Azipod & podded propulsion, explained

A conventional ship has a propeller on a fixed shaft and a separate rudder behind it to steer. A podded drive throws that out: the electric motor sits inside a pod hung below the hull, driving the propeller directly, and the entire pod rotates a full 360 degrees to point thrust in any direction. Azipod, ABB's brand, has become the generic name the way Hoover did for vacuums.

The advantages are why almost every large modern cruise ship uses them. There is no long shaft line eating internal space, the pods pull rather than push (a cleaner water flow that improves efficiency), and a ship that can vector its thrust needs far less tug assistance — the Icon-class and most mega-cruise ships can dock themselves. The propeller usually faces forward, ahead of the pod, in a puller configuration.

The trade-off is complexity and maintenance: a pod is an electric motor sitting in seawater under an enormous ship, and servicing it can mean drydocking. But for passenger ships — where manoeuvrability, quiet running and freeing up internal volume all matter enormously — the podded drive won the argument decisively, and it is one of the invisible technologies that made the 360-metre resort ship possible.