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Spinnaker

A spinnaker is a large, typically triangular or balloon-shaped sail constructed from lightweight nylon or similar synthetic fabric, designed for sailboats to use when running downwind or on a broad reach, where it is set forward of the mainsail on a spinnaker pole to capture wind and propel the vessel at higher speeds.^[1]^[2]^[3] The spinnaker originated in the mid-19th century as a racing innovation, with the first recorded use of such a sail occurring in 1865 on the British yacht Niobe during the Albert Cup regatta near Ryde, Isle of Wight, England, where it was specially built to provide a speed advantage in light winds.^[4]^[5] The term "spinnaker" first appeared in print in 1866 in a yachting publication describing a similar innovative downwind sail on the yacht Sphinx, likely derived from the yacht's name or a colloquial reference to how the sail "spun" or ballooned out.^[6] Initially shaped more like a conventional foresail with moderate curvature, the design evolved significantly in the 20th century with the advent of synthetic materials, allowing for greater fullness and aerodynamic efficiency.^[5] Spinnakers are categorized primarily into two types: symmetrical and asymmetrical. Symmetrical spinnakers are mirror-image sails flown from a spinnaker pole extended from the mast, optimized for deep downwind angles (around 135–180 degrees off the wind) where they require two sheets for control and provide maximum power in lighter conditions.^[7]^[8] In contrast, asymmetrical spinnakers, also known as "asyms" or "A-sails," feature a tack line attached directly to the bow or a sprit, with a shorter luff and designated head, tack, and clew corners; they excel on broader reaching angles (90–150 degrees) without needing a pole, making them easier to handle for cruising and modern racing.^[7]^[8]^[9] Setting and trimming a spinnaker demands precise coordination, as its large size and sensitivity to wind shifts can lead to instability if not managed properly, earning it a reputation among sailors as a challenging yet exhilarating sail to deploy.^[7]^[10] Both types are governed by measurement rules in competitive sailing, such as girth ratios and sail area limits, to ensure fairness in races, and they remain essential for optimizing performance in off-the-wind legs of regattas and ocean passages.^[11]^[12]

Etymology and History

Etymology

The term "spinnaker" entered English nautical vocabulary in 1866, denoting a large, lightweight sail used for downwind sailing on yachts. Its etymology remains debated among linguists and sailing historians. One commonly cited theory links it to the yacht Sphinx, owned by engineer Herbert Maudslay, which helped popularize the sail during a race in 1866; the sail's expansive size prompted crew members to nickname it "Sphinx's half-acre," a playful reference to its vast area; over time, this phrase was corrupted or abbreviated in speech to "spinnaker," possibly influenced by the existing term "spanker" for a large after-sail.^[6]^[13] An alternative derivation, tied to the first recorded use of the sail on the yacht Niobe in 1865, connects the word to a crew member's remark of "the sail to make her spin," evolving to "spin-maker" and then "spinnaker." Other theories suggest connections to "spin," evoking the rapid forward motion the sail enables, or to a colloquial nautical slang term like "spena ker," potentially a mishearing of "span a ker" (as in spanning an acre of canvas) in 19th-century British yachting slang. This view posits the name arose organically from the sail's impressive, billowing form when deployed, emphasizing its role in accelerating yachts before the wind.^[14]^[2]^[15] The first documented printed use of "spinnaker" appears in the 1866 edition of the Yachting Calendar and Review, describing its deployment in competitive sailing. By the late 19th century, the term had solidified in maritime literature, appearing in yacht design manuals and race reports as the conventional name for such ballooning sails, coinciding with innovations in 19th-century yacht construction for enhanced speed.^[16]^[4]

Historical Development

The spinnaker's origins are subject to some debate, but the first recorded use in competitive yacht racing occurred in 1865 during a match race under the Royal London Yacht Club in the Solent, England, where the yacht Niobe, owned by William Gordon, employed a large, ballooning sail to gain speed downwind.^[15] In 1866, the yacht Sphinx used a similar sail in a race at Ryde, Isle of Wight, initially referred to as a "spinker" by crew. This innovation addressed the need for additional downwind power in handicap races, where lighter yachts often struggled against heavier competitors. The sail's early use helped these yachts outperform rivals, marking the spinnaker's role in transforming downwind performance.^[4] By the 1880s, the spinnaker had crossed the Atlantic and become integral to American yacht racing, notably during the 1885 America's Cup challenge between the defender Puritan and challenger Genesta.^[17] Crews on both yachts deployed spinnakers to maximize speed in light winds, demonstrating the sail's value in high-stakes international competition and its rapid adoption among U.S. yacht clubs. This period solidified the spinnaker's use in handicap events, where it provided a tactical edge for underpowered boats without altering overall ratings. Post-World War II advancements in synthetic materials revolutionized spinnaker design, with lightweight nylon fabrics—originally developed for parachutes—replacing heavier cotton and silk for greater durability and efficiency.^[18] Introduced widely in the late 1940s, nylon allowed for larger, more resilient sails that performed better in variable winds, enhancing downwind speeds across racing fleets. The 1958 America's Cup between Columbia and Sceptre highlighted this evolution, as both 12-meter yachts relied on optimized nylon spinnakers for key maneuvers, contributing to tactical innovations in the event.^[19] The 1980s saw the rise of asymmetric spinnakers, designed for easier handling and broader wind angles without a traditional pole, first popularized in high-performance racing to simplify crew operations downwind.^[20] By the 1990s, these sails integrated into Olympic classes like the Tornado catamaran, boosting speeds and media appeal in events such as the 1996 Atlanta Games, while influencing multihull racing where large spinnakers became essential for planing performance.^[21]

Design and Types

Symmetric Spinnakers

Symmetric spinnakers exhibit a distinctive parachute-like shape with a full, rounded belly that provides a balanced, symmetrical form across the sail's centerline. This design features equal clews at the lower corners, with the head hoisted to the masthead and one clew attached to the forward end of a spinnaker pole projecting from the mast, stabilized by sheets and guys attached to the clews. The pole is positioned dynamically to keep the sail filled and optimized for the apparent wind direction.^[22]^[8] Sizing conventions for symmetric spinnakers account for varying wind conditions, with dedicated versions for light, medium, and heavy air to match performance needs. Light air sails, such as the S1 designation, are suited for winds of 0-7 knots at apparent wind angles (AWA) of 60-120 degrees, while medium air options like the S2 handle 6-18 knots at 115-170 degrees AWA, and heavy air variants such as the S4 perform in 14-30 knots at 120-170 degrees AWA. These sails ensure appropriate power without overwhelming the boat's rig.^[8]^[23] In traditional applications, symmetric spinnakers excel in downwind racing and cruising scenarios, particularly on broad reaching courses where the guy foresees the pole's windward position and the sheet controls the leeward clew for precise adjustment. This setup maximizes the sail's spherical profile and broad-shouldered girth, capturing more wind than tacked alternatives. Their inherent stability benefits larger boats by reducing collapse risk in gusts, contributing to their historical dominance in offshore sailing before the rise of easier-to-handle designs.^[24]^[22]

Asymmetric Spinnakers

Asymmetric spinnakers feature a non-symmetrical shape with a defined luff and leech, distinguishing them from traditional designs by allowing attachment via a tack line to the bow or a retractable sprit, secured by a single sheet led aft from the clew to the stern quarters. This configuration eliminates the need for a spinnaker pole, enabling simpler gybing maneuvers where the sheet is eased and the new sheet trimmed without repositioning hardware. Evolving from symmetric spinnakers, this tacked setup provides greater stability in reaching conditions by projecting the sail forward of the headstay. The foretriangle area, used for area comparisons, is calculated as (I × J)/2, where I is the height from deck to masthead forestay attachment and J is the distance from mast to bow along deck.^[25] Development of asymmetric spinnakers accelerated in the early 1980s, initially as a means to optimize performance under the International Offshore Rule (IOR), which influenced yacht design toward lighter, more agile hulls and rigs. Early examples emerged in high-performance classes like the Australian 18-foot skiffs, where retractable bowsprits facilitated their use for downwind speed. By the 1990s, advancements in sailcloth and furling systems made them viable for cruising, with sailmakers like Neil Pryde producing initial versions tailored for IOR-era boats. In modern racing under the International Measurement System (IMS) and Offshore Racing Congress (ORC) rules, asymmetric spinnakers have become standard, with provisions for their measurement and rating based on girth and luff dimensions to ensure fair handicapping. Sizing is typically smaller than that of symmetric spinnakers, often 75-85% of their area, with maximums up to about 1.5-1.8 times the foretriangle area under rating rules (e.g., 160-180% of the J measurement for the foot length), allowing for enhanced power in light airs. They are optimized for apparent wind speeds of 0-12 knots and angles from 50° to 130° off the wind, providing lift where genoas lose efficiency.^[26] Key advantages include streamlined handling for short-handed crews, as the pole-free design reduces setup time and the number of lines to manage, often requiring just two to three people for hoists and douses. Additionally, the forward tack minimizes chafe against bow pulpits or lifelines common on production cruisers, preserving sail integrity during prolonged use.

