Common Terms

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 Blockand 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 preventerwhich constrains boommotion 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 profileaveraging its silhouette area. Rudder profilemay be included in this average under various rules-of-thumb. In practice, the centre of lateral resistanceis 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 Methodand Shelf-Foot Method.

Depth of Curve:

The depth of a foil, measured perpendicular to its chordfrom its point of greatest curvature.

Developed Surfaceaka Developable Surface:

A surface entirely composed of section-of-coneand section-of-cylinderareas, smoothly joined. Such a surface may be covered by stiff, sheet construction materials, such as plywood or metal. Developed-surfacehulls are especially amenable to Do-It-Yourselfconstruction.

Do It Yourselfaka DIY:

The movement towards self-sufficiency, empowerment and independence. Junk rigis particularly amenable to DIYapproaches 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 tackleare 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 sheetingallows 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 Sheetsand 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 incidenceand sail twist, especially in large junk sails. See Double Sheets (Port and Starboard), and alternatives, Aft Led Sheetsand Single Sheets.

Downhaul:

A control linewhich tensions a junk sail’s upper spars in order to assist lowering in extreme conditions. [PJRp. 48] See Batten Downhauland Yard Downhaul.

Downwash:

Divergent flow opposite a foil’s convex side. In a sail (vertical foil), downwashis a transverse motion, diverting toward the wind. See Foiland Upwash.

Dmin aka Minimum Drift:

The minimum driftrequired for full and proper function of a rigging system. [PJRpg. 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. WHYPERLINK "http://en.wikipedia.org/wiki/Drag_(physics)":HYPERLINK "http://en.wikipedia.org/wiki/Drag_(physics)":HYPERLINK "http://en.wikipedia.org/wiki/Drag_(physics)"Drag

Draughtaka Draft:

The maximum extent of a vessel below its waterline. Draughtis 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. [PJRpg. 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 Anchorand Weathercock.

Elastic:

The ability both to stretchunder tensionand recover to (near) original dimension when tensionis released. In junk rig, elasticfabricmay be used for sailcloth, and elasticline for anchoring or sheets.

End View:

See Section View.

Engineer:

To construct a rigging componentto 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 rigsheeting 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. [PJRp. 59-61, Figs. 4.9-4.21and 4.51-4.52] See Friction Blockand Sheets.

Fabric aka Cloth:

Filaments, threads and/or yarnsof natural or synthetic fiberswoven in a particular weave. Edges may be selvedged, or not. Various fabrics arespecialised for weight, thread count, strength, stability, elasticity, UV resistance(resistance to sunlight), hydrophobia(resistance to water absorption), waterproofingand colour. Fabricis generally sold by lengthfrom bolts or rolls of varying width. WHYPERLINK "http://en.wikipedia.org/wiki/Fabric":HYPERLINK "http://en.wikipedia.org/wiki/Fabric":HYPERLINK "http://en.wikipedia.org/wiki/Fabric"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 yulohblade through water. Named for the (approximately) two dimensional pattern of a leaf, which arcs to and fro as it falls. See Yuloh.

Fan:

Junk sailregion whose profileis characterized by spars canted, fan-wise, with increasing angle from boomto 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 Fanand Roach, and alternative, Parallelogram.

Fanned Planform:See Fanned Sail.

Fanned (Sail) aka Fanned Planform:

A junk sailwhich 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 aerofoilshape, whose depth of curveis proportional to amount of sail twist. Cambermay also be shaped in one or more panels. A fanned sailgenerally has some roachwhich may foul aft led sheets. It may extend one or more battens from the leechto compensate, or employ double sheets. Negative stagger, forward, may bring the forward end of the yardabaft the mastlinewhen reefed, and may extend the yardforward of the luffto compensate. See Camber, Double Sheets, Regular Fanand Irregular Fan, and alternative Parallelogram Sail.

Fantail Rig:See Common Junk Rigs.

Fan Up:

The lifting of furled panels from the sail bundleby 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, riggingor 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 Preventerand 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 quartersinches 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 systemis being used, feet-inches-eighthsis 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. Fabricand line made directly from filaments are often stronger than alternatives, and may have other associated effects. See Fabricand alternatives, Threadand Yarn.

Flat Cut (Sail):

Any sail without initial camberengineered into its panels. Flat cutjunk sailsproduce some camberin their panels through battenbending and sailclothstretch. They produce whole sail, camberby allowing and controlling sail twistto adjust depth of curve. See Camber, Fanned Sailand 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 hydrodynamicallyand/or aerodynamicallyefficient. See Aerodynamic Theory, Aerofoil, Downwash, Drag, Hydrodynamic Theory, Lift, Lift to Drag Ratioand Upwash.

Foot:

Lower edge of sail. In junk rig, a boomis affixed along the foot, and occasionally a watersail. WGNTSee Watersail.

Force Vector:See Vector.

Fore Lift aka Forward Lift:

A liftforward of the mast, rigged standingor running. In junk sails with a large balance, it may have a sail gatherertowards the lower portions. This term is widely used, but doesn't appear in PJR, which conflates forward liftwith mast lift. [CSRpp. 4-5, figs. 1-2] [PJRp. 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 systemsto resist free movement of running lines toward equilibrium under pressure of wind, allowing the leechto be set to and retain a given shape. See Euphroe.

Furl:See Reef.

Furled Bundle:See Sail Bundle.

Gaff Rig (aka GR):

Non-junkrig composed of arrangements of quadrilateral sail(s) depending from a sparcalled a gaff, which is affixed along the sail’s head; the sail is constrained along its luff to the mast. Gaff sailsare usually supplemented by smaller, triangular sails. WHYPERLINK "http://en.wikipedia.org/wiki/Gaff_rig":HYPERLINK "http://en.wikipedia.org/wiki/Gaff_rig":HYPERLINK "http://en.wikipedia.org/wiki/Gaff_rig"GaffHYPERLINK "http://en.wikipedia.org/wiki/Gaff_rig"HYPERLINK "http://en.wikipedia.org/wiki/Gaff_rig"Rig

Ghoster:

A light, battenless headsail, often quite large, for use in very light wind. [PJR78, Figs. 5.1-5.8]

Goosewing Gybe (aka Chinese Gybe):

A partial, or incomplete gybein 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 gybegenerally prevents fan upand subsequent goosewing gybe. In junk rig, sheeted, full length battens reduce the risk of fan upand goosewing gybe. WGNT

Grommet:See Rope Grommetor Sail Grommet. WGNT

Gurney Flap:

A vertical section of fabricrunning along the leechof some junk sails, which recurves to windward. This may be integral to each panelor extend abaft the leechproper (in which case it takes its angle of incidence from aft led sheets). It is generally considered to degrade windward efficiencyby increasing dragand moving the centre of pressureaft, 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 sailbalancereduces 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). [PJRp. 208] See Accidental Gybe, Controlled Gybe, Goosewing Gybeand Gybe (noun).

