Human Error is the cause of most maritime accidents. In a majority of the cases the source of the Human Error is a lack of Situation Awareness. Endsley et al. have identified eight causes that corrupt the Situation Awareness of human operators, the so-called Demons of Situation Awareness (SA Demons). We analyzed over five-hundred maritime accident reports for each of the eight SA Demons to provide a ranking of the causes and to identify the most prominent ones. Addressing these SA Demons enables maritime system designers to enhance the Situation Awareness of maritime operators and thereby improves the safety at sea.