Aback (aka Backwinded):
A sail filled with wind on its ordinarily lee side is said to be aback. It may be backed as a manoeuvre, or set aback by circumstance. See Back and Backwind.
Accidental Gybe:
A gybe for which one is not prepared. It may arise from a wind shift or fluke, inattention at the helm or from sails tossed by a boat's motion in light winds. Junk rig is generally considered to be more forgiving of any gybe than other rigs. See Gybe (Manoeuvre) and Goosewing Gybe.
Advantage: See Mechanical Advantage.
Aerodynamic Theory aka Aerodynamics:
The branch of fluid dynamics dealing with the motion and physics of moving air, especially when interacting with a solid. It is generally accepted as providing the best explanation of how a sail works. [PJR p. 18]. See Wikipedia:Aerodynamics
Aerofoil aka Airfoil:
A streamlined surface designed in such a way that air flowing around it produces useful motion. Aerofoil cross-section is generally described (especially in sails) in terms of camber, chord and depth of curve, while efficiency is described in terms of lift, drag and lift to drag ratio. Wikipedia: Airfoil. See Aerodynamic Theory, Camber, Chord, Depth of Curve, Drag, Foil, Lift, and Lift to Drag Ratio.
Aerofoil Curve:
Any curve approximating the cross-sectional shape of an aerofoil. See Aerofoil.
Aerojunk Rig: SeeCommon Junk Rigs.
Aft Led Sheets: See Single Sheets.
After Lift:
Lift rigged abaft the mast. See Topping Lift.
Angle of Incidence(aka Angle of Attack):
Apparent Wind:
The direction and velocity of wind experienced by a moving observer, which is the result of true wind modified by the observer’s course and speed. Sails respond to apparent wind.
Airfoil: See Aerofoil.
Armchair Sailor:
One indulging in the pleasures of vicarious sailing. Term is most often jocular, but may on occasion be condescending.
Armchair Admiral:
Exasperated term for a person who projects expertise beyond their experience, and who may take liberties with positions of more authoritative persons. Forum participants are encouraged to verify information presented in online discussions. See Keyboard Captain.
Aspect Ratio:
The proportion of height to width. For example, a high-aspect ratiosail is tall for its width, while a low-aspect ratiosail is wide for its height. Aspect ratiois useful for designing or comparing junk sails, and foils in general. [PJRp. 97]
Note: In other fields, this ratio may be inverted (width:height). Check context.
Automatic Rig: See Common Junk Rigs. [PJR p. 8]
Back:
To force or trim a sail to windward, such that it fills with wind on its ordinarily lee side. A sail in this position is said to be backed, or aback. Backing a sail may be used as a manoeuvre to force bow or stern in the direction opposite the backwinded sail, or to sail backwards. When heaving to, a backed foresail balances a close-hauled after sail. See Backwind, and alternative Aback.
Backwind:
To have, cause or allow wind to blow onto the ordinarily lee side of a sail. Backwinding may occur in a wind shift when pinching, causes luffing, and can be used as a manoeuvre to force bow or stern in the direction opposite the backwinded sail, or to sail backwards. Wind flow altered by a forward sail may backwindan after sail. See Back, and alternative Aback.
Balance:
The area of a junk sail (or lug sail) extending forward of the mast line, often expressed as a percentage of the sail’s total area. Balancevaries with sail shape and attitude, relative to the mast. Shape (distribution of area) and total area are adjustable via tack parrel, yard hauling parrel and luff hauling parrel(s), when these are rigged. [PJR p. 10]
Balance:
Relationship between sail(s)’ centre(s) of effortand a vessel’s centre of lateral resistance. These are said to be ‘balanced’ when the centred helm has desired neutral helm or weather helm. Balance may be altered by adjustments of sail’s total centre of effort (via reefing or adjustments to individual sails), centres of pressure (via adjustments to sail incidence) or of the centre of lateral resistance (via changes to adjustable lateral resistance devices). Junk rigs, particularly those with multiple sails, are very flexible in achieving balance. See Lee Helm, Neutral Helm and Weather Helm.
Balanced Helm aka Neutral Helm:
The tendency to a steady course under centred helm, neither rounding up nor falling off the wind. See alternatives Lee Helm and Weather Helm.
Ballast Stability:
Hull stability arising from ballast. Ballast may increase stability initially, by lowering a vessel’s center of gravity, or in reserve, by increasing righting moment as the vessel heels. See alternative, Form Stability.
Barrel Method (Camber) (aka Round-Only Method):
Method for engineering camber in junk sail panels by shaping upper and lower edges to convex curves oriented away from the bunt (similar to barrel shape). As curves are affixed along a batten, they ‘collapse’ to a straight line. Fabric external to that line, in amount varying with the original curve, slackens the bunt. Under pressure of wind, an aerofoil shape results. [CP & SJR] See Camber, and alternatives, Broadseam Method, Dart Method, Lens Method and Shelf-Foot Method.
Batten:
A light spar or structure which, with other spars, spreads a junk sail. Battens, which may be horizontal or canted, extend between and are affixed to luff and leech, and generally fixed to the sail along its length by means of batten pockets, lashing, and/or various other means. Battens spread and support the sail, and provide landings for various rigging systems. Battens may range from rigid to ‘bendy’, and may incorporate mechanical means to achieve and limit curvature, and/or be themselves shaped to a given curvature. By convention, battens are numbered from bottom to top (the boom is sometimes considered the lowermost batten [number zero]). See Junk Sail, Boom, Bendy Batten, Half Wishbone Batten, Hinged Batten, Spilling Batten, Tuned Batten, Wishbone Batten; Batten Parrel and Luff Hauling Parrel; and Batten Pocket. [PJR 10, Fig. 1.4]
Batten Downhaul:
A downhaul affixed to one or more battens in order to assist lowering in extreme conditions. [PJR p. 48, Fig. 3.45]
Batten Parrel:
A parrel affixed to points on the same batten. Its principal function is to prevent a junk sail from blowing away from the mast on one tack. It may also constrain forward and/or aft motion of the sail. Batten parrels may be rigged long (ends affixed well clear of the mast) or short (one or both ends affixed close to the mast, limiting sail position). [PJR pp. 43-47, figs. 3.34-3.41]
Batten Pocket (aka Pocket):
Tubular fabric structures, sewn onto a junk sail along the run of a batten, and/or at its ends, in order to affix batten to sail. [PJR p. 154]
Batten Rise aka Rise aka R:
The vertical height of the clew, measured from the tack; the foot line is constructed from tack to clew, which determines the slope of spars within a junk sail parallelogram. Batten rise is generally determined by formula to produce a set amount of aft, positive stagger. [PJR p. 101, figs.6.15-6.19]
Batten Stagger:
The tendency of batten overlap at one end of the sail bundle. Positive stagger is overlap of lower battens by upper ones. Neutral stagger is no significant overlap. Negative staggeris overlap of upper battens by lower ones. Positive stagger is desirable, aft, when using aft led sheets because it allows sheet spans and blocks to hang freely. [PJR p. 22, Fig. 2.8]. See Negative Stagger, Neutral Stagger and Positive Stagger.
Bear Away (aka Bear Off aka Fall Off:
To alter course away from the wind (by choice) without changing tack. See Fall Off.
Becket:
Landing (or fitting) on a block to which a line may be made fast. See Block.
Bendy Batten:
A batten engineered to flex. This is generally accomplished by (non-mechanical) means of shaping and/or choice of scantlings and materials. See Tuned Battens, and alternatives Hinged Batten and Rigid Batten.
Bermudan Rig aka Bermudian Rig aka BR:
Non-junkrig composed of arrangements of generally triangular sail(s). When stayed, it is sometimes referred to as Marconi rig. Bermudan rig has been the benchmark rig for windward efficiency.
Bias:
The diagonal directions across the weave of fabric. Diagonal stresses on fabric are said to be acting on the bias, and cause more stretch than orthogonal stresses, which align with warp and weft. See Fabric and Sailcloth.
Bird's Mouth Joint:
Joint commonly used for construction of round-sectioned structures (typically spars). Multiple staves (six and eight are common choices, resulting in hexagonal and octagonal structures, respectively) are shaped with one edge squared, and one with a precisely-angled, 90° rabbet, resembling a bird's mouthin section. Staves are edge-joined, with the rabbet receiving the squared edge of the adjacent stave. The method increases gluing surface area and has good, self-aligning tendencies. Many staves will also be tapered precisely, lengthways, to produce a tapered spar. Duckworks Article.
Block:
A marine pulley, with one or more sheaves, used for low friction redirection of a line. A becket may provide a landing at the block. Line and block(s) may be combined in various arrangements to multiply purchase. Wikipedia: Pulley. See Rope-Stropped Block and Tackle.
Block and Tackle: See Tackle.
Boltrope aka Roping:
A ‘rope’ (term includes material such as webbing) affixed along the edges of a junk sail. Boltrope supports sail and spar weight, relieving sailcloth from associated tensional stresses. It further reinforces the physical connection among spars, tending to synchronize their motions. [PJR p. 17]
Boom:
The lowermost batten (zero, if numbered) of a junk sail. Its scantlings are generally increased to resist point loading from a tackline or boom vang, and may be fitted with hardware in support of topping lifts, sheet leads and other rigging components. [PJR p. 10] See Batten, Tack Hauling Parrel, Boom Parrel, Boom Vang, Tacklineand Topping Lift.
Boom Brake:
A specialized preventer which constrains boom motion by slowing and/or stopping its swing. Uncommon in general junk rig. Wikipedia: Boom brake
Boom Foot Sail: See Water Sail.
Boom Hauling Tackle aka Boom Hauling Parrel: See Running Tack Parrel.
Boom Parrel:
A standing parrel, similar to a batten parrel, fitted to the boom, which keeps the boom from blowing away from the mast, and may constrain forward movement. [PJR p. 52] See Batten Parrel.
Boom Vang (aka Kicking Strap):
Control line or hydraulic system which exerts downward force on a boom, tensioning and flattening the sail.
