BREMERTON, Wash. — The first group of enlisted women to serve on board a Navy submarine is preparing to sail on the USS Michigan.

The Kitsap Sun says the guided-missile sub, whose homeport is Naval Base Kitsap-Bangor, was recently reconfigured to include living quarters for up to three female chief petty officers and 36 female crew members.

Shipyard and ship crews enlarged the forward washroom, added four showers and created a new bunkroom. The Navy estimates the reconfiguration cost about $6 million.

The Michigan arrived at the Puget Sound Naval Shipyard and Intermediate Maintenance Facility in Bremerton for maintenance last August. On Friday it left dry dock and tied up at a nearby pier.

Seven Ohio-class subs will add about 550 enlisted women by 2020, comprising 20 percent of crews. Female officers have served aboard some submarines since 2011.