What the Gaff Adds

Keep the fore-and-aft sail’s leading edge beside the mast, but give its upper edge a beam projecting aft. The beam’s inner end can rise along the mast; its outer end can be raised to establish the upper edge’s slope. The cloth hangs below that supported edge.

This spar is the gaff, and a fore-and-aft sail supported along its head by a gaff is gaff-rigged. Here the sail’s head is an upper edge, as it was beneath a square yard. It is not the single head corner of our opening triangular mainsail.

The gaff supports a broad upper portion which a triangle running directly from masthead to clew would leave empty. For a given mast height and foot length, that permits additional area. It also adds a spar whose weight and sail loads must be supported, whose angle must be controlled and whose inner end must remain beside the mast while moving.

Raise two ends of one spar

The four-sided sail has two upper corners. Its upper forward corner, beside the mast, is the throat. Its upper after corner is the peak. These names also locate the adjacent ends of the gaff: its throat is the inner end, and its peak the outer end. Lacing along the head passes load from the cloth into the spar between them, while reinforced corner attachments take the concentrated loads at the ends.

The familiar tack and clew remain at the lower forward and after corners. The luff runs from tack to throat, the head from throat to peak, and the leech from peak to clew. That makes it possible to ask exactly which boundary a control is moving.

Begin with E. F. Knight’s 1889 small-yacht arrangement, with the luff retained beside the mast and the foot spread by a boom. Its two hoists have separate jobs. The throat halyard raises the inner end beside the mast. Its tackle has an upper block secured to the mast and a lower block attached at the gaff’s throat. Hauling draws those blocks closer, raises the throat and extends the sail’s luff. The upper attachment passes the tackle’s reaction into the mast.

The peak halyard supports the gaff farther out. Its pull raises the outer portion and changes the spar’s angle relative to the mast. It need not attach at the extreme tip: lifting at selected positions along the spar can support the peak while distributing the load. The throat and peak controls therefore act on one connected beam at different places.

Suppose the throat is held and the peak halyard is hauled. The outer end rises, carrying the sail’s peak with it and changing head and leech tension. Haul the throat while retaining the outer end’s height, and the inner end rises instead, flattening the gaff’s slope while extending the luff. Haul both during the hoist and the whole supported head rises. Because cloth connects all four corners, these are coupled movements; neither halyard adjusts an isolated strip of sail.

Knight describes raising the gaff with both controls, completing the throat hoist and then setting the peak. Once the inner end is at its required height, the crew can still adjust the slope of the head. The extra line permits that separate adjustment; the two settings work together to establish the sailmaker’s intended shape.

Retain the inner end without fixing it

The gaff’s throat must rise along the mast and swing around it with the sail. It must also bear against the mast and remain attached when the pull changes direction. A connection that rigidly clamps the two spars together would prevent the required movement.

Knight’s gaff jaws solve part of this problem with two arms projecting from the throat, one on either side of the mast. The curved bearing surface between them presses against the mast. This contact transmits force while allowing the assembly to slide and turn. Leather or another suitable facing can protect the contact surfaces. The jaws carry and guide; their open ends still leave a route by which the gaff could separate from the mast.

A rope closes that opening. It runs from one jaw, around the forward side of the mast, to the other jaw, retaining the spar without fastening it immovably to the mast. This is the jaw rope, also called the parrel rope in this arrangement. The rope and its associated retaining parts form the parrel, also spelt parral. The names describe related parts of the connection: the jaws provide the bearing, while the rope completes the restraint around the mast.

Parrel beads are bored pieces threaded onto that rope. They bear against the mast and keep the rope itself from dragging directly across the same surface. Their rounded contacts can move as the assembly travels, with clearance, alignment and the condition of the whole jaw-and-parrel connection governing how freely it slides.

As the peak rises or swings, the throat must remain free to follow its intended movement. A restrictive rope can make it bind; unsuitable freedom can leave the bearing unable to guide the spar. The mast’s size and shape, the jaws’ clearance and the halyards’ leads therefore have to suit one another. The connection must retain the gaff throughout its swing and hoist without obstructing either.

The lower spar can use a related fitting. Boom jaws straddle the mast at the boom’s inner end, providing a bearing and permitting the boom to swing. They occupy the lower connection rather than the travelling throat of the gaff. A rope retainer can close them in the same manner. The metal gooseneck encountered earlier supplies a different articulated boom-to-mast connection; recognising the common movement does not make the fittings identical.