Bootstrap Effect (aka Slot Effect): See Slot Effect.
Bowsing Tackle aka Bowsing Parrel: See Running Tack Parrel.
Brail:
To furl sail fully or partially, by means of a running lacing which gathers some or all of the bunt when tensioned. Uncommon in general junk rig, this method may be seen in auxiliary sails.
Broad Headed Sail:
A junk sail whose upper panels are wider, seen in profile than lower ones. [PJR p. 23, Fig. 2.10]
Broadseam Method(Camber):
Method for engineering camber in junk sailpanels by increasing the overlap on seams between adjacent sail cloths, broadening them towards the upper and lower edges. This ‘removes’ fabric along these edges, slackening the bunt. Typically used, in junk sails, in conjunction with the Barrel Method. Under pressure of wind, an aerofoil shape results. [CP & SJR] See Camber, and alternatives, Barrel Method, Dart Method,and Shelf Method.
Bundle: See Sail Bundle.
Bunt (of Sail):
The central body of sailcloth within an unsupported region of sail. In junk rig, each panel has its associated bunt.
Bury: See Mast Bury.
By the Lee: See Sailing By the Lee.
Camber:
Three dimensional shape in a junk sail as a whole, or in individual panel(s), approximating an aerofoil under pressure of wind. Camber is imparted to a whole junk sail by twist (under control of the sheeting system), batten bend and/or engineered batten curvature. Camber is engineered in a panel by joining shaped edges of constituent fabrics, to produce chain sections across the vertical bunt, and/or by selection of sailcloth for inherent stretch properties. For fabric shaping methods, see Fabric, Barrel Method, Broadseam Method, Dart Method, Lens Method and Shelf Foot Method. See Bendy Battens, Hinged Battens, Tuned Battens, Sail Twist, Spilling Battens and Wishbone Battens.
Camber aka Amount of Camber:
Amount of camber is generally expressed as the percentage of depth of curve to chord, and this amount is often referred to simply as camber.
Cambered Sail:
A junk sail, one or more of whose panels are cambered by design. See Camber, and alternative, Flat Cut Sail.
Cantilever:
To anchor an extended beam from one end. Unstayed spars (e.g., some masts, bowsprits and boomkins) are cantilevered. Wikipedia: Cantilever
Cat Rig:
Rig in which the foremost mast is stepped near the bow, after a traditional North American type called a catboat. Types include cat sloop, cat yawl, cat ketchand cat schooner. Due to a general absence of foresails, JR vessels are often some type of cat rig.
Catenary (Curve)aka Chain Section
The idealized curve formed by suspending a uniformly limber cable between two points, or any similar curve. Wikipedia: Catenary
Centre of Effort aka CE:
The idealised point on the surface of a foil, averaging force generated across its surface. In a sailplan, it is located at the geometric centre of the sail area as seen in profile.
Centre of Lateral Resistance aka CLR:
The idealised point on a vessel’s underwater profile averaging its silhouette area. Rudder profile may be included in this average under various rules-of-thumb. In practice, the centre of lateral resistance is the point around which a hull turns. Wikipedia:Center of lateral resistance
Centre of Pressure aka CP aka CoP:
The centre of a pressure field which is the momentary locus of forces generated by that field. Nautically, this generally refers to pressure fields developed by a foil. It is a dynamic centre, changing with conditions (as opposed to Centre of Effort, which is a static, idealised, geometric centre). Wikipedia: Center of pressure (fluid mechanics)
Chafe:
Degradation of material by friction. It is particularly noticeable in soft materials, such as fabric. See Chafe Strip and Chafe Gear.
Chafe Gear aka Anti-Chafe Gear:
Durable or sacrificial materials arranged to protect the vessel or its outfit from chafe. See Chafe and Chafe Strip.
Chafe Strip aka Anti-Chafe Strip:
A strip of sacrificial cloth added to junk sails under battens. Specialised chafe strips may be added to protect sailcloth from other rigging components.
Chain Section: See Catenary (Curve).
Chimney:
In junk rig, a vertical region adjacent to the mast, opposite the junk sail, which is not swept by spars within their designed range of motion. [PJR p.34, fig. 3.6]
Chinese Gaff Rig: See Common Junk Rigs.
Chinese Gybe:
(Sometimes derisive) term for a goosewing gybe occurring on a junk-rigged vessel. See Goosewing Gybe.
Chinese Lug Rig:See Junk Rig and Junk Sail.
Chord:
An idealised, straight line connecting the leading and trailing edges of an aerofoil. See Aerofoil, Camber and Draught.
Clew:
The lower, after corner of a sail.
Colvin Rig: See Common Junk Rigs.
Compression:
‘Squeezy’ forces acting longitudinally on a body from its ends toward its midbody. A body acting as a strut which resists compressionor compressive forces is said to be acting in compression. In junk rig, sheets impose compression loads on battens when eased under pressure of wind. A mast is compression loaded by tension between halyard and tack line. Wikipedia: Compression (physical) [PJR p. 13, fig 1.6] See Shear, Tension and Torque.
Control Line:
Any running line or tackle used to control the aspect, attitude, set or function of a junk sail.
Controlled Gybe:
A manoever in which course is altered or sail is trimmed to induce a gybe. See alternative, Accidental Gybe.
Crab Claw Rig:
A traditional Pacific Islanders’ sailplan, characterised by a nearly triangular sail set between two ‘limbs’. In JR, triangular panels, when present, are similar to Crab Claw sails, and may share functional characteristics. Wikipedia: Crab claw sail
Crease:
Tensional deformation of sailcloth caused by poor cut and/or poor set. Creases increase drag, degrading sail efficiency. [CP & SJR] See alternative, Wrinkle.
Dart:
To fold over and affix a bit of fabricon itself, tapering from a broad overlap to a point. A dartremoves material away from the bunt, inducing approximate curvature in otherwise flat fabric. It is sometimes used in (generally smaller) sails to induce camber. See Dart Method.
Dart Method (Camber):
Method for engineering camberin (generally smaller) junk sailpanels by darting paneledges, fore and aft. This ‘removes’ fabric along these edges along an approximate curve, slackening the bunt. Under press of wind, an aerofoilshape results. [CP&SJR] See Camber, and alternatives, Barrel Method, Broadseam Method,Lens Method and Shelf-Foot Method.
Depth of Curve:
The depth of a foil, measured perpendicular to its chord from its point of greatest curvature.
Developed Surface aka Developable Surface:
A surface entirely composed of section-of-cone and section-of-cylinder areas, smoothly joined. Such a surface may be covered by stiff, sheet construction materials, such as plywood or metal. Developed-surface hulls are especially amenable to Do-It-Yourselfconstruction.
Do It Yourself aka DIY:
The movement towards self-sufficiency, empowerment and independence. Junk rig is particularly amenable to DIY approaches due to its economy and simplicity of design, construction and maintenance.
Double-Blocked aka Chock-a-block aka Two Blocks:
Situation where two blocks sharing a tackle are drawn into contact, limiting further range of motion. WGNT
Double Sheets (Port and Starboard):
The use of two, separate sheeting systems, one for the port side and one for starboard. This type of double sheeting allows there to be a narrower gap between sails, and for backwinding, under control of the windward sheets, for manoeuvring or heaving to. This type of double sheetingis common in the East, though less so in the West. Unless otherwise specified, this is the type generally implied. [PJRp. 73, Fig. 4.47] See Double Sheets (Upper and Lower), and alternatives, Aft Led Sheets and Single Sheets.
Double Sheets (Upper and Lower):
The use of two, separate, aft led sheets, one controlling the upper leech, and one controlling the lower leech. This type is sometimes used to improve control of sail incidence and sail twist, especially in large junk sails. See Double Sheets (Port and Starboard), and alternatives, Aft Led Sheets and Single Sheets.
Downhaul:
A control line which tensions a junk sail’s upper spars in order to assist lowering in extreme conditions. [PJR p. 48] See Batten Downhaul and Yard Downhaul.
Downwash:
Divergent flow opposite a foil’s convex side. In a sail (vertical foil), downwash is a transverse motion, diverting toward the wind. See Foil and Upwash.
Dmin aka Minimum Drift:
The minimum drift required for full and proper function of a rigging system. [PJR p. 63]
Draft:
American spelling of Draught (British usage). See Draught.
Drag:
Friction from a fluid or gas flowing across a foil. See Aerodynamic Theory, Lift to Drag Ratio, and alternative, Lift. Wikipedia: Drag
Draught aka Draft:
The maximum extent of a vessel below its waterline. Draught is British usage, while draftis American usage.
Drift:
The limit (and sometimes range) of motion of specific rigging (such as a block) constrained by its rigging system. [PJR p. 63]
Drogue:
A drag device deployed into the sea from the stern, which slows a vessel’s forward velocity. It is generally deployed as a heavy-weather technique, and/or when a vessel is in danger of surfing down the face of a wave, risking a broach or burying in the backside of the wave ahead. See alternatives, Heave To, Lie A-hull, Sea Anchor and Weathercock.
Elastic:
The ability both to stretch under tension and recover to (near) original dimension when tension is released. In junk rig, elastic fabric may be used for sailcloth, and elastic line for anchoring or sheets.
End View: See Section View.
Engineer:
To construct a rigging component to behave in a given way by design. Methods include selection and/or shaping of materials, and/or mechanisms in support of the desired behaviour.
Euphroe:
A type of friction block often used in junk rig sheeting systems (especially in Asia), with one or more upper holes through which line(s) may freely run, and which may incorporate one or more sheaves in its base. [PJR p. 59-61, Figs. 4.9-4.21and 4.51-4.52] See Friction Block and Sheets.
Fabric aka Cloth:
Filaments, threads and/or yarns of natural or synthetic fibers woven in a particular weave. Edges may be selvedged, or not. Various fabrics are specialised for weight, thread count, strength, stability, elasticity, UV resistance (resistance to sunlight), hydrophobia (resistance to water absorption), waterproofing and colour. Fabric is generally sold by length from bolts or rolls of varying width. Wikipedia: Fabric. See Sailcloth.
