The original motor yacht drive system and still the best in some very important ways. The shaft drive pairs a propeller to a rudder for simple, reliable and versatile performance, with comparatively little tech or maintenance to get in the way.
Good for all types of hull types and sizes, shafts can run happily at slow displacement speeds or way above 30 knots. The shaft and rudder set up offer excellent grip and steerage, even at slow speeds, while having engine sited more centrally creates a good level of balance for the yacht.
The drag created by the prop and rudder, and the accompanying P bracket that supports the shaft, can make this drive slightly less efficient than a pod or sterndrive, but the overall performance is hard to beat or argue against. Similarly, the engine's central location is less helpful for accommodation, but this becomes far less of an issue as yacht size increases.