Sloping Yards and Diagonal Spars

A yard need not remain approximately level. Slope it upwards from a low forward end to a high after end and the supported edge changes direction. The sail can spread principally along the boat, while part of the yard still crosses in front of the mast.

That forward projection matters. A spar hanging beside the mast occupies one side of it, and the sail below may overlap it. When the wind changes sides, the mast can stand between the wind and the cloth, or the cloth can be pressed against the mast. The crew must either accept that changed contact or move the sail and spar to the other side.

These are questions about working arrangements. Our sequence compares their answers; it does not place the world’s sails in an order of invention.

Suspend a long sloping edge

A lateen sail is triangular, with one long edge attached to an oblique yard. The lateen yard extends from low and forward to high and aft, passing across the mast. The sail’s lower edge and its after edge run from the ends of that supported edge to the sheeted clew. In a boomless example, those two edges have rope reinforcement and tension but no continuous spar along them.

The yard’s lower end is its heel; its upper end is its peak. These are ends of the spar. Between them lies the sling point, the place where the hoisting attachment takes the yard’s load. A halyard leading upwards from this attachment lifts the yard, then passes through its upper lead to the hauling part. The point need not lie at the yard’s geometrical centre. Its position, the yard’s weight and the sail’s pulls affect how the spar hangs.

The yard must also be retained near the mast. A surrounding rope connection can hold it there while allowing movement, much as the previous chapter’s yard restraint did. The low forward part needs its own restraint, while the sheet pulls on the sail’s clew. Together these connections establish the sloping yard’s attitude and the cloth’s working shape. A lateen rig is the arrangement using this oblique-yard sail support, rather than a claim that every vessel carrying it has the same hull or number of masts.

The long yard is both the opportunity and a handling demand. It reaches well beyond the masthead without requiring a vertical mast to extend to the uppermost corner. Yet the yard itself must have the necessary length and bending resistance, and the crew must control its projecting ends. Warington Smyth’s 1906 account describes Mediterranean yards assembled from two or more pieces, hoisting tackle, a retaining rope around the mast, and controls at the low heel. A later fisheries study of East African sailing craft likewise records overlapping yard pieces lashed together. Joined spars, sound lashings and suitable cloth make the geometry usable; the outline alone does not.

Now shorten the extreme forward point of the sail’s triangular outline into a small forward edge. The resulting four-sided sail, still carried beneath an oblique yard, is a settee sail. This is an explanation of its shape, not a claim that sailmakers always produced one by cutting a corner off an existing triangle. In the narrower terminology used here, lateen sail identifies the triangle and settee identifies this quadrilateral. Historical and museum descriptions sometimes use lateen more broadly for both within a rig family.

Royal Museums Greenwich supplies a useful example of that convention. Its pre-1954 model of a Persian Gulf sambuk represents a dhow, a broad English label for several regional vessel traditions associated with the Indian Ocean and adjacent waters. The model shows a planked hull with a pointed bow, strongly sloping stem and flat transom at the stern. The museum describes this pearling and fishing craft as two-masted and lateen-rigged while identifying its sails as settee sails. Two masts, the hull form, the working purpose and the supported sail shape are separate pieces of information. Dhow alone does not prescribe one universal sail plan.

A felucca is another regional vessel name, associated with Mediterranean and connected traditions. The US National Park Service’s Nuovo Mondo represents the Mediterranean-derived fishing feluccas used in San Francisco: a broad, double-ended boat carrying a large lateen sail on a long yard. That one-mast example does not make one mast the definition of every felucca. The yard tells us how this sail is supported; the vessel’s name also carries a history of place and use.

Look beyond the triangular outline

A triangle can obtain support by a very different route. Knight’s leg-of-mutton sail is hoisted by its head to the masthead, with its luff retained along the mast by hoops or lacing. Its sheet controls the clew. In his boomless example there is no long sloping yard to move round the mast. The name describes the tapering outline; the attachment description tells us how it works. It does not by itself identify a particular complete yacht rig.

Two supported edges can also meet at one low corner. In the crab-claw family, spars spread those converging edges, leaving an opening between their outer ends. The actual outline and rigging vary. Taumako’s Te Puke voyaging canoe supplies one documented arrangement: curved spars meet at the tack, where a carved fitting receives the spar at the bow. Mast and reaching pole, supported by lines serving as shrouds and halyards, help hold the inclined assembly. A sheet controls its spread.

The Taumako account describes pandanus panels sewn together and tied to curved spars made from grown timber sections lashed together. Shape depends on weaving, joining and spar preparation as well as adjustment. When changing direction, the crew carries the sail to the opposite end and sets its tack in the new bow fitting. The canoe changes which end leads while keeping its outrigger to windward. This change of ends is called shunting. It is a different mast-and-sail movement from taking a bow through the wind and dipping a yard around its mast.

