10008636High Performance Reefable Wingsail Feasibility StudyClosedCollaborative R&DInnovate UKWingsails with flaps analogous to the flaps used by an airliner wing when taking off and landing to increase the lift available at relatively low airspeed can generate significantly more drive than a conventional sail of similar size as well as sailing closer to the wind. This allows the use of a smaller sail with a lower mast height, making it less obstructive to loading/unloading operations in port as well as enhanced sailing performance. Current high performance rigid framed wingsails with integral masts such as the F50 catamarans need a crane to rig/derig the boat every time it is used as the wing sail cannot be safely left up for long and a hangar to store it. Current more practical alternative wingsails either: * Can be lowered in a manner similar to a collapsible paper lantern in which the lowered part of the sail is just simply crumpled up, a process which effectively prohibits the use of efficient modern sailcloth made from sheet materials such as reinforced mylar or * usually consist of double sail surfaces that are effectively each a conventional soft sail and which rely on the stiffness of their battens unsupported by internal framework to maintain the shape of the sail. This results in a sail that tends to have greater curvature as it gets deformed by strong winds, whereas the opposite is required in order to reduce drive to maintain control of the boat in these conditions. This project studies the practical and economic feasibility of using high performance reefable/furlable wingsails based on rigid transverse frames which can straighten out to allow the sail covering on either side to be flaked or furled. The sailcloth/film panels are always in single curvature apart from a transition zone near the base of the mast where the curvature transition is gentle enough to avoid crumpling. This allows the performance advantages of a rigid wing sail with film based sailcloth/covering to be retained while allowing the sail covering film to be reefed or removed altogether while leaving the mast in place as is typically done for most beach cats and cruising yachts. Economic feasibility of using this rig as the primary means of propulsion for three multihull vessels, a 6.5m daysailing trimaran suitable for disabled (and ablebodied) crew, a 15m catamaran ferry and an oceangoing cruise ship is considered as well as the technical feasibility of retrofitting it to existing motor vessels.