Most sailing boats usually have a motor which can only be used for restricted, low-speed manoeuvres, such as entering the port, but they are not considered motor sailing boats because their main source of energy is the wind. What differentiates a motor sailing boat from the rest of the sailing boats is the source of propulsion. In a motor sailing boat, the propulsion comes from both the motor and the sails. The relationship between power of the motor and the surface area of the sail determines the proportion between it being a sailing boat and motor sailing boat: if the power provided by the motor represents at least 50%, then the vessel is considered a motor sailing boat.
The advantage of this type of boat is without a doubt its versatility, and the fact that in the absence of wind the boat can also travel thanks to the motor. It is considered quite an environmentally friendly type of boat and has a much higher autonomy than a normal motor boat, given that the motor doesn't have to be used constantly. A motor sailing boat also characterised for its harsher lines than the delicate lines of a sailing boat, which also offers much more space for the cabin and liveability.