Half Wishbone Batten:See Spilling Batten.

Halyard:

The control lineused to raise and lower sail. In junk rig, it is often attached to a halyard craneand 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 blockedor countered by a tack line. [PJRpp. 32-37, figs. 3.1-3.16] See Halyard Crane, Sling Point, Tack Lineand Yard.

Halyard Crane (aka Masthead Crane):

An extension off the mastheadto which the upper halyardblockaffixes. It is offset, precisely, to accommodate a junk sail’s offset yard, and is long enough to prevent blocks from chafingagainst the masthead. [PJRp. 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. WGNT

Head Sailaka 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 Rigand 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 toas a storm tactic, a stand-on manoeuvre, or to relieve crew. [PJR p. 208] See Weathercockand alternatives, Drogue, Lie Ahulland 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). WHYPERLINK "http://overview":HYPERLINK "http://overview":HYPERLINK "http://overview"HelmSee Lee Helm, Neutral Helmand Weather Helm.

Hem:

To fold over an edge of fabricone or more times and fix in place (generally by sewing). The resulting hemstops fraying, helps protect the edge of the fabricfrom 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 aerofoilshape.

Hollow:

Concavity cut into the leechbetween spars. This may help tame fluttering, and, when extreme, moves that panel’s Center of Effortforward/inboard.

Hong Kong Parrel:

Rope parrels, additional to batten parrels, running diagonally aft from the forward part of one battento the next lower spar. They constrain battenmovement, relative to one another, improving the set of their associated panel. They can, however, impose heavy stresses mid-batten. [PJRp. 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 camberin junk sailpanels by extending the upper and lower edges from the battentoward 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 aerofoilshape 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 Archerand 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. WHYPERLINK "http://en.wikipedia.org/wiki/Hydrodynamic":HYPERLINK "http://en.wikipedia.org/wiki/Hydrodynamic":HYPERLINK "http://en.wikipedia.org/wiki/Hydrodynamic"HydrodynamicHYPERLINK "http://en.wikipedia.org/wiki/Hydrodynamic"HYPERLINK "http://en.wikipedia.org/wiki/Hydrodynamic"TheorySee Foiland 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 systemworld-wide. WHYPERLINK "http://en.wikipedia.org/wiki/Imperial_system":HYPERLINK "http://en.wikipedia.org/wiki/Imperial_system":HYPERLINK "http://en.wikipedia.org/wiki/Imperial_system"ImperialHYPERLINK "http://en.wikipedia.org/wiki/Imperial_system"HYPERLINK "http://en.wikipedia.org/wiki/Imperial_system"SystemSee Feet-Inches-Eighths, and alternative, Metric System.

Incidence (Angle)aka Angle of Attack:

The angle of a foilrelative 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). httpHYPERLINK "http://en.wikipedia.org/wiki/Angle_of_incidence"://HYPERLINK "http://en.wikipedia.org/wiki/Angle_of_incidence"enHYPERLINK "http://en.wikipedia.org/wiki/Angle_of_incidence".HYPERLINK "http://en.wikipedia.org/wiki/Angle_of_incidence"wikipediaHYPERLINK "http://en.wikipedia.org/wiki/Angle_of_incidence".HYPERLINK "http://en.wikipedia.org/wiki/Angle_of_incidence"orgHYPERLINK "http://en.wikipedia.org/wiki/Angle_of_incidence"/HYPERLINK "http://en.wikipedia.org/wiki/Angle_of_incidence"wikiHYPERLINK "http://en.wikipedia.org/wiki/Angle_of_incidence"/HYPERLINK "http://en.wikipedia.org/wiki/Angle_of_incidence"AngleHYPERLINK "http://en.wikipedia.org/wiki/Angle_of_incidence"_HYPERLINK "http://en.wikipedia.org/wiki/Angle_of_incidence"ofHYPERLINK "http://en.wikipedia.org/wiki/Angle_of_incidence"_HYPERLINK "http://en.wikipedia.org/wiki/Angle_of_incidence"incidenceW::Incidence] WHYPERLINK "http://en.wikipedia.org/wiki/Angle_of_attack":HYPERLINK "http://en.wikipedia.org/wiki/Angle_of_attack":HYPERLINK "http://en.wikipedia.org/wiki/Angle_of_attack"AngleHYPERLINK "http://en.wikipedia.org/wiki/Angle_of_attack"HYPERLINK "http://en.wikipedia.org/wiki/Angle_of_attack"ofHYPERLINK "http://en.wikipedia.org/wiki/Angle_of_attack"HYPERLINK "http://en.wikipedia.org/wiki/Angle_of_attack"Attack

Irregular Fan:

A fanned region of a junk sailwhose spars do NOT radiate from a single point. [PJRp. 29, figs. 2.21-2.24]

JesterRig:See Common Junk Rigs.

Jiblet:

Forward, balanceportion of a panelwithin a split junk rig, forward of its slot. A Jibletestablishes slot effectfor the after portions of its (generally cambered) panel, increasing total lift to drag ratio(sail efficiency). See Slot Effectand Split Junk Rig.

Jibe:See Gybe.

Jointed Batten aka Segmented Batten:

Any battenwhich is segmented, and joined by flexible joints. Generally some stop mechanism will be engineered to limit degree of flex. See Bendy Battenand 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 sailwhich is fully battened from luffto leech, with a sheeting systemextending to all or most of the battens. Common usage often refers to the sail inclusive of its attached spars (yard,battens and boom). [PJRChapters 2 and 3]. See Junk Rig.

