BATH — The U.S. Navy has awarded Bath Iron Works a $21 million contract modification to provide engineering and design services for DDG 51-class destroyers.

Bath Iron Works spokesman Matt Wickenheiser said Friday that BIW had anticipated that the Navy would exercise its third-year option on the five-year contract for work on the DDG-51 line of Arleigh Burke-class destroyers.

The majority of the work will be performed at the shipyard’s Brunswick offices, with 28 percent at the Bath shipyard.

“This is a great example of the phrase ‘Bath built is best built,’” U.S. Rep. Chellie Pingree said in a statement Thursday. “BIW has done a great job as the lead shipbuilder on this contract, and it makes sense they get this additional contract to provide this kind of technical service to the other yard building these ships.”

According to a July report by the Congressional Budget Office, the Arleigh Burke-class destroyers cost approximately $1.5 billion.