noon
Slowly but steadily the vessel dropped away into the fathoms and was soon beyond the range of guns , depth bombs or other menacing projectiles . When at last the depth dial showed the desired depth the _ Monitor _ was headed straight out to the open sea and started ahead at eight knots an hour . Unmolested , but feeling her way cautiously along until well out of the danger zone of nets and mines , the _ Monitor _ moved out to sea and set her course for the Strait of Dover . By noon she had made excellent progress . Not a vessel had yet been sighted , and with the freedom of the open sea the sub was able to cruise on the surface at full speed . Several hours later the _ Monitor _ picked up H.M.S. _ Chesterton _ , turned over the German prisoners , and gave warning of the intended U-boat raid on the transports . `` We sank the mother ship of the submarines , '' McClure told the _ Chesterton 's _ commander , `` but they 'll probably get their supplies elsewhere and try to pull off the stunt . ''