Specialized Variants

The Parasailor is a specialized symmetric spinnaker variant featuring a horizontal wing that spans the sail's widest point, combined with a full-length sleeve along the luff, designed to enhance self-stabilization and minimize collapse in light winds, particularly for short-handed cruising crews.^[27]^[28] This wing creates a parafoil-like effect, allowing the sail to maintain shape without a pole in winds as low as 4 knots, while the sleeve facilitates easier deployment and gybing from the cockpit.^[29] Cruising asymmetric spinnakers often incorporate torsion lines integrated into the luff for reinforced durability and simplified handling in non-racing scenarios, enabling top-down furling without specialized hardware.^[30]^[31] These variants use heavier fabrics and anti-twist ropes to withstand repeated use in variable offshore conditions, prioritizing longevity over racing performance.^[32] The Code Zero represents a flat asymmetric spinnaker subtype with a straight luff and minimal camber, optimized for close-reaching in winds of 8 to 18 knots, and typically deployed on continuous-line furling systems for quick adjustment.^[33]^[34]^[35] Its design, with a mid-girth limited to 60-75% of the foot length under rating rules, bridges jib and spinnaker functions while allowing roller reefing from the cockpit.^[36] Other specialized variants include wing-on-wing setups, where an asymmetric spinnaker is poled out opposite the mainsail for deep downwind angles, and gennaker hybrids that blend genoa-like luff tension with spinnaker fullness for versatile light-air use.^[37] Under Offshore Racing Congress (ORC) rules, these sails must maintain a half-width of at least 75% of the foot length to qualify as spinnakers, while Performance Handicap Racing Fleet (PHRF) limits girth and foot to 1.8 times the J measurement to avoid penalties.^[38]^[39]

Materials and Construction

Fabrics and Materials

Traditional spinnakers have primarily utilized ripstop nylon fabrics, typically ranging from 0.75 to 1.5 ounces per square yard (oz/yd²), valued for their elasticity, which allows the sail to inflate fully under wind pressure, and inherent UV resistance that prolongs usability in prolonged exposure.^[40] This material, derived from post-World War II advancements in synthetic textiles originally developed for parachutes, became standard for spinnaker construction in the 1950s, enabling lighter and more durable downwind sails compared to earlier cotton or silk alternatives.^[41] Key properties include moderate air permeability to allow the sail to fill with wind while reducing heeling, and high tear resistance provided by the ripstop weave to withstand rigging contact and gusts.^[42] Additionally, coatings such as silicone or polyurethane enhance water repellency, minimizing weight gain in wet conditions while maintaining breathability.^[43] In modern applications, particularly racing, polyester ripstop fabrics have emerged as low-stretch alternatives to nylon, offering superior shape retention and reduced elongation under load for asymmetric spinnakers in high-performance scenarios. For grand prix events, specialized Superkote nylon fabrics provide enhanced stability and zero porosity through polyurethane coatings, allowing lighter sails to handle stronger winds without compromising power.^[44] Eco-friendly options, including recycled nylon or polyester derived from upcycled sails, are increasingly adopted for cruising spinnakers, promoting sustainability without sacrificing core performance attributes like durability and lightness. As of 2025, recycled nylon from post-consumer sails is gaining traction in sustainable production.^[45] Fabric selection involves inherent trade-offs: ultralightweight options (e.g., 0.75 oz/yd² nylon) maximize speed in light airs but may wear faster, whereas heavier variants (1.5 oz/yd² or coated) prioritize longevity in demanding trade wind conditions, balancing velocity against endurance.^[46]^[42]

Construction Methods

Spinnaker construction primarily employs radial or cross-cut panel layouts to optimize shape control and stress distribution while maintaining the sail's lightweight profile. Radial layouts, the most common for modern spinnakers, consist of triangular panels or gores radiating from the head, clew, and tack corners, allowing precise alignment of fabric threads with load paths for enhanced durability and aerodynamic shaping.^[47]^[48] These designs typically use multiple panels—often dozens in number—to enable three-dimensional contouring and minimize stretch under wind loads.^[49] In contrast, cross-cut layouts feature horizontal panels stacked perpendicular to the leech, offering a simpler, more cost-effective build suitable for smaller or less demanding sails, though they provide less refined load distribution compared to radial methods.^[50]^[51] Seams in spinnaker construction are engineered to add minimal weight while ensuring seam strength, typically comprising less than a small fraction of the total sail mass. Panels are joined using zigzag stitching with UV-resistant polyester thread, which creates flexible, durable bonds that resist environmental degradation without excessive bulk.^[52] Ultrasonic welding is occasionally applied for specific lightweight applications, fusing panels through high-frequency vibrations to produce flat, seamless joins that reduce airflow disruption.^[53] Triple-step zigzag patterns are favored for high-stress areas, enhancing tear resistance in the delicate nylon fabrics commonly used.^[54] Reinforcements focus on high-load points to protect the sail's integrity during deployment and handling. Corner patches, often radial in design, are sewn or adhered at the head, clew, and tack to distribute forces evenly and prevent tearing.^[55] Leech lines reinforce the trailing edge against flutter and abrasion, while asymmetric spinnakers incorporate anti-torsion cables integrated into the luff for stable furling and torsion resistance.^[56] Boltropes or continuous tapes along the head facilitate secure hoisting via the halyard swivel, ensuring smooth attachment without adding significant weight.^[57] Spinnakers are produced either as stock models for standard boat sizes or custom builds tailored to specific vessels. Custom construction leverages computer-aided design (CAD) software to model precise sail profiles, including camber depths typically ranging from moderate to deep for optimal downwind performance.^[48] This digital approach allows sailmakers to simulate load paths and refine panel shapes before cutting, resulting in sails that maintain form under varying conditions.^[47] Stock spinnakers, by comparison, follow predefined templates for quicker production and broader availability.^[58]

Aerodynamics and Performance

Aerodynamic Principles

Spinnakers generate propulsion primarily downwind by functioning as a parachute-like structure that traps wind, creating forward thrust through form drag rather than the profile lift dominant in upwind sails like mainsails.^[59] Their low aspect ratio enhances this drag-based mechanism by maximizing the projected area exposed to the apparent wind while minimizing induced drag inefficiencies associated with higher-aspect-ratio wings.^[60] This design contrasts sharply with upwind sails, which depend on attached airflow over cambered surfaces to produce lift via pressure differences, whereas spinnakers tolerate and exploit substantial flow separation to inflate and maintain their bulbous shape.^[61] The curved, highly cambered profile of a spinnaker induces pressure differentials across its surfaces, accelerating airflow over the leeward side and reducing pressure there in accordance with Bernoulli's principle, which contributes to both lift and overall thrust generation.^[62] These effects are most effective at apparent wind angles between 90 and 150 degrees, where the sail's inflation allows optimal wind capture without excessive collapse or fluttering.^[9] Within this regime, careful control of twist and camber ensures partial attachment of the airflow, particularly along the lower sections of the sail, to mitigate stall risks during gusts and maintain consistent propulsion.^[60] For symmetric spinnakers, the aerodynamic forces reflect their reliance on a combination of lift and drag components under separated flow conditions. Asymmetric variants exhibit similar principles but with slight variations in optimal trim due to their tacked configuration.^[61]

