Lecture by Michiel Kersten (Artetcetera) for the Dutch Bavaria Sailing Club (BZC) at their annual clubmeeting in Utrecht on the 13th of February 2016. A lecture on Willem van de Velde II and his contemporaries (Beerstraten, Vlieger - his teacher -, Backhuysen, Reinier Nooms, Hendrick Dubbels and others. The lecture concentrates of the First Anglo-Dutch War and a typical and popular sub-genre in maritime art: ships at anchor in a calm. Maritime painting between circa 1650-1665. Title of the lecture: Rustige en onrustiege dagen op zee.