An asymmetrical spinnaker is a sail used when sailing between about 90 and 165 degrees from the angle of the wind. Also known as an "asym",[1] "aspin",[2] or "A-sail"[3] it can be described as a cross between a genoa jib and a spinnaker. It is asymmetric like a genoa, but like a spinnaker, its luff is unstructured; its leading edge is allowed to float freely, unencumbered by an internal wire or hanks attaching it to a stay. Unlike a symmetric spinnaker, the asymmetric does not require a spinnaker pole, since it is fixed (tacked) to the bow or bowsprit.[4] The asymmetrical spinnaker has a larger camber than a genoa and a Spinnaker Mid-Gerth (SMG) -- also called Spinnaker Half Width (SHW) -- measurement greater than the length of its foot (a genoa is a pin-head sail so its mid-gerth dimension is shorter than its foot).
An asymmetrical spinnaker generates more lift at larger angles of attack than a genoa, providing the boat with more power when the apparent wind speed is dropping.
It can be also carried at higher angles to the wind than a conventional spinnaker. Since the apparent winds are higher at small angles, the boat should sail faster than it would with a conventional spinnaker. This may not, however, result in faster progress to a downwind destination, since less camber means that it an asymmetrical will not sail as deeply downwind as a conventional spinnaker.[1] This is demonstrated by a Polar diagram (sailing) showing the theoretical predicted boat speeds and carrying angles of a symmetrical vs. an asymmetrical spinnaker.
Polar diagram comparing the speeds and carrying angles of symmetrical with asymmetrical spinnakers when sailing
Due to its geometry, an asymmetrical spinnaker does not require the use of a spinnaker pole.[1] On cruising sailboats, the sail is often tacked to a bow pulpit, and can be known by other names, like "cruising chute" or a gennaker. In this duty, it is often paired with a Spinnaker chute for simpler or short-handed setting and retrieving.
When attached to a permanent bowsprit or "prod", an asymmetrical spinnaker can be much larger than a conventional sail (or a pulpit-connected asymmetrical), since it can be carried well forward of the boat and down to deck level.[1] Many modern sailboats have retractable bowsprits to enable this expansion.
Two sailboats flying asymmetrical spinnakers beam reaching in light wind
If the spinnaker is mounted to a bowsprit, it is often possible to fly the spinnaker and the jib at the same time; if not, then the spinnaker will be shadowed by the jib, and the jib should be furled when the spinnaker is in use.
Rigging is different from conventional spinnakers.[5] Like a jib, the asymmetric has two sheets and no "guy". Since there is no spinnaker pole, there is no longer need for a pole topping lift or a pole downhaul. An adjustable tack-line can be eased to allow the tack to lift, enabling the sail to also lift and its shoulders to rotate for deeper downwind angles. The asymmetric is simpler to gybe than a conventional spinnaker since it only requires releasing a sheet and pulling in the other one, passing the sail in front of the forestay.
An asymmetric spinnaker is particularly effective on fast planing dinghies and ultra-light displacement boats as their speed generates an apparent wind on the bow allowing them to sail more directly downwind.
History and Impactedit
In the 1960, catamaran sailors discovered that it is faster to sail downwind on a series of broad reaches with efficient airflow across the sail rather than directly downwind with the sails stalled. This technique had developed to the extent that in bar conversation at the end of one season Andrew Buckland observed that 18 Foot Skiffs had sailed all season (1982/83) without pulling the spinnaker pole back from the forestay and that all the systems could be simplified by eliminating the pole and setting the spinnaker from a bowsprit. The concept quickly evolved to a sail with a loose luff. Buckland collaborated with sailmaker Julian Bethwaite to rig and sail the first prototypes.[6][7] The first modern keelboat to incorporate a retractable bow sprit and an asymmetric spinnaker was the popular J/Boats J/105 designed in 1992.[8]
The concept has spread rapidly through the sailing world and has inspired the development of "code" sails, a family of hybrid sail designs that often combine a structured luff with positive mid-gerth that are used for very fast beam reaching and higher angles and may be furled.[9]
Notesedit
^ abcdFlynn, David (2010). (PDF). Quantum Atlantic. Quantum Sail Design Group, LLC. Archived from the original (PDF) on December 28, 2013. Retrieved November 6, 2013.
^Goodall, Sandy. "Inside the Asymmetrical Spinnaker" (PDF). FX Sails. Retrieved May 16, 2018.
^"How to Choose your Asymmetric Spinnaker". Yachting World. 19 October 2015. Retrieved 7 November 2019.
^. Archived from the original on 2010-01-20. Retrieved 2018-05-16.
^Goodall, Sandy. "Rigging Your Asymmetrical Spinnaker". FX Sails. Retrieved November 6, 2013.
^Bethwaite, Frank (2008). Higher Performance Sailing. Lond: Adlard Coles Nautical. p. 38. ISBN978-1-4081-0126-1.
^Buckland, Andrew (17 March 2020). "2020 JJ Giltinan Championship Race 6 & 7". YouTube. Sydney, NSW, Australia: 18footersTV. Archived from the original on 2021-12-21. Retrieved 21 March 2020.
^Robert H. Perry (November 2006). . Sailing Magazine. Archived from the original on September 27, 2007. Retrieved 2007-02-23.
Hancock, Brian. "Using the Asymmetrical Spinnaker". SailNet. Retrieved November 8, 2013.