Keep two supporting spars but separate their forward ends, and a quadrilateral can occupy the space between them. The tanja sail, documented by Horst Liebner in South Sulawesi, has an upper yard and a lower spar carrying the head and foot. The assembly is canted, with substantial sail extending along the vessel. A halyard supports the upper spar; lines leading from the yard, called vangs in this account, control its position; the sheet acts through the lower spar. These controls let the supported surface change inclination and presentation.

The lower spar can also serve as the core around which the cloth is rolled. That is an additional handling role for the member carrying the foot. Tanja identifies this particular supported quadrilateral and its tradition. The two spars do not converge at a single tack as in the crab-claw example, and its moving yard is not the masthead attachment of Knight’s leg-of-mutton sail.

Leave the yard on one side, or move it

A lugsail, also called a lug in the sail sense, is a four-sided sail hanging from a sloping yard which crosses the mast, with part of the yard and sail ahead of it. Its lug yard supports the head; the halyard lifts at a sling point along that yard. A lug rig uses this arrangement. Lug here is the sail name. An attachment lug on a metal fitting is a different object.

Knight’s standing lug places the sail’s tack near the mast. His yard hangs from a strop partway along its length, connected to a sliding ring around the mast. The ring’s enclosure retains the yard near the mast while the halyard raises it. At the foot, the tack is secured near the mast and the sheet restrains the clew.

The yard and sail remain on their chosen side when the boat tacks. On one tack, the wind carries the cloth away from the mast; on the other, the mast bears against part of it. This can change the local shape and flow. The crew accepts that asymmetry in exchange for leaving the hoisted assembly in place through the turn. Standing describes that handling relationship, not a sail incapable of being lowered.

The dipping lug changes it. In Knight’s described arrangement, the tack lies farther forward and the yard and sail are lowered sufficiently to pass round the mast, then hoisted on the new leeward side. The transfer places the mast on the windward side again, freeing the sail from the contact that the standing lug accepts on one tack.

With standing and dipping lugs, the crew’s work follows from the choice of support. One leaves the yard on the same side; the other requires it to be transferred. During that transfer the long yard must clear the mast and other rigging, and the sail temporarily leaves its working state. Different dipping arrangements use different leads and amounts of lowering, so this described route belongs to Knight’s example.

A downhaul supplies a controlled downward pull on a sail or spar. Its attachment determines what it moves. On a standing lug whose tack uses an adjustable restraint, a tack downhaul leads from the reinforced tack to a lower fastening or purchase near the mast. Hauling it draws that corner down against the halyard’s upward support, establishing tension along the sail’s forward edge. The reinforced corner takes the line load; the purchase and its hull or mast fastening take the opposing reaction.

The lug’s lower edge can also acquire a spar. A boom carrying its foot and projecting forward of the mast, with some sail area forward too, gives the balanced lug, or balance lug. The boom connects tack and clew, so their positions are linked by a spar as well as by the sail. In Knight’s example, a downhaul attaches to the boom near where it crosses the mast and leads to a lower mast attachment. Its pull restrains the boom’s rise and tensions the supported sail against the raised yard.

The forward area also changes the turning demand at the sheet. Air force on cloth ahead of the mast-side support can oppose the turning effect of force on cloth aft of it, reducing the net moment the sheet must restrain. How much it helps depends on the force distribution and its distances from that support, as well as the sheet’s own lead. The amount of area ahead alone cannot give a sheet-load reduction. This is balance within the sail’s control arrangement; the yacht’s tendency to turn at the helm still depends on its combined air and water forces.

This is a downhaul applied to the boom, even though Knight calls the controlling rope the tack. It does not attach directly to the sail’s forward corner like the tack downhaul just described. Force enters the boom at the mast crossing and reaches the sail through its corner and foot connections. With sail and spar projecting forwards, the downhaul also influences how the boom resists lifting at its after end.

The balanced lug keeps yard and boom on their chosen side when tacking. The mast’s contact with the overlapping sail changes as it does with the standing lug, while the boom continues to spread the lower edge. A turn therefore need not include the dipping lug’s transfer, but the crew has an additional spar and its connections to manage when lowering or reefing.

A lugger is a vessel carrying a lug rig. Reaper, built in 1902 for Scottish herring fishing, has a wooden, double-ended hull of the local Fifie type: its stern narrows to an end rather than ending in a broad transom. It has two masts, carrying a dipping lug forward and a standing lug aft. One vessel can make two different choices about the mast-crossing problem. Its museum also explains how powered capstans and tensionable wire sail edges helped crews handle increasingly large working rigs. Sail size was enabled by the available handling and supporting machinery, not simply by drawing a larger quadrilateral.

Compare the mast crossings

The same test clarifies the earlier arrangements. A lateen yard’s low heel and high peak lie on opposite sides of its sling point, with a long projecting length to move. If its sail remains on one side of the mast through a tack, the mast-and-cloth contact changes. Transferring the yard requires a route for that projecting heel and sail to clear the mast and its supporting lines. The settee’s short forward edge changes the cloth outline but leaves this oblique-yard problem. Lateen or settee alone does not specify a single universal transfer procedure.

