A spinnaker is a type of sail used on sailing boats, designed specifically for downwind sailing. It is typically larger and more balloon-like than other sails, allowing the boat to catch more wind and move faster when sailing with the wind at its back. Spinnakers come in various shapes and sizes, depending on the specific sailing conditions and the design of the boat. There are two main types of spinnakers: the symmetrical spinnaker and the asymmetrical spinnaker. The symmetrical spinnaker is shaped like a kite and is used with a pole to hold it out, while the asymmetrical spinnaker has a more streamlined shape and can be flown without a pole. Both types enhance a boat's performance during races and recreational sailing.