A motor yacht is a yacht with a motor, instead of a sail. Motorized yachts are more popular among people who go long distances, or for someone who does not like or care for sailing. You just start the motor on a motor yacht and you are off. There are big motors and small motors depending on the size and power you need to propel your yacht.
Motor yacht describes all yachts with motors, but in that category falls large and small, luxurious and frugal. There are some that look and feel like a palace on the water. They have every amenity that one can think of. A motor yacht can go long distances as long as you fuel it and the engine keeps running. Some have more than one engine so there is always one that will get you back. Motorized yachts became very popular after steamships went away.