Junk Rig (aka JR):

Fore and aft rigcomposed of one or more junk sailsand all associated spars and rigging. [PJRChapter 1] WHYPERLINK "http://en.wikipedia.org/wiki/Junk_rig":HYPERLINK "http://en.wikipedia.org/wiki/Junk_rig":HYPERLINK "http://en.wikipedia.org/wiki/Junk_rig"JunkHYPERLINK "http://en.wikipedia.org/wiki/Junk_rig"HYPERLINK "http://en.wikipedia.org/wiki/Junk_rig"Rig

Jury Rig:

A temporary rigimprovised until repairs are possible. Unstayed masts, when used, and multiple battens present many opportunities for jury rigging. [PJRp. 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 resistanceslide forward relatively easily, and sideways relatively poorly. Lateral resistanceis proportional to the profile, silhouette area of the structure or device, but may be enhanced by sectional shape. Lateral resistancecan be provided by the hullitself, keels, centreboards, leeboards, daggerboardsand rudders. When working to windward, lateral resistancecounters lateral components of sail lift, leaving a net, windward force vector. WHYPERLINK "http://en.wikipedia.org/wiki/Center_of_lateral_resistance":HYPERLINK "http://en.wikipedia.org/wiki/Center_of_lateral_resistance":HYPERLINK "http://en.wikipedia.org/wiki/Center_of_lateral_resistance"LateralHYPERLINK "http://en.wikipedia.org/wiki/Center_of_lateral_resistance"HYPERLINK "http://en.wikipedia.org/wiki/Center_of_lateral_resistance"ResistanceSee Centre of Lateral Resistance, Leewayand 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 effortis forward of the centre of lateral resistance. Generally expressed as a percentage of the waterline length. The amount of leadis generally determined by rule-of-thumb, taking into account sail and hull characteristics. [PJRp. 94] WHYPERLINK "http://overview":HYPERLINK "http://overview"BalanceHYPERLINK "http://overview"HYPERLINK "http://overview"ofHYPERLINK "http://overview"HYPERLINK "http://overview"Forces

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. WHYPERLINK "http://en.wikipedia.org/wiki/Lee_Helm":HYPERLINK "http://en.wikipedia.org/wiki/Lee_Helm":HYPERLINK "http://en.wikipedia.org/wiki/Lee_Helm"LeeHYPERLINK "http://en.wikipedia.org/wiki/Lee_Helm"HYPERLINK "http://en.wikipedia.org/wiki/Lee_Helm"HelmSee alternatives, Balanced Helmand 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. WHYPERLINK "http://en.wikipedia.org/wiki/Leeway":HYPERLINK "http://en.wikipedia.org/wiki/Leeway":HYPERLINK "http://en.wikipedia.org/wiki/Leeway"Leeway

Length Above Partners aka LAP:

Height of a mastmeasured from partnersto mast head. This value is especially useful for calculating mast diameterand mast buryin unstayed masts. See Mast Bury, Mast Diameterand Common Formulae and Ratios.

Lens Method(Camber): See Shelf Method.

Lie Ahull:

To drift, beam on to wind and seas. Junk sailsmay remain fully or partially raised, and allowed to weathercockwith eased sheets. [PJRp. 208] See alternatives, Drogue, Heave To, Sea Anchorand Weathercock.

Lift (Rigging):

Standingand/or runningrigging systemcomprising lines led to and from the masthead, around the boomvia positioning eyes. Lifts support the sail bundle, and gather the junk sailand 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 gathererattached. See After Lift, Forward Lift, Mast Lift, Topping Lift, Sail Bundle, Sail Gathererand 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. Liftis generally depicted by a force vectorand subject to vector analysis. Efficient foilshapes cant this force vectortoward the foil's leading edge. Sails generate lift, whose transverse vectorcomponents are countered by lateral resistance. WHYPERLINK "http://en.wikipedia.org/wiki/Lift_(force)":HYPERLINK "http://en.wikipedia.org/wiki/Lift_(force)":HYPERLINK "http://en.wikipedia.org/wiki/Lift_(force)"LiftSee Aerodynamic Theory, Hydrodynamic Theoryand Vector Analysis.

Lift to Drag Ratio

Measure of efficiency of a foil. The higher the ratio, the greater the efficiency. WHYPERLINK "http://en.wikipedia.org/wiki/Lift-to-drag_ratio":HYPERLINK "http://en.wikipedia.org/wiki/Lift-to-drag_ratio":HYPERLINK "http://en.wikipedia.org/wiki/Lift-to-drag_ratio"LiftHYPERLINK "http://en.wikipedia.org/wiki/Lift-to-drag_ratio"HYPERLINK "http://en.wikipedia.org/wiki/Lift-to-drag_ratio"toHYPERLINK "http://en.wikipedia.org/wiki/Lift-to-drag_ratio"HYPERLINK "http://en.wikipedia.org/wiki/Lift-to-drag_ratio"DragHYPERLINK "http://en.wikipedia.org/wiki/Lift-to-drag_ratio"HYPERLINK "http://en.wikipedia.org/wiki/Lift-to-drag_ratio"RatioSee Aerodynamic Theory, Dragand 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 loftedwith the help of a batten. Generally, sails and hulls are lofted. WHYPERLINK "http://en.wikipedia.org/wiki/Lofting":HYPERLINK "http://en.wikipedia.org/wiki/Lofting":HYPERLINK "http://en.wikipedia.org/wiki/Lofting"Lofting

Long Batten Parrel:See Batten Parrel.

Loom:

The long, central shaft of an oar, yulohor ro. WGNT

Luff:

The forward edge of sail. WGNT

Luff (Sail):

The luff(forward edge of sail) is said to luffas wind from forward begins to round to the lee side of the sail, indicating that one is pinching. The luffof a flat-cutjunk sailis tensioned by the weight of the lower paneland boom, so tends to lufflate, 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):

Runningluff 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 luffis considered sufficient for good sail set. [PJRp. 47, figs. 3.42-3.44]

Luff Parrel:

Any parrelwhich constrains and/or controls the luffof a junk sail. A luff parrelmay be standingor running, and several of either or both may be rigged in one sail. [PJRpp. 44-48, figs. 3.35-3.44] See Luff Hauling Parrel, Standing Luff Parreland Throat Hauling Parrel.