Spread the peak pull

The peak halyard’s attachment can itself distribute force. A peak bridle connects the hoisting load to separated attachment points along the gaff, sharing the pull instead of concentrating it at one small fitting. The connecting length spanning those points is a peak span. In common usage these names can overlap; they need not identify two additional fittings fitted one after the other.

One documented arrangement uses a flexible wire span secured along the gaff, with a halyard block able to travel on it. Pull from the halyard enters the block, then divides into tension towards the span’s two attachments. Those attachments pass the support into the spar at separated positions. As the gaff’s angle changes, the block can change its position on the span. The span’s length, attachments and permitted travel determine how far it can move; free movement without suitable limits could let the gaff adopt an unwanted angle.

A span distributes attachment load. A peak purchase provides mechanical advantage through the reeved halyard and its moving blocks. The two jobs can be combined in one system, but neither name explains the other.

In Dana’s 1847 arrangement, two single blocks are attached at separated positions along the gaff, and a double block is secured high on the mast. Starting at the hauling end on deck, the line goes up through one mast-block sheave, down through the inner gaff block, up through the other mast-block sheave, down through the outer gaff block, then back up to its fixed end at the upper block. The gaff blocks move with the spar; the upper block and fixed end take their reactions into the mast.

Hauling brings in rope from several supporting parts, exchanging additional travel at the crew’s end for reduced required pull. The sloping rope parts act at different positions on a rotating spar, so a simple count alone does not give the peak’s vertical lifting force in every position. Dana’s blocks are strapped directly to the gaff; the travelling span-block arrangement is a different way to distribute the support, not an extra route hidden inside this example.

Easing the lifting gear does not always bring the peak down where the crew wants it. Other loads or a reluctant sliding connection can oppose gravity. A peak downhaul acts at the outer portion of the gaff and leads towards the deck, supplying a downward pull with which to draw or restrain that end.

A gaff saddle offers another construction at the upper spar. In John Leather’s illustrated metal example, a curved saddle plate bears against the mast, while a pivot joins it to fittings on the gaff. The curved plate takes the mast contact; the joint lets the spar change angle relative to that plate. The surrounding retainer still prevents separation. A saddle therefore changes the bearing and articulation, rather than removing the need to guide and retain the throat.

With a steeply raised gaff, the forces also try to twist this connection. The saddle’s shape, pivot freedom and the halyards’ alignment must suit that working angle.

Not every gaff sail has the two separate hoisting falls we began with. The Norfolk wherry Maud raises her gaff and sail with a single halyard operated by a winch. A separate line from the gaff’s after end controls its peak while hoisting or lowering. Her documented arrangement separates the main lifting job from control of the outer end differently. The gaff’s supported head is the defining feature; a universal count of two halyards is not.

Lateral control has another name. A gaff vang leads from the peak towards the vessel’s side; Dana describes one towards each rail. Tension restrains sideways movement of the gaff, with the opposite line able to ease as its position changes. These vangs act on the upper spar. A boom vang instead restrains the lower boom from rising: it pulls down on that spar, controlling a different member and direction of movement. We will follow its complete arrangement with the boom’s other controls.

Compare the two upper supports

The previous chapter’s spritsail rig supported its upper outer corner with a diagonal compression member. The sprit’s heel pushed into a snotter beside the mast, and its upper end pushed into the sail corner. Those two seated ends preserved the diagonal’s effective reach. The sail’s upper edge did not acquire a continuous beam merely because its corner was propped out.

Here the gaff carries the head along its length. Halyards pull upward on the spar, while its throat connection guides it at the mast. Its outer portion is suspended instead of being supported by a sprit heel thrusting down into a snotter. The peak bridle or span distributes the suspended load, and the peak purchase helps the crew lift it.

The distinction also leaves the sprit boom in its proper place. In a sprit-boom rig, that separate diagonal member pushes the clew out from its own mast-side support. It controls the lower after corner. Replacing the upper sprit with a gaff would not automatically replace this lower member’s job. A sail’s upper and lower supports must each be identified before the whole arrangement can be understood.

Knight described sprit, lug and gaff equipment in the same 1889 book because they were available alternatives. The gaff’s useful combination was a broad supported head, a mast-side connection that travelled, and control over the spar’s elevation. Its extra spar, fittings and lines were the cost of that combination. This comparison explains a design choice without making the gaff the inevitable historical successor to every diagonal sail.

Fill the space above the gaff

If the mast extends above the gaff’s throat, another sail can occupy the opening between that upper mast and the sloping gaff. This is a gaff topsail: a topsail in the fore-and-aft, above-the-gaff sense. It is a separate surface, with its own head, tack and clew. A square topsail instead spreads on a transverse yard above a lower square sail. That supported stack will need its own explanation later.