Fall Off (aka Bear Off or Bear Away):
To wander away from the wind (inadvertently) without changing tack, risking sail stall. See alternative Bear Away.
Falling Leaf Pattern:
Poetic phrase describing the motion of a yuloh blade through water. Named for the (approximately) two dimensional pattern of a leaf, which arcs to and fro as it falls. See Yuloh.
Fan:
Junk sail region whose profileis characterized by spars canted, fan-wise, with increasing angle from boom to yard, resulting in quasi-triangular panels and roach. Scallop developed by flat-cut, fanned panels are approximately conic in section. Cambered panels may affect furling properties. See Fanned Sail, Irregular Fan, Regular Fan and Roach, and alternative, Parallelogram.
Fanned Planform: See Fanned Sail.
Fanned (Sail) aka Fanned Planform:
A junk sail which is mostly or entirely fanned. It is generally accepted that fanned sails enhance the control of sail twist-induced camber; as canted battens twist, the horizontal sail section assumes an aerofoil shape, whose depth of curve is proportional to amount of sail twist. Camber may also be shaped in one or more panels. A fanned sail generally has some roach which may foul aft led sheets. It may extend one or more battens from the leech to compensate, or employ double sheets. Negative stagger, forward, may bring the forward end of the yard abaft the mastline when reefed, and may extend the yard forward of the luff to compensate. See Camber, Double Sheets, Regular Fan and Irregular Fan, and alternative Parallelogram Sail.
Fantail Rig: See Common Junk Rigs.
Fan Up:
The lifting of furled panels from the sail bundle by wind (most often from astern). Generally, this affects the after end of panels and attached spars most strongly. The overall effect resembles the unfurling of a fan, regardless of sail geometry. As after ends of spars raise upwards, the forward ends may depress and foul the mast, rigging or bunts of sail, and/or result in a goosewing gybe. Various preventers may be rigged to limit fan up. [PJR p. 208, Fig 15.4] See Fan Up Preventer and Goosewing Gybe.
Fan Up Preventer (aka FUP):
Any of various rigging systems which prevent fan up. Generally, these are temporarily rigged. See Fan Up.
Feet-Inches-Eighths:
A method of representing measurements within the imperial system, in which fractional forms are not used (all are converted to eighths-of-an-inch). For example, eight feet, four and three quarters inches would be represented as 8-4-6 (eight feet-four inches-six eighths). A trailing plus or minus (‘+’ or ‘-’) may be appended to adjust the value up or down by 1/16th of an inch and a second to adjust by 1/32nd of an inch. Where the imperial system is being used, feet-inches-eighths is commonly used in lofting of hulls and sails for improved clarity over other methods. See Imperial System.
Fenix Rig(s): See Common Junk Rigs.
Filament:
A linear strand of material, which may be solid or hollow. Fabric and line made directly from filaments are often stronger than alternatives, and may have other associated effects. See Fabric and alternatives, Thread and Yarn.
Flat Cut (Sail):
Any sail without initial camber engineered into its panels. Flat cut junk sails produce some camber in their panels through batten bending and sailcloth stretch. They produce whole sail, camber by allowing and controlling sail twist to adjust depth of curve. See Camber, Fanned Sail and Parallelogram Sail, and alternative, Cambered Sail.
Flat Sheeted: See Sheeted Flat.
Foil:
A streamlined surface designed in such a way that fluid flowing around it produces useful motion. This term is often used to describe shapes which are hydrodynamically and/or aerodynamically efficient. See Aerodynamic Theory, Aerofoil, Downwash, Drag, Hydrodynamic Theory, Lift, Lift to Drag Ratio and Upwash.
Foot:
Lower edge of sail. In junk rig, a boom is affixed along the foot, and occasionally a watersail. See Watersail.
Force Vector: See Vector.
Fore Lift aka Forward Lift:
A lift forward of the mast, rigged standing or running. In junk sails with a large balance, it may have a sail gatherer towards the lower portions. This term is widely used, but doesn't appear in PJR, which conflates forward lift with mast lift. [CSR pp. 4-5, figs. 1-2] [PJR p. 51 figs. 3.49-3.50] See Mast Lift.
Form Stability:
Vessel stability arising from hull shape. On a given footprint, the less the hull is cut away from the rectangular slab measuring length x beam x draught, the greater the form stability. See alternative, Ballast Stability.
Forward Lift: See Fore Lift.
Free Standing Mast: See Unstayed Mast.
Free Standing Rig: See Unstayed Rig.
Friction Block:
A sheaveless block. In junk rig, friction blocks may be used in sheeting systems to resist free movement of running lines toward equilibrium under pressure of wind, allowing the leech to be set to and retain a given shape. See Euphroe.
Furl: See Reef.
Furled Bundle: See Sail Bundle.
Gaff Rig (aka GR):
Non-junk rig composed of arrangements of quadrilateral sail(s) depending from a spar called a gaff, which is affixed along the sail’s head; the sail is constrained along its luff to the mast. Gaff sails are usually supplemented by smaller, triangular sails. Wikipedia: Gaff Rig
Ghoster:
A light, battenless headsail, often quite large, for use in very light wind. [PJR p 78, Figs. 5.1-5.8]
Goosewing Gybe (aka Chinese Gybe):
A partial, or incomplete gybe in which the lower sail gybes, but the upper sail does not, or vice versa. In quadrilateral sails, this puts the headand footof the sail on opposite sides along with the attached spars. Often, the boom, and possibly other spars will fan up, slackening the leech, leading to or exacerbating the situation. Sheeting well in before executing a controlled gybe generally prevents fan up and subsequent goosewing gybe. In junk rig, sheeted, full length battens reduce the risk of fan up and goosewing gybe.
Grommet: See Rope Grommet or Sail Grommet.
Gurney Flap:
A vertical section of fabric running along the leech of some junk sails, which recurves to windward. This may be integral to each panel or extend abaft the leech proper (in which case it takes its angle of incidence from aft led sheets). It is generally considered to degrade windward efficiency by increasing drag and moving the centre of pressure aft, and has not been widely adopted.
Gybe aka Jibe (noun):
A situation in which the wind, blowing from aft, rounds the leech of a sail, throwing it suddenly from one side to the other. Unlike a tack, at no point is the sail depowered. Junk sailbalance reduces the force of a gybe, and where shrouds are absent there is no potential for impact between them and the boom. See Accidental Gybe, Controlled Gybe, Goosewing Gybe, Gybe (verb), and alternative, Tack (noun).
Gybe aka Jibe (verb):
A manoever in which course or sail incidence is altered to bring the wind from one side of the sail to the other, incurring a gybe (noun). [PJR p. 208] See Accidental Gybe, Controlled Gybe, Goosewing Gybe and Gybe (noun).
Half Wishbone Batten: See Spilling Batten.
Halyard:
The control line used to raise and lower sail. In junk rig, it is often attached to a halyard crane and a sling point on the yard, with the fall led to deck level, and rigged to provide considerable mechanical advantage. It may raise the sail until double blocked or countered by a tack line. [PJR pp. 32-37, figs. 3.1-3.16] See Halyard Crane, Sling Point, Tack Line and Yard.
Halyard Crane (aka Masthead Crane):
An extension off the masthead to which the upper halyard block affixes. It is offset, precisely, to accommodate a junk sail’s offset yard, and is long enough to prevent blocks from chafing against the masthead. [PJR p. 133, figs. 8.19-8.21]
Hasler/McLeod Rig: See [PJR p.30, Fig. 2.25] See Common Junk Rigs.
Head:
The upper edge of a quadrilateral sail. In junk rig, the head is affixed to a yard.
Head Sail aka Headsail:
Any sail set ahead of the foremost mast. Generally, a triangular sail set from a forward stay. In junk rig, foresails must function clear of a junk sail’s balance. They tend to be relatively small, therefore, or not used. There are many exceptions, however, including the special case of Aerojunk rig. See Aerojunk Rig and Colvin Rig.
Heave To:
A sailing manoeuvre which brings a vessel to a near stand-still, possibly fore-reaching slightly and making leeway, while taking waves on a forward quarter. Motion is reduced, even in very poor conditions. After sail is generally sheeted flat, and the tiller often lashed to leeward, heading the bow into the wind. Forward sail, may be backed, as well, balanced against the drive from the after sail. A vessel may be hove to as a storm tactic, a stand-on manoeuvre, or to relieve crew. [PJR p. 208] See Weathercock and alternatives, Drogue, Lie Ahull and Sea Anchor.
Heel of Mast: See Mast Heel.
Helm:
The steering station (US), and/or steering mechanism of a vessel (e.g., tiller, wheel or whipstaff). See Lee Helm, Neutral Helmand Weather Helm.
Hem:
To fold over an edge of fabric one or more times and fix in place (generally by sewing). The resulting hem stops fraying, helps protect the edge of the fabric from chafe, and reinforces it against tensional stress. In junk sails, hems are sometimes used instead of roping.
Hi-Power Rig: See Common Junk Rigs.
Hinge and Stop Batten: See Hinged Batten.
Hinged Batten (aka Hinge and Stop Batten):
A segmented batten, hinged at the joints, with stop mechanisms to limit range of its hinges' motion. Generally, the stops are engineered to approximate an aerofoil curve. Under wind pressure, the sail presses battens out to their stops, making on an aerofoil shape.
Hollow:
Concavity cut into the leech between spars. This may help tame fluttering, and, when extreme, moves that panel’s Center of Effort forward/inboard.
Hong Kong Parrel:
Rope parrels, additional to batten parrels, running diagonally aft from the forward part of one batten to the next lower spar. They constrain batten movement, relative to one another, improving the set of their associated panel. They can, however, impose heavy stresses mid-batten. [PJR p. 46, figs. 3.40-3.41]
Horizontally Hinged Hybrid Rig aka Triple H Rig: See Common Junk Rigs.
