Île d'Yeu
Once the allied convoy was within of Île d'Yeu, a well-defined oil slick was sighted between the American warship and the British steamer, off "Danse"′s port bow. "Christabel" cruised over to the slick for better observation but saw nothing to further indicate a German submarine's presence. The convoy continued for a little while when at 17:20 the wake from was spotted by the officer-of-the-deck and a lookout, about off the port quarter.