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Tacking (sailing)

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Tacking from starboard tack to port tack. Wind shown in red. ① on starboard tack, ② turning to windward to begin the tacking maneuver or "preparing to come about", ③ headed into the wind; the sail luffs and loses propulsion, while the vessel makes way on momentum to provide rudder steerage, ④ making way on the new port tack by sheeting in the mainsail, ⑤ on port tack.
Beating to windward on a series of port and starboard tacks, tacking between each at points 1, 2, and 3.

Tacking or coming about is a sailing maneuver by which a sailing craft (sailing vessel, ice boat, or land yacht), whose desired course is into the wind, turns its bow toward and through the wind so that the direction from which the wind blows changes from one side of the boat to the other, allowing progress in the desired direction.[1] Sailing vessels are unable to sail higher than a certain angle towards the wind, so "beating to windward" in a zig-zag fashion with a series of tacking maneuvers, allows a vessel to sail towards a destination that is closer to the wind that the vessel can sail directly.

A sailing craft, whose course is downwind, jibes (or "wears" if square-rigged) by having the apparent wind cross the stern from one tack to the other.[2][3]

Beating to windward

Points of sail: the shaded area is the "no-sail" or "no-go" zone.

A sails are limited in how close to the direction of the wind they can power a sailing craft. The area towards the wind, defining those limits, is called the "no-sail zone" or "no-go zone". To travel towards a destination that is within the no-sail zone, a craft must perform a series of zig-zag maneuvers in that direction, maintaining a course to the right or the left that allows the sail(s) to generate power. Each such course is a "tack". The act of transitioning from one tack to the other is called "tacking" or "coming about".[2] Sailing on a series of courses that are close to the craft's windward limitation (close-hauled) is called "beating to windward".[4]

For various sailing craft

The method of tacking of sailing craft differs, depending on whether they are fore-and aft, square-rigged, a windsurfer, a kitesurfer, or a proa.

  • Fore-and-aft rig – A fore-and-aft rig permits the wind to flow past the sail, as the craft head through the eye of the wind. Modern rigs pivot around a stay or the mast, while this occurs. For a jib, the old leeward sheet is released as the craft heads through the wind and the old windward sheet is tightened as the new leeward sheet to allow the sail to draw wind. Mainsails are often self-tending and slide on a traveler to the opposite side.[5] On certain rigs, such as lateens[6] and luggers,[7] the sail may be partially lowered to bring it to the opposite side.
  • Square rig – Unlike with a fore-and-aft rig, a square-rigged vessel's sails must be presented squarely to the wind and thus impede forward motion as they are swung around via the yardarms through the wind as controlled by the vessel's running rigging, using braces—adjusting the fore and aft angle of each yardarm around the mast—and sheets attached to the clews (bottom corners) of each sail to control the sail's angle to the wind.[8] The procedure is to turn the vessel into the wind with the hind-most fore-and-aft sail (the spanker), often pulled to windward to help turn the ship through the eye of the wind. The main (and often mizzen) sails are braced around onto the new tack as the ship approaches the eye of the wind. Once the ship has come about, the remaining sails are adjusted to align properly with the new tack. Because square-rigger masts are more strongly supported from behind than from ahead, tacking is a dangerous procedure in strong winds. The ship may lose forward momentum (become caught in stays) and the rigging may fail from the wind coming from ahead. Under these conditions, the choice may be to wear ship—to turn the away from the wind and around 240° onto the next tack (60° off the wind).[9]
  • Windsurfer rig – Sailors of windsurfers tack by walking forward of the mast and letting the sail swing into the wind as the board moves through the eye of the wind; once on the opposite tack, the sailor realigns the sail on the new tack. In strong winds on a small board, an option is the 'fast tack', whereby the board is turned into the wind at planing speed as the sailor crosses in front of the flexibly mounted mast and reaches for the boom on the opposite side and continues planing on the new tack.[10]
  • Kitesurfer rig – When changing tack, a kitesurfer rotates the kite end-for-end to align with the new apparent wind direction. Kite boards are designed to be used exclusively while planing; many are double-ended to allow an immediate change of course in the opposite direction.[11]
  • Proa – Double-ended sailing vessels, such as proas, may tack by shunting: turning off the wind, switching the sails and steering mechanism end-for-end and then proceeding on the opposite tack with the former stern functioning as the new bow, and with the outrigger on the windward side as before.[12]

The bearing from the current location of a sailing craft of destination or racing mark that lies within the no-sail zone, may lie on one side or other of being directly upwind. The tack on that side is "favored", because the destination lies closest to the craft's highest point of sail—its "best course" is close-hauled on that tack. Wind shifts that improve the angle towards the destination are called "lifts"; those that increase the angle away from the destination are called "headers". A sufficiently large wind shift may cause the destination to lie on the opposite side of the direction from which the destination or mark lies and indicate a tack to the favored side—tacking on a header.[13]

Racing

Sailing courses laid out for racing purposes always have one leg directly to windward. This is where the highest sailing skills often form the essence of the race. Sail trim and keeping the boat moving most efficiently are of the utmost importance. In these circumstances tacking duels will often develop.

