| Efficient Sailing | | | | passage is the best part of two days wasted on the |
| Sails today are very different from their ancestors in | | | | average ocean crossing, though in fairness I have met |
| the period before the polyester revolution. Shape has | | | | people who don't press on because they seem to like |
| always been the most important factor in sail | | | | it out there. |
| efficiency, and time was when you chose your most | | | | Sail combinations |
| suitable canvas for the conditions, pulled it up and | | | | Una-rigged craft often sail excellently. A single, |
| sheeted it in. Some cruising sails are still made like this. | | | | well-shaped aerofoil set from a lightly stayed or |
| They work well enough, but the cloth from which they | | | | unstayed mast can be shaped with great precision |
| are cut often means that their performance potential is | | | | and can be remarkably closewinded. Two notable |
| nowhere near that of a modern sail whose geometry | | | | examples of the truth of this are the Finn dinghy and |
| can be modified to suit the wind and sea. Such | | | | the North American cat boat. As yachts become |
| equipment has worked its way into cruisers following | | | | larger, a single sail becomes a worse proposition for |
| the lead set by racing yachts, whose hi-tech vanguard | | | | reasons of handling and of shipping a spar of sufficient |
| have now moved on to cloths of such sophistication | | | | proportions to carry it. From time immemorial, therefore, |
| and stability that the shape cut into their sails is barely | | | | sail plans have been divided. |
| compromised until they literally burst. | | | | In addition to the benefits above, split rigs offer two |
| | | | further advantages. Because individual sails are set |
| This requirement is underlined by the fact that as the | | | | forward and abaft the centre of lateral resistance |
| wind increases, a sail naturally becomes fuller and the | | | | (CLR) about which the boat effectively pivots, they |
| point of maximum camber is blown aft towards the | | | | can be sheeted so as to balance her steering |
| leech. Both these results are the opposite of what is | | | | characteristics. At speeds too low for the rudder to be |
| desirable, and something must be done to mitigate | | | | useful, the sails can even be used to persuade the |
| them. | | | | vessel to point where you want her to go. Secondly, |
| In addition to the question of camber control, there is | | | | the slot between two sails produces a venturi effect, |
| also the matter of twist. Most sails twist away from | | | | accelerating the air which is squeezed through it. This |
| the wind in their upper sections. This tendency is built | | | | raised velocity increases the power not only of the rig |
| into them deliberately and can be controlled so that it | | | | as a whole but also of its individual components. Those |
| works to your advantage. | | | | who doubt that this is happening have only to stand in |
| Twist is a shut book to many sailors, but to ignore it will | | | | the slot of a yacht sailing to windward in 15 knots of |
| measurably compromise your boat speed. The reason | | | | breeze. Tell them to hang on to their hats, though. It's |
| for its importance is this: wind blows more strongly | | | | breezier in there than they'd ever have believed back |
| aloft than near the deck, because surface friction with | | | | in the cockpit. |
| the sea slows it down. When a boat sails along, the | | | | As skipper, you have the balance of the boat's rig at |
| wind she actually experiences is a composite known | | | | your fingertips, and assuming that she is well designed, |
| as apparent wind. She may be powered by a true | | | | there is plenty you can do about it. The yacht should |
| wind from abeam, but she is making a ghost breeze | | | | be easy and light to steer, showing a gentle tendency |
| from dead ahead in an equal and opposite direction to | | | | to turn into the wind if left to her own devices. If she |
| her own progress through the flowing air. This | | | | has too much mainsail on and only a small jib, a sloop |
| phantom combines with the true wind to generate the | | | | will want to round up. The result is weather helm. This |
| actual breeze across the sails. The apparent wind | | | | tires the unfortunate who must steer, as well as |
| which they form comes from further ahead and is | | | | slowing the vessel down through the drag of the |
| stronger than the true wind, so long as it is not blowing | | | | rudder. The dreaded lee helm, on the other hand, is the |
| from well abaft the beam. | | | | lot of the sailor whose boat is carrying too much |
| Clearly, the faster the true wind for a given boat | | | | canvas forward and too little aft. |
| speed, the less will be the interference caused by the | | | | Lee helm is a dismal condition. It makes manoeuvring |
| boat's movement. Because the true wind aloft is a little | | | | difficult, steering frustrating, and it has a debilitating |
