Oasis-class cruise ships, each of which held the title of the largest cruise ship in the world at the time of delivery. Another further development of the original electric podded propulsion concept is the Compact Azipod, a smaller Azipod unit introduced in the early 2000s. It is intended for smaller ships such as research vessels and yachts as well as dynamically positioned drilling rigs that may utilize up to eight such propulsors. The smaller Azipod Compact differs from the full-size unit by its permanent magnet synchronous motor which is directly cooled by sea water. For drilling vessels, it is also available in "pushing" configuration and can be fitted with a nozzle to increase bollard pull thrust in stationkeeping applications. Unlike the full-sized Azipod units which are assembled in Finland, the Compact Azipod units are manufactured in China. Bearing-related problems During the initial years in service, some widely publicised cruise ship service disruptions with the bigger Azipod V design have occurred. The latest design, the Azipod X, incorporates these improvements, with a view to a service interval of five years, and features bearings that can be taken apart and repaired from inside the pod while the ship is harbored normally. See also Manoeuvring thruster Azimuth thruster Z-drive Cycloidal drive Rim-driven thruster References Marine propulsion Finnish inventions