Begin with the simple triangular topsail described by A. J. Kenealy in 1903. A topsail halyard lifts its head towards an upper mast attachment. The lower forward corner is the topsail tack, and its securing or downhauling line is also called the topsail tack, or tack line. The corner is part of the sail; the line pulls that corner down against the halyard’s upward support. Kenealy’s example uses a purchase for this downward tension.

The clew is drawn out towards the gaff’s outer end. Its controlling line is the topsail sheet. In this gaff-topsail arrangement it also performs the topsail outhaul job: drawing the clew out along the support below it and tensioning the foot. These names can identify one line by its attachment and its action; they do not require two independent lines at the same corner.

Knight gives a definite sheet lead for his yarded topsail. From the clew the sheet leads through a sheave at the gaff’s peak, then through a block below the throat and down to the deck. Hauling moves the clew towards the outer sheave; the sheave and inner block transfer the line’s turning forces into the gaff. The crew can therefore trim a corner high above them from a working position below.

Knight’s topsail has an additional light upper yard to which the cloth is laced. The halyard lifts that yard at a selected point, carrying the sail with it. A downhaul attached to the yard’s heel controls that lower end. The spar permits the supported cloth to extend beyond the height obtainable by merely hauling an unsupported head to the mast’s halyard lead. This yard-heel downhaul acts on the spar; it should not be mistaken for Kenealy’s tack line attached directly to a sail corner.

Another spar can extend the topsail’s foot beyond the gaff’s peak. This is the jackyard. It carries the lower edge farther out, so the gaff’s tip is no longer the final support beneath the sail’s outer portion. A topsail with this foot-extending spar is a jackyard topsail. Club topsail is also used for such extended topsails, particularly in American usage; the labels overlap across traditions rather than defining two universally different mechanisms.

On Chloe, as described in Sailing Gaffers, the topsail yard’s heel line leads through a cheek block on the after side of the mast to the deck. A line from the jackyard leads through a cheek block on the gaff, then through a block near its jaws and down. The two spars have separate leads: one restrains the upper yard, the other controls the jackyard’s outward position. Each also has its own load and movement. To gain the cloth beyond the original opening, the crew has acquired more equipment to raise, guide and recover.

A topsail can be taken in while the main gaff sail remains set. It divides the added area into a separately handled surface, whose halyard, sheet and restraints pass their reactions into the existing mast and gaff. The crew gains a choice about exposed area while the whole rig carries the chosen combination.

Raise the upper spar nearer upright

There is another way to alter the upper outline. Raise the gaff’s outer end steeply and use a suitably cut sail beneath it. A high-peaked gaff has a steeper working inclination, with its peak higher relative to its throat. It still carries a head edge and bears at its inner connection. The steep angle changes the directions in which its halyards and throat fitting are loaded; appearance alone cannot show whether those parts permit the required movement.

In a gunter rig, an upper spar extends the sail’s support above a shorter mast and is raised to work nearly upright beside it. This moving upper member is the gunter yard. In the sliding gunter arrangement it travels along the mast during hoisting and lowering, supplying height aloft while remaining a separate, lowerable spar.

The Mirror dinghy’s documented gunter gear provides a concrete example. Its rigging guide calls the upper spar the gaff. The mainsail’s head and upper luff enter a groove in this spar, while the lower luff is laced to the mast. The halyard attaches to a band partway along the upper spar, passes through the masthead block and returns to the crew. Hauling raises the spar and its attached sail.

Jaws at the spar’s lower end fit around the mast. A closing rope or elastic retainer keeps them in place, allowing the lower end to travel as the upper member rises towards its nearly vertical working position. The lower sail lacing retains that portion beside the fixed mast, and a tack downhaul tensions the lower forward corner. Thus the halyard supplies lift, the jaws and retainer guide the moving spar, the groove supports the upper sail attachment and the lacing supports the lower one.

When lowered and unrigged, the Mirror’s separate mast and upper spar are shorter pieces than one fixed mast reaching the same working height. That practical advantage comes from dividing the support into moving members, not from calling its outline triangular. The boat’s fittings establish how the members overlap and travel.

A steep gaff and a gunter yard can consequently approach similar silhouettes. Their actual head or luff attachment, mast overlap, guide and hoisting arrangement identify how they work. No single angle measured from a photograph can supply all that information.

One tall mast can carry a triangular mainsail directly, without a moving upper spar. That removes the gaff’s hoisting and guiding jobs, but also the beam supporting its broad head. The mast and sail must provide a different route to the required height, area and support.