A Sail Divided by Battens

A triangular mainsail can use battens to support its leech or extend that support across the cloth. Now give the battens another job. Attach the sheet system to several of their after ends, so that the crew’s pull reaches the sail at several heights. Retain those battens beside the mast, and arrange for them to gather with the cloth when the sail is lowered.

A junk sail uses this combination of full battens and distributed sheeting. Junk rig names the resulting support and control system. Its many spars divide a single sail into manageable supported portions, without requiring each portion to have a separate halyard.

Junk also names vessels. The Keying, exhibited in Britain in 1848 after voyaging from Hong Kong via America, was described as a Chinese junk. A commemorative medal records a teak-built hull and represents three masts. That historical vessel designation carries information about a craft and its use; it is distinct from the sail system which can be fitted to another kind of hull. Slieve McGalliard’s Poppy, for example, received a junk rig on a Westerly Longbow yacht.

We will follow Arne Kverneland’s documented Johanna-style sail, including its later controls on the yacht Ingeborg. Other owners’ arrangements will supply specific comparisons. The word junk does not require all of them to carry the same equipment.

Put supporting members across the sail

The yard supports the head. The boom carries the foot. Between them, full-length battens extend from the forward to the after edge, each supporting the cloth adjoining it. The fabric between neighbouring spars forms a panel of the working sail. A halyard attached near the middle of the yard raises that yard; the attached cloth then lifts successive battens below it.

Compare the lug yard from the earlier chapter. It crossed the mast with part of the sail ahead, while a balanced lug added a boom projecting forwards too. The Johanna-style junk sail has that broad relationship of sloping yard, forward area and lower spar. Calling it lug-like identifies a useful geometric comparison, not a proven historical descent from the European lug rig.

As with a standing lug, this sail remains on its chosen side of the mast through a tack; it is not dipped around the mast as the dipping lug was. On one tack the spars bear towards the mast; on the other the restraining lines must prevent the assembly moving away. The full battens and their several sheet connections make the behaviour different from merely adding a boom to a lugsail.

The area ahead of the mast is the sail’s balance in the junk-rig sense. Force on that forward cloth can oppose the turning effect of force aft of the mast-side support, reducing the net moment restrained by the sheet system. Kverneland uses that contribution when arranging his sail and its sheeting.

Balance is often stated as an area proportion. In a hypothetical 30-square-metre outline with 6 square metres ahead of the mast line, it is 20 per cent. The actual turning effects also depend on pressure distribution and moment arms; a 20-per-cent area balance is not a 20-per-cent reduction in sheet tension. Nor is it the yacht’s helm balance, which concerns the combined forces tending to turn the whole boat.

Spar directions also need references. Yard angle is the yard’s inclination to a stated line, here the horizontal in side view with the boat upright. The selected Johanna-style yard rises more steeply than most of the battens beneath it. Batten rise, in the parallelogram convention used by Hasler and McLeod, is the vertical distance from the forward to the after endpoint. That distance and the horizontal run determine the batten’s slope. A rise given in metres and a yard angle given in degrees describe different quantities.

A parallelogram sail has largely parallel battens in its lower portion, with the corresponding cloth panels having a broadly parallelogram outline. The upper panels may depart from it to meet the steeper yard. A fanned sail deliberately sets successive battens at different angles. Their spreading directions belong to the intended design. Neither profile by itself specifies how the sail is sheeted or how its cloth forms camber.

Connect cloth and spar

A short leech batten stiffens a local after-edge region. The junk sail’s batten reaches across a whole panel boundary and receives a sheet connection as well. Its bending resistance and attachments must now help preserve the working arrangement across the sail, not just support the edge.

A batten pocket can connect cloth along that member. The pocket’s seams pass load into the surrounding sailcloth; suitable end restraints keep the spar in its intended position. This gives the panel a supported boundary through which its load reaches the batten.

The batten box or receptacle on a conventional full-batten mainsail can transmit the forward batten’s compression into a luff attachment or car. The chosen junk arrangement restrains its crossing battens with lines around the mast. It therefore has another route at that contact. A full-length batten does not imply that every sail uses the same forward fitting.