Performance Characteristics

Spinnakers deliver substantial enhancements to downwind sailing performance, particularly in velocity made good (VMC), with asymmetric variants optimizing reaching angles in winds of 5-15 knots where their operational range typically spans apparent wind angles (AWA) of 115-160 degrees. In these conditions, polar diagrams from sail design analyses indicate peak efficiency around 120 degrees AWA, allowing boats to maintain higher speeds compared to alternatives like poled genoas. Symmetric spinnakers, by contrast, excel in deeper running angles beyond 140 degrees AWA, providing superior VMC in moderate to strong winds above 14 knots by enabling courses 10 degrees off square, which translates to gains of 30-60 seconds over asymmetric setups at the bottom mark.^[63]^[64] Stability characteristics differ markedly between spinnaker types and sea states. Symmetric spinnakers promote greater overall boat stability when trimmed for dead downwind running, reducing heel through balanced thrust distribution and proving advantageous in choppy or wavy conditions where maintaining course is challenging. Asymmetric spinnakers, while offering faster planing in flat water due to their reaching bias, carry a higher risk of collapse or forestay wrapping in gusty or sustained winds exceeding 20 knots, necessitating precise trimming to mitigate instability. These factors underscore the importance of matching spinnaker type to expected conditions for optimal control and safety.^[22]^[64] Efficiency metrics for spinnakers emphasize their role in maximizing thrust over drag minimization, operating at comparatively low lift-to-drag ratios that prioritize power generation in separated airflow downwind. Velocity prediction programs (VPP), such as those employed by the Offshore Racing Congress (ORC), quantify these benefits through simulated polars, with crossover points to spinnaker use evident around 90-120 degrees true wind angle where efficiency gains become pronounced.^[65]^[66]

Usage and Handling

Setting the Spinnaker

Setting the spinnaker requires careful preparation and coordinated crew action to ensure a smooth deployment, minimizing risks such as twists or uncontrolled inflation. Prerequisites include rigging the necessary lines—sheets and guys for both types, plus the pole for symmetric spinnakers—and attaching the halyard, with the sail often pre-fed into a sock or turtle bag for controlled hoisting.^[67]^[68] For symmetric spinnakers, preparation involves positioning the bag on the leeward side and securing it to the guardwires, while rigging the pole to the mast at shoulder height with jaws facing upwards and attaching the uphaul and downhaul. The guy is threaded through the pole end and clipped to the windward clew, with the leeward sheet attached to the other clew; all lines must be checked for free runs and coiled neatly. The halyard is attached to the head, and the sail is flaked with leech and luff separated to avoid tangles.^[67]^[68] The hoisting sequence for a symmetric spinnaker begins on a broad reach from the leeward side: with sheets eased, the halyard is hoisted swiftly to prevent partial inflation, the pole is raised to square the sail, and then the sheets are trimmed as the sail fills. For smaller sails up to 50 m², a team of three (helmsman plus two) rigs the pole, hoists the halyard, and hauls in the sheet or guy, calling "top" when fully raised. Larger sails require more crew to guide the sail and adjust lines during the hoist.^[67]^[68] Asymmetric spinnakers differ primarily in lacking a pole, with the tack attached to a bow line led through a block outside the pulpit. Preparation mirrors the symmetric process but positions the bag leeward, attaches the sheet to the clew with a bowline or shackle, and ensures the halyard and tack line are ready. The hoisting sequence involves bearing away to about 160° off the wind, easing the mainsail for shadow, attaching the halyard, and hoisting quickly with the sheet slack before luffing slightly to fill the sail with apparent wind; if using a sock, it is pulled up post-hoist to deploy.^[69]^[67] Crew roles scale with team size from 2 to 6 persons: in a minimal 2-person setup, one handles foredeck rigging and hoisting while the other manages the cockpit lines and helm; larger teams divide tasks with dedicated roles for pole adjustment, halyard pull, and sheet control to achieve a coordinated lift. In racing, the hoist should be completed swiftly, ideally under 1 minute, to maintain speed. Beginners should limit attempts to winds under 12 knots true wind speed to reduce handling difficulties.^[68]^[70]^[67] Common errors include over-sheeting before full hoist, which causes twists or halts deployment, and failing to check line leads, potentially leading to jams. Safety checks are essential: verify all attachments are secure, lines run freely without stopper knots, and the pole is properly tensioned to prevent recoil injuries.^[67]^[68]

Trimming and Control

Trimming a spinnaker involves fine adjustments to its shape, angle, and tension to maintain optimal airflow, maximize boat speed, and prevent collapses or instability while sailing downwind. For symmetric spinnakers, the spinnaker pole's position and sheet tension are primary controls, with the pole typically set perpendicular to the apparent wind in reaching conditions and slightly aft for running to avoid the mainsail's wind shadow.^[71] The pole height is adjusted via the topping lift and downhaul so the tack is slightly lower than the clew on reaches, promoting even luff tension, while on runs it is set parallel to the waterline for symmetry.^[71] Fore-aft positioning of the pole is often fine-tuned relative to the mast in moderate conditions to balance the sail's projection without excessive twist.^[67] Sheet tension on symmetric spinnakers is adjusted to induce a slight twist at the leech, ensuring the upper sections fill without stalling, typically by trimming until a small, consistent curl forms at the luff—about 6 inches in light to moderate winds.^[67] Gybing is commonly performed end-for-end for smaller boats, where the crew bears away, releases the working guy, detaches the pole from the mast and sail, swings it across the foredeck suspended by the uphaul, reattaches it to the new guy, and trims the new sheet as the boat turns through the wind.^[67] This technique minimizes sail collapse and allows quick transitions, with the pole jaws kept upward throughout. Asymmetric spinnakers, flown from a bowsprit or tack line without a pole, rely on sheet leads and downhaul adjustments for control, with the sheet angled at 45-60 degrees to the centerline on reaches—closer to 50 degrees apparent wind in winds under 10 knots—to optimize lift and reduce drag.^[72] A barber hauler or twing line is used to tension the luff and prevent the clew from rising or the leech from dumping on broader angles, pulling the sheet lead forward while easing the downhaul to let the tack float 4-6 feet off the deck for running.^[72] Over-trimming in puffs is avoided by monitoring the luff for excessive curl, instead bearing off slightly to keep the sail full.^[72] In gusts, both symmetric and asymmetric spinnakers are depowered by easing the sheets to spill excess wind, combined with steering down to maintain stability and monitoring the boat's heel angle to prevent excessive weather helm or broaching.^[71] For symmetric kites, the pole is eased forward in lulls and aft in puffs to adjust projected area, while asymmetric sails benefit from lowering the tack in stronger winds.^[67] Heel is kept moderate—ideally 5-10 degrees to windward on runs—to enhance righting moment without stalling the mainsail.^[71] Key tools for precise control include telltales attached along the luff to visualize airflow, indicating optimal trim when both windward and leeward sets stream evenly with a minor curl on the windward side.^[71] Winches are employed for fine sheet adjustments, with slow, incremental cranks to avoid shocking the sail into collapse, and pre-marked sheets help replicate ideal positions across wind shifts.^[72] Masthead wind indicators further aid in aligning the pole or sheet to the apparent wind direction.^[71]

