Complex sentence: The U-boat returned to Wilhelmshaven on 12 October after 34 days at sea where Lott was reprimanded for his actions, which were regarded as having endangered his crew.
Split into simpler sentences: The U-boat returned to Wilhelmshaven on 12 October after 34 days at sea. Were Lott was reprimanded for his actions, which were regarded as having endangered his crew.