Any boat in clear air to windward has an aerodynamic advantage over other boats. To keep this advantage the lead boat will often try to "blanket" the trailing boat(s) by maneuvering to keep them in the disturbed foul air she is creating to her lee. This involves constant anticipation and balancing many different dynamic factors. Conversely the trailing boats will try to overtake or otherwise escape the bad air blanket created by the lead boat and head for clear air without losing too much speed or momentum.

A tacking duel develops when two or more boats execute multiple usually excessive course changes (tacking) in very close quarters. A duel may lead to bending, or breaking, the safety right-of-way-rules, and intentionally creating dangerous and threatening conditions between the dueling boats. Each skipper is trying to gain the lead and the advantage of clear air. This can sometimes become counter-productive as some speed and time is always lost in each tack.

Roll tacking

Roll tacking, usually while racing sailing dinghies, involves aggressive heeling of the sailboat, as the skipper and crew move towards the windward side during the first half of the tack when the boat crosses into irons.[14] The skipper and crew then roll the boat back to an even keel following the completion of the tack, allowing the sails to immediately resume their optimum shape on the new tack.[15] The form of the boat in the water, not the rudder, is the primary mechanism for changing course from one tack to the other. Some keel boats may also be roll tacked.[16]

See also

References

  1. ^ Keegan, John (1989). The Price of Admiralty. New York: Viking. p. 281. ISBN 0-670-81416-4.
  2. ^ a b Sailing, American (2010-01-01). Sailing Made Easy: The Official Manual For The ASA 101 Basic Keelboat Sailing Course. American Sailing. pp. 48–51. ISBN 978-0-9821025-0-3.
  3. ^ McEwen, Thomas (2006). Boater's Pocket Reference: Your Comprehensive Resource for Boats and Boating. Anchor Cove Publishing. pp. 186–. ISBN 978-0-9774052-0-6.
  4. ^ Jobson, Gary (2008-09-08). Sailing Fundamentals. Simon and Schuster. p. 73. ISBN 978-1-4391-3678-2.
  5. ^ Jobson, Gary (2008). Sailing Fundamentals (Revised ed.). Simon and Schuster. p. 224. ISBN 978-1-4391-3678-2.
  6. ^ Campbell, I.C. (1995), "The Lateen Sail in World History" (PDF), Journal of World History, vol. 6, no. 1, pp. 1–23, archived from the original (PDF) on 2016-08-04, retrieved 2017-06-16
  7. ^ Skeat, Walter W. (2013). An Etymological Dictionary of the English Language. Dover language guides (Reprint ed.). Courier Corporation. p. 351. ISBN 978-0-486-31765-6.
  8. ^ Biddlecombe, George (1990). The Art of Rigging: Containing an Explanation of Terms and Phrases and the Progressive Method of Rigging Expressly Adapted for Sailing Ships. Dover Maritime Series. Courier Corporation. p. 13. ISBN 9780486263434.
  9. ^ Findlay, Gordon D. (2005). My Hand on the Tiller. AuthorHouse. p. 138. ISBN 9781456793500.
  10. ^ Hart, Peter (2014). Windsurfing. Crowood. p. 176. ISBN 978-1-84797-963-6.
  11. ^ Gratwick, Andy (2015). The Kiteboarding Manual: The essential guide for beginners and improvers. Bloomsbury Publishing. p. 106. ISBN 978-1-4081-9204-7.
  12. ^ World, Yachting (2021-04-08). "Jzerro: The oceangoing Pacific proa". Yachting World. Retrieved 2021-11-12.
  13. ^ Royce, Patrick M. (2015). Royce's Sailing Illustrated. Vol. 2 (11 ed.). ProStar Publications. p. 161. ISBN 9780911284072.
  14. ^ K, Matt (2022-08-30). "How To Roll Tack: A Comprehensive Guide". How to Sail. Retrieved 2022-09-20.
  15. ^ Textor, Ken (1995). The New Book of Sail Trim. Sheridan House, Inc. pp. 54–57. ISBN 978-0-924486-81-4.
  16. ^ Westling, Niclas (2016-03-13). "Roll tacking in a keelboat - two methods to try". Sail better!. Retrieved 2022-09-20.
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