Horizontal Hinge Method (Camber):
Method for engineering camber in junk sailpanels by extending the upper and lower edges from the batten toward the bunt (similar to shelf foot method) by means of alternating pockets, fitting round the bounding battens in the manner of a door hinge (battens serving as ‘hinge pins’). As hinges of varying length are affixed along a batten, they add their length to the vertical distance, measured across the bunt, creating commensurate slack. Under wind pressure, an aerofoil shape results. See Camber, and alternatives, Barrel Method, Broadseam Method, Dart Method, and Shelf Method.
Hullform:
A general class comprising hulls related by shape, history and/or features (e.g., sharpie, dory, Colin Archer and junk).
Hydrodynamic Theory aka Hydrodynamics:
The branch of fluid dynamics dealing with the motion and physics of moving water, especially when interacting with a solid. It is generally accepted as providing the best explanation of how a hull works. Wikipedia: Fluid dynamics See Foil and Vortex Theory.
Imperial System:
System of measurement based on factors of 12 (1,2,3,4,6,12) and rational fractions based on denominator powers of 2 (1,1/2,1/4,1/8,1/32,1/64, etc.). Still widely used in the USA, it has for the most part been replaced by the metric system world-wide. Wikipedia: Imperial system See Feet-Inches-Eighths, and alternative, Metric System.
Incidence (Angle) aka Angle of Attack:
The angle of a foil relative to a reference line. Generally, in boats, the angle will lie in plan, relative to the centreline of the boat (in the case of, say, a rudder), or the wind (in the case of a sail). Wikipedia: Angle of incidence / Wikipedia: Angle of attack
Irregular Fan:
A fanned region of a junk sail whose spars do NOT radiate from a single point. [PJR p. 29, figs. 2.21-2.24]
Jester Rig: See Common Junk Rigs.
Jiblet:
Forward, balance portion of a panel within a split junk rig, forward of its slot. A Jiblet establishes slot effect for the after portions of its (generally cambered) panel, increasing total lift to drag ratio (sail efficiency). See Slot Effect and Split Junk Rig.
Jibe: See Gybe.
Jointed Batten aka Segmented Batten:
Any batten which is segmented, and joined by flexible joints. Generally some stop mechanism will be engineered to limit degree of flex. See Bendy Batten and Hinge and Stop Batten.
Junk (aka Sampan [rare]):
Term loosely applied to a broad class of traditional, eastern hullforms, generally characterised by high sterns and sometimes, a widened foredeck. If a sailing hull, the rig is usually junk rig.
Junk Sail:
A standing, lug sail which is fully battened from luff to leech, with a sheeting system extending to all or most of the battens. Common usage often refers to the sail inclusive of its attached spars (yard, battens and boom). [PJR Chapters 2 and 3]. See Junk Rig.
Junk Rig (aka JR):
Fore and aft rig composed of one or more junk sails and all associated spars and rigging. [PJR Chapter 1] Wikipedia: Junk rig
Jury Rig:
A temporary rig improvised until repairs are possible. Unstayed masts, when used, and multiple battens present many opportunities for jury rigging. [PJR p. 214]
Keyboard Captain:
Exasperated term for an online person who projects expertise beyond their experience, and who may take liberties with positions of more authoritative persons. Forum participants are encouraged to verify information presented in online discussions. See Armchair Admiral.
Kicking Strap: See Boom Vang.
Kick-Up Rudder:
A rudder designed to be raised in shoal water. It may be raised manually, or automatically on contact with the bottom.
Lateral Resistance:
Resistance to transverse (lateral) motion. Generally, the lateral motion to be resisted is leeway. Structures providing lateral resistance slide forward relatively easily, and sideways relatively poorly. Lateral resistance is proportional to the profile, silhouette area of the structure or device, but may be enhanced by sectional shape. Lateral resistance can be provided by the hull itself, keels, centreboards, leeboards, daggerboards and rudders. When working to windward, lateral resistance counters lateral components of sail lift, leaving a net, windward force vector. Wikipedia: Center of lateral resistance. See Centre of Lateral Resistance, Leeway and Vector Analysis.
Lazy-Jack: See Topping Lift.
Lead:
The angles at and along which a line is led. WGNT
Lead:
The amount by which the sail plan's total centre of effort is forward of the centre of lateral resistance. Generally expressed as a percentage of the waterline length. The amount of lead is generally determined by rule-of-thumb, taking into account sail and hull characteristics. [PJR p. 94]
Lee:
The direction away from the wind.
Lee (In the lee of):
The side away from the wind.
Lee Helm:
The tendency to fall off the wind, despite a centred helm. Wikipedia: Lee helm. See alternatives, Balanced Helm and Weather Helm.
Leech:
After edge of sail. WGNT
Leeward:
The direction generally opposite the wind.
Leeway:
Travel or drift to leeward. In sailing, this may be expressed as an angle of incidence, or as a transverse vector. Wikipedia: Leeway
Length Above Partners aka LAP:
Height of a mast measured from partners to mast head. This value is especially useful for calculating mast diameterand mast bury in unstayed masts. See Mast Bury, Mast Diameter and Common Formulae and Ratios.
Lens Method (Camber): See Shelf Method.
Lie Ahull:
To drift, beam on to wind and seas. Junk sails may remain fully or partially raised, and allowed to weathercock with eased sheets. [PJR p. 208] See alternatives, Drogue, Heave To, Sea Anchor and Weathercock.
Lift (Rigging):
Standing and/or running rigging system comprising lines led to and from the masthead, around the boom via positioning eyes. Lifts support the sail bundle, and gather the junk sail and attached spars. If rigged running, they may adjust the height and slope of the sail bundle. The lower portions may bifurcate one or more times, and/or have a sail gatherer attached. See After Lift, Forward Lift, Mast Lift, Topping Lift, Sail Bundle, Sail Gatherer and Upward Reef.
Lift aka Aerodynamic Lift aka Hydrodynamic Lift:
Force produced by a foil, at roughly right angles to the foil on its convex side, as wind or water pass across it. Lift is generally depicted by a force vector and subject to vector analysis. Efficient foil shapes cant this force vector toward the foil's leading edge. Sails generate lift, whose transverse vector components are countered by lateral resistance. Wikipedia: Lift (force) See Aerodynamic Theory, Hydrodynamic Theory and Vector Analysis.
Lift to Drag Ratio
Measure of efficiency of a foil. The higher the ratio, the greater the efficiency. Wikipedia: Lift to drag ratio See Aerodynamic Theory, Drag and Hydrodynamic Theory.
Loft:
To lay out cut, join, place and fold lines and points, full sized, onto construction materials. Often, this involves curves which may be lofted with the help of a batten. Generally, sails and hulls are lofted. Wikipedia: Lofting
Long Batten Parrel: See Batten Parrel.
Loom:
The long, central shaft of an oar, yuloh or ro.
Luff:
The forward edge of sail.
Luff (Sail):
The luff (forward edge of sail) is said to luff as wind from forward begins to round to the lee side of the sail, indicating that one is pinching. The luff of a flat-cut junk sail is tensioned by the weight of the lower panel and boom, so tends to luff late, giving tardy warning of pinching. See alternative Stall.
Luff aka Luff Up:
To round up into the wind far enough to reduce sail drive. This point is often indicated by luffing and reduced angle of heel. It can be a technique temporarily to reduce sail power in a gust, or to aid timing in making an entrance. See alternative Bear Away.
Luff Hauling Parrel (aka LHP):
Running luff parrels(s) allowing adjustment of the luff's position on the mast. Tensioning hauls the luff (and junk sail) aft, countering a junk sail's general tendency to swing forward under the influence of gravity, possibly distorting sail shape in the process; easing allows it to swing forward. Separate luff hauling parrels may be rigged to control some or all of the luff. Generally, control of mid- to upper luff is considered sufficient for good sail set. [PJR p. 47, figs. 3.42-3.44]
Luff Parrel:
Any parrel which constrains and/or controls the luff of a junk sail. A luff parrel may be standing or running, and several of either or both may be rigged in one sail. [PJR pp. 44-48, figs. 3.35-3.44] See Luff Hauling Parrel, Standing Luff Parrel and Throat Hauling Parrel.
Lug:
The spar from which a lug sail depends. In junk rig, the convention is to refer to it as a yard. See Yard.
Lug Rig:
Vessel rigged with one or more lug sails and all associated rigging. Lug sails are rigged either standing (sail always on one side of its mast) or dipping (sail is transfered from one side of its mast to the other by lowering (dipping) the lug and bringing it across while near vertical). Wikipedia: Lugger
Lug Sail:
Quadrilateral sail suspended from a lug, extending forward of the mast forming sail balance, and held in place at the bottom by the sheet and tack downhaul. See Chinese Lug Sail, Junk Sail, Lug Rig and Yard.
Mallory Rig: See Common Junk Rigs.
Mast:
Principal, vertical or raked spar, on which sail is set. In Junk Rig, it is generally circular in section, conic in profile, tapering from full mast diameter at the partners to half or less that at the masthead, and often free-standing. It may be constructed solid (usually of grown timber or laminated wood), or hollow (from hollowed timber, wooden staves, drawn aluminium, galvanized steel or fiber/resin composite). A mast is subject to compression loading from tension between halyard and tack line, and torqued by the halyarda nd halyard crane. Mast flex tensions the windward side and compresses the leeward side (approximately speaking). [PJR Chapter 8] See Mast Bury, Mast Diameter, Mast Rake, Masthead, Mast Heel, Mast Step, Partners and Tabernacle.
Mast Bury:
The proportion of a cantilevered, unstayed mast below mast partners to its length. In free-standing masts, adequate mast bury is essential, with a minimum of 9% of the mast's overall length, or about 10% of its length above partners. [PJR p. 115] [CSR p. 38, fig. 9]
Mast Diameter:
The diameter of a mast at any given point along its length. In Junk Rig circles, it generally refers to the point of widest diameter, just above the partners, unless noted otherwise. A Junk Rigmast is generally circular in section, and tapers from full diameter, just above the partners to one half or less of that at the masthead. Mast diameter is generally calculated by formula according to material, height of mast, sail area, and beam of vessel, and augmented by a safety factor. [PJR p. 121, Fig. 8.2] See Masta nd Common Formulas.
