However, in the 1980s a new concept appeared, starting with the Sydney Harbour 18ft Skiff fleet. RS K6 keelboat with an asymmetric spinnaker on a retracting bowsprit.Īsymmetrical spinnakers resembling large jibs and flown from spinnaker poles are not a new idea and date back to at least the 19th century. The sail may be flown on a spinnaker pole or with the tack attached to the bow of the boat. This feature makes the sail easier to keep inflated, but detracts from its performance. Parasailor Ī Parasailor is a symmetrical spinnaker with a paraglider wing inserted into a gap in the sail approximately mid-way up. The symmetric spinnaker also requires care when packing, since the three corners must be available on the top of the packing. On running the spinnaker is angled for maximum drag, with the spinnaker pole at right angles to the apparent wind. When reaching, the sail camber allows only some attached flow over the leeward side of the spinnaker. When correctly set for reaching, the leading edges of a symmetric spinnaker should be nearly parallel to the wind, so the flow of air over the leading edge remains attached. Symmetric spinnakers when sailing across the wind (reaching) develop most of their lift on the forward quarter, where the airflow remains attached. However, it can be sailed in all downwind wind directions. The spinnaker pole must be moved in each gybe, and is quite difficult for beginners to use. It attaches to the clew of the spinnaker and is used to control the shape of the sail. The leeward (downwind) line is called the sheet. The windward line, or guy, is attached to the corner called the tack of the sail, and is stabilized by a spinnaker pole. The symmetric one is the most classic type, running symmetrical alongside the boat controlled by lines known as a sheet and a guy running from the lower two corners of the sail. Symmetric Ĥ20 class dinghies with symmetric spinnakers. While a fully equipped racing boat might have a number of spinnakers, both symmetric and asymmetric, to cover all courses and wind conditions, cruising boats almost always use an asymmetric, due to the broader application and easier handling afforded by the asymmetric. This makes asymmetrics a better choice on reaching courses than symmetric spinnakers, which excel when running. Asymmetric spinnakers operate more like a jib, generating lift from the side, rather than the top like a symmetric spinnaker. There are two main categories of spinnakers, symmetric and asymmetric depending on whether a plane of symmetry exists for that particular sail. They are attached at only three points and said to be flown. They may be designed to perform best as either a reaching or a running spinnaker, by the shaping of the panels and seams. Spinnakers are constructed of lightweight fabric, usually nylon, and are often brightly colored. Bear of Britain, a Farr 52 with masthead spinnaker in front of Calshot SpitĪ spinnaker is a sail designed specifically for sailing off the wind on courses between a reach (wind at 90° to the course) to downwind (course in the same direction as the wind).
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