A sail furling/unfurling device comprises at least an outer foil wound about and made rigid with an inner foil or stay designed for transmitting the furling torque required for furling a sail being wound on a sheath profiled element, thereby the device allows to furl and unfurl large downwind foresails, i.e. asymmetrical spinnakers or the like, such as gennakers or MPS and can be easily used to hoist and lower the sails, in a simplified manner for a cruiser sailing with a short-hand crew.