Systems and Equipment

Launching Systems

Launching systems for spinnakers enable controlled and efficient deployment, minimizing chaos during hoists and allowing sailors to manage large sails safely, particularly in cruising or racing scenarios. These systems range from simple fabric enclosures to advanced mechanical furlers, each designed to contain the sail until wind can fill it progressively. Common options include sock systems, launch chutes, and top-down furlers, with setups emphasizing secure attachments and preventive maintenance to ensure reliability. Sock systems, also known as turtles or sleeves, provide a straightforward method for controlled spinnaker deployment. The spinnaker is packed into a mesh fabric tube that encases the sail from head to foot, featuring a rigid hoop at the bottom for stability and a separate channel for the control line to avoid tangling. During launch, the sock is hoisted via the spinnaker halyard to the masthead, keeping the sail contained and preventing premature inflation. Once at height, pulling the uphaul line opens the bottom of the sock, allowing wind to progressively fill the sail from the head down, enabling a smooth and tangle-free deployment suitable for single-handed or short-handed crews.^[73] Launch chutes, prevalent in racing setups, consist of rigid or semi-rigid tubes mounted forward near the bow or amidships to facilitate rapid hoists and retrievals. The spinnaker is packed into the chute with sheets and guys led aft to winches, and a retrieval line threaded through the system for pulling the sail back in after use. For deployment, the crew haists the sail directly from the chute using the halyard, with the tube guiding it clear of the boat to inflate quickly in the apparent wind. This setup allows for sub-minute launches in regattas, enhancing tactical speed around marks.^[74] Top-down furlers are specialized for asymmetric spinnakers, offering automated and cockpit-controlled launching. The system employs an anti-torsion cable (such as Dyneema) wrapped by a continuous furling line from the head swivel down the luff, with the tack attached to a ring above the drum for even torque distribution. To launch, the furled sail is hoisted to the masthead and secured, then deployed by easing the furling line while maintaining sheet tension at angles of 120–160 degrees apparent wind, unfurling from the top in approximately 30 seconds without leaving the cockpit. This method suits larger yachts, reducing physical effort and enabling quick adjustments in variable conditions.^[75] Effective setup of launching systems requires precise bridle attachments, halyard locks, and routine maintenance to prevent operational failures. Bridles, typically Dyneema lines with stainless rings, connect the spinnaker sheets or guys to poles or bowsprits, distributing loads evenly and allowing adjustable positioning during deployment. Halyard locks, lightweight mechanisms at the masthead, secure the spinnaker halyard without clutches, reducing weight aloft and compression on the rig for faster, more reliable hoists. Maintenance involves flaking rather than coiling halyards to avoid knots, inspecting lines for chafe, and lubricating moving parts annually to prevent tangles during critical launches.^[76]^[77]

Dousing Systems

Dousing systems for spinnakers are essential for safely and efficiently lowering the sail to prevent accidents, reduce drag, and prepare for maneuvers or storage. These methods vary by sail type, crew size, and conditions, with symmetric spinnakers often requiring coordinated crew actions to gather the sail to leeward while easing sheets and hauling down the halyard.^[78] Manual dousing of symmetric spinnakers typically involves gathering the sail to leeward by easing the pole forward to the forestay and over-trimming the sheet to tighten the foot, making it accessible for the foredeck crew. The halyard is then released in stages: the initial third is eased quickly to collapse the luff and deflate the sail, followed by full release as crew members pull the leeches aboard, stuffing the sail into a forward hatch to avoid tangles with the jib sheets. This technique, known as the stretch-and-blow douse, allows the boat to maintain speed nearly to the leeward mark while keeping the clews out of the water to prevent scooping and instability.^[78]^[79] Snuffer bags provide a controlled top-down collapse for cruising spinnakers, using a downhaul line to retract a protective sleeve over the sail, minimizing air spill and water drag during retrieval. To douse, the boat bears off to a broad reach, the sheet is eased to collapse the sail partially, the downhaul is pulled to draw the snuffer down from the head, the guy is released, and the halyard is lowered, containing the sail within the bag for easy stowing. This method is particularly valued for shorthanded operations, as it reduces the need for multiple crew to handle the large sail manually.^[80]^[81] Sock takedowns, similar to snuffers but using a tubular sleeve, involve releasing the downhaul to deflate the spinnaker by collapsing it from the top, followed by lowering the halyard while the sheet is eased just enough to allow the sock to descend without refilling. In racing, this facilitates quick transitions such as gybe douses, where the sail is retrieved during a gybe to maintain momentum, often by blanketing the spinnaker behind the mainsail before pulling the downhaul. The sock then contains the deflated sail for rapid lowering and repacking.^[70]^[82] Safety in dousing emphasizes clear crew communication, such as verbal cues for halyard release and sheet easing, to synchronize actions and prevent overloads or falls. Avoiding wraps requires checking lines for knots and ensuring free runs before starting, while in heavy air, wet dousing techniques—where the sail is allowed to touch the water briefly after foot tightening—depower it rapidly but demand quick gathering to avoid dragging or capsizing risks. Crew should never stand in bights of lines and must secure the afterguy until the sail is fully stowed.^[83]^[78]^[84]

Racing and Regulations

Role in Yacht Racing

In competitive yacht racing, spinnakers play a pivotal strategic role during downwind legs of fleet races, enabling boats to maximize speed and positional advantages over rivals. Symmetric spinnakers are favored in endurance offshore events such as the Rolex Sydney to Hobart Yacht Race, where their design allows sailing at deeper true wind angles close to dead downwind, optimizing performance over long distances in variable conditions.^[85]^[86] In contrast, asymmetric spinnakers dominate inshore fleet racing classes like the J/80, permitting boats to sail higher and faster on broad reaches, which suits shorter courses with frequent maneuvers around marks.^[87] Key tactics involving spinnakers revolve around disrupting opponents and precise execution. Blanketing occurs when a leading boat positions itself to shadow the wind of a trailing competitor, collapsing their spinnaker and slowing their progress, particularly effective in tight fleet situations.^[88] Optimal gybe angles for spinnakers typically involve turning through 20-30 degrees from a broad reach to maintain momentum, avoiding excessive heel or collapse, while set timing at leeward marks demands coordinated crew work to hoist the sail immediately after rounding for an immediate speed burst.^[89] In Olympic and match racing, spinnaker usage varies by class to balance speed and handling. The 49er skiff employs an asymmetric spinnaker for explosive downwind acceleration, with crews trapezing to manage its 38 square meter area, often emblazoned with national flags for visual impact.^[90] Conversely, classes like the Star keelboat ban spinnakers entirely to emphasize simplicity and upwind tactics in one-design competition.^[91] The America's Cup has seen spinnaker evolution from integral tools to obsolescence in modern formats. During the 12 Metre era (22nd to 26th editions, 1958-1987), symmetric spinnakers were crucial for reaching and running legs, providing decisive speed edges in match racing.^[92] In the shift to foiling craft, with the 35th Cup (2017) using AC50 foiling catamarans and the 36th Cup (2021) using AC75 foiling monohulls, spinnakers were eliminated; high foiling speeds downwind render them unnecessary, with stacked asymmetric variants occasionally tested for burst maneuvers in transitional designs but not adopted in final protocols.^[93]^[94]

Rating and Measurement Rules

In the Offshore Racing Congress (ORC) and International Measurement System (IMS), spinnaker measurements are governed by specific dimensional rules to ensure fair handicapping based on predicted performance via the Velocity Prediction Program (VPP). For symmetric spinnakers, the mid-girth (SMG) must be at least 75% of the foot length (SF), with the maximum width (SMW) limited to 1.8 times the spinnaker pole length (SPL) or J (foretriangle base), whichever is greater.^[95] Asymmetric spinnakers follow similar girth requirements, with SMG ≥ 0.75 × SF, but their luff (SLU) is typically 5% longer than the leech (SLE), and the effective luff is calculated as 0.6 × SLU + 0.4 × SLE to account for shape differences.^[96] Sails with mid-girth to foot ratios between 0.75 and 0.85 are classified as spinnakers, while those below 0.75 may be rated as headsails or code sails, influencing aerodynamic coefficients in the VPP.^[97] Spinnaker area is calculated using formulas such as 0.72 × (0.5 × SL × SF + 0.66 × SL × (SMG - 0.5 × SF)) for asymmetric types, with maximum dimensions often capped relative to rig measurements like ISP (spinnaker halyard height) and J to prevent excessive size; typical limits allow areas up to approximately 175% of the foretriangle base (I × J / 2) in standard configurations, though exact caps vary by certificate.^[98] These measurements, taken by certified measurers, feed into ORC certificates for handicap calculations.^[99] Under Performance Handicap Racing Fleet (PHRF) systems, handicaps adjust for spinnaker type to reflect handling differences, with ratings expressed in seconds per mile (sec/mi). Symmetric spinnakers typically incur a penalty of 3-6 sec/mi relative to non-spinnaker configurations in many fleets, while asymmetric spinnakers receive 0-3 sec/mi, depending on setup.^[100] For example, boats rated with symmetric spinnakers may sail with an asymmetric without additional penalty if the area does not exceed the symmetric's rated size, but oversized asymmetric girths (beyond 180% of J) trigger progressive penalties of 3 sec/mi per 10% excess.^[39] These adjustments are fleet-specific and based on observed performance data to maintain competitive equity.^[101] In one-design classes, spinnaker rules emphasize uniformity to control costs and performance parity, often specifying exact dimensions and material restrictions. For the Melges 24, the maximum spinnaker luff length is 11.585 m, with leech limited to 10.000-11.078 m and foot to 6.300 m maximum.^[102] Super-light fabrics (below 0.75 oz nylon) are prohibited to prevent unfair speed gains and excessive wear, with measurements verified at events via girth stations at mid and three-quarter points along the luff.^[103] Similar limits apply in classes like the J/24, where spinnaker area is approximately 42 m² based on dimensional rules. These rules prioritize measurable compliance over VPP modeling, with violations leading to disqualification. Post-2000 rule evolutions in ORC/IMS and PHRF have increasingly favored asymmetric spinnakers to accommodate short-handed racing trends and reduce physical crew demands. Effective January 1, 2001, IMS updated measurements to use SMG for asymmetric area calculations, replacing prior symmetric-focused metrics and enabling dedicated handicaps for tacked-on-centerline sails.^[95] This shift, driven by growing adoption in offshore events, lowered penalties for asymmetric setups in PHRF (e.g., credits up to 6 sec/mi for bowsprits) compared to symmetric poles, reflecting empirical data on faster handling in shorthanded crews.^[104] By 2010, ORC VPP refinements further integrated asymmetric coefficients for wind angles 60-150 degrees, promoting their use without disproportionate rating inflation. As of 2025, ORC VPP includes updated asymmetric spinnaker force coefficients for wind angles 60-150 degrees, reflecting short-handed trends.^[96]^[105]

