VETUS Prop Kit f/BOW4512DProp Kit for BOW4512D This is the 6 bladed propeller kit for the BOW4512D bow thruster. Working in close collaboration with the Maritime Research Institute Netherlands (MARIN), the world famous hydrodynamic laboratory, VETUS has optimized the performance of its thrusters. This has been achieved by utilizing a unique propeller blade profile. As cavitation produces unwanted noise, this new blade design offers a major reduction in operating sound levels.