following shakedown in the chesapeake bay area, "monadnock" operated in the 5th naval district until 25 march, when she sailed for the british west indies. while in the caribbean, 1 may 1942, she was redesignated minelayer cm-9. returning to virginia, 20 may, she resumed operations in the 5th naval district. in late october she joined a convoy bound for north africa. arriving off casablanca on 8 november, she remained in the assault area through the 11th, when she got underway for her return voyage across the atlantic, arriving at yorktown, virginia, on the 30th.