The Hunt class is a class of thirteen mine countermeasure vessels of the Royal Navy. As built, they combined the separate roles of the traditional minesweeper and that of the active minehunter in one hull, but later modifications saw the removal of mine-sweeping equipment. They have a secondary role as offshore patrol vessels. Development Upon introduction in the early 1980s they were the largest warships ever built out of glass-reinforced plastic and were the last in operation to use the Napier Deltic diesel engine. All were built by Vosper Thornycroft in Woolston except and , which were built by Yarrow Shipbuilders Limited on the River Clyde. was the last ship of the class launched. Following the sale of and to the Greek Navy, the sale of and to the Lithuanian Navy and the decommissioning of , a contract to re-engine the remaining eight vessels was signed by BAE Systems in 2008, whereby the existing 30-year old Napier Deltic 9-59K power units were replaced by Caterpillar CAT C32 engines, together with new gearboxes, bow thrusters, propellers and control systems, in a six year refurbishment programme that was completed in 2018. The capabilities of the remaining eight vessels of the Hunt class have been significantly enhanced by the installation of Sonar Type 2193 and the NAUTIS 3 command system. The performance of Sonar 2193 exceeds that of any other mine hunting sonar in service in the world today and is capable of detecting and classifying an object the size of a football at a distance of up to . In late 2007 Chiddingfold used the Seafox drone, the Royal Navy's mine disposal system, during Exercise Neptune Warrior off Scotland. Seafox is described by the MOD as a "state of the art fire and forget system, capable of destroying mines in depths of up to 300 metres". The 2021 defence white paper announced that all the Hunt-class vessels would be retired from Royal Navy service in the 2020s and replaced by automated systems. It was subsequently indicated that the withdrawal would occur in the 2029 to 2031 period. Ships in the class All 13 ships of this class re-used names from the World War II . Four of the names had also been used for World War I s: these were HMS Bicester, Cattistock, Cottesmore and Quorn. had been a paddlewheel minesweeper in 1916, and was a coaster taken up from trade in