The Hunt class is a class of thirteen mine countermeasure vessels (MCMV) of the Royal Navy. They combine the separate role of the traditional minesweeper and that of the active minehunter in one hull. They have a secondary role as fisheries patrol vessels. Upon introduction in the early 1980s they were the largest warships ever built out of glass-reinforced plastic and are the last in operation to use the Napier Deltic diesel engine. All were built by Vosper Thornycroft in Woolston except HMS Cottesmore and Middleton, which were built by Yarrow Shipbuilders Limited on the River Clyde. HMS Quorn was the last ship of the class launched. 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 up to 1,000 metres. In late 2007 HMS Chiddingfold used Seafox, the Royal Navy's new mine disposal system, during Exercise Neptune Warrior off Scotland. Seafox is described by the MOD as "state of the art fire and forget system, capable of destroying mines in depths of up to 300 metres"