Modernisation upgrades completed on guided-missile destroyers USS Chung-Hoon and USS James E Williams

USS Chung-Hoon, shown here firing a Standard Missile, recently received modernised combat systems. (US Navy)

US Navy (USN) DDG 51 Flight IIA guided-missile destroyers USS Chung-Hoon (DDG 93) and USS James E Williams (DDG 95) have completed their depot modernisation periods (DMPs) as part of the DDG Modernization 2.0 programme, USN officials confirmed on 29 June.

The USN is retrofitting its Flight IIA ships with Surface Electronic Warfare Improvement Program (SEWIP) and an Air-and-Missile Defense-Radar (AMDR) variant, AN/SPY-6(V)4, meant to provide these older vessels DDG 51 Flight III-like capabilities, USN officials have said publicly during recent updates of the modernisation programme.

The AN/SPY-6(V)1 uses four fixed-antenna assemblies with each antenna having 37 radar modular assemblies (RMAs). The AN/SPY-6(V)4 will use four fixed-antenna faces, with each antenna face having 24 RMAs.

Destroyer Modernization 2.0 calls for initial Flight IIA ships to first get SEWIP during one availability and then get the new radar suites during another, later availability.

However, the USN later intends to do both installations in one availability, along with a new and more powerful cooling system to meet the extra demand needed for the new systems.

“To maintain DDG 51's edge against emerging air and ballistic missile threats, including hypersonic missile technologies, the class is evolving to incorporate key capabilities for long-range fires and terminal defence,” said the US Navy Shipbuilding Plan, released in May.

“Specifically, the new Flight III variants are entering service fully equipped with advanced systems to include the SPY-6 radar, Aegis Baseline 10, and SEWIP Block III, enabling them to replace cruisers as air-and-missile defence commander (AMDC) in CSGs [carrier strike groups],” the shipbuilding plan said.