# Yoon Youngha-class patrol vessel

The Yoon Youngha-class patrol vessel (Hangul: 윤영하급 미사일고속함) also known as PKG-class patrol vessel is a class of patrol ship of the Republic of Korea Navy. One variant is in active service and a smaller variant is planned. The first being the PKX-A or Yun Youngha-class missile patrol ship (Hangul: 윤영하급 고속함), and the second the PKX-B class [ko] patrol boat (also known as Chamsuri-211-class patrol boat or Gumdoksuri-class patrol vessel).

## Development

The Republic of Korea Navy (ROKN) began development of the PKG class in 2003 after a Chamsuri-class (PKM-class) patrol boat was sunk during a naval clash with North Korean patrol boats on June 29, 2002. The codenamed PKX (Patrol Killer eXperimental) program is the patrol boat modernization project of the ROKN.
The PKX consist of two main designs. The larger, missile armed PKX-A(PKG) of approximately 500 tons and the smaller gun armed PKX-B(PKMR) of approximately 200 tons. PKX-A(PKG) is planned to take up some of the operations done by Pohang-class corvettes, and the PKX-B(PKMR) is planned to replace the aging Chamsuri-class fleet.
The first PKX-A(PKG) vessels were ordered from Hanjin Heavy Industries. The lead ship of the class, Yoon Youngha, named after Lieutenant Commander Yoon Youngha who was killed during the second battle of Yeonpyeong, was launched on June 28, 2007 and commissioned on December 17, 2008. The production of the PKX-A(PKG) are being divided between Hanjin Heavy Industries and STX in lots of four.
The PKX-B variant includes a 130 mm guided rocket launcher at the stern. The first vessel was launched in July 2016 and was commissioned in late 2017; all four ships in the first batch will be delivered by the end of 2019. A contract was awarded to Hanjin Heavy Industries for ships 5 through 8 in June 2017, which are scheduled to be delivered after 2020. The contract for ships 9 through 12 were awarded in early 2018. The PKX-B was specifically designed to counter North Korean fast swarming crafts. The 12-canister 130 mm guided rocket launcher can hit targets between 3–20 km (1.9–12.4 mi; 1.6–10.8 nmi) using a rocket weighing 80 kg (180 lb) with an 8 kg (18 lb) warhead. Rockets have GPS/INS midcourse guidance with data uplink and terminal IIR homing, and three can be fired simultaneously.

