Meanwhile, Pasley was attempting to locate merchantmen detached from the convoy she was escorting in appalling weather from Russia via Aspö Fjord, 100  km north of Bergen, to Lerwick, and had resorted to displaying a white light halfway up the mast by night for guidance. Weathering the heavy seas and blinding rain squalls, Cary sighted Pasleys light; forewarned a U-boat was in the area, he gave the order to attack.
Concurrently, Pasley was trying to identify merchant vessels separated from the convoy she was protecting in harsh weather conditions from Russia via Aspö Fjord, 100 km north of Bergen, to Lerwick, and had resorted to displaying a white light halfway up the mast by night for navigation. Enduring the turbulent seas and blinding rain squalls, Cary spotted Pasley's light; forewarned that a U-boat was in the vicinity, he gave the order to launch an attack.