GROTON — U.S. Rep. Joe Courtney and a senior House Armed Services Committee member asked the Navy to explain by November 20 why three leaders of the Groton-based USS South Dakota were removed from their posts in October.

Courtney, of Connecticut, and Rep. Adam Smith, of Washington, said in a letter released November 12 that the Navy relieved the submarine’s commanding officer, executive officer and chief of the boat on October 14. The lawmakers said the Navy had yet to formally brief the House Armed Services Committee about the dismissals or what led to them.

The letter asks whether the removals followed a grounding or another incident at sea. If there was a mishap, the lawmakers want to know whether anyone was injured, whether the submarine was damaged and how long any repairs would take. The letter leaves those questions open.

Courtney is the ranking member of the House Seapower and Projection Forces Subcommittee. Smith is the ranking member of the full Armed Services Committee. The USS South Dakota is a Virginia-class submarine that operates out of Naval Submarine Base New London in Groton.