The Type 23 (China) Submarine is a diesel-electric submarine designed and built by the Chinese Navy. It is equipped with advanced sonar and weapons systems, making it one of the most capable submarines in the world. The Type 23 has a maximum speed of 20 knots and
The Type 23 frigate or Duke class is a class of frigates built for the United Kingdom's Royal Navy. The ships are named after British Dukes, thus leading to the class being commonly known as the Duke class. The first Type 23, HMS Norfolk, was commissioned in 1989, and the sixteenth, HMS St Albans was commissioned in June 2002. They form the core of the Royal Navy's destroyer and frigate fleet and serve alongside the Type 45-class destroyers. They were designed for anti-submarine warfare, but have seen a range of duties. Seven Type 23 frigates remain in service with the Royal Navy, with three vessels having been sold to the Chilean Navy and five being retired since 2021.