April 7, 2020: South Korea is donating one of its recently retired Pohang class corvettes to South American nation Colombia. Another Pohang was donated to the Philippines and was delivered in 2019. A second retired Pohang will also be given to the Philippines. These transfers are largely good-will gestures to nations that are or might become customers for South Korean products, in particular weapons.

While the Pohangs were built for anti-submarine warfare, they were only really effective against the 20 or so larger ocean-going North Korean subs. These are all elderly, noisy boats, which rarely went to sea. Most of North Korea's 90 subs are much smaller than the ocean-going ones and operate along the coast. These shallow waters have more currents and a lot more underwater noise. The Pohang's sonar, while adequate on the high seas against noisy older boats, is very inadequate close to the shore. Even before a Pohang was sunk in 2010 by one of these smaller North Korean subs, there were efforts to find and install more powerful sonar in the Pohangs. No suitable sonar system could be found that would fit. And even if a new sonar did fit, it would weigh so much more that it would unbalance the ship.

The Pohangs are small ships built in the 1980s. They are only 88.3 meters (290 feet) long and displace 1,200 tons. The crew of 95 operates a large number of weapons. There are four Harpoon anti-ship missiles, two 76mm cannon, two twin-40mm autocannon, six torpedo tubes (each with a Mk46 324mm/12.75 inch anti-submarine torpedo), and twelve depth charges. Max speed is 59 kilometers an hour, cruising is 28 kilometers an hour. Endurance is about ten days.

Between 1983 and 1993 24 Pohangs were put into service. One Pohang was retired and turned into a museum ship. Another was sunk by a North Korean torpedo. So far three others have been donated. Seven ships are in reserve and most of these will be scrapped unless other countries are interested in a retired corvette. The remaining twelve Pohangs are wearing out and are all due for retirement by 2030.

FFX class frigates are replacing the Pohangs, but these are only being built at the rate of one or two a year. Twelve Pohangs still in service. Because of that, an attempt has been made to provide better anti-torpedo defenses. This involved installing devices that can detect the sound of incoming torpedoes, along with acoustic (noise-making) decoys that can divert the aim of some types of torpedoes. These defenses are of limited effectiveness. For the moment, the Pohangs are as vulnerable as they were in 2010.

Giving away retired Pohangs to the Philippines came after the Philippines ordered two South Korean frigates in 2016. These will cost $169 million each and are smaller versions of the South Korean FFX (Incheon class) frigate. The first FFX entered service in 2013 and six are now active. The FFXs are 3,200 ton ships and are each armed with a 127mm gun, eight anti-ship or cruise missiles, three torpedo tubes, a RAM anti-missile/aircraft launcher, and a Phalanx anti-missile gun system. There is space aft for two helicopters. The ships are highly automated, requiring a crew of only 140. Top speed is 61 kilometers an hour. Range is 8,000 kilometers. Most of the equipment (including electronics) and weapons are locally built. South Korea planed to build 18-24 FFXs. The six FFXs cost about $233 million and another eight are planned. The second, and additional batches, will be improvements over earlier ones.

South Korea planned to export the FFX to many navies who want high quality, low cost, warships. Meanwhile, South Korea has also developed a slightly larger FFX II frigate and subsequent FFXs will be this version. But for export customers, South Korea will make smaller versions as it is doing for the Philippines. This approach was pioneered by European shipyards and later adopted by Russia. The United States had always done this but mainly because the U.S. usually built larger numbers of each class ship over a longer period. In many cases, construction went on for decades with dozens of ships built. It was inevitable that there were lessons learned from the earlier ships already in service and, based on these, modifications to the initial design were made.