Mast Head: See Masthead.
Mast Heel aka Heel of Mast:
Lower end of the mast, stepped in a mast step or fixed (in a tabernacle) by a mast stop.
Mast Lift aka Forward Lift:
A standing or running lift gathering and supporting the sail bundle at the mast. PJR uses the same term for a lift rigged forward of the mast, but many prefer to draw a distinction, using forward lift in this case. See Forward Lift, Liftand Topping Lift. [PJR pp. 50-51, Figs. 3.49 and 3.50]
Mast Line aka Mastline (aka ML):
The designed or actual position of the mast across its associated junk sail. If the sail's position on the mast is adjustable, there may be more than one mast line specified, generally at the limits of adjustment range(s). [PJRp. 109, fig. 6.28]
Mast Partners:
The structures supporting a stepped mast at deck or cabin-top. [PJR pp. 141-145, figs 9.1-9.7] See Mast Step.
Mast Pivot:
In a tabernacle, the point around which a mast pivots when lowered. Generally, a hinge structure is arranged around a pivot bolt, from which the mast is hung. Generally, the pivot bolt determines the point from which mast bury is determined. See Tabernacle.
Mast Position:
The position of a mast within the hull.
Mast Rake aka Rake:
Inclination of a mast, fore or aft, from vertical. In still conditions mast rake, in conjunction with gravity, influences the rest position of a junk sail. If raked forward, the tendency is to swing outboard. If raked aft, the tendency is to swing inboard. If vertical, there is no tendency to swing (random rest position within range of permitted swing). Forward mast rake is generally considered to be helpful in spreading sail in light airs and to delay a gybe. [PJR p. 40, figs. 3.21-3.23] See Rake.
Mast Step:
The structure receiving, supporting and securing a mast heel. A mast may be stepped at the keel, the deck or in a tabernacle. See Mast and Tabernacle.
Mast Stop:
In a tabernacle, a means of affixing the mast heel. In conjunction with the mast pivota nd tabernacle structure, it holds the mast in cantilever. See Tabernacle.
Mast Topping Lift: See Topping Lift.
Masthead aka Head of Mast (aka Mast Head):
Upper end of mast, to which a masthead fitting may be affixed. WGNT
Masthead Crane: See Halyard Crane.
Masthead Fitting aka Masthead:
Fabricated hardware mounted at the masthead to provide landings for all lines led to the masthead (e.g., halyard, lifts, stays, etc.), and additional masthead hardware (e.g., antennas, windvanes, etc.). See Masthead Crane. [PJR p.133, figs. 8.19-8.21]
Mastheel: See Mast Heel.
Mastline: See Mast Line.
Mechanical Advantage aka Advantage:
A measure of the force amplification achieved by using a tool, mechanical device or machine system. Typically, advantage is expressed as a ratio of force output to force input. For example, a system with mechanical advantage of 3:1 (spoken three to one) generates total force approaching three times the input force, but takes three times as long to do the same amount of work as a 1:1 system. In all hardware systems, some force is lost to friction between parts in relative motion.. Wikipedia: Mechanical advantage See Purchase.
Metric System:
System of measurement based on powers of 10 (...,1/1000,1/100,1/10,1,10,100,1000,...). Metric has become the standard, world-wide, though the imperial system is still widely used (outside the scientific community) in the USA. Wikipedia: Metric system See alternative, Imperial System.
NACA Aerofoil:
A protocol to specify Aerofoil shapes developed by the National Advisory Committee for Aeronautics (NACA, predecessor to NASA). Aerofoil shape is described using a series of digits following the word NACA. Parameters in the numerical code can be entered into equations to precisely determine the cross-section of the aerofoiland calculate its properties. Wikipedia: NACA airfoil
Negative Stagger:
Among battens furled into the sail bundle, overlap of upper battens by lower ones. Negative stagger at the aft end of the sail bundle may foul aft lead sheets. At the forward end, excessive negative stagger may critically reduce or eliminate extension of battens and/or yardforward of the mast(line), leading to fouling if uncompensated. [PJR p.22, fig. 2.8]
Neutral Helm: See Balanced Helm.
Neutral Stagger:
No significant overlap among battens furled into the sail bundle. Neutral stagger at the aft end of the sail foul aft lead sheets. Neutral stagger may result from camber cut into junk sailpanels, and may require compensating rigging or geometry to force aft, positive stagger.
P (Panel Height):
In some discussions, refers to height of a panel, understood as a variable for some exact value. Where it is measured varies. Check context. See Panel Height. [PJR p. 96, fig. 6.8]
Panel:
In a junk sail, sailcloth separated by spars and, by JRA convention, numbered from the lowermost (number one) upward. These may be sewn from multiple pieces of fabric and pocketed, or grommeted and lashed for attachment of spars. [PJR p. 5]
Panel Height (aka P):
The height of a given panel. It is often measured precisely along the leech, but may also be used generically without reference to a precise value. Check context. [PJR p. 96, fig. 6.8]
Parallelogram:
Area of a Junk sail whose profile is characterized by parallel edges and spars of constant length. Generally, these spars are canted by a precise amount of aft elevation (batten rise) to yield positive stagger at the after sail bundle. Scallop developed by flat-cut, parallel panels are approximately cylindrical in section. Cambered panels may affect furling properties. Parallelograms are often incorporated into junk planforms for their constant furling qualities and straight leech, which work well with aft lead sheets. See Rise, and alternative Fan.
Parallelogram Planform: See Parallelogram Sail.
Parallelogram Sail aka Parallelogram Planform:
A junk sail embodying a significant parallelogram. Generally, the parallelogramis engineered for positive stagger at the after sail bundle. [PJR p. 24, fig. 2.11] See Rise, and alternative, Fanned Sail.
Parrel:
Any one of a number of junk rig lines passing from spar, across or around the mast, to spar, and any associated rigging. Parrels may be rigged standing or running (the latter often designated as a hauling parrel). They are used to position, constrain and control the junk sail. See Batten Parrel, Boom Parrel, Boom Hauling Parrel, Luff Parrel, Snotter, Throat Hauling Parrel, Tack Parrel, Yard Hauling Parrel and Yard Parrel. [PJR pp. 42-48, figs. 3.30-3.44]
Partners: See Mast Partners.
Peak:
The aft, upper corner of a quadrilateral sail, including the junk sail. WGNT
Peak Up (the Sail or Yard):
To raise or tension the peak. In practice, the after end of the yard is tensioned (peaked up) by downward tension at the throat, and/or by moving the sling pointaft. See Sling Point and Throat Hauling Parrel.
Pinch:
To point so high into the wind that sail lift diminishes or fails (luffs). Flat cut junk sails tend not to signal pinching by sail flutter along the luff, so extra attention from the helm is required. WGNT
Pivot Bolt (Tabernacle):
In a tabernacle a transverse bolt arranged in a hinge arrangement with mast and tabernacle structure, from which the mast is hung, and around which it pivots while lowering. See Mast Pivot.
PJR (Practical Junk Rig): See Practical Junk Rig.
Planform (aka Sail):
A family of sails and variants whose geometry follows a particular set of guidelines or tradition, and individual sails within such a family. For example, "The Reddish planform (or Reddish sail) is fanned." Often a planform will have certain rigging strongly associated. See Rig, Sailplan and Common Junk Rigs. [JRA]
Plan View:
View from top or bottom (as specified). Deck and interior layouts are generally presented in plan view. WGNT See Profile View, Section View and View.
Pointing Ability:
The angle of incidence of a vessel's heading relative to the wind. A vessel which is able to point high into the wind (low angle of incidence) is said to have greater pointing ability. Generally, junk rigged vessels have had less pointing ability than, say, Bermudan rig, though recent developments are promising. Pointing ability is just one factor in windward efficiency. See Aerojunk Rig, Camber, Slot Effect, Split Junk Rig and Windward Efficiency.
Positive Stagger:
Among battens furled into the sail bundle, overlap of lower battens by upper ones. Adequate positive stagger at the after sail bundle lets sheet spans hang clear of battens and one another, virtually eliminating fouling of aft lead sheets. Positive stagger is generally engineered via sail geometry, but may be imposed by various rigging. [PJR p.22, fig. 2.8 and Chapter 2]
Practical Junk Rig aka PJR (aka JR Bible):
1988 book by HG Hasler and JK McLeod containing detailed analysis of general Junk Rig construction and use.
Preventer:
Any line (often temporary), rigged to constrain movement of spars. They may be rigged to prevent or reduce accidental gybes, fan ups, sail twist, etc.. See Boom Vang and Kicking Strap.
Profile View:
View from port or starboard (as specified). Known as 'side elevation' in architecture. Sails are presented in profile view by convention. WGNT See Plan View, Section Viewand View.
Purchase:
Mechanical advantage derived from blockand tackle or similar arrangements. Generally, advantage equals the number of line parts in motion (i.e., not affixed) relative to the block hauling a load, minus a percentage of loss to friction. In junk rig, halyards, hauling parrels and sheet systems apply purchase in varying amounts to control the rig. Wikipedia: Mechanical advantage. See Block and Tackle, Mechanical advantage and Tension.
Quilting:
The diamond pattern formed in some (especially some traditional) junk sails by stitching and/or reinforcing strips. Aerodynamic benefits, if any, are contested.
R ((Batten) Rise):
In some discussions, refers to batten Rise, understood as a variable for some exact value. Check context. See Batten Rise.
Rake:
Said of a structure which has been inclined from vertical (e.g., a mast, bow or transom). Generally, the subject is specified initially for a given discussion, which is then assumed until further notice (e.g., "Our mast has forward rake" or "Our mast rakes aft" becomes "rake helps swing the boom outboard" (mast rake assumed)). Check context. See Mast Rake. WGNT
Reddish Rig: See Common Junk Rigs.
