Ultra Electronics has won an £18m contract with the Ministry of Defence to supply sonobuoys for the Royal Navy's Merlin maritime patrol helicopter.Optioned for four years, the contract will be executed over the next two years to ensure the Royal Navy maintains a persistent anti-submarine warfare surveillance capability against hostile submarines, said Ultra Electronics on Tuesday.The company's chief executive Rakesh Sharma noted: "This is a significant opportunity which demonstrates Ultra's continuing ability to supply and support cutting edge, affordable and value for money solutions to the Royal Navy."We look forward to working with the DE&S team on this programme."