Niigata Z-Peller

The Niigata Z-Peller is an azimuthing thruster (steerable Z-drive propulsion unit) from Niigata Power Systems of Japan, not an engine. It transmits power from an inboard medium-speed diesel through two right-angle bevel-gear sets (the Z-shaped path) to a propeller that rotates a full 360 degrees, giving omnidirectional thrust and steering without a separate rudder. Fixed and controllable-pitch versions use a kaplan propeller in a kort nozzle for high bollard pull. The ZP series powers tugs, escort vessels, and offshore support craft, with ratings to about 2,200 kW per unit and bollard pull in the 80 to 90 tonne range on large tugs.