Lug:

The sparfrom which a lug saildepends. 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 lugand bringing it across while near vertical). WHYPERLINK "http://en.wikipedia.org/wiki/Lugger":HYPERLINK "http://en.wikipedia.org/wiki/Lugger":HYPERLINK "http://en.wikipedia.org/wiki/Lugger"LugHYPERLINK "http://en.wikipedia.org/wiki/Lugger"HYPERLINK "http://en.wikipedia.org/wiki/Lugger"Rig

Lug Sail:

Quadrilateral sail suspended from a lug, extending forward of the mastforming sail balance, and held in place at the bottom by the sheetand tack downhaul. See Chinese Lug Sail, Junk SailLug Rigand 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 diameterat the partnersto 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 mastis subject to compressionloading from tensionbetween halyardand tack line, and torqued by the halyardand halyard crane. Mastflex tensions the windward side and compressesthe leeward side (approximately speaking). PJRChapter 8] See Mast Bury, Mast Diameter, Mast Rake, Masthead, Mast Heel, Mast Step, Partnersand Tabernacle.

Mast Bury:

The proportion of a cantilevered, unstayed mastbelow mast partners to its length. In free-standing masts, adequate mast buryis essential, with a minimum of 9% of the mast's overall length, or about 10% of its length above partners. [PJRp. 115] [CSRp. 38, fig. 9]

Mast Diameter:

The diameter of a mastat 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 Rigmastis generally circular in section, and tapers from full diameter, just above the partners to one half or less of that at the masthead. Mast diameteris 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 Mastand Common Formulas.

Mast Head:See Masthead.

Mast Heel aka Heel of Mast:

Lower end of the mast, stepped in a mast stepor fixed (in a tabernacle) by a mast stop.

Mast Lift aka Forward Lift:

A standingor runningliftgathering and supporting the sail bundleat the mast. PJRuses the same term for a liftrigged forward of the mast, but many prefer to draw a distinction, using forward liftin this case. See Forward Lift, Liftand Topping Lift. [PJR pp. 50-51, Figs. 3.49 and 3.50]

Mast Lineaka Mastline(aka ML):

The designed or actual position of the mastacross its associated junk sail. If the sail's position on the mastis adjustable, there may be more than one mast linespecified, generally at the limits of adjustment range(s). [PJRp. 109, fig. 6.28]

Mast Partners:

The structures supporting a stepped mastat deck or cabin-top. [PJRpp. 141-145, figs 9.1-9.7] See Mast Step.

Mast Pivot:

In a tabernacle, the point around which a mastpivots when lowered. Generally, a hinge structure is arranged around a pivot bolt, from which the mast is hung. Generally, the pivot boltdetermines the point from which mast buryis determined. See Tabernacle.

Mast Position:

The position of a mastwithin 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 rakeis generally considered to be helpful in spreading sail in light airs and to delay a gybe. [PJRp. 40, figs. 3.21-3.23] See Rake.

Mast Step:

The structure receiving, supporting and securing a mast heel. A mastmay be steppedat the keel, the deck or in a tabernacle. See Mastand Tabernacle.

Mast Stop:

In a tabernacle, a means of affixing the mast heel. In conjunction with the mast pivotand tabernaclestructure, it holds the mastin 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 fittingmay be affixed. WGNT

Masthead Crane:See Halyard Crane.

Masthead Fitting aka Masthead:

Fabricated hardware mounted at the mastheadto provide landings for all lines led to the masthead(e.g., halyard, lifts, stays, etc.), and additional mastheadhardware (e.g., antennas, windvanes, etc.). See Masthead Crane. [PJRp.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, advantageis 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.. WHYPERLINK "http://en.wikipedia.org/wiki/Mechanical_advantage":HYPERLINK "http://en.wikipedia.org/wiki/Mechanical_advantage":HYPERLINK "http://en.wikipedia.org/wiki/Mechanical_advantage"MechanicalHYPERLINK "http://en.wikipedia.org/wiki/Mechanical_advantage"HYPERLINK "http://en.wikipedia.org/wiki/Mechanical_advantage"AdvantageSee 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 systemis still widely used (outside the scientific community) in the USA. WHYPERLINK "http://en.wikipedia.org/wiki/Metric_system":HYPERLINK "http://en.wikipedia.org/wiki/Metric_system":HYPERLINK "http://en.wikipedia.org/wiki/Metric_system"MetricHYPERLINK "http://en.wikipedia.org/wiki/Metric_system"HYPERLINK "http://en.wikipedia.org/wiki/Metric_system"SystemSee alternative, Imperial System.

NACA Aerofoil:

A protocol to specify Aerofoilshapes 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. WHYPERLINK "http://en.wikipedia.org/wiki/NACA_airfoil":HYPERLINK "http://en.wikipedia.org/wiki/NACA_airfoil":HYPERLINK "http://en.wikipedia.org/wiki/NACA_airfoil"NACAHYPERLINK "http://en.wikipedia.org/wiki/NACA_airfoil"HYPERLINK "http://en.wikipedia.org/wiki/NACA_airfoil"Aerofoil

Negative Stagger:

Among battens furled into the sail bundle, overlap of upper battens by lower ones. Negative staggerat the aft end of the sail bundlemay foul aft lead sheets. At the forward end, excessive negative staggermay critically reduce or eliminate extension of battens and/or yardforward of the mast(line), leading to fouling if uncompensated. [PJRp.22, fig. 2.8]

Neutral Helm:See Balanced Helm.

Neutral Stagger:

No significant overlap among battens furled into the sail bundle. Neutral staggerat the aft end of the sail bundlemay foul aft lead sheets. Neutral staggermay result from cambercut into junk sailpanels, and may require compensating riggingor 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. [PJRp. 96, fig. 6.8]

Panel:

In a junk sail, sailclothseparated by spars and, by JRAconvention, numbered from the lowermost (number one) upward. These may be sewn from multiple pieces of fabricand pocketed, or grommeted and lashed for attachment of spars. [PJRp. 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. [PJRp. 96, fig. 6.8]

Parallelogram:

Area of a Junk sailwhose profileis characterized by parallel edges and sparsof constant length. Generally, these spars are canted by a precise amount of aft elevation (batten rise) to yield positive staggerat 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 junkplanforms 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 sailembodying a significant parallelogram. Generally, the parallelogramis engineered for positive staggerat the after sail bundle. [PJR p. 24, fig. 2.11] See Rise, and alternative, Fanned Sail.

