Long after reviewing the North Korean Navy, here is the response: The Republic of Korea Navy, today the third largest in Asia, behing Japan and China, a crucial factor amidst growing tensions facing the second world’s largest fleet. Founded in 1949 the ROKN as abbreviated, and its initial HQ was Deoksan airfield (Jinhae) under Lt Col. Shin Hyun-joon which also created the Korean Marines.
Basically, this Navy survibed the Korean war and moved from a small coast guard force to a Green water Navy in the space of 30 years, creating an impressive shipbuilding industry on the process to deliver custom-built ships in great numbers and quickly. There were three splendid examples of this:
-The Ulsan class frigates, Pohang class corvettes, and Chamsuri class patrol boats.
However the immense majority of the fleet was made of ex-US ships, either patrol boats, sub-chasers (the first was purchased in 1948), minesweepers, up to modernized Fletcher, Gearing and Allen M Sumner class destroyers (FRAM I-II).
The great swap happened in 1990 at the end of the cold war: Not only the ROKN achieved its transition to a blue water navy, but the yards delivered three class of missile destroyers, Kwanggaeto the Great, Chungmugong Yi Sunshin class, up to the AEGIS type Sejong the Great class, even venturing into the realm of near-aircraft carriers with the Dodko LHD and her sister ship in the 2000s. In addition the ROKN saw its Marine Corps extended to new levels and benefiting of the aura of an elite force born during the Korean Wars. At last, South Korea also bolstered its fleet air arm, now comprising 16 long range ASW patrol turborpop planes.
So, this article is a complete overview of the Korean Navy during the cold war, from its early inception to the last phase. A “modern” (1990-2020) page is also in writing.