the task of seizing arendal fell on "gruppe 4" of the german invasion fleet. the primary objective of "gruppe 4" was the capture of the main port in southern norway, kristiansand. a single torpedo boat, "greif", was detached from the task force on 8 april, "gruppe 4" having left wesermünde in germany at 05:00 the same day. before proceeding on her own, "greif" had been escorting the e-boat tender "tsingtau" off the west coast of denmark.