Parrel:

Any one of a number of junk riglines passing from spar, across or around the mast, to spar, and any associated rigging. Parrels may be rigged standingor 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 Parreland 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 tensionthe peak. In practice, the after end of the yardis tensioned (peaked up) by downward tensionat the throat, and/or by moving the sling pointaft. See Sling Pointand Throat Hauling Parrel.

Pinch:

To point so high into the wind that sail liftdiminishes or fails (luffs). Flat cutjunk 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 tabernaclea transverse bolt arranged in a hinge arrangement with mastand tabernaclestructure, from which the mastis 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 planformwill have certain riggingstrongly associated. See Rig, Sailplanand Common Junk Rigs. [JRA]

Plan View:

View from top or bottom (as specified). Deck and interior layouts are generally presented in plan view. WGNTSee Profile View, Section Viewand View.

Pointing Ability:

The angle of incidenceof a vessel's heading relative to the wind. A vessel which is able to pointhigh into the wind (low angle of incidence) is said to have greater pointing ability. Generally, junk rigged vessels have had less pointing abilitythan, say, Bermudan rig, though recent developments are promising. Pointing abilityis just one factor in windward efficiency. See Aerojunk Rig, Camber, Slot Effect, Split Junk Rigand Windward Efficiency.

Positive Stagger:

Among battens furled into the sail bundle, overlap of lower battens by upper ones. Adequate positive staggerat the after sail bundlelets sheet spans hang clear of battens and one another, virtually eliminating fouling of aft lead sheets. Positive staggeris generally engineered via sail geometry, but may be imposed by various rigging. [PJRp.22, fig. 2.8 and Chapter 2]

Practical Junk Rigaka PJR (aka JR Bible):

Book by HG Hasler and JK McLeod containing detailed analysis of general Junk Rigconstruction and use. Originally published in 1988, its update is currently the subject of a JRAHYPERLINK "http://www.junkrigassociation.org/member_proj_forum?mode=MessageList&eid=1407438"HYPERLINK "http://www.junkrigassociation.org/member_proj_forum?mode=MessageList&eid=1407438"MemberHYPERLINK "http://www.junkrigassociation.org/member_proj_forum?mode=MessageList&eid=1407438"HYPERLINK "http://www.junkrigassociation.org/member_proj_forum?mode=MessageList&eid=1407438"Project. See Sources.

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 Vangand Kicking Strap.

Profile View:

View from port or starboard (as specified). Known as 'side elevation' in architecture. Sails are presented in profile viewby convention. WGNTSee Plan View, Section Viewand View.

Purchase:

Mechanical advantagederived from blockand tackleor similar arrangements. Generally, advantageequals the number of line parts in motion (i.e., not affixed) relative to the blockhauling a load, minus a percentage of loss to friction. In junk rig, halyards, hauling parrels and sheet systems apply purchasein varying amounts to control the rig. WHYPERLINK "http://en.wikipedia.org/wiki/Mechanical_advantage":HYPERLINK "http://en.wikipedia.org/wiki/Mechanical_advantage":HYPERLINK "http://en.wikipedia.org/wiki/Mechanical_advantage"PurchaseSee Block and Tackle, Mechanical advantageand Tension.

Quilting:

The diamond pattern formed in some (especially some traditional) junk sails by stitching and/or reinforcing strips. Aerodynamicbenefits, if any, are contested.

R ((Batten) Rise):

In some discussions, refers to battenRise, 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 masthas forward rake" or "Our mastrakesaft" becomes "rakehelps swing the boomoutboard" (mastrakeassumed)). Check context. See Mast Rake. WGNT

Reddish Rig:See Common Junk Rigs.

Reef (aka Furl aka Shorten Sail):

To reduce standingjunk sailarea 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 halyardfast, 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 compressionloads on the battens mount; rounding up to some extend may be advisable. [PJRp. 205] See Reef Upward, Sail Bundleand Upward Reef.

Reef Upward:

To furl one or more panels upward, generally by hauling one or more runninglifts. 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. [PJRp. 24, figs. 2.12-2.20]

Rig (noun):

A planformor type with its associated riggingand 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., JesterRig), or the person who developed it (e.g., Reddish Rig). See Planformand Sailplan. [JRA]

Rig (verb):

To implement or install a system. Generally referring to rigging, but may be used in other contexts. See Engineerand Jury Rig. WGNT

Rigging:

Any item or coherent collection of line or tackleincorporated into a rig. WGNT

Rigging:

The aggregate of rigging systemsor rigging componentsassociated with the subject under discussion (e.g., riggingof 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 systemor halyard). Typically, these systems will position, constrain and control spars and/or sails. They may be rigged standing, runningor a combination. See Control Lines.

Rigid Batten:

A battenengineered for minimal bending. Rigid battens have been generally preferred, especially in more traditional junk rigs. See alternatives, Bendy Battenand Tuned Batten. [PJRp. 13, figs. 1.6-1.8]

Rise:See Batten Rise.

Ro aka Ryo:

Japanese variant of the yuloh, distinguished by precise loomangles and a longer blade. See Yuloh. [Douglas Brooks: A Different Way to RoWBM192:54]

Roach:

Convex curve in the leechof 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 roachwhen 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 eyealong 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 grommetforms the strop of a rope stropped block. WGNTSee Grommetand Rope Stropped Block.

Rope Stropped Block:

A blockwhose bailand becket(if present) are attached by means of a siezed, rope grommet. See Blockand Rope Grommet. WGNT

Roping:See Bolt Rope.

Round Only Method:See Barrel Method.

Running Back Stay:

A running stayleading 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 staysare common on rigs such as junk rigand gaff rig, in which the peak would foul a stay riggedstandingalong the vessel's centerline.

