Biomechanics of motorboat propeller injuries: how can a pattern of trauma be related to a propeller and a boat?

Propeller-related injuries are a cause of death during recreational water activities. However, there are no articles in the literature that analyze the nature of the propeller and/or the vessel that may be involved in the accident in relation to the type of injuries. Based on the case of a woman injured by a propeller of a boat, and a review of the literature, we focused on determining the type of propeller and engine involved in relation to the nature of the injuries. In this case, investigations confirmed collision with a vessel with a high-speed planning hull. The small spacing of the lesions indicates that the relative speed between the victim and the boat was low with the possibility that the victim was trapped under the boat and dragged. The analysis of the nature of metallic residues identified in the lesions provide the composition of the propeller and point towards a category of boat. However, given the difficulty of the exercise, it is preferable to remain cautious in asserting the responsibility of a boat and instead provide a response in terms of « compatibility or exclusion».