported three twin 25mm machine guns as light anti-aircraft armament. F-22 woudl recieve the same upgrade by late 1941.
During the war they supported most major KnK and IJN naval operations, from the invasion of the Aleutians to the attempted invasion of Espiritu Santo, during which F-22 was sunk by planes from the USS Saratoga.
F-24 took part in the evacuation of the Solomon Islands, then was deployed to the Aleutians. Here, in late 1944, she was caught and bombed by US B-24 and badly damaged. Five bombs hit the stern and quarterdeck destroying the aft 140mm mount, toppling the mainmast and crippling the engines. The stern was further damaged when the explosion of some deck-stored depth charges set a fire below deck, jamming the rudder. Down by the stern and listing 24° to starboard the ship burned for hours, her sinking was avoided thanks to the heroic damage-control work put up by the crew and by the fact that the ship was carrying a reduced complement of mines, which the crew managed to move and secure to avoid them beign caught in the fire.
Towed back to Koko, the ship was moored in hokuto's harbor on Tenji island were she recieved temporary repairs before beign sent to Taniguchi (Yomei island) for more thorough works.
Since her engine damaged was deemed irreparable, effectively cutting her top speed from 20 to 15 knots, it was decided to turn her into a testbed for full-scale examination of Thiarian electronics, obtained in late 1943 by submarine KI-33 during a bilateral exchange between KnK and Thiarian Navy.
During the works the 140mm guns (the aft moutnwas now inoperable) were landed and replaced by twin 127mm ones, a new, smaller mainmast was fitted and the aircraft catapult removed, replaced by an expanded aft deckhouse, the 76mm guns were removed too. Anti-aircraft armament was augmented with the addition of seven triple, a twin and twelve single 25mm machine guns, bringing the total count to 41 barrels. The older 4,5m rangefiner for the 140mm guns was removed and replaced by a new composite rangefinder-director set for the 127mm guns, directors for the 25mm machine guns was also aded. And hydrophone was added and the deptch charge complement increased as much as possible, with the entire mine inventory landed. the foremast was modificed to fit a Type22 surface-search radar. Finally, electronics built in Koko based on Thiarian documentations and samples were fitted: R3FD surface, R2FA air search, R4CA air fire control raders and a R6R high frequency direction finder. No camouflage was apinted except for a fake bow wave to give the impression of an higher top speed.
Examination of Thiarian sistems continued for most of 1945, even after Thiaria signed an armistice with the Allies. Then on November 6th 1945, few days after Koko uprisings had started, F-24 blew up while berthed at Fuyuki. It was alter revealed that the ship own crew had deliberately scuttled tehir ship to avoid the electronics to fall into IJA hands. F-24 wreck was raised and scrapped after the war.
Ships in class: (laid down-launched-commissioned - fate)
F-22 1934-1935-1936 - Sunk 1943
F-24 1936-1937-1937 - Scuttled 1945
Someone might have noticed the absence from this thread of the aforementioned Minelayer (Fusetsukan) 19, whose pennant fits between the F-18 and the F-22 class. This is just because I've chosen, for the most part, to depict ships chronologically by commissioning date.