Reef (aka Furl aka Shorten Sail):
To reduce standing junk sail area by lowering one or more panels into the sail bundle. The procedure in a junk rigged vessel is generally as follows: a) release the halyard, b) lower desired number of panels into the sail bundle (sheets will slacken as the sail is lowered), c) make halyard fast, d) trim sail, and e) if other control lines have slackened, trim as necessary. Reefing generally takes a matter of seconds from start to finish. Rounding up is generally unnecessary, though when reefing while running, eased sheets slacken further to let the sail swing forward, and compression loads on the battens mount; rounding up to some extend may be advisable. [PJR p. 205] See Reef Upward, Sail Bundle and Upward Reef.
Reef Upward:
To furl one or more panels upward, generally by hauling one or more running lifts. See Upward Reef.
Reefed Bundle: See Sail Bundle.
Regular Fan:
A fanned region of a junk sailwhose spars radiate from a single point, external to the sail. [PJR p. 24, figs. 2.12-2.20]
Rig (noun):
A planform or type with its associated rigging and spars as is common, designed or implemented. They are often named for a feature (e.g., Split Junk Rig), a vessel strongly associated with it (e.g., Jester Rig), or the person who developed it (e.g., Reddish Rig). See Planform and Sailplan. [JRA]
Rig (verb):
To implement or install a system. Generally referring to rigging, but may be used in other contexts. See Engineer and Jury Rig. WGNT
Rigging:
Any item or coherent collection of line or tackle incorporated into a rig. WGNT
Rigging:
The aggregate of rigging systemsor rigging components associated with the subject under discussion (e.g., rigging of the junk sail, the mast, the vessel as a whole). WGNT
Rigging System:
Any assemblage of cordage and hardware (e.g., blocks, fairleads, cleats, etc.) into a coherent system (e.g., sheeting system or halyard). Typically, these systems will position, constrain and control spars and/or sails. They may be rigged standing, running or a combination. See Control Lines.
Rigid Batten:
A batten engineered for minimal bending. Rigid battens have been generally preferred, especially in more traditional junk rigs. See alternatives, Bendy Batten and Tuned Batten. [PJR p. 13, figs. 1.6-1.8]
Rise: See Batten Rise.
Ro aka Ryo:
Japanese variant of the yuloh, distinguished by precise loom angles and a longer blade. See Yuloh. [Douglas Brooks: A Different Way to Ro WBM 192:54]
Roach:
Convex curve in the leech of a fanned portion of a junk sail. In junk rig, this may interfere with aft lead sheets, and require them to be manually passed around the roach when tacking. WGNT
Rope Grommet aka Grommet:
A loop made from a single strand of laid line or twine. It is made by laying the strand around itself to reconstruct the lay, then splicing the ends against and into the lay. Small ones may be used to form sail grommets with associated techniques. Larger ones may be used to create an eye along any spar, post or open rail by draping the flat loop around one or more times, and feeding one bight through the other. One or more thimbles or eyes may be seized into a bight or bights. A grommet forms the strop of a rope stropped block. WGNT See Grommetand Rope Stropped Block.
Rope Stropped Block:
A block whose bail and becket (if present) are attached by means of a siezed, rope grommet. See Block and Rope Grommet. WGNT
Roping: See Bolt Rope.
Round Only Method: See Barrel Method.
Running Back Stay:
A running stay leading aft and to one side of the mast, typically rigged in pairs. Generally, on each tack, the windward stay is set up taut to provide support against wind pressure, and the leeward stay is eased. Running back stays are common on rigs such as junk rig and gaff rig, in which the peak would foul a stay rigged standing along the vessel's centerline.
Running (Line or Rigging):
Rigging which is adjustable in the normal course of sailing. Running lines are generally control lines and are often designated as hauling lines. In junk rig the fall of a running line is generally led to the cockpit. See entries beginning with Hauling or Running, and alternative, Standing (Line or Rigging). WGNT
Running Spanline (aka Sheet Hauling Span aka Spanline):
A control line, rigged running, led through a euphroe, and linking sheet and sheet spans and/or aft batten ends. The running spanline is adjusted to shape the sail's leech, controlling sail twist and 'belly'. Position is held by friction holes in the upper euphroe. The running spanline may require shortening as the sail is reefed, generally after each two or three panels are furled. [PJR pp. 74, figs. 4.51-4.52] See Euphroe, Sheet Span and Sheeting System.
Running Tack Parrel (aka Tack Hauling Parrel aka Boom Hauling Parrel aka Bowsing Tackle):
A parrel toward the tack, rigged running, and variously along the forward boom. It is used to haul the junk sail aft, reducing balance for on-the-wind sailing. When eased, the sail is allowed to swing forward, increasing balance for offwind sailing. [PJR p. 42, fig. 3.24]
Ryo: See Ro.
S (Sling Point):
In some discussions, refers to Sling point. Check context. See Sling Point.
Sail: See Planform.
Sail Bundle aka Bundle aka Reefed Bundle aka Furled Bundle:
The portion of a fully or partially reefed junk sail and spars which accumulate in sail gatherer portions of lifts. Ends of spars lowered into the sail bundle develop stagger. See Lift, Sail Gatherer and Stagger.
Sail by the Lee:
A phrase which describes the situation where the wind has crossed the vessel's stern (to the same side as the sail), but the sail has not (yet) gybed. When sailing by the lee, one is at risk of imminent, accidental gybe. The margin of error in sailing by the leeis, however, higher among junk rigged vessels, especially those with unstayed masts. See Gybe.
Sail Gatherer (aka Sail Catcher):
Extra lines, or a fabric pouch, affixed to lower lifts for the purpose of gathering bunts when furled into the sail bundle. [PJR p. 53, fig. 3.53]
Sailcloth:
The fabric or film portion of a sail, or its constituant lengths. In a junk sail, sailcloths are generally oriented lengthwise, parallel with the leech, in line with tensional stresses transferred from the yard. Wikipedia: Sailcloth See Fabric.
Sail Grommet aka Grommet:
A smallish eye affixed to sailcloth, through which a line may be passed. It's purpose is to spread the load imposed by the line, and protect sailcloth from chafe. Often, these are made of two metal components, pressed and peened together. Spur-tooth grommets have teeth between their components which 'bite' sailcloth for enhanced hold. Rarely, a sail grommet may be fashioned from a very small rope grommet sewn in place. See Grommet and Rope Grommet.
Sailplan aka Sail Plan:
The design for a specific sail, specifying dimensions, location of spars, rigging and particulars. By convention, the sail is drawn in profile. WGNT. See Planform and Rig.
Sail Twist aka Twist:
Greater angle of sail incidence (relative to the vessel centerline) aloft than alow. Degree of sail twist in fully battened, junk sails imparts some camber to the sail as a whole. These battens are controlled along the leech by sheeting systems (an advantage over western rigs, which are not).
Sampan:
Usually a smaller, traditional, eastern water craft, often with a wide, overhanging bow and bow transom, and high stern. Occasionally, indicates a hullform reminiscent of those craft, such as a junk. Wikipedia: Sampan. See Junk.
Scallop:
Tendency of the bunt of junk sail panels to curve to leeward under press of wind, drawing their bounding spars slightly toward the panel's center of pressure. Scalloping is approximately cylindrical in section, when battens are parallel, and conic in section, when battens are fanned (camber complicates this simplified account). [PJR p. 16, figs. 1.10-1.11] See Camber, Fan, Parallelogramand Vortex Theory.
Scantling:
The dimensional specifications for construction elements (e.g., timbers, frames, planks, etc.), especially spars. WGNT [PJR chapters 8 and 10]
Sea Anchor:
A drag device deployed into the sea from or near the bow, which holds it up to meet seas while stopping all forward progress. Generally, the setting of a sea anchor is a heavy weather tactic. Junks were the first known vessels to deploy them. See alternatives, Drogue, Heave To, Lie A'Hull and Weathercock.
Seam:
Join between two lengths of fabric. In sailcloth, seams are generally overlapped and sewn. See Broadseam and Sailcloth.
Section View aka Sectional View aka End View:
View from forward or aft (as specified); possibly transected by a plane, as one might slice a loaf of bread. See Plan View, Profile View and View. WGNT
Section-of-Cylinder aka Cylindrical Section:
A curved shape, such as may be cut from the sides of a cylinder, in which all longitudinal lines run parallel. In junk rig, parallelogram panels are generally section-of-cylinder, especially when flat cut. Sheet construction materials can assume cylindrical section shapes.
Section-of-Cone aka Conic(al) Section:
A curved shape, such as may be cut from the sides of a cone, in which all longitudinal lines run convergent. In junk rig, fanned panels are generally section-of-cone. Sheet construction materials can assume conical section shapes.
Segmented Batten: See Jointed Batten.
Self Tending (Sail or Rig):
Any sail which need not be adjusted between tacks, or a rig composed of such sails. Junk sails are typically self tending, and junk rigged vessels without fore sail(s) generally are, as well. WGNT
Selvage: See Selvedge.
Selvedge aka Selvage
An edge along a length of fabric which is woven back on itself, leaving no loose ends to fray. Wikipedia: Selvedge. See Fabric.
Shear:
'Scissory' forces acting across the longitudinal run of a body. For example, a pair of scissors (shears) cutting paper are applying shear forces to that paper. A body engineered to resist shear or shear forces is said to be acting in shear. In junk rig, many fasteners and fittings work in shear. Wikipedia: Shear force. See Compression, Tensionand Torque.
Sheave:
The wheel component of a block, rotating about a pin with relatively low friction. Bearings may further reduce friction. WGNT
Sheet:
A running line which principally controls sail incidence relative to the vessel centerline. A sheet may be manipulated from one or both ends. It typically tensions a euphroe or sheet span, but occasionally attaches directly to an aft batten end. [PJR Chapter 4] See Double Sheets, Euphroe, Running Spanline, Sheeting System, Sheets, Single Sheetsand Sheet Span.
Sheet Hauling Span: See Running Spanline.
Sheet Span (aka Sheetlet aka Bridle):
Standing part of a junk rig sheeting system linking two or more batten aft ends to the sheet or running spanline. Sheet spans may be rigged for various distributions of force, transferred among the battens they connect. [PJR p. 56, figs. 4.3-4.5] See Sheet, Running Spanline, Sheeting System.
