This second volume of the trilogy about Willy Meyer describes the young boatmate's entry into the elite unit of the Reichsmarine, the new submarine weapon, and the "happy time," the era of the hunters. U-47 under Captain Lieutenant Günther Prien is arguably the best-documented submarine of World War II. Naturally, the daring journey of this submarine into the "supposedly safe" naval port of Scapa Flow, as well as the sinking of the British battleship HMS "Royal Oak" and the victorious return to Germany, are described in detail. As in the sixth and eighth volumes, this documentation also features previously unpublished private photos from the author's archive.