The ROK Navy continued shipbuilding programs to upgrade its fleet with local shipbuilders. In order to replace the aging "Pohang"-class corvettes and "Ulsan"-class frigates, and to take over multi-role operations such as coast patrol and anti-submarine warfare, the ROK Navy commissioned six 2,300-ton "Incheon"-class frigates between 2013 and 2016, and the lead ship (FFG 818) of the 2,800-ton "Daegu"-class frigates in March 2018. Two ex-USN "Edenton"-class salvage and rescue ships were replaced with two locally built 3,500-ton "Tongyeong"-class ships between 2014 and 2016. The Navy commissioned a 3,000-ton minelayer, ROKS "Nampo" (MLS 570), in June 2017. The lead ship of the PKX-B fast rocket craft, ROKS "Chamsuri 211" (PKMR 211), was commissioned in November 2017 to relieve the aging fleet of "Chamsuri"-class patrol craft. The ROK Navy commissioned four 4,500-ton "Cheonwangbong"-class dock landing ships between 2014 and 2018. In May 2018, the Navy launched the "Marado" (LPH 6112), which was the second ship of the "Dokdo"-class amphibious transport dock. In June 2018, the Navy launched a 4,500-ton training ship, the "Hansando" (ATH 81), which was also designed as a casualty receiving and treatment ship (CRTS).