What Is a Jib?, Self-Tacking Jibs | Cruising World

Self-Tacking Jibs: Revisiting an Old Idea

The trend in boat design today is toward larger mainsails and nonoverlapping headsails that, in many cases, take care of themselves with self-tacking jibs.

self tacking jib

To ensure that the self-tacking jib’s car slides smoothly on its track, Hanse Yachts, among others, leads the sheet well up onto the mast, then down and to the cockpit. Leech and foot tension on the headsail are set by adjusting where the block attaches to the clew.

Billy Black

On a whole lot of sailboats that are still out there sailing, the crew has often worked up a sweat after cranking the genoa around during a series of short tacks. Too often, somebody also has to scurry to the foredeck to help the genoa around the inner forestay and to free flailing sheets from a deck fitting. For too long, boat designers seemingly forgot that genoas were created primarily as rule beaters. Headsail area in excess of the foretriangle was lightly taxed, leading eventually to such monstrosities as 180-percent genoas (measured as a percentage of the foretriangle) sheeted to a boat’s aft quarters.

Sure, the extra canvas added power, but it was well known, even as we hoisted those acres of canvas, that a tall blade jib with slight overlap is far more efficient for a given area. What made matters worse was that the favorable handicap for genoas encouraged designers to expand the size of foretriangles, position masts sometimes ridiculously far aft, and shrink mainsails until these sails became mere shadows of their former selves. The worst of these sail plans seriously degraded the handling characteristics of boats that already suffered from misshapen hull forms, also encouraged by racing rules. As a result, many of these boats lacked, among other liabilities, the power and balance to allow the crew to sail under mainsail alone.

Thank Aeolus that sailors managed to kill such rules as the I.O.R., and designers could turn once again to making efficient wings to drive better-balanced hulls. The blade jib returned, first augmented by a more manageable genoa of, perhaps, 130 percent. At the same time, mainsails grew again, a real boon to boats needing to maneuver in harbors under main alone.

As is often the case, advancements in sail plans often trickle down from the racing crowd, and we can trace the move to more easily handled rigs to offshore circuits featuring shorthanded sailing, which were unfettered by handicap rules. At the same time, multihullers, particularly catamaran sailors, couldn’t set the same headstay tension as monohull racers, so they needed smaller jibs to go upwind well. These cats and tris and the monohulls that followed, especially the “aircraft carrier” style of open-class racers that evolved for such contests as the BOC/Around Alone and the Vendée Globe, required very efficient sail plans. These included more powerful mainsails and smaller headsails so that shorthanded crews no longer had to wrestle with enormous and heavy headsails while changing them in every puff or lull.

On a generic boat of this type, skippers would fly a 100-percent to 120-percent jib for moderate conditions. As winds strengthened, they’d reef the more easily controlled mainsail first. Rolling the jib (and/or striking it) and unrolling a smaller staysail would carry the boat into heavy conditions. To put the pedal to the metal in light airs, crews employed an ever-increasing spectrum of specialized headsails, from code zeros for upwind work in light airs to gennakers, screachers, and asymmetric spinnakers set forward of the blade jib, often on a bowsprit, to handle sailing off the wind. Eventually, many designers eliminated all overlap on the working jibs so they could employ longer spreaders and take the shrouds out to the rails of even quite wide boats, which reduces the loads on rigging and spars and decreases their weight.

What’s in It for the Cruisers?
These trends have finally begun flooding into the design of production boats. What’s more, many manufacturers have asked, “Why not go one more step? Let’s really ease the sailhandling problem, while giving away just a little performance, by using self-tacking jibs.” Wally Yachts became notable by churning out such elegantly austere deck layouts that, when assisted by electronic or hydraulic winches, a competent captain could get a maxiboat or even a megayacht under way, then drive it and tack it without assistance.

Of course, the modern evolution of self-tacking jibs is another case of déjà vu all over again. Traditional wooden boats for work or pleasure have employed self-tacking headsails for centuries. Most were set on jib booms. In general, a block rides across the foredeck on a raised, bent bar of metal called a horse. The sheet runs between this block and another up on the jib clew. With this system, if you then lead the sheet from the clew to the sail tack on the centerline before turning it aft, the required sheet length remains the same on either board, so the crew needn’t adjust it when tacking. The jib boom also holds the sail out away from the rail when reaching or running, keeping the sail form more efficient than a loose-footed sail, with its aft area hooked back to the rail or so twisted that the top flogs about. The only real drawbacks include the added weight of the jib boom, which can flatten the sail’s leech in light airs and off the wind, just when you want a bit of twist. There also is some risk to anybody caught on the foredeck during an unintentional jibe or when the headsail begins flogging about. One might get clobbered by the thing and injured or flung overboard, but such things also are known to occur on boats without self-tacking setups. In fact, any self-tacking arrangement probably vastly increases a boat’s safety by reducing the required amount of foredeck work, especially during heavy conditions.

