Unbeknownst to Léon Gambetta, she had been stalked for a day and a half by (Lieutenant Commander) Georg Ritter von Trapp, the new commander of U-5, when the submarine was finally able to make her attack at 00:40 on 27 April, roughly 15 nautical miles south of Santa Maria di Leuca (the south-eastern tip of Italy in the Ionian Sea).