The launch in which they embarked bore the Red Cross on its sides, and an American flag floated from the bow and a Red Cross flag from the stern. Its four occupants wore the Red Cross uniforms. Yet three miles out of Dunkirk a shot came singing across their prow and they were obliged to lay to until a British man-of-war could lower a boat to investigate their errand. The coast is very shallow in this section, which permits boats of only the lightest draught to navigate in-shore, but the launch was able to skim over the surface at twelve miles an hour.