Gennaker

Last updated April 03, 2019

A gennaker is a sail that was developed around 1990. Used when sailing downwind, it is a cross between a genoa and a spinnaker. It is not symmetric like a true spinnaker but is asymmetric like a genoa, but the gennaker is not attached to the forestay like a jib or genoa. The gennaker is rigged like a spinnaker but the tack is fastened to the hull or to a bowsprit. It has greater camber than a genoa (but significantly less camber than a spinnaker). This is optimal for generating lift at larger angles of attack. An early form of gennaker was the "gollywhomper", used briefly in the 1870s.^[1]

Sail surface supported by a mast to propel a sailing vessel

A sail is a tensile structure—made from fabric or other membrane materials—that uses wind power to propel sailing craft, including sailing ships, sailboats, windsurfers, ice boats, and even sail-powered land vehicles. Sails may be made from a combination of woven materials—including canvas or polyester cloth, laminated membranes or bonded filaments—usually in a three- or four-sided shape.

Sailing Propulsion of a vehicle by wind power

Sailing employs the wind—acting on sails, wingsails or kites—to propel a craft on the surface of the water, on ice (iceboat) or on land over a chosen course, which is often part of a larger plan of navigation.

A genoa sail is a type of large jib or staysail that extends past the mast and so overlaps the main sail when viewed from the side, sometimes eliminating it. It was originally called an "overlapping jib" and later a Genoa jib. It is used on single-masted sloops and twin-masted boats such as yawls and ketches. Its larger surface area increases the speed of the craft in light to moderate winds; in high wind, a smaller jib is usually substituted, and downwind a spinnaker may be used.

The gennaker is a specialty sail primarily used on racing boats to bridge the performance gap between a genoa and a spinnaker. It is sometimes the only downwind sail on board because it is easier to use and less expensive than a spinnaker. Due to its geometry, the sail is less prone to collapsing than a spinnaker. A gennaker is optimal for a beam reach, while an asymmetrical spinnaker is optimal for a broad reach or run.

In sport, racing is a competition of speed, against an objective criterion, usually a clock or to a specific point. The competitors in a race try to complete a given task in the shortest amount of time. Typically this involves traversing some distance, but it can be any other task involving speed to reach a specific goal.

An asymmetrical spinnaker is a sail used when sailing downwind. Also known as an "asym" or "aspin", it can be described as a cross between a genoa jib and a spinnaker. It is asymmetric like a genoa, but, the asymmetrical spinnaker is not attached to the forestay over the full length of its luff, being rigged like a spinnaker. The asymmetrical spinnaker has a larger camber than a genoa, making it optimal for generating lift at larger angles of attack, but the camber is significantly less than that of a spinnaker.

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The Ross 930 is a class of fast cruiser-racer yachts named after its designer, New Zealander Murray Ross. The design is marked by light weight and moderate sail area, with a sail-area-to-displacement (SA/D) ratio of about 24, and displacement-to-length (D/L) ratio of 98. The bow section is quite narrow, providing relatively low wave-making resistance and reducing pounding while sailing upwind in waves, and the stern section is wide and flat, making the boat easy to control sailing fast downwind. The interior of the Ross 930 is comfortable, including fitted berths for five, a two-burner stove, galley with sink, and a head. The standard engine is an outboard in a well, but a few boats were built with small inboard diesel engines.

The Hobie Cat is a small sailing catamaran manufactured by the Hobie Cat Company. Hobie's line of products ranges from surfboards to catamaran sailboats to kayaks and stand-up paddle boards, though the Hobie Cat Company is most famous around the world for its catamarans. Hobie also designed a very successful monohull, the Hobie 33.

The Laser 4000 is a well known racing dinghy crewed by two persons. Its one-design weight-equalised system enables physically differing sailors to compete on a level playing field. It is most popular in Europe, particularly the UK, France and Italy.

A headsail of a sailing vessel is any sail set forward of the foremost mast. The most common headsails are staysails, a term that includes jibs and the larger genoa. Other headsails, such as the spinnaker, are set independently of any forestays.

A spinnaker pole is a spar used in sailboats to help support and control a variety of headsails, particularly the spinnaker. However, it is also used with other sails, such as genoas and jibs, when sailing downwind with no spinnaker hoisted.

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A Pirate is a type of German sailing dinghy. It was first constructed in 1935, and has no trapeze. The Pirate was designed in 1934 by the German boat builder Carl Martens. The boat was originally manufactured in solid wood, although since the 1960s glass-reinforced plastic, or a sandwich of the two, is also used. According to the regulations for this class of boat, kevlar and carbon fiber are forbidden. Approximately 6,000 boats have been built.

The Melges 32 is a one-design class of sailboat commonly used for racing. The sportsboat is notable for its ability to plane over the water downwind in modest winds, and for its combination of a simple design that is highly tunable.

The Laser 3000 is a racing sailing dinghy crewed by two persons with a trapeze for the crew. Launched in 1996, the 3000 was developed from the Laser 2, using the original Frank Bethwaite-designed planing hull combined with a brand new self-draining deck by Derek Clark. Clark also re-designed the rig, using spars and sails from premium proprietary sources and replacing the symmetric spinnaker of the Laser 2 by a larger asymmetric spinnaker (gennaker). The gennaker is chute-launched and retrieved using a single halyard line, and is set on a retractable bowsprit. Helm balance and handling were improved using a shorter-footed mainsail with two full-width battens giving a larger roach. A mast with conventional spreaders replaced the now-unusual diamond arrangement of the Laser 2.

The 3000(formally the Laser 3000) is a racing sailing dinghy crewed by two persons with a trapeze for the crew. Launched in 1996 as the Laser 3000, the 3000 was developed from the Laser 2, using the original Frank Bethwaite-designed planing hull combined with a new designed self-draining deck by Derek Clark. Clark also re-designed the rig, using spars and sails from premium proprietary sources and replacing the symmetric spinnaker of the Laser 2 by a larger asymmetric spinnaker (gennaker). The gennaker is chute-launched and retrieved using a single halyard line, and is set on a retractable bowsprit. Helm balance and handling were improved using a shorter-footed mainsail with two full-width battens giving a larger roach. A mast with conventional spreaders replaced the now-unusual diamond arrangement of the Laser 2.

MG14 is a two-person skiff with a high-performance development hull, single trapeze and asymmetrical spinnaker.

The Esse 850 is an 8.5 metre long racing sportboat designed by Umberto Felci and built by Josef Schuchter Sportboats of Stafa, Switzerland. The first hull was sold in 2004 and the Esse 850 International Class Association was begun in 2005 in Europe.

The Esse 990 is a 9.9 meter long racing sportboat designed by Umberto Felci and built by Josef Schuchter Sportboats of Stafa, Switzerland. The first hull was sold in 2008 and series production was begun in 2009.

The International J/80 is a fixed keel One-Design sportsboat certified for offshore sailing, normally crewed by 3 to 5 people. As well as its mainsail & headsail, the J/80 has a 65 m² (700 sq ft) gennaker for downwind sailing, which when the wind rises over 15 knots gets the boat on the plane downwind.

References

↑ "Nautical Dictionary". My Boat Works. Archived from the original on 2011-12-25.

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[1] "Nautical Dictionary". My Boat Works. Archived from the original on 2011-12-25.