By contrast, Knight’s leg-of-mutton sail has its luff attached along the mast and no upper yard spanning across it. Its after portion changes sides around that retained leading edge. In the Taumako crab-claw example, changing ends relocates the tack and inclined assembly to a different bow fitting while preserving the outrigger’s windward position. These arrangements cannot be assigned the dipping lug’s procedure merely because each sail looks triangular or sloping.

For tanja, the reconstruction sailed by Nick Burningham gives a specific further answer. His Borobudur ship changed tack by turning its stern through the wind, wearing round. The crew brought the yard towards vertical by hauling its heel down, while the vangs restrained the upper end. Swinging the heel across to the new windward side brought the yard’s upper end to the new leeward side; the sheet had to travel round the bow with the sail before being secured and trimmed. This was a controlled movement of the whole supported sail around the masthead. It was not the bow-through-wind tack of our opening boat, nor Knight’s lowered lug. Burningham’s account documents that reconstruction’s demanding method, with experienced Indonesian crew, rather than every historical tanja rig.

The mast crossing has consequences beyond the sail’s outline. In one arrangement the cloth remains beside the mast; in another the spar must clear it, or the whole sail moves to a new bow. The retaining connections determine which movements are possible.

Prop the outer corner from below

There is another way to hold a four-sided sail’s upper outer corner out. Hoist its forward upper corner, retain its leading edge near the mast, then push the outer upper corner up and away with a diagonal spar. That spar is a sprit. A fore-and-aft sail extended this way is a spritsail, and its arrangement is a spritsail rig. The later square sail carried beneath a bowsprit, the spar projecting from the bow, uses another sense of spritsail.

In Knight’s small-boat example, the sprit’s upper end enters an eye at the outer upper corner. Its lower end, the sprit heel, sits in a rope eye beside the mast. The diagonal spar transmits compressive thrust between those contacts, opposing the sail’s tendency to pull its outer corner down and in. Its stiffness keeps the supported distance, while its ends must remain seated.

The rope support at the mast is the snotter. Knight forms it from a rope ring around the mast, seized across its middle to produce an eye receiving the heel. The heel bears into that eye; tension in the rope passes the reaction around the mast. Raising and retaining the snotter changes the sprit’s supported position and the sail’s tension. A tackle can supply that adjustment and prevent the support slipping down.

The thrust now has a route through both ends. At the mast, the heel bears into the snotter, which locates and supports that lower contact. At the far end, the sprit pushes into the reinforced sail corner. A diagonal stick with either end free to escape would not maintain the required shape. The sail’s halyard and luff attachments still carry their own loads beside this compression member.

Push the clew out instead

A sprit boom applies a related principle to the lower after corner. It runs from a support near the mast, above the foot, diagonally across the cloth to the clew. Its inboard end bears in a suitable snotter, and its outer end bears at the reinforced clew connection. Compression in the spar pushes the clew out. A sail using that lower-corner support is described as sprit-boomed, or as using a sprit-boom rig.

A conventional boom lies along or close to the foot and connects near the mast at its heel. The sprit boom crosses above the foot to reach the clew; the cloth below it can remain free of a continuous spar. The mast-end support, compression member and corner attachment therefore form a different lower-sail load route.

Adney and Chapelle’s account of Mi’kmaq birchbark canoes records arrangements carrying both members: one sprit supporting the upper outer corner and a sprit boom supporting the clew, each with its own mast-side support. They can coexist because they do different jobs. Calling both diagonal spars does not identify which corner either one holds.

Gather the cloth towards the mast

A diagonal sprit need not prevent the sail being drawn into a compact state. In Knight’s described spritsail, a line passes through a block on the mast and around the sail. Hauling it draws the enclosed cloth towards the mast. The line’s contact with the sail gathers material, while the block changes the pull’s direction and passes its reaction into the mast.

This gathering line is a brail, or brailing line. Brails is the plural for such lines. To brail up, or to perform brailing, is to haul those gathering lines so that the cloth collects towards its support. Here the support is the mast, and the diagonal sprit remains part of the gathered assembly. The working sheet must be allowed to travel as the sail changes shape.

The crew can gather this cloth and release it again while its supporting assembly remains aloft. The sheet still has the separate job of restraining the working clew. The previous chapter’s clewline lifted a corner towards a yard; its buntlines gathered the centre upwards. This brail encircles the spritsail and draws it towards its mast. Each reduces exposed cloth through a different route and contact, without necessarily lowering the whole rig.

These choices were already coexisting when Knight wrote in 1889. They have different working costs: a yard that must be transferred, a boom that ties two corners together, a diagonal prop whose ends must stay seated, or a gathering line that changes the cloth’s state without lowering everything. Regional practice, routes, materials and available hands shaped useful combinations. None supplies a universal next step after the square sail.

The upper corner can also be held out by a spar along the sail’s head, wholly aft of the mast. Let that spar’s inner end travel along the mast and the four-sided fore-and-aft sail acquires an upper beam. Its two ends can then be controlled separately to set the height and angle of the supported edge.