Other Applications

Non-Sailing Uses

Spinnaker-derived designs, leveraging lightweight ripstop nylon fabric, have been adapted for traction in wind sports like kite surfing and parakiting since the 1990s, where chute-like kites provide propulsion across water or land. These traction kites are frequently constructed from spinnaker cloth for its high strength-to-weight ratio and ability to capture wind efficiently without excessive weight.^[106]^[107] The durable nylon construction of spinnakers also lends itself to decorative and commercial applications outside sailing. Retired spinnaker sails are commonly repurposed into reusable products such as handbags, canopies, and garden spinners to minimize waste, with initiatives in regions like Cornwall transforming end-of-life sails into sustainable accessories.^[108] For instance, hot air balloon-themed wind spinners are fabricated from spinnaker nylon for its fade-resistant and weatherproof qualities, serving as ornamental garden features.^[109] In emergency contexts, spinnaker fabric's parachute-like properties have historical parallels in aviation, where nylon, the primary material in spinnaker fabric, substituted for silk parachutes during World War II shortages.^[110]

Modern Innovations

In the 2010s and 2020s, spinnaker design has incorporated smart fabrics featuring embedded sensors to provide real-time data on sail performance and trim. These innovations allow sailors to monitor load distribution, environmental exposure, and shape retention directly via mobile apps, optimizing adjustments during races. For instance, North Sails' SmartLuff system integrates a Bluetooth-enabled wireless load sensor into Helix composite sails, including spinnakers, enabling instant feedback on luff tension to prevent overload and enhance efficiency.^[111] Similarly, Spinlock's Sail-Sense sensor, sewn into the sail fabric near stress points, tracks UV exposure, hours of use, G-force, flogging, and tacks to predict wear and inform maintenance schedules, extending sail life in high-performance applications.^[112] Automated systems have streamlined spinnaker deployment and retrieval in modern racing yachts, particularly in classes like the TP52, where electric winches and hydraulic controls minimize crew involvement. These setups use powered winches to hoist and drop large asymmetric spinnakers rapidly, often via string-drop mechanisms that store sails below deck in seconds, reducing physical demands on the 11-person crew during sets and gybes.^[113] Harken's hydraulic pedestal systems, standard across the TP52 fleet, integrate with electric actuators for precise control, allowing smoother transitions in competitive environments like the 52 Super Series.^[114] While full AI optimization remains emerging, these automated furlers and winches represent a shift toward semi-autonomous handling, enabling smaller effective crews for downwind maneuvers. Sustainability drives recent material advancements, with bio-based nylons and 3D-printed components reducing environmental impact without compromising performance. North Sails' SOLOTEX fabric, comprising 37% bio-based polymers derived from plant sources, offers a lighter, more eco-friendly alternative to traditional synthetics for spinnaker construction, lowering carbon emissions during production.^[115] OneSails has pioneered fully recyclable composite sails using bio-derived resins, adopted in events like the 2023 Rolex Middle Sea Race under the Clean Regattas program, which certifies eco-friendly practices and has grown to over 150 events by 2025.^[116]^[117] For reinforcements, 3D-printed nylon or carbon-filled parts, such as batten receptacles and corner patches, provide targeted strength with minimal added weight; these custom-printed elements have been integrated into square-top mainsails and spinnaker heads for superyachts and racers, enhancing durability in the 2020s.^[118] Foiling integrations have led to ultra-light asymmetric spinnakers tailored for high-speed IMOCA 60 yachts in the Vendée Globe, emphasizing low weight to maximize lift from hydrofoils. These sails, often constructed from advanced laminates like North Sails' 3Di, achieve areas up to 400 m² to generate propulsion in light winds while minimizing drag during foiling runs exceeding 30 knots.^[119] In the 2024 Vendée Globe, IMOCA boats featured these optimized asymmetrical spinnakers fixed to bowsprits, contributing to record-breaking downwind speeds as foils reduce hull contact with water.^[120]