| stronger than at deck level, the apparent wind up there | | | | effect on the yacht's capacity to sail close to the wind |
| is somewhat more `free' than the air lower down. If the | | | | without making excessive leeway. A touch of weather |
| upper part of the sail can be twisted to take | | | | helm holds the rudder a degree or two to leeward, |
| advantage of this, its resultant force will produce a | | | | which diverts the flowing water, just enough to help |
| larger forward component than that being delivered by | | | | the keel lift the vessel in opposition to the sideways |
| the lower section of the same area of canvas. | | | | forces. Lee helm achieves the converse effect. |
| Furthermore, the whole of the sail will be setting | | | | Hull balance |
| cleanly, with no part either lifting or stalling. | | | | In addition to the disposition of her sail plan, a yacht's |
| In the case of a fractional rig, the upper section of the | | | | helm balance varies depending on how much she is |
| mainsail cuts undisturbed air, while the lower parts | | | | heeling. As she heels to leeward, any tendency to |
| receive their wind already bent further aft by the | | | | weather helm will increase. Rolling to windward |
| headsails. Twist control is vital if the top of the sail is | | | | generates lee helm. This makes sense when you |
| not to be stalled completely. | | | | consider that the whole outfit is being pulled along by |
| Too much twist can generate a fearsome loss of | | | | the rig. As the boat heels, the centre of effort of the |
| power if it is allowed to go unchecked while you are | | | | mast and sails moves outboard. If you dragged the |
| reaching on a windy day. The boom kicks up in disgust, | | | | boat through the water by a rope on the end of a |
| while the upper third of the mainsail dumps its air | | | | beam lashed athwartships across her deck, she would |
| unceremoniously to leeward over its tortured leech. | | | | try to swing away from that side. The same thing |
| Shaping the headsails | | | | happens with the rig. |
| In most boats, the primary tool for headsail camber | | | | Boats with flat, beamy midships sections such as are |
| control is the halyard winch. Some traditional craft are | | | | found in many high-performance modern cruisers and |
| equally well served by a tack downhaul, but whatever | | | | racers suffer from a more subtle source of heel |
| method is employed, the crucial feature of the sail at | | | | induced weather helm. As they lean over, the leeward |
| any given time is its luff tension. | | | | side of the immersed hull becomes rounded to a point |
| Hoist the sail, then steer the boat on, or nearly on a | | | | of exaggeration. The weather side is correspondingly |
| closehauled heading. Now look up at the mid-part of | | | | flattened. The imbalance produces weather helm |
| the sail. If it has a 'go-fast stripe' your task is made | | | | which, in certain cases, appears suddenly and |
| easier. If not, you'll have to judge its shape by looking at | | | | uncontrollably above a critical angle of heel. You need |
| the seams. The camber should swell out to a | | | | to watch out for this in such a vessel, particularly if you |
| maximum 35-40% of the way aft from the luff. If it is | | | | are sailing in a river on a gusty day, surrounded by |
| too far aft, tension up the halyard and watch the | | | | expensive moored yachts. |
| draught move forward. If the luff is too `hard' (ie, the | | | | Shortening sail |
| camber is too far forward), slack away a few inches | | | | Shortening sail as the wind strengthens is part of the |
| and keep looking. | | | | sailor's everyday life. It is not something to be put off. |
| If the sail seems susceptible to this treatment, check it | | | | The process should be as natural as shifting gears in |
| again once your boat speed has built up. The apparent | | | | the family car. Not only does carrying the right canvas |
| wind will now be greater and the sail may require | | | | for the conditions give you a drier ride and increase |
| some adjustment. It's important to do this with your | | | | your chances of arriving with the boat in one piece, it |
| fully open roller reefing genoa as well as a hanked-on | | | | keeps the yacht more upright. As we have just |
| sail. | | | | discussed, the less a boat is heeling, the easier she will |
| As the wind picks up, keep hardening the luff until your | | | | be on the helm. This benefit is assisted by the fact that |
| efforts to maintain a good camber become fruitless. | | | | the centre of effort of a smaller headsail or a reefed |
| The sail should now be overpowering the boat if the | | | | genoa is further forward than that of a larger one. |
| sailmaker and the designer got their sums right. | | | | Similarly, a reef in the mainsail moves the leech inboard |
| Change it for a smaller one, which should also be | | | | along the boom. The sails are therefore generating |
| flatter cut, or roll some away. | | | | less weather helm than if the yacht were spreading |
| The converse of keeping your sails reasonably flat as | | | | everything she carried. With a sensible awareness of |