Running (Line or Rigging):

Riggingwhich is adjustable in the normal course of sailing. Runninglines are generally control linesand are often designated as haulinglines. In junk rigthe fall of a runningline is generally led to the cockpit. See entries beginning with Haulingor 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 sheetand sheet spans and/or aft battenends. The running spanlineis adjusted to shape the sail's leech, controlling sail twistand 'belly'. Position is held by friction holes in the upper euphroe. The running spanlinemay require shortening as the sail is reefed, generally after each two or three panels are furled. [PJRpp. 74, figs. 4.51-4.52] See Euphroe, Sheet Spanand Sheeting System.

Running Tack Parrel(aka Tack Hauling Parrel(aka Boom Hauling Parrelaka Bowsing Tackle):

A parreltoward the tack, rigged running, and variously along the forward boom. It is used to haul the junk sailaft, reducing balancefor on-the-wind sailing. When eased, the sail is allowed to swing forward, increasing balancefor offwind sailing. [PJRp. 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 sailand spars which accumulate in sail gathererportions of lifts. Ends of spars lowered into the sail bundledevelop stagger. See Lift, Sail Gathererand 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 fabricpouch, affixed to lower lifts for the purpose of gathering bunts when furled into the sail bundle. [PJRp. 53, fig. 3.53]

Sailcloth:

The fabricor 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. WHYPERLINK "http://en.wikipedia.org/wiki/Sailcloth":HYPERLINK "http://en.wikipedia.org/wiki/Sailcloth":HYPERLINK "http://en.wikipedia.org/wiki/Sailcloth"SailclothSee 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 sailclothfrom chafe. Often, these are made of two metal components, pressed and peened together. Spur-tooth grommetshave teeth between their components which 'bite' sailclothfor enhanced hold. Rarely, a sail grommetmay be fashioned from a very small rope grommetsewn in place. See Grommetand Rope Grommet.

Sailplan aka Sail Plan:

The design for a specific sail, specifying dimensions, location of spars, riggingand particulars. By convention, the sail is drawn in profile. WGNTSee Planformand Rig.

Sail Twist aka Twist:

Greater angle of sail incidence(relative to the vessel centerline) aloft than alow. Degree of sail twistin fully battened, junk sailsimparts some camberto the sail as a whole. These battens are controlled along the leechby 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 hullformreminiscent of those craft, such as a junk. WHYPERLINK "http://en.wikipedia.org/wiki/Sampan":HYPERLINK "http://en.wikipedia.org/wiki/Sampan":HYPERLINK "http://en.wikipedia.org/wiki/Sampan"SampanSee Junk.

Scallop:

Tendency of the buntof junk sailpanels to curve to leeward under press of wind, drawing their bounding spars slightly toward the panel's center of pressure. Scallopingis approximately cylindrical in section, when battens are parallel, and conic in section, when battens are fanned (cambercomplicates this simplified account). [PJRp. 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[PJRchapters 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 anchoris a heavy weather tactic. Junks were the first known vessels to deploy them. See alternatives, Drogue, Heave To, Lie A'Hulland Weathercock.

Seam:

Join between two lengths of fabric. In sailcloth, seams are generally overlapped and sewn. See Broadseamand 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 Viewand 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 sectionshapes.

Section-of-Coneaka 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 sectionshapes.

Segmented Batten:See Jointed Batten.

Self Tending(Sail or Rig):

Any sail which need not be adjusted between tacks, or a rigcomposed 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.

Selvedgeaka Selvage

An edge along a length of fabric which is woven back on itself, leaving no loose ends to fray. WHYPERLINK "http://en.wikipedia.org/wiki/Selvedge":HYPERLINK "http://en.wikipedia.org/wiki/Selvedge":HYPERLINK "http://en.wikipedia.org/wiki/Selvedge"SelvedgeSee Fabric.

Shear:

'Scissory' forces acting across the longitudinal run of a body. For example, a pair of scissors (shears) cutting paper are applying shear forcesto that paper. A body engineered to resist shearor shear forcesis said to be acting in shear. In junk rig, many fasteners and fittings work in shear. WHYPERLINK "http://en.wikipedia.org/wiki/Shear_force":HYPERLINK "http://en.wikipedia.org/wiki/Shear_force":HYPERLINK "http://en.wikipedia.org/wiki/Shear_force"ShearSee 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 linewhich principally controls sail incidencerelative to the vessel centerline. A sheetmay be manipulated from one or both ends. It typically tensions a euphroeor sheet span, but occasionally attaches directly to an aft battenend. [PJRChapter 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 rigsheeting systemlinking two or more battenaft ends to the sheetor running spanline. Sheet spans may be rigged for various distributions of force, transferred among the battens they connect. [PJRp. 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 flatwhen 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 leechof a junk sailat or near battenends, 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 battenlandings, countering fan-uptendencies. 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 sheetsmay be riggedon a given sail. This system of sheeting along the leechis a distinguishing characteristic of junk rig. [PJRChapter 4] See also Double sheets, Euphroe, Sheet, Sheet Span, Single Sheetand Running Spanline.

Shelf Method (aka Shelf Foot Method aka Lens Method):

Method for engineering camberin junk sailpanels 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 aerofoilshape 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. Shroudslimit lateral movement of the mast. WGNTSee alternative, Stay.

Single Sheets aka Aft Lead Sheets:

Single sheetsaffixed along the leechand led to (near) deck level. A single sheetis 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 sheaveat 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. [PJRp. 59, figs 4.7-4.9] See Block.

Sling Point aka S:

The point from which the yardattaches (is slung) from the halyard, usually at or slightly aft of the yard's midpoint. Positioning the sling pointaft of mid-point helps peak upa junk sail. See Peak Upand Yard.

Slot Effect:

Aerodynamiceffect 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 rigvessels seldom carry overlapping foresails. The slot effectmay 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 Rigand Split Junk Rig. WHYPERLINK "http://sail_trimming":HYPERLINK "http://sail_trimming":HYPERLINK "http://sail_trimming"SlotHYPERLINK "http://sail_trimming"HYPERLINK "http://sail_trimming"Effect

Soft Wingsail Rig:See Common Junk Rigs.

Snotter:

A control linewhich tensionsa spar, usually from its forward and/or lower end. See Sprit, Sprit Boomand Sprit Sail, Boom Hauling Parrel, Throat Hauling Parrel, Yard Hauling Parrel. WGNT

Spanline:See Running Spanline.