"Spinnaker controls". West Marine. Retrieved November 6, 2013.[permanent dead link]
January 01, 1970
asymmetrical, spinnaker, asymmetrical, spinnaker, sail, used, when, sailing, between, about, degrees, from, angle, wind, also, known, asym, aspin, sail, described, cross, between, genoa, spinnaker, asymmetric, like, genoa, like, spinnaker, luff, unstructured, . An asymmetrical spinnaker is a sail used when sailing between about 90 and 165 degrees from the angle of the wind Also known as an asym 1 aspin 2 or A sail 3 it can be described as a cross between a genoa jib and a spinnaker It is asymmetric like a genoa but like a spinnaker its luff is unstructured its leading edge is allowed to float freely unencumbered by an internal wire or hanks attaching it to a stay Unlike a symmetric spinnaker the asymmetric does not require a spinnaker pole since it is fixed tacked to the bow or bowsprit 4 The asymmetrical spinnaker has a larger camber than a genoa and a Spinnaker Mid Gerth SMG also called Spinnaker Half Width SHW measurement greater than the length of its foot a genoa is a pin head sail so its mid gerth dimension is shorter than its foot An asymmetrical spinnaker generates more lift at larger angles of attack than a genoa providing the boat with more power when the apparent wind speed is dropping It can be also carried at higher angles to the wind than a conventional spinnaker Since the apparent winds are higher at small angles the boat should sail faster than it would with a conventional spinnaker This may not however result in faster progress to a downwind destination since less camber means that it an asymmetrical will not sail as deeply downwind as a conventional spinnaker 1 This is demonstrated by a Polar diagram sailing showing the theoretical predicted boat speeds and carrying angles of a symmetrical vs an asymmetrical spinnaker Polar diagram comparing the speeds and carrying angles of symmetrical with asymmetrical spinnakers when sailing Due to its geometry an asymmetrical spinnaker does not require the use of a spinnaker pole 1 On cruising sailboats the sail is often tacked to a bow pulpit and can be known by other names like cruising chute or a gennaker In this duty it is often paired with a Spinnaker chute for simpler or short handed setting and retrieving When attached to a permanent bowsprit or prod an asymmetrical spinnaker can be much larger than a conventional sail or a pulpit connected asymmetrical since it can be carried well forward of the boat and down to deck level 1 Many modern sailboats have retractable bowsprits to enable this expansion Two sailboats flying asymmetrical spinnakers beam reaching in light wind If the spinnaker is mounted to a bowsprit it is often possible to fly the spinnaker and the jib at the same time if not then the spinnaker will be shadowed by the jib and the jib should be furled when the spinnaker is in use Rigging is different from conventional spinnakers 5 Like a jib the asymmetric has two sheets and no guy Since there is no spinnaker pole there is no longer need for a pole topping lift or a pole downhaul An adjustable tack line can be eased to allow the tack to lift enabling the sail to also lift and its shoulders to rotate for deeper downwind angles The asymmetric is simpler to gybe than a conventional spinnaker since it only requires releasing a sheet and pulling in the other one passing the sail in front of the forestay An asymmetric spinnaker is particularly effective on fast planing dinghies and ultra light displacement boats as their speed generates an apparent wind on the bow allowing them to sail more directly downwind History and Impact editIn the 1960 catamaran sailors discovered that it is faster to sail downwind on a series of broad reaches with efficient airflow across the sail rather than directly downwind with the sails stalled This technique had developed to the extent that in bar conversation at the end of one season Andrew Buckland observed that 18 Foot Skiffs had sailed all season 1982 83 without pulling the spinnaker pole back from the forestay and that all the systems could be simplified by eliminating the pole and setting the spinnaker from a bowsprit The concept quickly evolved to a sail with a loose luff Buckland collaborated with sailmaker Julian Bethwaite to rig and sail the first prototypes 6 7 The first modern keelboat to incorporate a retractable bow sprit and an asymmetric spinnaker was the popular J Boats J 105 designed in 1992 8 The concept has spread rapidly through the sailing world and has inspired the development of code sails a family of hybrid sail designs that often combine a structured luff with positive mid gerth that are used for very fast beam reaching and higher angles and may be furled 9 Notes edit a b c d Flynn David 2010 Just The Facts A Guide to Asymmetrical Spinnakers PDF Quantum Atlantic Quantum Sail Design Group LLC Archived from the original PDF on December 28 2013 Retrieved November 6 2013 Goodall Sandy Inside the Asymmetrical Spinnaker PDF FX Sails Retrieved May 16 2018 How to Choose your Asymmetric Spinnaker Yachting World 19 October 2015 Retrieved 7 November 2019 Gear for Gaffers Archived from the original on 2010 01 20 Retrieved 2018 05 16 Goodall Sandy Rigging Your Asymmetrical Spinnaker FX Sails Retrieved November 6 2013 Bethwaite Frank 2008 Higher Performance Sailing Lond Adlard Coles Nautical p 38 ISBN 978 1 4081 0126 1 Buckland Andrew 17 March 2020 2020 JJ Giltinan Championship Race 6 amp 7 YouTube Sydney NSW Australia 18footersTV Archived from the original on 2021 12 21 Retrieved 21 March 2020 Robert H Perry November 2006 J 105 Sailing Magazine Archived from the original on September 27 2007 Retrieved 2007 02 23 Pingel Bob What s a Simpler Sail Setup for my Boat Sailing Magazine 1 Oct 2010 https sailingmagazine net article 2262 what s a simpler sail setup for my boat html Retrieved 13 Jan 2024 External links editHancock Brian Using the Asymmetrical Spinnaker SailNet Retrieved November 8 2013 Spinnaker controls West Marine Retrieved November 6 2013 permanent dead link Retrieved from https en wikipedia org w index php title Asymmetrical spinnaker amp oldid 1204629401, wikipedia, wiki, book, books, library,