The panels remain sailcloth carrying tension. Their battens do not turn them into rigid plates. A draft stripe can still reveal the loaded curve across a panel, while a sail window supplies a view through the cloth where fitted. Neither feature takes over the batten’s supporting job. The spar, its cloth attachments and its control-line connections establish the load path.

Keep the sail beside its mast

A batten parrel retains one batten near the mast. In a simple arrangement, its ends attach at two points on the same batten, with the line passing round the mast’s far side between them. When the sail tries to move away, the loop takes tension and restrains that separation. When the sail bears towards the mast, the batten and its protective contact take the corresponding bearing load. The loop must allow the intended rise, fall and swing.

A boom parrel applies that retaining job to the bottom spar. A separate tack parrel locates the lower forward region relative to the mast. Kverneland’s selected standing tack parrel runs from the forward boom region round the mast and back, limiting how far that region can travel forwards. It lies above and inside the supporting mast lift which we will follow shortly. His separate tack line pulls down from the boom to a lower attachment; the parrel’s position restraint and the tack line’s downward pull have distinct effects.

Each of these spars needs room to travel and swing while remaining beside the mast. Its loop does the retaining job that the gaff parrel did, but the contact has changed: the batten crosses beside the mast, where the gaff slid on shaped jaws or a saddle.

A luff parrel constrains the sail’s forward region; a luff hauling parrel makes that restraint adjustable. Kverneland later concentrated this control near the top. His throat hauling parrel begins at the yard’s forward end, passes round the mast, then through a block near the forward end of batten 2 and down towards the deck. Here battens are numbered from the top, excluding the yard. The pull acts between the upper forward sail and its mast contact, drawing the throat down and aft and helping establish the upper panels’ attitude.

Kverneland developed this from his longer luff-hauling arrangement, reducing the number of batten regions in the running route. He reports that positioning the top better reduced the demands on the diagonal restraints below. This is a documented adjustment to one working system: fewer bends and a more focused pull changed both handling and the way the sail hung.

Locate the yard and the panel diagonals

A yard parrel retains the upper spar near the mast. The yard hauling parrel makes that restraint adjustable. In Kverneland’s later arrangement, it begins about two-thirds of the way from the yard’s forward end towards its peak, passes round the mast, returns through a block near that yard attachment and descends to a deck lead. Hauling draws that region towards the mast. Acting above and aft of the halyard’s sling point, the pull also helps raise the peak relative to the throat. The halyard supports the assembly while the hauling parrel locates it.

The yard hauling parrel and throat hauling parrel therefore act at different places on the same upper assembly. Their pulls must cooperate. A yard drawn too far or a throat insufficiently restrained can leave the panels hanging in an unintended relationship. The line leads, sling point and permitted movement determine the result; adding tension everywhere is not a general cure for a poor set.

Some panels also need diagonal restraint. A Hong Kong parrel runs from the forward part of one batten to a point farther aft on the batten below. In the selected Kverneland arrangement it passes on the sail side of the mast, rather than encircling the far side. Its fixed length limits the relative movement of those batten points, helping keep the panel from distorting into a diagonal crease.

This diagonal carries tension into its two batten attachments. Those pulls can bend the battens, so the restraint’s size and position must suit the assembly. Unlike the ordinary batten parrel, it does not primarily keep the whole sail from blowing away from the mast. Its useful job is between neighbouring spars. The mast-side loops, diagonal restraints and upper hauling controls together preserve different aspects of the sail’s position.

Bring one sheet to several heights

On the simple Bermuda mainsail, the mainsheet acted through the boom. In this junk system, the after ends of several battens also receive a share of the sheet’s pull. Changing the length of the sheet changes the sail’s angle, while the distribution of that pull helps establish how much the upper panels twist relative to the lower ones.

Begin with two neighbouring batten ends. A sheet span is a line joining them, with the sheet system pulling through a connection carried on that span. The pull divides towards the two attachments, giving each batten a reaction. The selected connecting point and the lines’ angles affect that division; two branches do not automatically deliver equal useful turning effects to the sail.