Spar:

Generic term for mast, yard, battenand boomin Junk Rig, and similar components of other rigs. See Batten, Boom, Mastand 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 luffand leechonly, and able to rotate at the attachment points. Under press of wind, sailclothconforms to its curve, assuming an aerofoilshape. See Battenand Wishbone Batten.

Split Junk Rig:See Common Junk Rigs.

Sprit:

A sparwhich cuts across the buntof a sail. It may cut diagonally across a quadrilateral sail, from (near the) tackto peak(spritof 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. WGNTSee Sprit Boomand Sprit Sail.

Sprit Boom:

A sprit, rigged from mid-luffto 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. WGNTSee Sprit, Sprit Boomand Sprit Sail.

Sprit Sail:

A sail spread by a sprit, rigged diagonally across a quadrilateral sail, from (near the) tackto peak. The spritisgenerally tensioned from its forward end by a snotter. It may be rigged as a smaller sail on otherwise junk rigged vessels. WGNTSee Snotterand Sprit.

Stability (Fabric):

Resistance of a fabricto stretch. Stabilityis 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 rigrelated discussions, the stagnation pointis generally raised in reference to foils.WHYPERLINK "http://en.wikipedia.org/wiki/Stagnation_point":HYPERLINK "http://en.wikipedia.org/wiki/Stagnation_point":HYPERLINK "http://en.wikipedia.org/wiki/Stagnation_point"StagnationHYPERLINK "http://en.wikipedia.org/wiki/Stagnation_point"HYPERLINK "http://en.wikipedia.org/wiki/Stagnation_point"PointWHYPERLINK "http://en.wikipedia.org/wiki/Static_pressure":HYPERLINK "http://en.wikipedia.org/wiki/Static_pressure":HYPERLINK "http://en.wikipedia.org/wiki/Static_pressure"StaticHYPERLINK "http://en.wikipedia.org/wiki/Static_pressure"HYPERLINK "http://en.wikipedia.org/wiki/Static_pressure"Pressure

Note: A full definition is outside the scope of the JRG. 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 incidenceto the apparent windincreases to a critical degree (when sailing too far off the wind). See alternative Luff (Sail).

Standing (Line or Rigging):

Riggingwhich is fixed (not adjusted) during normal sailing. Generally, if a line is not specified as runningor hauling, it is assumed to be standing, though there are exceptions such as halyardand sheets. Check Context. WGNTSee 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 boomand lowermost batten, which constrains forward movement of these spars. [PJRp. 42, Fig 3.26]

Standing Luff Parrel:

A luff parrel, rigged standing, affixed to one or more sparends, generally returning to another along the luff. These constrain a junk sails position, relative to the mast. [PJRp. 44, figs 3.35-3.38] See alternatives Short Batten Parreland Luff Hauling Parrel.

Standing Tack Parrel:

A parrel, rigged standing, starting and ending at the tack. It constrains forward movement of the boomrelative to the mast. [PJRp. 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. [PJRp. 46, fig. 3.39]

Standing Yard Parrel aka Yard Parrel:

A parrel, rigged standing, affixed near the sling pointand forward end of the yard. It prevents the yardfrom blowing awayfrom the mast. In some cases it may be rigged around the halyardand/or lifts to prevent fouling with the yardend 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 stayor shroud, generically speaking. A mastrigged with either or both is said to be stayed. WGNTSee Stayed Mastand Unstayed Mast.

Stayed Mast (orRig):

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 fabricto deform under tensional load, greatest along the bias. If stretched fabricrecovers as tensioneases, it is said to be elastic. In sailcloth, inelasticstretchgenerally degrades sail performance, and specialized fabrics are often used to minimize stretch. In junk sails, however, stretchmay contribute to camber. See Fabricand Sailcloth.

Strop:

A short length of line or rope grommetused 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 cantilevermastat its lower end (generally near deck level). The mast is generally hinged around a pivot bolt, with mast heelsecured by a mast stop. A tabernaclegenerally facilitates raising and lowering a mast. A mastis said to be stepped in a tabernacle, despite having no mast step, in the usual sense. Unstayed mastsare often stepped in a tabernacle, with sufficient burybetween pivot boltand 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 Parreland Running Tack Parrel.

Tackle aka Block-and-Tackle:

A runningcombination of line and block(s), often comprising all or part of a rigging system. WHYPERLINK "http://en.wikipedia.org/wiki/Block_and_tackle":HYPERLINK "http://en.wikipedia.org/wiki/Block_and_tackle":HYPERLINK "http://en.wikipedia.org/wiki/Block_and_tackle"BlockHYPERLINK "http://en.wikipedia.org/wiki/Block_and_tackle"HYPERLINK "http://en.wikipedia.org/wiki/Block_and_tackle"andHYPERLINK "http://en.wikipedia.org/wiki/Block_and_tackle"HYPERLINK "http://en.wikipedia.org/wiki/Block_and_tackle"TackleSee Rigging.

Tackline:

Short, standing line affixed to the boomabaft the mastand to a deck eye close to the mast. It constrains and tensions the fully raised junk sailagainst the pull of the halyard. [PJRp. 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 tensionor tensional forcesis said to act in tension. In junk rig, many fasteners, all control lines and sailclothsact in tension. WHYPERLINK "http://en.wikipedia.org/wiki/Tension_(physics)":HYPERLINK "http://en.wikipedia.org/wiki/Tension_(physics)":HYPERLINK "http://en.wikipedia.org/wiki/Tension_(physics)"TensionSee Compression, Shearand 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 fabricand to hemand sew lengthstogether. 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 throatof a junk sail, controlling its position relative to the mast. It helps peak up the yardfor better sail set. This line has been developed in support of fannedand cambered sails. [JRA]

Topping Lift aka Aft Lift (aka Lazy Jack):

Rigging systemled from the mastheaddown one side of a junk sail, through eyes on the boomand back to the mastheadon the opposite side of the sail. It gathers and supports the sail bundle, and may be rigged standingor running. It may divide into sail gatherers in the lower portions. See Lift, Forward Lift, Mast Liftand Sail Gatherer. [PJRp.50, figs 3.47-3.48]

Torque aka Wrack:

'Twisty' forces acting on a body. In junk rig, the masthead cranetorquesthe mast. WHYPERLINK "http://en.wikipedia.org/wiki/Torque":HYPERLINK "http://en.wikipedia.org/wiki/Torque":HYPERLINK "http://en.wikipedia.org/wiki/Torque"TorqueSee Compression, Shearand Tension.

