Aircraft Carrier Yongyang
Displacement: 7,950 tons standard / 10,575 tons full load
Length: 176.56 m
Beam: 20.5 m
Draught: 5.5 m
Propulsion: 100,000 shp turboelectric drive on two shafts
Speed: 35.0 kt
Range: 10,000 nmi at 16 knots
Complement: 850
Aircraft carried: 24 standard
Flight Deck: 157.5 m x 24 m
Armament:
- 4 x 10 cm/65 dual purpose guns (2x2)
- 24 × 4 cm/56 AA guns (12x2)
Korea's first commissioned aircraft carrier since the start of the Sino-Korean War. Entering service after a long and tortuous construction process, it would go on to take an iconically important role in KJH.
Yongyang was originally born as "Ryujo" in Japan. It was co-designed by Japan and Korea as a small and lightly built vessel in an attempt to exploit a loophole in the Washington Naval Treaty of 1922 that carriers under 10,000 long tons standard displacement were not regarded as "aircraft carriers". Article Three of the London Naval Treaty of 1930 closed this loophole in the midst of construction and thus took away the reasoning for Ryujo.
More important to Japan, however, was the installment of a capital ship holiday. The idea of a holiday was brought up in Washington before, but was not adopted due to the various countries that needed to construct to fill their limits. With all signatories having essentially reached their limit one way or another by this time, this holiday was installed, which put Japan in the bad position of being left with the overaged Kongo and Ise class which it had planned to replace. Reconstruction was necessary, and with Japan already at its agreed limit of 353,000 tons, it had to bargain with Korea for additional tonnage.
The resulting agreement was the following: Korea would scrape one of its Kwanmo-class battleship and transfer 25,000 tonnage to Japan, which could be used to reconstruct the outdated ships. In exchange, Korea was to receive 15,000 tons of the carrier limit and the hull of Ryujo after launching. This balanced the Korea:Japan ratio at 207,000:378000 for capital ships and 52,500:97,500 for carriers.
While Korea welcomed the increase in carrier tonnage, it considered Ryujo to be just a deadweight incapable of fitting into KJH's plans. With two 16,250 ton carriers already commissioned and a new 20,000 ton carrier planned to fill up the increased limit, this left no room for Ryujo. Therefore, it was basically abandoned in the Busan Naval Yard for two years after being transferred in 1935. Only the appearance of the Crown Princess saved the ship from being scrapped.
While visiting the Busan Naval Yard in 1935, Princess Cheonhwa came upon Ryujo and heard the story. The report of her comment "I don't think she should be put down like this, the poor thing all alone" led to public donations for resuming construction. Combined with the changing geopolitical circumstances of a hostile China's denunciation of the Washington Naval Treaty, KJH set up a plan to finish the vessel and use her as a platform for naval aviation experiments and an imperial crown yacht (satisfying public support). She was "renamed" Yongyang under Princess Cheonhwa's adamant stance that "one does not change the original name just because of being adopted".
Yongyang kept the simple single hanger design of the original plan (Japan had considered the addition of a second hangar atop the first doubled aircraft stowage requirement to 48), but was redesigned with an island to free up space in the superstructure bridge as the imperial crown suite. At the same time, the machinery was replaced and upgraded to 100,000 horsepower from the original mere 65,000, and additions of fuel tanks allowed her an incredible 35 knots maximum speed and operational range of 10,000 nautical miles at 16 knots. It was also the first vessel to have the new Cheonlian Jeontamgi (radio detection device), which would become the standard for all large vessels during the war.
Ultimately, Yongyang was pushed onto the main stage, with the eruption of the Sino-Korean War forcing her to combat ferocious aerial onslaughts. The knowledge and training gained from this would influence all later carriers, turning her into a second "mother" carrier succeeding the role of Bongyang, the first "true" aircraft carrier.
Note 1: Basically what Ryujo became in this world. Instead of the historically top-heavy unstable mess of Ryujo, Yongyang sticks to being a light carrier able to back a bigger punch through use of electronics and other methods.
Note 2. The political aspect of Yongyang shows the ongoing imperial cult surrounding Princess Cheonhwa. No normal country would have public donations simply because of the comments of a 7-year-old, nor consider the specific use as imperial crown yacht (not even HTMS
Chakri Naruebet, regardless of its unfounded white elephant reputation, is that blatant). This will come back to hinder Korea at various moments.