Sheeted Flat aka Flat Sheeted:
When sheets are hauled in to their limit, forcing sail as close to the centerline as possible. Standing sails are generally sheeted flat when the vessel is to be weathercocked.
Sheeting System: See Sheets.
Sheetlet: See Sheet Span.
Note: American Designer Tom Colvin uses the term sheetlet for what PJR refers to as running span line.
Sheets (aka Sheeting System):
Assembly of control line(s) affixed along the leech of a junk sail at or near batten ends, which collectively control sail incidence (ease out, haul in), and sail twist (to a degree varying with implementation). They further provide downward tension at aft batten landings, countering fan-up tendencies. They minimally include a sheet, generally include one or more sheet spans, and may include one or more euphroes, sheet hauling spans and various blocks. Single sheets or double sheets may be rigged on a given sail. This system of sheeting along the leech is a distinguishing characteristic of junk rig. [PJR Chapter 4] See also Double sheets, Euphroe, Sheet, Sheet Span, Single Sheet and Running Spanline.
Shelf Method (aka Shelf Foot Method aka Lens Method):
Method for engineering camber in junk sail panels by extending from each upper and lower panel edge a longitudinal, cambered strip of fabric (the ‘shelf’), extending from battens, with their convex edges toward the panel’s bunt, to join the corresponding edge of a central panel. At each point along their length, they add to the vertical distance measured across the bunt, creating commensurate slack. Under press of wind, an aerofoil shape results. [CP & SJR] See Camber, and alternatives, Barrel Method, Broadseam Method, Dart Method,and Horizontal Hinge Method.
Short Batten Parrel: See Batten Parrel.
Shroud:
Transverse, standing lines led from high on the mast to deck level, at near right angles to the vessel's centerline, in support of the mast. Shrouds limit lateral movement of the mast. WGNT. See alternative, Stay.
Single Sheets aka Aft Lead Sheets:
Single sheets affixed along the leech and led to (near) deck level. A single sheet is generally, but not always, rigged for first pull from top (hauling part tensions upper leech). See Sheets, and alternative, Double Sheets.
Sister Block:
A specialized block, or linked blocks, with a sheave at each end. These may be employed where the bights of two lines are to run freely, one along the other (typically in various arrangements of sheet spans). They have been found to be unnecessary, so long as any single blocks involved have sufficiently wide, smooth bails. [PJR p. 59, figs 4.7-4.9] See Block.
Sling Point aka S:
The point from which the yard attaches (is slung) from the halyard, usually at or slightly aft of the yard's midpoint. Positioning the sling point aft of mid-point helps peak up a junk sail. See Peak Up and Yard.
Slot Effect:
Aerodynamic effect wherein a sail alters the airflow around its associated, overlapping foresail creating a lifting windshift (increased upwash) ahead of the foresail, and increasing airflow velocity along its windward side. This makes the foresail more efficient than it would be on its own. Junk rig vessels seldom carry overlapping foresails. The slot effect may apply in junk rig- disputed where not overlapping - in cases of multiple sails, when a sail is fitted with headsails, or in adaptations of the junk rig, such as the Aerojunk Rig and Split Junk Rig.
Soft Wingsail Rig: See Common Junk Rigs.
Snotter:
A control line which tensions a spar, usually from its forward and/or lower end. See Sprit, Sprit Boom and Sprit Sail, Boom Hauling Parrel, Throat Hauling Parrel, Yard Hauling Parrel. WGNT
Spanline: See Running Spanline.
Spar:
Generic term for mast, yard, batten and boom in Junk Rig, and similar components of other rigs. See Batten, Boom, Mast and Yard. WGNT
Spilling Batten aka Half Wishbone Batten:
A curved batten, which spills from tack to tack, convex side leeward. It is affixed to the sail at luff and leech only, and able to rotate at the attachment points. Under press of wind, sailcloth conforms to its curve, assuming an aerofoil shape. See Batten and Wishbone Batten.
Split Junk Rig: See Common Junk Rigs.
Sprit:
A spar which cuts across the bunt of a sail. It may cut diagonally across a quadrilateral sail, from (near the) tack to peak (sprit of a sprit sail, or from mid-luff to clew (sprit boom) It is never used on a junk sail, but may be rigged on smaller sails on otherwise junk rigged vessels. WGNT. See Sprit Boom and Sprit Sail.
Sprit Boom:
A sprit, rigged from mid-luff to clew. It is self-vanging, and generally tensioned from its forward end by a snotter. It is never used on a junk sail, but may be rigged on smaller sails on otherwise junk rigged vessels. WGNT. See Sprit, Sprit Boom and Sprit Sail.
Sprit Sail:
A sail spread by a sprit, rigged diagonally across a quadrilateral sail, from (near the) tack to peak. The sprit is generally tensioned from its forward end by a snotter. It may be rigged as a smaller sail on otherwise junk rigged vessels. WGNT. See Snotterand Sprit.
Stability (Fabric):
Resistance of a fabric to stretch. Stability is always least along the bias. See Fabric, and alternative, Stretch.
Stagger: See Batten Stagger.
Stagnation Point:
A point in a flow field where the local velocity of the fluid or gas is zero. Stagnation points exist at the surface of objects in the flow field, where the fluid is brought to rest by the object. (Static) Pressure is highest when the velocity is zero and hence pressure is at its maximum value at stagnation points. In junk rig related discussions, the stagnation point is generally raised in reference to foils.Wikipedia: Stagnation point. Wikipedia: Static pressure
Note: A full definition is outside the scope of this glossary. Please consult references for further information.
Stall:
Separation of airflow from the lee side of the sail, disrupting and greatly reducing aerodynamic lift. Stall occurs when the sail’s angle of incidence to the apparent wind increases to a critical degree (when sailing too far off the wind). See alternative Luff (Sail).
Standing (Line or Rigging):
Rigging which is fixed (not adjusted) during normal sailing. Generally, if a line is not specified as running or hauling, it is assumed to be standing, though there are exceptions such as halyard and sheets. Check Context. WGNT See entries beginning with Standing, and alternative, Running (Line or Rigging).
Standing Lower Luff Parrel:
A luff parrel, rigged standing, affixed to the forward ends of the boom and lowermost batten, which constrains forward movement of these spars. [PJR p. 42, Fig 3.26]
Standing Luff Parrel:
A luff parrel, rigged standing, affixed to one or more spar ends, generally returning to another along the luff. These constrain a junk sail's position, relative to the mast. [PJR p. 44, figs 3.35-3.38] See alternatives Short Batten Parrel and Luff Hauling Parrel.
Standing Tack Parrel:
A parrel, rigged standing, starting and ending at the tack. It constrains forward movement of the boom relative to the mast. [PJR p. 42, Fig. 3.25]
Standing Throat Parrel:
A parrel, rigged standing, affixed to the throat, and forward end of an upper batten. It constrains forward movement of the throat, and helps to peak up the yard. [PJR p. 46, fig. 3.39]
Standing Yard Parrel aka Yard Parrel:
A parrel, rigged standing, affixed near the sling point and forward end of the yard. It prevents the yard from blowing away from the mast. In some cases it may be rigged around the halyard and/or lifts to prevent fouling with the yard end during a fan-up. [PJR p. 55, fig. 3.56]
Stay:
A line led from high on the mast to deck level, generally along the vessel's centerline, limiting fore and aft motion. Sails may be set on a stay. WGNT
Stay:
A stay or shroud, generically speaking. A mast rigged with either or both is said to be stayed. WGNT See Stayed Mast and Unstayed Mast.
Stayed Mast (or Rig):
One or more Masts supported by stays and/or shrouds. These may be strongly or lightly tensioned. See alternative, Unstayed Mast.
Steerageway:
Sufficient flow of water over the rudder to enable response to the helm. Requisite velocities vary by vessel and rudder characteristics. WGNT
Stretch (Fabric):
The tendency of fabric to deform under tensional load, greatest along the bias. If stretched fabric recovers as tension eases, it is said to be elastic. In sailcloth, inelastic stretch generally degrades sail performance, and specialized fabrics are often used to minimize stretch. In junk sails, however, stretch may contribute to camber. See Fabricand Sailcloth.
Strop:
A short length of line or rope grommet used to affix one item of rigging to another, or to the vessel. See Rope Stropped Block.
Sunbird Rig(s): See Common Junk Rigs.
Tabernacle:
A box-like structure securing a cantilever mast at its lower end (generally near deck level). The mast is generally hinged around a pivot bolt, with mast heel secured by a mast stop. A tabernacle generally facilitates raising and lowering a mast. A mast is said to be stepped in a tabernacle, despite having no mast step, in the usual sense. Unstayed masts are often stepped in a tabernacle, with sufficient bury between pivot bolt and mast step. See Bury, Mast Step, Pivot Boltand Unstayed Mast. WGNT
Tack (noun):
Lower, forward corner of sail. WGNT
Tack aka Come About (verb):
A sailing manoeuvre in which course is altered, bringing wind across the bow from one forward quarter to the other. During this manoever, while more or less head to wind, the sail is depowered and luffs. See alternatives, Gybe (verb) and Wear Around.
Tack Hauling Parrel: See Running Tack Parrel.
Tack Parrel: See Standing Tack Parrel and Running Tack Parrel.
Tackle aka Block-and-Tackle:
A running combination of line and block(s), often comprising all or part of a rigging system. Wikipedia: Block and tackle. See Rigging.
Tackline:
Short, standing line affixed to the boom abaft the mast and to a deck eye close to the mast. It constrains and tensions the fully raised junk sail against the pull of the halyard. [PJR p. 45, Fig 3.36]
Tension:
'Stretchy' forces acting longitudinally on a body, to pull it apart or away from an attachment point. A body engineered to resist tension or tensional forces is said to act in tension. In junk rig, many fasteners, all control lines and sailcloths act in tension. Wikipedia: Tension (physics). See Compression, Shear and Torque.
Thread:
A specialized yarn, which is generally of small diameter, twisted and laid (like very small rope). It is used in the manufacture of fabric and to hem and sew lengths together. See Fabric.