Kverneland’s Johanna drawing shows how spans and moving blocks divide that pull. The main sheet’s fixed end attaches to a span assembly serving the lowest three battens. From there the rope leads through a deck block, up around a block in a travelling assembly, and back down through a deck turning block to the crew. Two parts of this sheet pull the travelling assembly down, while its fixed end pulls the lower group through one part.

The travelling assembly connects to the upper sail through another rope. One end is secured to that assembly; the rope runs up through a block at the after end of batten 2, down through a second block on the travelling assembly, and then to a fixed span joining battens 3 and 4. These numbers again run from the top, excluding the yard. Three parts of this connector act at the travelling assembly. Two reach the batten-2 block and one reaches the span below it, dividing the upper group’s pull again.

This traced arrangement gives the upper sail a different share of the sheet load from the lower sail. Line angles and friction affect the actual forces, and each span’s branches further divide its reaction. The purpose is to control twist instead of concentrating all the pull at the boom. The attachments must transmit those loads into the spars, not just into an unreinforced flap of cloth.

Those sheet connections must reach the batten ends where the sail’s geometry puts them. A parallelogram’s near-parallel battens present different attachment positions from a fanned arrangement. Batten rise affects where their after ends lie, while the steeper yard angle locates the upper panels without making the yard another parallel batten. Copying the same line lengths and leads onto another outline can change both their travel and their force distribution.

Receive the lowered sail

Ease the halyard and the yard descends. The lowest panels collapse first between their supporting spars, while the remaining upper panels can stay exposed. The accumulating cloth and spars form the sail bundle. The reduction works because the battens can settle together and because something supports the growing stack.

The forward lift supports the forward part of that bundle. Kverneland calls his particular arrangement a mast lift: a line runs from high on the mast down beside it, beneath the boom and around the mast, then back upwards. Its lower loop receives the boom while its upper attachments transmit the load into the mast. The loop also helps contain the forward cloth as it falls. Other authors distinguish forward lift and mast lift differently, so the route matters more than assuming the labels are universal synonyms.

Farther aft, topping lifts and lazyjacks cradle the boom and collect the sail on both sides. As the halyard releases the weight of spars and cloth, these lines receive it. Lowering the sail transfers its weight to another part of the rig.

This is a different movement from brailing up the earlier spritsail. Its brails drew cloth towards the mast while its supporting assembly could remain aloft. Here the battens and yard descend with the cloth into a supported stack. Similar aims of reducing exposed sail do not make the moving parts or load routes identical.

Batten stagger is the fore-and-aft offset between batten ends in the lowered bundle. With suitable stagger, the upper after ends project far enough beyond those beneath for their sheet connections to hang clear. Unhelpful overlap can catch a line or block against a lower spar. The intended angles, parrel lengths and sail cut therefore affect both the set sail and its resting stack.

The lines that held the set sail in position must also make room for this growing bundle. Batten and boom parrels descend around the mast, while the tack parrel keeps the boom located above its lift. The Hong Kong diagonals become slack as their attachment points draw together. Their loose lengths must fall clear of the gathering spars. The yard and throat hauling controls change geometry too, locating the part still exposed as the hoist is reduced.

At the after ends, fixed spans now join closer battens and can hang in loops. Their blocks need room beside the stack. Kverneland’s development towards a more upright sail and revised sheeting addressed this handling problem as well as the set sail’s shape: sheet connections had to remain clear when their supporting geometry changed.

Change a retaining or sheeting route

The lower sail’s forward position need not be fixed. A running tack parrel makes that restraint adjustable. Platt describes an inhaul at the forward end of High Tea‘s working lower spar: the rope passes round the mast and returns through a forward lead to its hauling part. Taking in the line draws the forward end back towards its restrained position. Easing it permits more forward movement within the other connections’ limits. The mast supplies the contact around which the line turns.

