SolidSail, sometimes referred to as Solid Sail or SolidSail Mast Factory (SMAF) in reference to the eponymous subsidiary, is a wind propulsion technology designed for large vessels, developed by Chantiers de l'Atlantique in Saint-Nazaire, France. This system is based on rigid sails made of composite materials and a tilting gaff rigging, enabling hybrid or primary wind propulsion for commercial and cruise ships. It is also the name of the subsidiary created by Chantiers de l'Atlantique in 2023.