References

[1]
SPINNAKER Definition & Meaning - Merriam-Webster
noun spin· na· ker ˈspi-ni-kər : a large triangular sail set on a long light pole and used when running before the wind.<|control11|><|separator|>
[2]
SPINNAKER Definition & Meaning - Dictionary.com
Spinnaker definition: a large, usually triangular sail carried by a yacht as a headsail when running before the wind or when the wind is abaft the beam.
[3]
THE DIFFERENCE BETWEEN A SPINNAKER AND A GENNAKER
A popular online dictionary defines spinnaker as: “a large three-cornered sail, typically bulging when full, set forward of the mainsail of a yacht when running ...Missing: history - | Show results with:history -
[4]
Spinnaker stories September - Mysailing
THE FIRST recorded use of the word spinnaker is believed to have been in 1866, in reference to a downwind sail specially built for the yacht Sphinx in 1865.
[5]
https://www.oxfordreference.com/display/10.1093/oi/authority.20110803100523889
[6]
Spinnaker - Oxford Reference
At first the sail was shaped like a foresail, with only a moderate amount of flow or bulge in the belly, but with the introduction of synthetic fibres, such as ...
[7]
ASYMMETRICAL VS. SYMMETRICAL SPINNAKERS - North Sails
The quick answer is that symmetric spinnakers sail better at deeper angles and asymmetric spinnakers are better reachers.
[8]
All About Spinnakers - Precision Sails
May 8, 2019 · Asymmetrical Spinnakers have a designated Head, Tack, and Clew due to their shape and do not require a Spinnaker pole.
[9]
Racing Spinnakers - UK Sailmakers
Light Air Reaching Asymmetrical Spinnaker. In the past would have been called a VMG spinnaker. Used in winds too light to sail deeper than 110 degrees AWA.
[10]
Why do they call the spinnaker the “death sail”? - Quora
Sep 1, 2018 · A spinnaker is a sail designed specifically for sailing off the wind from a reaching course to a downwind, i.e. with the wind 90–180° off bow.Can you explain what a spinnaker pole is and its purpose ... - QuoraWhat causes a sailboat under a spinnaker to round up? - QuoraMore results from www.quora.com
[11]
Boat Measurements & Definitions
The Spinnaker Foot (SF) is the shortest path on the surface of the sail connecting the tack and clew. For most spinnakers the maximum width will be near the ...
[12]
Racing Symmetric and Asymmetric Spinnakers - OneSails
OneSails make a broad range of hi-performance spinnakers for racing boats. The design of every spinnaker is customized for the boat in order to give truly ...
[13]
Spinnaker - Etymology, Origin & Meaning
The word, from 1866, means a large triangular sail; its origin is uncertain, possibly linked to "spin" (to go rapidly) or the yacht "Sphinx."
[14]
SPINNAKER definition in American English - Collins Dictionary
Word origin. C19: probably from spin + (mo) ... The fractional rig carries around 1000 square feet (93 m) of sail area, main, jib and spinnaker combined.
[15]
SPINNAKER. - languagehat.com
Dec 3, 2011 · The Sphinx first set her spinnaker in the Solent in 1865, and the first recorded use of the word was in 1866 in the August edition of Yachting ...
[16]
The 150th anniversary of the spinnaker - Yachting Monthly
Mar 16, 2016 · The Albert Cup in 1866 is thought to be the first time a yacht flew what is now known as a spinnaker, the large balloon-like three-cornered sail used for extra ...Missing: origin word<|control11|><|separator|>
[17]
[PDF] centen y of the
The word spi1111aker seems to have had two origins. The famous old British racing skip- per Torn Diaper in his memoirs, written in 1939 and pub- lished in 1950 ...
[18]
Page 8 — St. Paul Pioneer Press 12 September 1885 — Minnesota ...
Puritan and Genesta Try Again, but Fail to Cover ... yacht with half its sail and the tug with all its steam. ... spinnaker on the other—a long sausage of sail ...<|control11|><|separator|>
[19]
Nylon: A Revolution in Textiles | Science History Institute
Oct 3, 2008 · The invention of nylon in 1938 promised sleekness and practicality for women and soon ushered in a textile revolution for consumers and the military alike.
[20]
CUP RACING RESUMES AFTER THE SECOND WORLD WAR
Furthermore, an additional 'Protocol in Resolution' was adopted by the Board of Trustees of the Cup on 27th March 1958 that redefined the language used in the ...
[21]
Riding the 'A'-train - Practical Sailor
... asymmetrical spinnaker back in the early 1980s. Based in Stratford, Conn., Neil Pryde Sails builds a line of asymmetrical spinnakers it calls Vectrix, which ...
[22]
The History - International Tornado Class Association
By the early 1990s, sailing faced new challenges: increasing competition from newer, flashier catamaran designs and the need to boost media appeal for televised ...
[23]
ASYMMETRICAL VS. SYMMETRICAL SPINNAKERS - North Sails
Symmetric spinnakers are symmetrical with a vertical center, while asymmetric spinnakers are triangular with three corners. Symmetric sails are better for ...Missing: features sizing conventions traditional
[24]
Symmetrical Spinnakers: S4 Medium / Heavy Running
Matrix uses narrow, four-sided shaped panels aligned with the sail's primary load paths. This full radial layout reduces distortion, maximizes strength-to- ...Why Add An S4? · Spinnaker Painting Program · Other Sails To Consider
[25]
Symmetric spinnakers design - specifications - isails ispinnakers
Symmetrical spinnakers are multi-purpose sails with a S2 Tri-Radial cut, using Contender or Challenge cloth, and come in 18 sizes. They have a larger sail area ...Missing: features traditional
[26]
The Advantages of a Parasailor, a Modified Symmetrical Spinnaker
Jan 4, 2017 · The Parasailor is a symmetrical spinnaker that is deployed from a snuffer but with one unique feature— a wing that flies horizontally in front ...
[27]
Parasailor - Ocean Chandlery
The Parasailor has two unique features over a conventional spinnaker; firstly the wing - which stretches across the sail at its widest point, and secondly the ...<|separator|>
[28]
Parasailor - ISTEC - The Downwind Company
The spinnaker with a wing for safe and easy downwind sailing · The choice is yours - the next-generation Parasailor is available in 15 exciting color designs.Missing: features | Show results with:features
[29]
Cruising Symmetric and Asymmetric Spinnakers - OneSails
Features like weight, shape control and deformation resistance means better performance compared to traditional panelled sails. 3. Quality. Sails are designed ...Fast, Safe And Easy To... · Ifs Sail Codes · Ffr - Flat Furling ReacherMissing: conventions | Show results with:conventions
[30]
New Twist on Furlers: New Generation of Roller-Furling Systems For ...
Facnor also offers the Asym-FX, a torsion-rope version designed for asymmetric spinnaker furling. ... It offers an easy-loading feature to engage the endless ...
[31]
Sailing With a Spinnaker - Asymmetrical Basics (Gennakers and ...
Mar 24, 2023 · In light wind, however, you must strike a balance between the weight of the hoisted line and the durability required to support the sail ...
[32]
Code zero - SailSelect Sailmakers
The code zero has a flatter profile than a gennaker and a straight luff, making it easily used with a furler/roller. Furthermore, it is interesting that the ...
[33]
What type of Asymmetrical Spinnaker? Code Zero vs Code D.
Apr 4, 2021 · The code zero is very flat and is designed for close reaching. It has a nearly straight luff, a mid girth about 60-65% of the sail's foot length ...Missing: furling | Show results with:furling
[34]
Code Zero - Downwind Sails
The optimal wind speed for this sail is 3 to 18 knots true wind speed and in lighter winds, you can carry this sail up to a 45-degree true wind angle.
[35]
Performance Code Zero | iSpinnakers
This sail has a nearly straight luff and is generally designed with a built-in Liros (Germany) antitorque rope to be used with our Seldén CX furlers. The sail ...
[36]
Rules question, Assy poled out wing on wing - Sailing Anarchy Forums
Dec 7, 2014 · Only one spinnaker pole or whisker pole shall be used at a time except when gybing. When in use, it shall be attached to the foremost mast. You ...spinnaker wing on wing | Page 2Asymmetrical Spinnakers on PHRF BoatsMore results from forums.sailinganarchy.com
[37]
Sails - ORC.org
The half width of any spinnaker shall be 75 % or more of the foot length. The symmetric spinnaker shall be symmetric ...Missing: wing- wing hybrids limits
[38]
Rating Rules and Adjustments - PHRF of the Chesapeake
g) Spinnaker pole length shall not exceed 100% of J without penalty. 8) Asymmetrical Spinnakers. a) Choice of Symmetrical, Code Sail, and Asymmetrical shall be ...
[39]
FIBERS & FABRICS: A SAILOR'S GUIDE | SAILCLOTH ... - North Sails