| the wind hardens is that a sail can sometimes be set | | | | the principles of sail balance in your mind, it isn't difficult |
| up to be too shallow-cambered. It will then lack the | | | | to reduce your canvas in such a way that the boat's |
| power to drive the boat in light airs. If the sail seems | | | | behaviour remains docile. |
| lifeless, ease the halyard, and the sheet too if | | | | It would be unwise to generalise about where to begin |
| necessary, so as to power up the canvas. | | | | sail reductions. A masthead cruising sloop will usually |
| Attention to the luff of the sail may cause the leech to | | | | set out by tying one reef into the mainsail. This may be |
| require service. The leechline, if fitted, is a light piece of | | | | followed by one or two changes of headsail before |
| small stuff sewn into the trailing edge of the sail. It | | | | going for the second reef, and so on. A |
| should be gently 'tweaked' just far enough to stop the | | | | fractional-rigger often reduces the size of her headsail |
| leech beating, and no further. Too much tension | | | | first. A ketch or yawl has a mizzen to consider as well, |
| causes a hooked leech, which is hateful to behold. If | | | | but the principles remain the same. |
| the leech is already hooked, slack away the line as far | | | | The years since the mid-1970s have seen the rapid |
| as the sail will let you. | | | | rise and general acceptance of patent reefing |
| The twist of a headsail is determined mainly by the | | | | systems. The best of those offered for headsail roller |
| position of the sheet leads. Most boats have these on | | | | reefing have by now achieved high reliability and are |
| sliders. If yours doesn't, the sail must be cut to the | | | | able to reef the sail to a moderate degree without too |
| position of the fixed leads. | | | | much sacrifice in shape. Poorer gears produce a |
| Sheet-lead positions are crucial. When the helmsman | | | | dismally reefed sail which looks more like a flour bag |
| brings the sail a little too close to the wind from | | | | than a number 3 genoa. With the canvas rolled away |
| closehauled or a close reach, the luff should lift evenly | | | | to storm jib size the result is execrable. None the less, |
| all the way up. If the bottom of the luff lifts first, the | | | | all such arrangements give the benefit of instant sail |
| lead is too far forward, making the leech too tight so | | | | area adjustment. In a short-handed craft this |
| that the sail is not twisting enough. If the top goes first | | | | sometimes more than compensates for what is lost in |
| there is too much twist, caused by the lead being too | | | | pure performance. No boat must go to sea, however, |
| far aft. The best position can only be found by | | | | without making at least some arrangements for the |
| experiment, but luff 'tell-tales' are a tremendous help. If | | | | day when the gear fails. The most satisfactory |
| you don't have any, install them now. All you need are | | | | answer is a separate forestay that can be readily set |
| three 8 in (20 cm) lengths of wool pushed through the | | | | up and to which a storm jib may be handed. Indeed, |
| sail with a sail needle, about 6 in (15 cm) abaft the tuff | | | | this produces the best of all worlds because such a jib |
| (in a 35-footer) and knotted on both sides. The | | | | will invariably set better than the deeply rolled genoa. It |
| windward ones will always flick up just before the sail | | | | can therefore be used routinely for heavy weather |
| lifts. If the leeward ones go dancing they tell you | | | | sailing. |
| without room for argument that the sail has stalled | | | | Mainsail reefing systems now exist which are way in |
| either from oversheeting on a reach, or because the | | | | advance of the old 'round-the-boom' roller reefing. Such |
| person steering the boat to windward is driving her to | | | | a method was never ideal on the bermudan rig, though |
| leeward of her best course. | | | | it remained in use for decades. By far the simplest and |
| Shaping the mainsails | | | | best way to reef the main is with `slab' reefing, but if |
| As in a headsail, mainsail camber is largely controlled | | | | you cannot bring yourself to make even that much |
| by luff tension. However, sails on boats with any | | | | effort, in-mast and in-boom systems can be bought off |
| pretension to performance generally also offer a clew | | | | the shelf. In-mast gears put considerable weight aloft |
| outhaul. The effects of this will extend approximately | | | | and add to the awful sum of the rig's windage. They |
| to the lower third of the sail. Haul it out to flatten the | | | | may or may not be reliable, and a sail built for such a |
| sail as the breeze fills in. | | | | setup will probably have a straight leech with no |
| A mainsail that is set behind a genoa will emphatically | | | | battens. On a contemporary rig this looks downright |
| not require a hard entry. Such a form will often result in | | | | sad and it's certainly less powerful than the elliptical |
