Hi Schottel is as described a shrouded propeller that can rotate its direction like a rudder. The drive for it is in the hull.
Azimuth drive is an underwater pod that also turns like a rudder but the motor is contained in the pod.
On the many large cruise ships that are around they may also have a fixed pod drive at the bow and 2 azimuth drives at the stern. The pods are used prop first in direction.
No rudders are used in both of these type of drives.
One of the benefits for the cruise ships is that the big diesels can be arranged around the hull to distribute the weight and also a diesel can be serviced at sea as it is probably one of four or more supplying the power needs.
The diesels all drive alternators that produce eventually a DC current. This goes to a central control and for the engines it is turned into a variable frequency AC which drives the engines which are very similar to brushless motors. It will also supply standard mains AC at 50 htz.
When a cruise ship is in a hot/warm climate the air conditioning may well be as much or perhaps more than the power needed for the engines.
If you check the performance of a cruise ship you will see that in the main cruising speed is about 18 knots, top speed is about 22 knots. Length of ship comes into play as well.
Do not confuse purpose built cruise ships with North Atlantic Liners. I think QM 2 is the last of these and they can maintain 30+ knots and are strengthened at the bow to stand the rough weather in the Atlantic.
A further point is that the quoted tonnage is not the displacement of the ships it is just the Gross Tonnage measured as 1 tonne per cubic meter of usable (what can be sold) space so e.g. the engine room is not included.
So whatever the latest largest cruise ship is and quoted as say 140,000 tons the displacement is a lot less!
Where-as for Naval aircraft carriers it is a displacement measurement.
Well there you are, feel free to pick me up on any errors!
Hope this answers your question. If you want absolute information then Richard Simpson who writes for Model Boats magazine is your man. I wrote an article on the workings of the Queen Victoria at launch and Richard checked it over for me before publishing.