X20 and X23 arrived in position on 4 June and due to the delay caused by bad weather, remained in position until 4:30 a.m. on 6 June (D-Day) when they surfaced, erected the navigational aids, an 18 feet telescopic mast with a light shining to seaward, a radio beacon and echo sounder, tapping out a message for the minelayers approaching Sword and Juno.