What is the purpose of using a dive knife in wreck diving?

The purpose of using a dive knife in wreck diving is primarily to cut potential entanglements and quickly resolve emergencies. Wreck diving often involves navigating through tight spaces where lines, nets, and other debris can create hazards. A dive knife allows divers to easily and swiftly cut themselves free if they become entangled, which is crucial for ensuring safety during a dive. This emergency tool is designed to be readily accessible and can serve multiple functions in high-stress situations, making it an essential piece of equipment for divers.

While other options mention uses like fishing or decoration, they do not align with the primary safety function of the dive knife in an underwater wreck environment where entanglement poses a significant risk.