## Ships in the class

| Name | Pennant number | Builder | Launched | Commissioned | Status |
| PKX-A(PKG) |||||||
| Yoon Youngha (윤영하) | PKG-711 | Hanjin Heavy Industries | 28 June 2007 | 17 December 2008 | Active |
| Han Sanggook (한상국) | PKG-712 | STX Offshore & Shipbuilding | 23 September 2009 | 14 September 2011 | Active |
| Jo Chunhyung (조천형) | PKG-713 | STX Offshore & Shipbuilding | 23 September 2009 | 14 September 2011 | Active |
| Hwang Dohyun (황도현) | PKG-715 | STX Offshore & Shipbuilding | 11 December 2009 | 13 January 2012 | Active |
| Suh Hoowon (서후원) | PKG-716 | STX Offshore & Shipbuilding | 11 December 2009 | 28 November 2011 | Active |
| Park Donghyuk (박동혁) | PKG-717 | Hanjin Heavy Industries | 28 July 2010 | 28 November 2011 | Active |
| Hyun Sihak (현시학) | PKG-718 | Hanjin Heavy Industries | 28 July 2010 | | Active |
| Jung Geungmo (정긍모) | PKG-719 | Hanjin Heavy Industries | 2 November 2010 | 19 December 2011 | Active |
| Ji Deokchil (지덕칠) | PKG-721 | Hanjin Heavy Industries | 2 November 2010 | 23 December 2011 | Active |
| Lim Byeongrae (임병래) | PKG-722 | STX Offshore & Shipbuilding | 20 November 2012 | 3 September 2013 | Active |
| Hong Siuk (홍시욱) | PKG-723 | STX Offshore & Shipbuilding | 20 November 2012 | 10 October 2013 | Active |
| Hong Daeseon (홍대선) | PKG-725 | STX Offshore & Shipbuilding | 20 November 2012 | 4 November 2013 | Active |
| Han Munsik (한문식) | PKG-726 | Hanjin Heavy Industries | 24 April 2013 | 28 January 2014 | Active |
| Kim Changhak (김창학) | PKG-727 | Hanjin Heavy Industries | 24 April 2013 | 4 March 2014 | Active |
| Park Dongjin (박동진) | PKG-728 | Hanjin Heavy Industries | 24 April 2013 | 1 April 2014 | Active |
| Kim Soohyun (김수현) | PKG-729 | STX Offshore & Shipbuilding | 30 April 2014 | 30 September 2014 | Active |
| Lee Byungchul (이병철) | PKG-733 | STX Offshore & Shipbuilding | 30 April 2014 | 28 November 2014 | Active |
| Jeon Byeongik (전병익) | PKG-732 | STX Offshore & Shipbuilding | 24 June 2016 | 11 January 2018 | Active |
| PKX-B(PKMR) |||||||
| Chamsuri-211(참수리-211) | PKMR-211 | Hanjin Heavy Industries | 28 July 2016 | 30 October 2017 | Active |
| Chamsuri-212(참수리-212) | PKMR-212 | Hanjin Heavy Industries | 21 December 2018 | 28 November 2019 | Active |
| Chamsuri-213(참수리-213) | PKMR-213 | Hanjin Heavy Industries | 21 December 2018 | 18 December 2019 | Active |
| Chamsuri-215(참수리-215) | PKMR-215 | Hanjin Heavy Industries | 21 December 2018 | 31 December 2019 | Active |
| Chamsuri-216(참수리-216) | PKMR-216 | Hanjin Heavy Industries | 13 December 2019 | | Active |
| Chamsuri-217(참수리-217) | PKMR-217 | Hanjin Heavy Industries | 13 December 2019 | | Active |
| Chamsuri-218(참수리-218) | PKMR-218 | Hanjin Heavy Industries | 13 December 2019 | | Active |
| Chamsuri-219(참수리-219) | PKMR-219 | Hanjin Heavy Industries | 13 December 2019 | | Active |
| Chamsuri-221(참수리-221) | PKMR-221 | Hanjin Heavy Industries | 29 December 2020 | | Active |
| Chamsuri-222(참수리-222) | PKMR-222 | Hanjin Heavy Industries | 29 December 2020 | | Active |
| Chamsuri-223(참수리-223) | PKMR-223 | Hanjin Heavy Industries | 29 December 2020 | | Active |
| Chamsuri-225(참수리-225) | PKMR-225 | Hanjin Heavy Industries | 29 December 2020 | | Active |
| Chamsuri-226(참수리-226) | PKMR-226 | Hanjin Heavy Industries | 12 May 2022 | | Active |
| Chamsuri-227(참수리-227) | PKMR-227 | Hanjin Heavy Industries | 12 May 2022 | | Active |
| Chamsuri-228(참수리-228) | PKMR-228 | Hanjin Heavy Industries | 12 May 2022 | | Active |
| Chamsuri-229(참수리-229) | PKMR-229 | Hanjin Heavy Industries | 12 May 2022 | | Active |
* The PKX-A first six ships were named after the sailors of patrol boat PKM 357, who were killed during the Second Battle of Yeonpyeong in 2002.
* South Korean navies do not use the number '0', '4' when assigning Pennant numbers to their ships. In Korea, there is a superstitious belief that '4' is an unlucky number (much like Friday the 13th). '0' is also considered as bad luck. There are two exceptions, though - MLS 560 Wonsan and submarines.