| the backwinding of the main luff when the boat is | | | | trailing edge of the conventional mainsail. The Spitfire |
| closehauled. Instead, a gentle curve aft to a maximum | | | | didn't have those beautiful wings just to look pretty. |
| camber virtually in the centre of the sail will work well if | | | | Mainsail reefing options therefore subdivide into three |
| the boat is masthead rigged. The more powerful sail of | | | | choices: in-mast roller, inboom or round-boom roller, and |
| a fractional rigger should carry its maximum camber | | | | traditional gear for reducing the sail in `slabs' at the foot. |
| somewhat further forward, but still with a flat, gentle | | | | Of the three, slab produces by far the best sail shape; |
| entry. | | | | it's extremely reliable and, in any case, is readily |
| Mainsail twist is highly controllable on a modern yacht. | | | | repaired at sea. Mainsails of under 500 sq ft (46 sq m) |
| Leech tension, the essential element, is determined by | | | | are easily handled by two healthy adults and can be |
| the mainsheet when closehauled. With the kicking strap | | | | dealt with singlehanded without major inconvenience. |
| (or kicker, or centre boom vang) let off, juggle the | | | | To compromise this vital sail out of laziness or lack of |
| sheet tension until the top batten of the sail lines up | | | | stomach for getting wet seems odd to me, especially |
| with the boom when viewed from directly underneath. | | | | when the latest fully battened mainsails and lazy-jack |
| There is no need to lie in the bottom of the cockpit, a | | | | systems make the job of stowing child's play. |
| glance will suffice. | | | | Nonetheless, the roller alternatives do have a place. |
| Once you have the twist you are after - and if the | | | | They help huge yachts to be run without numerous |
| sails are well cut, the leech of the main will now | | | | deck-hands. They also enable the elderly or the unfit to |
| sweetly follow that of a well-trimmed genoa - the | | | | keep on enjoying their cruising, but if these options are |
| mainsail's angle of attack can be determined by using | | | | to be chosen, it's important to be aware of their |
| the mainsheet traveller, so long as the wind is well | | | | limitations in sail shape and, potentially, their unreliability. |
| forward of the beam. This means in practice that | | | | At least an in-boom reefing system is within reach in |
| when you are beating or close-reaching you shape the | | | | the event of failure. Furthermore, the mainsail has a |
| sail with halyard, outhaul and sheet, then trim it with the | | | | conventional halyard and can always be dropped. |
| traveller. If you are far enough off the wind to want to | | | | Although in-mast systems have improved greatly, they |
| ease the sheet, set up the kicker to maintain leech | | | | still represent a total commitment to the dependability |
| tension when the sheet can no longer supply it. | | | | of the gear. A trip to the masthead in a gale holds little |
| On a race boat, the powerful kicker may be brought | | | | appeal for any of us. |
| into service even closehauled to help flatten the sail. | | | | Cruising chutes |
| Such fine tuning is a waste of effort on most cruising | | | | Today's Bermudan-rigged yachts have much in their |
| mainsails, but the basics should never be neglected. I've | | | | favour, but sailing downwind in light and moderate going |
| heard people complain along the lines of `All this sail | | | | is not one of them. Ideally, this endemic shortfall is |
| shape nonsense is for the boy racers. Who cares | | | | cured by using a spinnaker, but this lies beyond the |
| about Y knot?' I do, for one. At 6 knots it is worth 6 | | | | comfort zone of many cruising sailors. The answer is |
| miles over 24 hours. To be an hour later than you | | | | a `cruising chute'. This has been developed from the |
| might have been could lose you a tide, resulting in a | | | | modern asymmetric racing spinnaker and is really a |
| further three hours' delay. It may also be the last straw | | | | light, extra-full genoa that only attaches at tack, head |
| for a fatigued crew, causing a fatally bad decision in | | | | and clew. It works in airs too gentle for a multi-purpose |
| the face of a rising gale which you would otherwise | | | | genoa, and can be set on a very broad reach without |
| have missed. Or you might merely get in after the | | | | a pole. Sailmakers will deliver them complete with a |
| shops have closed. | | | | `snuffer' - a sort of sleeve which rolls down over the |
| Whatever the result, not to give your boat her best | | | | sail, spilling its wind miraculously. This removes the |
| chance to perform well is unseamanlike. You don't | | | | worry from using so powerful a tool. In short, a |
| have to thrash a boat to extract that extra Y knot, yet | | | | downwind passage in light weather without a chute is |
| carried to its logical conclusion, 6 miles lost in a 24-hour | | | | like the proverbial day without sunshine. |