A standing luff parrel fixes the forward batten region’s relationship to the mast. On Paul Fay’s Ti Gitu, a loop runs from a batten’s forward end round the mast and returns to that same forward region. In addition to the ordinary batten parrels, these fixed loops restrain the forward ends and help them settle in the intended relationship as the sail stacks. Fay describes using tube-covered rope at the mast contact. That is one owner’s construction, not a requirement that every parrel contain that tubing.

Platt’s High Tea luff line passes from an upper forward attachment round the mast, through a lead at the next forward batten region, and continues through further mast-and-batten turns to its hauling part. Shortening that route draws those forward points towards their intended positions. Several bends also introduce friction.

Platt tried a running restraint, then replaced it on High Tea with a fixed collar made from fire hose. Its ends carried metal triangles joined by a shackle to the yard. This standing yard parrel enclosed the mast and retained the yard while allowing its necessary movement; it did not require a hauling tail to set its length.

Names vary between accounts. Kverneland and Practical Junk Rig use sheetlet for a fixed sheet span. Other authors, including Colvin, use sheetlet for a running connecting line. Running spanline and sheet hauling span identify that adjustable connector: a line leading between the sheet connection and batten spans, through the chosen guides, whose working lengths change as it is hauled or paid out. A fixed span has its endpoints secured to its batten group; a running connector moves through its guides. Establish which is meant before tracing the pull.

Platt’s High Tea shows a particular running arrangement. His euphroe is an elongated wooden fitting pierced with fixed holes. The thinner connecting line runs to and fro between those holes and the batten connections, using the small blocks and intermediate guides shown in his account. Pull reaches several heights through this network. The main sheet block is attached to the euphroe by a strop, so the sheet’s reaction enters the fitting and then the connecting lines.

The holes guide rope by sliding contact and friction; they contain no rotating sheaves. Length can be redistributed through them to adjust the batten relationships. Platt leaves the lower end of the connecting line available for adjustment, either secured at the lowest batten or retained from running out. Taking up that end corrects excess connecting-line length, including the changed requirement after reefing. He calls these running connections sheetlets, so his word identifies a different piece from Kverneland’s fixed spans.

After reefing, the closer battens no longer need so much connecting-line length. Platt’s adjustment takes up the surplus while the euphroe continues to distribute the sheet pull and the lifts receive the bundle’s weight. The same lowered state that mattered in the Johanna system now has different moving contacts, friction and means of adjustment.

Cloth attachments can change too. On High Tea, bamboo battens lay outside the sail, with thin slats on the opposite face holding the cloth between them. The clamped strip replaces the pocket’s connection while retaining support along the panel boundary.

A sail gatherer adds lines or fabric to collect the lowering cloth. McGalliard’s Poppy uses a fabric catcher carried by its lazyjack system, with extensions that close over the furled sail. The cloth catcher spreads contact; its supporting lines pass the bundle’s weight to the rig.

Pull down a reluctant member

Gravity may not lower every spar as intended when wind pressure, friction or the sail’s motion opposes it. A batten downhaul supplies a downward pull at its attached batten. McGalliard combines this with a retaining parrel. In his earlier illustrated version, a rope starts at one batten, passes around the mast and returns through a thimble attached to the same batten. From that guide it descends to a common bight, then rises through the second batten’s thimble, passes around the mast and ends at the second batten. A separate hauling line pulls the bight down through a deck ring and leads to the cockpit.

Hauling draws the returning rope through the two batten guides. The loops restrain the battens against the mast, while the downward pull on their guides helps bring the battens down. The common bight distributes the hauling connection between the pair. McGalliard also shows a later version with different mast contacts; the route described here belongs to the earlier drawing.

One rope now retains two battens and helps pull them down. A fixed loose batten parrel alone supplies no independently hauled downward pull; a downhaul tied elsewhere can lower a member without enclosing the mast. McGalliard’s route combines those jobs, with friction and the relative lengths of its paired branches affecting the result.

A yard downhaul acts on the upper spar. In the arrangement described by the Junk Rig Association, a line leads from an upper batten’s after region through a block on the yard and down to the deck. Hauling draws the yard towards the batten and the lower lead as the halyard is eased. Its attachment and moving block distinguish it from the yard hauling parrel which chiefly locates the spar against the mast.

