The entanglement of a rope around a propeller shaft is one of the most serious situations with which one may be confronted at sea. It may even cause the sinking of your vessel. The rope cutter is the simple answer to this risk: a blade fixed around the shaft systematically cuts rope, or seaweed that might otherwise ensnare the propeller. Among the products on the market AD has chosen one-piece 316 L stainless steel models, which act by slicing and not by shear. The shear models contain a fixed and movable part. We consider them more dangerous because they run the risk of getting stuck when they meet a cable with too large adiameter, and may thus block or damage the propeller shaft.