Nylon is widely used for spinnakers and asymmetric spinnakers (Gennakers™) because it is low cost, is lightweight for its strength, and exhibits good UV ...
[40]
Our History - Marine Textile Wholesaler - Bainbridge International
Bainbridge pioneered Stabilkote, the first acceptable nylon ripstop spinnaker material, coated for improved tear resistance and porosity characteristics.Missing: properties | Show results with:properties
[41]
1.5 oz. Nylon Spinnaker Cloth - Sailmaker's Supply
1–6 day delivery 30-day returnsAdvertised as the most durable nylon in the world, the finish adds virtually no weight resulting in the maximum number of fibers per weight.Missing: yd² air permeability CFM tear strength
[42]
Spinnaker Fabrics AIRX - Bainbridge International
AIRX is a high-performance, race-proven fabric with high tenacity nylon, double ripstop weave, high water repellency, and low porosity, ideal for asymmetric ...Missing: oz/ yd² permeability CFM
[43]
https://bainbridgeintusa.com/airx/
[44]
Recycled sails – Sustainable sailing gear by Resail
Resail offers high-quality recycled sails, including headsails, mainsails and downwind sails. Eco-friendly, durable, and performance-ready.Missing: eco- friendly
[45]
https://www.resail.org/recycled-sails/
[46]
Construction Methods - UK Sailmakers
Radial cut sails are made with long narrow triangular panels called gores which attempt to align the warp thread of the laminate with the primary load paths of ...Missing: reinforcements | Show results with:reinforcements
[47]
Spinnaker - SailSelect Sailmakers
The Full Radial design is the most popular choice and strongest construction. The radial shaped panels fan out from the three corners Head, Clew and Tack and ...Missing: methods reinforcements
[48]
4.3 - Spinnakers - UK Sailmakers
The full radial panel layout allows for precise articulation of cloth threadline to match primary sail loadings. Each panel is shaped individu-ally by our ...
[49]
Cross Cut vs. Radial Sail Construction by Dan Dickison
Cross-cut versus Radial Sail Construction includes a look at Dacron versus laminate sails.Missing: reinforcements | Show results with:reinforcements
[50]
Crosscut and Tri-Radial Sails
May 28, 2019 · Tri-radial sails are constructed with panels radiating from the three corners of the sail. The panels orient out from the Head, Clew, and Tack and have an ...Missing: reinforcements | Show results with:reinforcements
[51]
Spinnaker repair: how to do it yourself - Practical Boat Owner
Dec 5, 2023 · I used UV-rated polyester thread and a tricot stitch, like a zigzag but with an extra stitch halfway between zags. A person using a sewing ...Missing: construction ultrasonic welding
[52]
[PDF] Ultrasonic welding of textiles - UNSWorks
Traditional stitching of textiles often requires great skill to operate very complicated machines. Non-stitch joining, especially ultrasonic welding, is one ...
[53]
Cruising Symmetric Spinnaker | Sailmakers | Sailloft - Horizon Sails
In stock Free deliveryThis cruising symmetric spinnaker features tri-radial cut panels, 6-stroke triple zig-zag seam, UV resistant thread, and is designed for cruising and fast ...
[54]
Sail Craftmanship | Precision Stitching & Cutting
Corner Patches. We design corners patches that better distribute the load, whether it's with standard block patches or stronger reinforced radial patches.Missing: ultrasonic welding
[55]
https://www.precisionsailloft.com/education/build-process/craftmanship/
[56]
Torque Rope - Colligo Marine
$$4.86 to $19.90 In stockOur Torque ropes are custom luff lines for code zero style sails and torque lines for top down furled spinnakers.Missing: reinforcements corner patches leech
[57]
Our asymmetrical spinnakers specifications | iSpinnakers
The asymmetrical design allow for an easy set up: unlike symmetrical spinnakers, there is no need for a spinnaker pole or extra hardware, and you can set them ...Missing: attachment history development 1980s IMS ORC
[58]
https://ispinnakers.com/asymmetrical-spinnaker/
[59]
https://doi.org/10.1016/S0167-6105(01)00135-0
[60]
https://doi.org/10.1017/flo.2023.1
[61]
[PDF] Experimental Investigation of Asymmetric Spinnaker Aerodynamics ...
Oct 8, 2014 · Generally the pressure distributions show a leading edge suction peak, occurring at 5 to 10% of the chord length, followed by a pressure ...
[62]
Wind Specifications For Cruising Asymmetrical Spinnakers
Mar 25, 2021 · It is normally manufactured from light 3 / 4 ounce to medium 1.5 ounce weight spinnaker cloth to help with lower apparent wind speeds. The ...
[63]
Symmetric Versus Asymmetric Spinnaker in IRC: What's Best & Why?
Add to that, an asymmetric sail is more efficient going at higher angles compared to boats with symmetric spinnakers.
[64]
Vortex flow of downwind sails - Cambridge University Press
Feb 22, 2023 · This paper sets out to investigate the vortex flow of spinnaker yacht sails, which are low-aspect-ratio highly cambered wings used to sail downwind.
[65]
[PDF] Speed Guide Explanation 2025 (PDF) - ORC.org
The ORC Speed Guide is a custom-calculated manual for improving performance for an individual boat. It is intended to augment, not to replace, ...
[66]
Spinnaker handling: an experts full guide to using the kite
Oct 16, 2023 · Spinnaker sheets run outside everything to a block on the quarter. They need to be long. In the case of a broach you need to be able to let out ...
[67]
[PDF] Using a spinnaker - Selden Mast
Jan 5, 2007 · These instructions have been compiled with both the beginner and the experienced sailor in mind. Our aim has been to.<|separator|>
[68]
Beginners guide to using a Spinnaker! - Sail-World.com
Mar 20, 2021 · Their video shows a clear, step-by-step guide on how best to hoist, trim and drop your Asymmetrical Spinnaker. Hoisting the Asymmetrical ...
[69]
Setting and Striking a Spinnaker Made Easy and Safe
Aug 26, 2021 · Some of the most fun and satisfying sailing we can do is under spinnaker, particularly since the invention of the asymmetric spinnaker freed ...Missing: Rogers | Show results with:Rogers
[70]
Symmetric Spinnaker Flow Control | Sailing World
Jul 22, 2016 · In reach mode, wind flows horizontally, entering the luff and exiting the leech. In run mode, wind flows vertically, entering near the head and ...
[71]
PERFECT SPINNAKER JIBES - North Sails
There are two basic jibing techniques: End-for-end jibes for smaller boats and dip-pole jibes for larger boats. Photo Chris Howell Our divide and conquer.
[72]
[PDF] ASYMMETRICAL TRIM GUIDE - Quantum Sails
circular as it is with a symmetrical spinnaker. The position of maximum camber or draft is likely to be forward of 50 percent. An asymmetrical spinnaker ...Missing: depth | Show results with:depth<|separator|>
[73]
Sailboat Spinnaker Sleeve | ATN Sailing Equipment
Spinnaker Sleeve for safe handling of a spinnaker by one person. Sailing equipment for fun and safety.Missing: turtle | Show results with:turtle<|control11|><|separator|>
[74]
How to use deck chutes for improved spinnaker handling
Nov 19, 2024 · A fuse is just a few hitches of whipping twine that are strong enough to do the job of leading the retrieval line and the kite to the back of ...Missing: amidships tubes
[75]
Top-Down Furling 101 | Cruising World
Sep 20, 2016 · Ultimately, a spinnaker sock is the least expensive solution to spinnaker handling, costing around $1,500. Top-down furlers start at that ...Missing: chute bridle
[76]
https://www.upffront.com/halyard-locks-496
[77]
Spinnaker Pole Accessories - Vela Sailing Supply
Free delivery over $450 30-day returnsSpinnaker Pole Accessories ; Allen Brothers 50MM Stainless Steel Single Mast Bracket · $42.42 · $38.17 ; Allen Brothers 50-70MM Stainless Steel Twin Mast Bracket.
[78]
Spinnaker Dousing - UK Sailmakers
To keep the clews out of the water and make the foot tight, the pole is eased forward to the headstay and the spinnaker sheet is tightened as much as possible.Missing: snuffer | Show results with:snuffer
[79]
HOW TO DO the Stretch-and-Blow Spinnaker Douse - UK Sailmakers
Mar 4, 2020 · The Stretch-and-Blow Spinnaker Douse allows you to sail practically right up to the leeward the mark with the sail drawing fully.Missing: manual | Show results with:manual
[80]
HOW TO HOIST AND DOUSE A GENNAKER OR SPINNAKER
A cruising spinnaker or Gennaker is set with a tack line from the bow, a halyard, and a sheet led to the aft quarter. For shorthanded sailing, a spinnaker ...
[81]
Dousing Sock - UK Sailmakers
The dousing sock was designed to help shorthanded crew handle the cruising spinnaker or gennaker. The sock takes the place of several long-armed crew members.
[82]
J70 Tuning Guide | North Sails
There are three basic types of spinnaker douses used on the J/70. The windward douse, the leeward douse and the gybe douse, sometimes called the 'Mexican'. ...