Another unwanted movement is fan-up. The yard and upper battens can rotate upwards and forwards beyond their intended relationship, possibly catching in the lifts. The sheet’s downward restraint can fall slack during a gybe, while wind and the yacht’s motion move the upper spars. Kverneland also demonstrated a slow fan-up in harbour by hauling too far on the yard hauling parrel on a reduced sail. It is different from a deliberately fanned sail, whose diverging batten angles belong to its designed set.

Kverneland’s tested fan-up preventer supplies a further downward restraint. In his original arrangement, a line attached to batten 2 leads down near the after ends of the lower battens, through a guide near the boom’s after end, forwards along the boom and through lower leads to the crew. Hauling its slack holds that upper batten down. Loose auxiliary loops on lower battens guide the line and limit their ability to rise past it. His later version altered the leads and reduced the number of loops to reduce friction.

This is a documented local development, with tests on his boats. Its useful principle is to restrain the unwanted motion through a known attachment and load path. The complete rig still needs clearance and suitable strengths in both its raised and lowered states; the name preventer is not proof that every possible entanglement has been eliminated.

Form the curve between battens

Full battens do not settle the question of camber. Flat-cut panels can deform under load, but the amount and location of that deformation depend on cloth, restraint and wind. Deliberately shaping the support or the cloth gives the sailmaker more control over the intended section.

A bendy batten is designed to flex into a useful continuous curve. Its material and section determine how much it bends under a given load. The supported panel follows that curve, but a different wind load can produce a different bend. A hinged batten instead uses joined sections whose permitted angles create the shape. Stops or other restraints limit those angles. The jointed member obtains its curvature by articulation where the bendy member obtains it by deformation along its length.

A cambered junk sail can also place the shaping in the cloth between comparatively stiff battens. Curved panel boundaries or suitably shaped seams provide fullness which forms a three-dimensional section when the fabric is loaded. Kverneland experimented with hinged battens in the early 1990s, then developed sewn camber in the panels. McGalliard explicitly credits that work among the influences on his later design. These are documented connections between practitioners, rather than an inferred progression from a line of silhouettes.

Recall the sailmaker’s panel seam and broadseam: joining pieces with controlled geometry can produce fullness. In one cambered-panel method, curved cloth edges are fitted to straight batten boundaries so that the intervening material has room to form its designed bulge. The panel between two battens may itself contain several sewn cloth pieces. A batten panel and a single piece cut from a roll therefore need not be the same unit.

The sailmaker still has to choose the cloth directions within each supported panel. A woven panel’s bias can distort more than its warp or weft directions, changing the curve under load. Crosscut, radial or tri-radial piece layouts offer the reinforcement choices already examined; the batten layout supplies their surrounding support. A fanned arrangement can therefore use shaped cloth without making the fan itself the source of camber.

Leave room beside the mast

The split junk rig changes the panel near the mast. In McGalliard’s Poppy arrangement, each relevant panel is divided into forward and after cloth portions by a slot just ahead of the mast. Continuous battens span both portions, while sheet connections remain at their after ends. The forward cloth can take its intended camber without having to lie across the mast on one tack.

The split changes a local contact and flow arrangement. It does not turn the forward pieces into independently hoisted sails: they remain part of the batten-supported system. Their shape, the opening and the mast’s position must work together. McGalliard describes developing the arrangement through models and trials on the Westerly hull, then revising details after use. His reported results establish that particular development; they do not rank every split sail against every Bermuda or unsplit junk sail.

A split, balance and camber describe three different properties of the same sail. The split provides clearance between cloth portions near the mast. Balance locates area ahead of the mast, and camber describes a panel’s loaded curve. Each can change while the others retain their own definitions.

The several spar and line families we have examined answer questions about supporting one sail. Even a well-supported surface can become large or occupy only part of the space available. The next question is how to divide area among separate sails, beginning with the space ahead of the mast.