Final drive (azimuth thruster)

The final drive of an azimuth thruster is the lower right-angle gear set inside the submerged pod that turns the vertical input shaft 90 degrees to drive the horizontal propeller shaft. A pair of spiral-bevel gears in an oil-filled gearcase transmits the full propulsion torque to the propeller while the whole unit steers through 360 degrees. The upper bevel set at the deck connects the diesel or electric motor to the steerable vertical shaft, and the lower set is the final drive at the propeller. Makers include Schottel, Kongsberg, and Thrustmaster. The gearcase oil is monitored for water ingress, since a failed shaft seal floods the gears and contaminates the lubricant.