Transitional Panel:

One or more panels of a junk sailwhich transition between a parallel battened region (parallelogram), below, and a fanned region above. It is, in effect, the lowermost, fanned panelof the upper fanned region, but generally has more in common with those below than those above, being distinguished by a modest increase in battenangles, 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 cantilevermastwithout stays or shrouds (see Stayed Mast), or the rigbuilt 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 mastis an unstayed mast. Absence of shrouds allows the boomto be let swing fully forward, an advantage in many situations. During a gybe, risk of boomimpact 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 afoil's convex side. In a sail (vertical foil), upwashis transverse motion, flowing toward the lee. See Foiland 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 vectoris 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 vectormay be represented as the productof two (or more) vectors. Uses include analysis of forces acting on foils, the hull, rigging, and course. WHYPERLINK "http://vector_diagrams_and_formulas":HYPERLINK "http://vector_diagrams_and_formulas":HYPERLINK "http://vector_diagrams_and_formulas"VariousHYPERLINK "http://vector_diagrams_and_formulas"HYPERLINK "http://vector_diagrams_and_formulas"SailingHYPERLINK "http://vector_diagrams_and_formulas"HYPERLINK "http://vector_diagrams_and_formulas"RelatedHYPERLINK "http://vector_diagrams_and_formulas"HYPERLINK "http://vector_diagrams_and_formulas"VectorHYPERLINK "http://vector_diagrams_and_formulas"HYPERLINK "http://vector_diagrams_and_formulas"DiagramsHYPERLINK "http://vector_diagrams_and_formulas"HYPERLINK "http://vector_diagrams_and_formulas"andHYPERLINK "http://vector_diagrams_and_formulas"HYPERLINK "http://vector_diagrams_and_formulas"Formulas

View:

A conventional direction in which plans are presented. See Plan View, Profile Viewand Section View. WGNT

Voluntary Turbulence:

Intentional turbulence introduced into flow across a foilby 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 Rigand Vortex Theory.

Vortex:

A turbulent, high pressure whorl of gas or fluid. In standard hydrodynamic theory, a vortexgenerated by a foilor other shape is deemed to increase drag. However, vortex theoryclaims that they may be harnessed in some circumstances to produce lift. WHYPERLINK "http://en.wikipedia.org/wiki/Vortex":HYPERLINK "http://en.wikipedia.org/wiki/Vortex":HYPERLINK "http://en.wikipedia.org/wiki/Vortex"VortexSee Voluntary Turbulenceand 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 sailclothand/or spars produce net lift. It is proposed that quasi-triangular, conic section sails (e.g., Crab Clawand panels of fanned sections of junk sails) develop additional drive under this theory. Vortex theoryis a contested application of hydrodynamicrepercussions of chaos theory. [ST&P] See Voluntary Turbulenceand Vortex.

Warp:

Filament, threador yarnrunning longitudinally along the weave, and run of woven fabric. WHYPERLINK "http://process_and_terminology":HYPERLINK "http://process_and_terminology":HYPERLINK "http://process_and_terminology"WarpSee Fabricand 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 weathercockquietly without flogging, when allowed, spread and supported by their battens. Junk rigged vessels can sheet flatto weathercockthe vessel in lieu of heaving toas a riding technique, whether at anchor or in heavy weather. Alternatively they can ease sheets and weathercockthe sails while lying a'hull. [PJRp. 6] See Drogue, Heave To, Lie A'Hulland 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 Helmand Balanced Helm. WHYPERLINK "http://en.wikipedia.org/wiki/Weather_helm":HYPERLINK "http://en.wikipedia.org/wiki/Weather_helm":HYPERLINK "http://en.wikipedia.org/wiki/Weather_helm"WeatherHYPERLINK "http://en.wikipedia.org/wiki/Weather_helm"HYPERLINK "http://en.wikipedia.org/wiki/Weather_helm"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. WHYPERLINK "http://process_and_terminology":HYPERLINK "http://process_and_terminology":HYPERLINK "http://process_and_terminology"WeavingSee Bias, Fabric, Thread Count, Warpand Weft.

Weftaka Woof:

Filament, threador yarnrunning transversly across the weave, and run of woven fabric. WHYPERLINK "http://process_and_terminology":HYPERLINK "http://process_and_terminology":HYPERLINK "http://process_and_terminology"WeftSee Fabricand Weave, and alternative, Warp.

Weight(Fabric):

Weight of fabricis 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 weightartificially. 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 sailgeometries have greatly increased the rig's performance. See Camber, Lift to Drag Ratioand 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 Rakeand Preventer.

Wing and Wong:: Jocular, junk rigsynonym for wing and wingin 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 sailsare 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 sailat luffand leech. Under press of wind, the sail is free to billow to the limit imposed by their curve, without being cutas 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):

Sparaffixed along the headof a junk sail, and from which the sail depends. A halyardis affixed to the yard, at the sling point. See Halyard, Sling Point, Throat Hauling Parreland Yard Parrel. [PJRp. 10, fig. 1.4]

Yard Angle:

The angle at which the yardis 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. [PJRp. 30 and p. 97, fig. 6.8]

Yard Downhaul:

A downhaulrigged for the yardin order to assist lowering in extreme conditions. Generally, it will be be affixed to an upper, aft battenend somewhat below the sling point, through a blockat the yard, and thence to deck level. [PJRp. 49, Fig. 3.46]

Yard Hauling Parrel (aka YHP aka Snotter):

A parrel, riged running, affixed to and led via the sling pointto deck level. It is used to position the yardrelative to the mastand constrain fore and aft, pitching motion of the junk sail. It is adjusted each time the sail is reefed. [PJRp. 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 fabricand line. WHYPERLINK "http://en.wikipedia.org/wiki/Yarn":HYPERLINK "http://en.wikipedia.org/wiki/Yarn"YarnSee Fabricand 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 loomis worked from side to side. Loomcurvature 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.