Thread Count:
A value given to represent the density of a weave. For any given method, the higher the count, the more dense the weave. Standards for these measures are not yet firmly established. Check context for units and methods involved. See Weave.
Throat: Upper, forward corner of a sail. WGNT
Throat Hauling Parrel(aka THP):
A parrel, rigged running, which pulls aft and down on the throat of a junk sail, controlling its position relative to the mast. It helps peak up the yard for better sail set. This line has been developed in support of fanned and cambered sails. [JRA]
Topping Lift aka Aft Lift (aka Lazy Jack):
Rigging system led from the masthead down one side of a junk sail, through eyes on the boom and back to the masthead on the opposite side of the sail. It gathers and supports the sail bundle, and may be rigged standing or running. It may divide into sail gatherers in the lower portions. See Lift, Forward Lift, Mast Lift and Sail Gatherer. [PJR p.50, figs 3.47-3.48]
Torque aka Wrack:
'Twisty' forces acting on a body. In junk rig, the masthead crane torques the mast. Wikipedia: Torque. See Compression, Shear and Tension.
Transitional Panel:
One or more panels of a junk sail which transition between a parallel battened region (parallelogram), below, and a fanned region above. It is, in effect, the lowermost, fanned panel of the upper fanned region, but generally has more in common with those below than those above, being distinguished by a modest increase in batten angles, and possibly a change of height. [JRA]
Triple H: See Horizontally Hinged Hybrid Rig and Horizontal Hinge Method.
Triple H Rig: See Common Junk Rigs.
Tuned Battens aka Bendy Battens:
Battens which have been shaped and/or reenforced to flex a certain amount under press of wind. Typically, they are engineered to flex the optimum amount, and in the optimum proportions, for a given wind strength, with respect to the amount of sail left standing.
Twist (Sail): See Sail Twist.
Twist:
Spiral fouling of rigging.
Unstayed Mast aka Free Standing Mast:
A cantilever mast without stays or shrouds (see Stayed Mast), or the rig built around such masts. Junk rigged vessels frequently have one or more unstayed mast(s). See Unstayed Rig.
Unstayed Rig aka Free Standing Rig:
Rig in which the principle mast is an unstayed mast. Absence of shrouds allows the boom to be let swing fully forward, an advantage in many situations. During a gybe, risk of boom impact on shrouds and associated stress is eliminated, while extra swing range allows a sail to fully de-power. See Unstayed Mast.
Upward Reef:
One or more panels furled upward, generally by means of running lifts. This may be done to reduce sail, increase forward visibility or clear a deck load.
Upwash:
Divergent flow toward a foil's convex side. In a sail (vertical foil), upwash is transverse motion, flowing toward the lee. See Foil and Downwash.
(Van Loan Rig):
Erroneous attribution of Mallory Rig to Derek Van Loan, who popularized it in The Chinese Sailing Rig. See Mallory Rig and Common Junk Rigs.
Vang: See Boom Vang.
Vector aka Force Vector:
Force with magnitude and direction. A vector is generally represented diagrammatically by an arrow indicating direction of force, and whose length represents magnitude of force. See Vector Analysis.
Vector Analysis:
The analysis of one or more force vectors to find their net product, generally employing diagrammatic methods. Any single vector may be represented as the product of two (or more) vectors. Uses include analysis of forces acting on foils, the hull, rigging, and course.
View:
A conventional direction in which plans are presented. See Plan View, Profile View and Section View. WGNT
Voluntary Turbulence:
Intentional turbulence introduced into flow across a foil by means of elective irregularities. This term arose around certain of Maj. Bunny Smith's efforts, inspired by vortex theory, to improve windward performance of junk sails. His results are contested. See Fenix Rig and Vortex Theory.
Vortex:
A turbulent, high pressure whorl of gas or fluid. In standard hydrodynamic theory, a vortex generated by a foil or other shape is deemed to increase drag. However, vortex theory claims that they may be harnessed in some circumstances to produce lift. Wikipedia: Vortex. See Voluntary Turbulence and Vortex Theory.
Vortex Theory:
A theory of sail drive. In brief, it proposes that turbulent vortices (see Vortex) are created by certain sail-shapes (especially conic sectioned ones, bounded by spars... see Fanned Sails), which, as they roll along sailcloth and/or spars produce net lift. It is proposed that quasi-triangular, conic section sails (e.g., Crab Claw and panels of fanned sections of junk sails) develop additional drive under this theory. Vortex theory is a contested application of hydrodynamic repercussions of chaos theory. [ST & P] See Voluntary Turbulence and Vortex.
Warp:
Filament, thread or yarn running longitudinally along the weave, and run of woven fabric. See Fabric and Weave, and alternative, Weft.
Water Sail (aka Boom Foot Sail):
Any sail set from and below the boom. WGNT
Weathercock:
To swing in line with the wind (or nearly so), under the influence of aft windage. Junk sails weathercock quietly without flogging, when allowed, spread and supported by their battens. Junk rigged vessels can sheet flat to weathercock the vessel in lieu of heaving to as a riding technique, whether at anchor or in heavy weather. Alternatively they can ease sheets and weathercock the sails while lying a'hull. [PJR p. 6] See Drogue, Heave To, Lie A'Hull and Sea Anchor.
Wear Around (verb):
A sailing manoeuvre in which course is altered to bring wind from one forward quarter to the other, by falling off, gybing, and rounding up again. This manoeuvre is generally used when tacking is for some reason unachievable or inadvisable. See alternatives, Gybe (verb) and Tack (verb).
Weather Helm:
The tendency to round into the wind despite a centered helm. See Lee Helm and Balanced Helm. Wikipedia: Weather helm
Weave:
The pattern of overlapping threads or filaments making up woven fabric. Different weaves have varying properties, especially affecting elasticity and strength. Density of weave is usually given as thread count. See Bias, Fabric, Thread Count, Warp and Weft.
Weft aka Woof:
Filament, thread or yarn running transversly across the weave, and run of woven fabric. See Fabric and Weave, and alternative, Warp.
Weight (Fabric):
Weight of fabric is given in grams per square meter (GSM) or ounces per square yard (Oz). However, standards are not universally followed, and 'square units' may be substituted by 'unit of length', increasing weight artificially. Check supplier for units. See Fabric.
Whipstaff:
Essentially a vertical tiller, but which takes up far less cockpit space. Mechanical linkages are required. HG Hasler installed one aboard Jester. WGNT
Wind up the chuff:
Wind from directly aft. The word chuff refers to one’s backside.
Windward Efficiency:
A general reference to the ability of a sailing vessel to sail upwind. It may be used in a more or less specific manner, possibly referring to pointing ability, velocity made good and/or course made good. Lower windward efficiency relative to other modern rigs has weighed against other merits of the junk rig. However, recent innovations in shaped (cambered) panels and junk sail geometries have greatly increased the rig's performance. See Camber, Lift to Drag Ratio and Split Junk Rig.
Wing and Wing (aka Wing and Wong):
Running before the wind with sail eased out on both sides. This set may be assisted by preventer(s) or forward raked mast(s). See Mast Rake and Preventer.
Wing and Wong::
Jocular, junk rig synonym for wing and wing in multi-masted junk rigged vessels. See Wing and Wing.
Wing Sail:
A sail in which a framework structure is skinned over to form an airfoil. Wing sails are sometimes rigid, or sometimes allow their shape and/or area to be manipulated.
Wishbone Batten:
A specialized, symmetrical, two part batten. Each half is shaped in catenary curves, joined at their ends and affixed to a junk sail at luff and leech. Under press of wind, the sail is free to billow to the limit imposed by their curve, without being cut as by a straight batten. While wishbone battens may be adapted to any junk sail, they are specified for Aerojunk Rigand Softwing Junk Rig.
Wrack aka Wracking Force: See Torque.
Wrinkle:
Minor deformation of otherwise smooth sailcloth, caused by fiber 'memory'. Unlike creases, wrinkles tend to relax under press of wind, and are not diagnostic of poor set or cut. [CP & SJR] See alternative, Crease.
Yard (aka Lug):
Spar affixed along the head of a junk sail, and from which the sail depends. A halyard is affixed to the yard, at the sling point. See Halyard, Sling Point, Throat Hauling Parrel and Yard Parrel. [PJR p. 10, fig. 1.4]
Yard Angle:
The angle at which the yard is fixed when the sail is fully raised. Angle is generally measured relative to horizontal, though usage occasionally varies. Various theories have been put forward, advocating across the range from high to low yard angles. [PJR p. 30 and p. 97, fig. 6.8]
Yard Downhaul:
A downhaul rigged for the yard in order to assist lowering in extreme conditions. Generally, it will be be affixed to an upper, aft batten end somewhat below the sling point, through a block at the yard, and thence to deck level. [PJR p. 49, Fig. 3.46]
Yard Hauling Parrel (aka YHP aka Snotter):
A parrel, rigged running, affixed to and led via the sling point to deck level. It is used to position the yard relative to the mast and constrain fore and aft, pitching motion of the junk sail. It is adjusted each time the sail is reefed. [PJR p. 37, fig. 3.19]
Yard Parrel: See Standing Yard Parrel.
Yarn:
A continuous length of closely interlocked, natural or synthetic fibers, generally loosely twisted. Yarns are used in the manufacture of fabric and line. Wikipedia: Yarn. See Fabric and Thread.
Yuloh:
An eastern sculling oar. It is characterized by a bent upper loom, a large blade, flat on its upper, aft surface and rounded on its lower, forward surface, pivoting on a fulcrum (generally a pin and dimple) and tied by lanyard to the deck from the forward end of the loom. The loom is worked from side to side. Loom curvature and lanyard work to spill the blade in a falling leaf pattern. The lanyard further opposes the tendency of the blade to dive, sparing the operator the effort. [STOTY]
Zig-Zag Stitch:
The sewing stitch generally used for the construction of sails. It allows a slight amount of adjustment, which works to smooth transitions across seams in sailcloth.