[83]
Dousing The Spinnaker :: CSNTS Training page
(1) Ensure sheets and halyards are clear to run and not tangled. (2) DO NOT stand in any bights. (3) Communication is the key to safe, smooth spinnaker flying.
[84]
How to execute the perfect spinnaker drop when sailing short-handed
Oct 3, 2016 · Pulling on the drop line once the tack has been released will 'fold' the spinnaker, collapsing it and allowing you to gather the bulk starting ...
[85]
Rolex Sydney Hobart Yacht Race 2025
Dec 24, 2007 · ... spinnaker pole, Limit has continued to fly symmetrical spinnakers from a pole. This proved effective on the lighter-air days of the Rolex ...
[86]
The deciding day? - Rolex Sydney Hobart Yacht Race 2025
Dec 28, 2007 · Chutzpah has been planing; we have been driving deeper, using our (symmetrical) spinnakers to the maximum advantage. "We had a great run on ...
[87]
Training material for asymmetric spinnaker sailing
Mar 7, 2024 · I am looking for books and or video tutorials etc for sail trim and handling the asymmetric spinnaker. We are relatively new to racing with our J/80.
[88]
TACTICS TO WIN By Nick Craig - ILCA UK
Apr 26, 2025 · To attack one boat, you should aim to blanket their wind. This makes playing the spinnaker for your opponent hard as the wind is disturbed.
[89]
Sportboat Wing-on-Wing Guide - Sailing World
Jul 11, 2023 · A boat with the spinnaker squared back is basically the same as being wing-on-wing. When in this mode, you'll jibe through about 20 to 30 ...Missing: gybe | Show results with:gybe
[90]
49er - World Sailing
The spinnaker, one of three sails along with the mainsail and jib, is decorated in each country's flag at the Olympic Games, making this class one of the most ...
[91]
International Star Class - US Sailing
Does this class have a spinnaker or gennaker? No. How many people sail as a ... USA Junior Olympic Sailing Festivals · Adult Sailing · 2025 Offshore Double ...
[92]
THE CUP THAT CHANGED EVERYTHING - 37th America's Cup
Liberty used her waterline and powerful spinnakers on the two reaching legs to close the gap to 43 seconds at the first leeward mark and then dictated a 33-tack ...
[93]
Farewell Spinnaker. Do AC 75s only go upwind? PHOTOS
Sep 29, 2022 · While these criticisms are in part clichés to be debunked, it is true that the AC 50 first and the AC 75 later brought to the big Cup stage a ...
[94]
Why Don't SailGP Boats Use Spinnakers?!?!? - YouTube
May 19, 2022 · For most boats, launching a spinnaker and bearing away is the fastest way to get downwind, but the foiling boats they use in the America's ...Missing: evolution | Show results with:evolution
[95]
[PDF] INTERNATIONAL MEASUREMENT SYSTEM
Spinnaker Mid Girth Length (SMG). From 1/1/2001, the recorded measurement on which asymmetric spinnaker area is calculated shall be SMG (replacing SMW ...
[96]
[PDF] ORC Rating Systems 2023
108.4 Foretriangle height IM shall be calculated as follows: ... Symmetric spinnaker rated area shall be the largest measured area of any symmetric spinnaker in.
[97]
Understanding Sail Declarations for ORC Rating Certificates
Jun 4, 2024 · Specialty sails with a midgirth ratio between 75% and 85% will be classified as spinnakers, while those under 75% will be categorized as a “ ...Missing: IMS luff
[98]
[PDF] ORC Multihull Rating Systems
ORC Multihull Rating Systems use IMS and VPP to rate boats based on predicted sailing speeds, calculated for various wind speeds and angles.Missing: ratio | Show results with:ratio
[99]
https://www.phrfchesbay.org/page/ratings/measurementdefinitions
[100]
[PDF] 2022 ECSA PHRF REGULATIONS
ADDITIONAL NON-SPINNAKER. REGULATIONS. A. The intent of non-spinnaker racing is that boats sail off the wind with the same sails they use to sail on the wind.<|separator|>
[101]
[PDF] Performance Handicap Racing Fleet - 2023 - PHRF-NB
Boats using both symmetric and asymmetric spinnakers from a standard spinnaker ... pole/symmetrical spinnaker pole will receive between 2 and 14 sec/mile credit.Missing: per | Show results with:per
[102]
[PDF] Midwest PHRF - Handicapping Rules, Credits, and Penalties (HRCP*)
May 7, 2022 · The new formulas will hit an oversized spinnaker a bit harder than before but may allow larger mainsail area increases within the 3 sec/nm ...
[103]
[PDF] International Melges 24 Class Association - World Sailing
Luff length. 8460 mm 8560 mm. Leech Length. 7775 mm 7903 mm. Foot Length. 2926 mm ... c) Length: maximum 800mm d) Thickness of the body of the number is ...
[104]
2nd Hand Melges 24 Asymmetric | Sailing Anarchy Forums
Nov 8, 2007 · From the Melges 24 website, class rules, mins and max's: Spinnaker halyard height: 9455mm. 9475mm. Luff length. 11285mm 11585mm. Leech length.Spinnaker Sizes | Sailing Anarchy ForumsRacing sail budget for a successful class - Sailing Anarchy ForumsMore results from forums.sailinganarchy.com
[105]
PHRF Handicaps for J/Boats Models
Maximum spinnaker size (without penalty) conforms to local PHRF regulations defining base spinnaker size, except where One Design definition of spinnaker size ...
[106]
Large kite fabric - Kite Making - KiteLife Forum
Jun 10, 2019 · Icarex is a material originally use for boat sails. (It's spinnaker cloth.) It should be more than strong enough for what you are doing, but ...
[107]
Traction Kiting 102: Your Next Flights with a Four-Line Kite
Feb 1, 2011 · After your first flight with your 4-line traction kite, you'll have a better idea how to judge the best wind conditions as you'll know more ...
[108]
Saving spinnakers from landfill: Cornwall businesses tackle sailing ...
Jan 22, 2024 · "We're extremely proud that we're able to repurpose end-of-life spinnaker sails and transform them into durable and reusable bags which will be ...
[109]
Hot Air Balloon Marine - Skyblue Leisure
Stunning Brookite Hot Air Balloon Spinner made from durable spinnaker nylon, ideal for use with windsock poles. Comes with swivel attachment. Length 135cm.
[110]
How did Britain obtain enough silk to make all the parachutes which ...
Mar 27, 2021 · Parachute fabric is very similar to spinnaker cloth used to construct sails so a sail supply is another good source, as is ParaGrear Equipment ...When did they stop making parachutes out of silk? - QuoraWhat kinds of parachute systems were used for World War II ... - QuoraMore results from www.quora.com
[111]
NORTH SAILS INTRODUCES WIRELESS LOAD SENSING FOR ...
North Sails is proud to introduce SmartLuff, an easy-to-use Bluetooth smart sensor that optimizes your sail by monitoring sail load in real-time.Missing: embedded | Show results with:embedded
[112]
Sailsense, the Spinlock sensor for monitoring sail ageing
Nov 20, 2018 · This sensor, sewn onto the sails of boats near the listening point, records the environmental parameters experienced during sailing. It measures ...
[113]
Inside Look: TP52 Systems - Quantum Sails
May 24, 2017 · TP52 Gladiator Captian Feargal Finlay takes you inside the systems of the TP52 and shows us where–and how–the magic happens.Missing: class automated electric furlers reduction
[114]
Kite strings - Seahorse Magazine
Today Harken supplies winches to 100 per cent of the TP52 fleet, plus hydraulic systems driven by Harken MX Wing and Air pedestals were selected by eight boats; ...Missing: automated | Show results with:automated
[115]
Materials & Technologies - North Sails
Comprising 37% bio-based polymers, SOLOTEX® is a more sustainable alternative to common synthetic fibers. These bio-derived plant ingredients reduce the ...
[116]
Sustainable Sails - OneSails
For the first time ever! Over 10 years of research and development have led to the creation of sails that win in regattas, last over time, have low CO2 ...Missing: eco- 2020s
[117]
World Sailing's inaugural Impact Report charts a new course for a ...
Jul 24, 2025 · Environmental Stewardship: An 11% reduction in carbon footprint against the 2019 baseline. Clean Regattas increased by 17% to 153 events.Missing: eco- 2020s
[118]
From Superyacht to Cruiser: How We Built a Square-Top Mainsail
The sail set with a beautiful, efficient shape. The 3D-printed and glassed receptacles held perfectly under load. The immediate performance gain was undeniable: ...
[119]
EN: All you need to know about IMOCA boats - Vendée Globe Junior
The spinnaker is the largest of the sails, measuring up to 400 m2. It can be used downwind in manageable wind conditions.Missing: square meters<|separator|>
[120]
What sails are on board an IMOCA for the Vendée Globe?
Nov 24, 2024 · On IMOCAs, it is an asymmetrical spinnaker that is fixed at the tack to the bowsprit. It is found less and less on new foiling boats, but ...Missing: ultra- | Show results with:ultra-