Headsails

Headsails are rigged before the mast. They include the jib, genoa, and various types of spinnaker. A jib extends aft no farther than the mast when close hauled. A genoa extends past the mast and can overlap the mainsail by as tack to mast. Genoas are characterized by this percentage of overlap.

A headsail flown forward and to leeward of a mainsail produces twice the force of a main the same size because it has no boom to disturb the airflow and because leeward-directed airflow near the main gives the headsail a lift by shifting its apparent wind aft. Although less powerful for its size, the mainsail is more efficient because airflow off the headsail moves across its leech with less eddying. We therefore trim the headsail to maximize power and the main for max efficiency.

How to
trim a
headsailHeadsails are trimmed by adjusting the luff tension and the size and position of the draft. Luff tension is changed by means of the jib halyard or, sometimes, the backstay. Draft is changed by sheet angle and sheet tension. Sheet angle depends on the point where the headsail sheet meets the deck, usually at a turning block on a car that can move forward and aft along a track, or sometimes at a snatch block that can be moved along the toe rail.

Jib luff
tensionTo set the jib luff tension, while sailing close hauled, harden up the jib halyard until vertical wrinkles appear along the luff and then ease back just until they vanish. If horizontal or curved wrinkles appear, you have eased too much. Luff the sails while hardening up and take several turns around a winch while easing. Do not harden up without luffing, nor fail to ease afterwards, as these can result in unequal tension at the top and bottom of the luff. turning block car along its track, so that the line of the sheet bisects the angle formed by the foot and the leech. Then adjust it by observing the windward jib telltales while luffing. If the upper telltales flutter first, move the sheet turning point forward. If the lower telltales lift first, move it aft.

When setting the jib sheet angle, in any but the lightest air, set the windward sheet, which is not under strain, and then tack to achieve that setting.

Jib car
positionWhen falling off from close hauled to a reach or run, you will of course ease the jib sheet and must therefore move the turning point forward to maintain good jib trim. It also helps to move the turning point outboard, away from the center of the boat, if the rigging allows this. Doing so will open up the slot between jib and mainsail making room to ease the mainsail.

Roller furling (pros and cons) A headsail can be hanked on or roller furled. Roller furling is more convenient because the sail gets stowed from the cockpit by wrapping it around the

Wing on
wingWhen running, the jib might become essentially useless because it will be blanketed by the main unless it is pulled across to the other side and trimmed to sail wing-and-wing or, as some say, wung out. Do this by easing the main until the boom or sail nearly but not quite touches the shrouds and rigging a preventer to avoid an accidental gybe. Then pull the jib across and shake it full on the opposite side. Rigging a whisker pole might help to keep the jib from collapsing. Wing-and-wing is the fastest way of running but requires a deft touch at the helm. furled. Roller furling is more convenient because the sail gets stowed from the cockpit by wrapping (pros and it around the

at the helm. A headsail can be hanked on or roller furled. Roller furling is more Roller convenient because the sail gets furling (pros and stowed from the cockpit by wrapping cons) it around the

forestay without the need to go forward, hank it on, reeve the sheets, unhank it, and bag it. It has the further advantage that the headsail can be reefed by furling it partially to reduce sail or improve forward visibility by raising the clew.

A roller furled sail, when reefed, is far less efficient than a hanked on sail, particularly upwind, owing mainly to the bulk of cloth around the forestay and the inability to adjust luff tension in the absence of solid head and tack attachment points, but it is still vastly more convenient than a change of sail. Roller furling can be hazardous, however, because the furler might jam and because it becomes increasingly difficult to furl the sail as the wind rises.

Never put the furling line on a winch, as this will only pull the furling line blocks and stanchions loose or break the furler. If the furling line cannot be hauled in, turn downwind so that the main blankets the jib and ease the sheet, if necessary, to let the jib stream forward of the boat while furling. (Should even this fail, harden the sheet and head up, then turn through the wind without tacking the jib, as when heaving to, and sail close hauled with the jib backwinded while pulling it down to strike it.) If the furling line jams, go forward and furl the jib by hand. A jam can also occur aloft when the halyard wraps around the forestay, particularly if the halyard pulls only up and not also somewhat aft at the masthead, as is sure to occur if the upper swivel restrainer can remedy this.

It is difficult for one person to raise a roller furled headsail, because of the need to feed the luff tape into the foil slot while hoisting, or to lower it, because the luff will not simply fall to the deck and instead must be pulled down the foil slot. The exquisite pleasure of sailing into an anchorage at full speed, heading up, dropping the sails, and coasting to a stop within boathook reach of a mooring or anchor spot will rarely be felt on boats with roller furling.

Besides becoming difficult or impossible to furl in high wind, roller furled headsails also run the risk of coming unfurled at dock should the wind gust to 50 knots or more. This will quickly destroy the sail, of course, and also likely damage the rigging. To keep the sail furled, it is essential to have equal tension on the working sheet and the furling line, and that both are cleated off securely. (This is contrary to the commonly seen practice of coiling the sheets and stowing them forward near the furled sail, which is not recommended because, even if cleated off forward, the sheets then pull only down and not aft.)

Furling under slight sheet tension keeps the sail compact around the forestay. Taking several extra turns of the working sheet around the forestay, when furling, also helps to secure the sail. Consider adding a sail tie if high wind is likely.

Cleating only the lazy sheet near the bow, while the working sheet stays cleated aft, prevents the clew from riding up in a gust. When high wind is below, either bagged or not, is a good precaution. Check, also, the condition of the furling line; if it breaks or comes uncleated, the sail will unfurl itself even in light wind.

Headsail
sizeThe size of a headsail can be expressed in canvas area, as a percentage of its overlap with the mainsail, or as a number. The smallest number is the largest headsail in the boat's inventory. The #1 headsail might be a 150% genoa, for example, that overlaps the main by about half. The #2 sail might be a 135% or 110% genoa, the #3 a working jib, and the #4 a storm jib. Higher numbered sails are sewn from progressively heavier weights of cloth. Strictly speaking, the percentage of overlap is the distance from the clew to the luff, along a line perpendicular to the luff, divided by the J dimension.

Rigging
a jib
sheetIf the jib sheet runs free while the boat is motor sailing into the wind, it will be difficult to retrieve and it can stream overboard and foul the prop. Some use a stopper knot at the end of the jib sheet to prevent it from running free. Others consider this to be bad practice because the sheet cannot be fully eased quickly in an emergency. The combination of a stopper knot and a handy knife might be a good compromise.

Tacking
and
gybingGoing upwind toward a destination, you can tack once or you can tack many times. The distance sailed is the same either way. Since the sails impart no power during a tack, tacking only once is the

and gybing fastest course, all else being equal. This assumes constant wind, and if the wind veers or backs, as wind often does, it might be better to tack when headed because a header on one tack becomes a lift on the other. Going downwind, again it is best to tack in most boats. A downwind tack, where the stern passes through the wind, is called a gybe. As when beating, the boom will cross the cockpit, but because the mainsheet is now loose, it will travel much farther and faster than when tacking upwind and can crash across, damaging the gooseneck at the mast, the traveller, and other parts of the rig. When gybing in all but the lightest air, first harden up the mainsheet to center the boom and then ease it after the boom comes across. Avoid sailing by the lee, when the wind crosses the boat astern and blows from the leeward side, lest you gybe accidentally without having time to center the boom. When running, be always alert for signs that the boat is about to gybe. When it turns directly downwind, the boat will stop heeling and stand upright. The jib will empty and flutter as the mainsail begins to block its wind.