Motor sailers are nautical hermaphrodites. A boat is called a motor sailer if it has a similar construction to a sailing yacht, but contains undersized rigging (and thus less sail area), and a well dimensioned drive unit in the form of one or two diesel engines. Thus, the sails are only used to support engine power. Motor sailers are in this sense not demanding sailing yachts, but are slow running motor vessels dressed as a sailing yacht. Advantages of the motor sailer are generously sized rooms, and more space on deck and below. With its powerful drive, the motor sailer is especially useful in low wind regions. During storms and large waves, the small sail area keeps the motor sailer stable and thus adds more security.