Sails are controlled by ropes. But in proper usage, a 'rope' becomes a 'line' when it is in use. All sailboatsfrom 15-foot dinghies to 150-foot megayachts require the same lines to control their sails, and all the lines have the same names. The only difference among the various boats is the placement of those lines. So the first thing to do when you go aboard any boat is to 'learn the ropes'. Pay attention to details, difficult during your early learning stages, since all these lines and systems will tend to blur. Avoid that tendency by studiously isolating one line from the others. Follow it with your eyes and imagine where the lines will go and what they need to do when the sails are hoisted. Each line has two important points along its lenght. One end will always be attached to the sail or, in the case of the mainsail, to the boom. The other end - the one you pull on - must be 'led' and finally positioned somewhere within conveniently tighten or ease it - will help you sort out specific lines and understand their function. To forestall confusion, most sailors use different-color lines.
Most sailors use different-color lines.
Halyards hoist sails. This means, of course, that one end of the halyard must always be attached to the head of the sail. But the position of the other end varies from boat to boat. Check out your jib halyard. If it goes up to hoist the sail, then the other end has to come down. But where?
In order to streamline the mast, halyards usually tun inside the mast from the top and exit through a cutout above deck level, thence to some attachement point. On large boats with heavier sails, a winch often mounted on the side of the mast replaces the cleat. The custom today, even on relatively through a turning block near the base of the mast and aft along the deck to a winch mounted on the cabin top. The purpose of this more complicated arrangement is to avoid the necessity for someone to leave the cockpit when setting or dousing the sails. The same applies to main halyards. The tail either be fixed at the mast or led aft to the cickpit.
As with all things sailing, there are advantages and disadvantages to both halyard placements. But never mind; the important point for you at this early stage is to figure out where the tails of the halyards are positioned.
Sheets control the angle at which the salis meet the wind; it's called angle of attack, a term borrowed from aviation. In the coarsest terms, when the wind is forward of the beam, you tighten the sails by hauling on the sheets in order to bring the sails toward the centerline of the boat. Conversely, when the wind meets the sails from aft of the beam, the sheets must be eased.
Head Sail Sheets
Headsail sheets are tied directly to the clew using that most valuable of knots, the bowline. On bigger boats, with their larger-diameter sheets, the knots are replaced with metal shackles. All headsails need two sheets, the tails of which are led around either side of the mast and aft to winches in the cockpit. On a big genoa, the sheets are led aft outboard of the shrouds, while on a 100% jib, the sheets will probably be led inboard of the shrouds. But only one sheet is working at any one time. For instance, on starboard tack, that is, when the wind is blowing over the staboard bow, the portside sheet is active, actually pulling on the headsail clew, since the sail will be drawing on the side of the boat. The other sheet, the lazy sheet, lies limply along the windward side of the boat doing nothing until it's time to tack or jibe.
But notice as you follow the headsail sheets aft that they pass through a roller or pulley on either side before reaching the cockpit. This is called the headsail-sheet lead. The placement of the lead determines the direction of pull on the clew of headsail. In order for the headsail to draw efficiently, the sheet must pull evenly on two parts of the sail-the foot and the leech. Say you tied your headsail sheet to the clew and then ran the sheet directly aft to the cockpit without passing the line through a lead. In that case you'd have plenty of tension on the foot of the sail, but none on the leech.
It would sag away to leeward, spilling wind from the middle and upper parts of the sail. In the opposite extreme, if you position the lead directly below the headsail clew, you can exert plenty of downward pull on the leech, but none on the foot. No, you have to set your lead-the lead block is fixed to a track bolted to the deck so that the lead can be moved as necessary-such that it exerts equal down and aft tension. So how do you know where to position the lead in order to split the difference, thus attaining equal pull on the foot and the leech?
Position the lead such that the sheet seems to bisect the angle formed by the foot and the leech. Often the sailmaker sews a strip of reinforcement material against the stresses on the clew that also bisects the angle for you. Set your lead such that your sheet and the reinforcement strip form a straight line. Now you have a proper basic lead position: The sheet pulls down and aft, producting equal tension on both the foot and the leech.
Mainsheets run between a point at or near the aft end of the boom to a point near the centerline of the boat directly below. Mainsails are more complex than headsails. That is to say, mainsails require more and different lines to control their trim than headsails. Sit down in the cockpit and study the main-sheet. Notice that it has several 'parts' running up and down between pulleys (called blocks in sailing speak), one set of blocks shackled to the boom, the other to the boat. Because the weight of the wind in the mainsail is too great to handle with a single line, those multiple parts running through blocks afford enough mechanical advantage to overcome the wind force in the sail.
The outhail is another control unique to mainsails. Attached to the clew, it tightens or loosens the foot of the main dependingon wind velocity and direction relative to the boat's heading. The tail of the outhaul is typically led forward inside the boom to an exit hole and a cleat mounted near the forward end of the boom. All race boats have adjustable outhauls. On most cruising boats the outhaul is not rigged to allow much fore-and-aft movement. It's merely an attachment point for the clew.
The boom vang, still another mainsail control, is rigged to pull down on the boom. The forward end of the vang is mounted near the back of the mast at or near the deck, and the aft (upper) end of the vang is shackled to the boom several feet aft of the gooseneck. The vang's purpose is to exert downward pull on the leech.
When the sails are pulled in tight alng the centerline, as when sailing to windward, the mainsheet exerts adequate downward pull on the boom and the mainsail. In that case, no vang tension is necessary. But when the wind is blowing over the back of the boat, and the boom is eased accordingly outside the lifelines, the mainsheet, angling outboard horizontally, no longer pulls down on the boom. The force of the wind on the sail therefore tends to cause the boom to rise, and this in turn causes the leech of the main to sag off the leeward, spilling wind. Tightening the vang lowers the boom to a more efficient position roughly parallel to the surface of the water. Keep in the back of your mind for now that the vang, like the sheet, is a leech control. And this suggests a broader principle about sail trim worth noting now to be elaborated upon later: The various lines control individual parts of each sail, luff, leech, and foot. By easing or tightening their respective lines, you change the angle of the sail to the wind or you change the shape of the sail. When you have the parts working together in unison and in balance, you have the correctly trimmed your sails.