More recently, a new jib boom has become popular on such boats as Island Packets and the Alerions. Traditional jib booms typically pivot on universal joints near the tack end, but the Hoyt jib boom, named for its designer, Garry Hoyt, is a solid extrusion that’s bent down forward to sit in a socket in the deck. The rigid tack end prevents the Hoyt boom from flailing about, and designers can adjust the mounting angle of the boom to approximate the ideal leech tension as the sail is eased or sheeted home.

Because the angle to the deck of the Hoyt boom is fixed, this allows the use of a simple sheet arrangement much like that found on a mainsail boom, and without the need for a traveler. You can run the sheet from the jib boom down to either a block on the boat’s centerline or from a padeye on one side of the deck, then up to the jib boom and back to a block opposite the padeye, before leading it aft. You can also run a second sheet between a jib-boom outhaul and the sail’s clew so you have the ability to adjust foot tension, hone twist, and allow the sail to be set on a roller furler and used at various reefed positions.

Sailors looking at newer boats also can choose from several optional self-tacking arrangements without jib booms. These employ jib-sheet traveler tracks mounted forward of the mast. Tracks can be curved or straight, and their outer ends can arch upward and/or forward to others set flush with the deck. Frankly, all can work as long as the configuration doesn’t restrain the jib from coming across when the wind pressure comes off the sail, then backs it as the boat comes around. The traveler cars should then simply slide from side to side.

In this sort of arrangement, there are several ways you can lead the sheet between the traveler, the sail, and a cleat or winch aft that will require the crew to make no adjustments as the boat comes about and falls off to the same sailing angle on the opposite tack. As with a jib boom, you can run a sheet between a traveler block and a clew block as many times as you want to produce the required mechanical advantage before running the sheet forward to a turning block at the tack, then aft. Today, though, a winch usually supplies most of the mechanical advantage, so sheets can be significantly shortened and routed more directly.

In an increasingly popular setup, the standing end of the sheet is secured to a padeye on one end of the traveler track. The lead then runs through a single block on the closest traveler car, up through a single sheave attached to the sail clew, then back through another single block on a separate traveler car and, finally, through a block on the opposite end of the track before running aft. This provides a 2-to-1 purchase, works very smoothly, and reduces deck clutter. The only drawback is that it requires a little longer track to allow space for two traveler cars for any given sheeting angle. Another basic option, which I first saw on Wally’s large boats, runs the sheet from the mast itself, usually well above the deck, down to one traveler block, up to the jib clew, down to the other traveler block, and back up the mast before turning back down to the deck via mast exits, much like an internal halyard. Similarly, one can run the sheet between blocks on the traveler and the clew before running the tail up to the mast.
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Handling the Self-Tackers**
Unlike a “normal” jib, which employs sheets that lead to cars that you can adjust fore and aft on tracks to maintain good sail shape no matter the height of the tack or strength or angle of the wind, the traveler position for self-tackers is fixed fore and aft. To set up and control the shape of a self-tacking jib, the sail requires a clew board with multiple positions to which to attach the sheet or sheet block.

Sailors will be wise to carry a temporary sheet or a handy billy (a tackle with one single and one double block) so they can take tension off the clew and change the position of the sheet on the clew board while under way. In actuality, though, once most cruisers get the sail adjusted properly for moderate airs, rarely will they change the clew block’s position.

The wider the boat, the longer the jib’s traveler track can be and the more a self-tacking jib will remain well shaped for work off the wind. Especially on a narrow boat that’s broad-reaching, the aft portion of the jib can still hook significantly back toward the rail, inducing drag rather than power. In that case, the crew on such a boat may want to use a reaching strut or some other type of pole to hold the clew outboard. On the other hand, when going upwind, the wider boats need to restrain the traveler cars from sliding too far outboard.

More important, there will be times a crew will want its jib not to self-tack. When the wind begins to roar, for example, you may want to heave to with a backed jib. Sailors can again employ a handy billy or rig a similar removable tackle to secure the jib in place. Some layouts, particularly for very wide travelers, include traveler control lines similar to those for a mainsail traveler. The crew can then fix the block positions or adjust the amount that the sheet blocks slide outboard.
Most boats can be retrofit with self-tacking arrangements, though this may require adding structural reinforcements for the track and any padeyes needed for blocks. But for those in the market for a more modern boat, chances are good that they’ll see an increasing number of self-tacking designs that offer a skipper greater ease and security for either a singlehanded outing on a sunny afternoon or a fully crewed offshore romp in a blow.

Steve Callahan, an occasional CW_ contributor, is a boat designer and author._

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