The leech is the back edge of the sail. Definition of luff in the Definitions.net dictionary. Your mast length should be shorter than the luff length, so that with the mast extension you match both sizes. To recap that information, the luff is that vertical portion of the sail that is nearest the mast, and the leech is the vertical portion farthest away from the mast. One source of sail data online is the Sailrite Sailplan Database. ‘If it's a sailboat, luff it up into the wind and drift to a complete stop, then allow it to sail backwards - a boat-length is long enough to appease the spirits.’ 1.1 with object Obstruct (an opponent in yacht racing) by sailing closer to the wind. First of all, you'll need to gather the mast, the boom and the sail. Whether large or small, each sail consists roughly of the same elements. But I did want to show some additional detail of the typical gaff main sail. The straighter the luff curve, the flatter the sail and the more the leech twists. In order to make a smoother roller reefed shape, we apply thin foam in a crescent shape along the luff of the sail. The stuff luff system reduces the compression on the mast, as rather than turning a loaded halyard around a jib halyard sheeve (almost doubling the compression load on the mast), the forestay is fixed to the mast. Each Furling System will have a specific luff tape size that will slide nicely up the track without coming out while under force. At the heart of this development is changing how the load in the luff of a sail is distributed, and with the reduction of luff sag, the sail has more power to drive the boat forward. Subtract the preload from the design length to find the relaxed length. The battens force the luff of the sail into the back of the mast. Foot curve is the amount of curve along the edge of the sail from the tack to the clew. However, the luff rope on my main sail is not attached to the sail at all except in the sense that it is threaded through a number of points in the luff. Examples of how to use “luff” in a sentence from the Cambridge Dictionary Labs For clarity's sake I've took an image of a sail from the world wide webs and added the different part names to it: Head: Top of the sail; Tack: Lower front corner of the sail; Foot: Bottom of the sail; Luff: Forward edge of the sail; Leech: Back edge of the sail Photo Credit: Beau Outteridge. It is either laced on or attached to hoops, or else the sail rope fits in a slot in the mast. The edges of a quadrilateral fore-and-aft sail: 1)foot 2)luff 3)leech 4)head. The headsail of a sailboat is any sail set forward of the mast (on a single masted boat) or foremast (the mast nearest the bow). I am used to boltropes that are stitched into the luff. The process of adding the luff wire to a small pocket on the luff of a sail is a simple one if the procedure is followed correct.y. Divide the luff length by 10 to find the amount of preload. 0. The clew is the bottom back corner of the sail (furthest from the mast). Sometimes plastic slugs are attached to the sail and these slide into the mast slot. Don’t over-tighten the halyard preventer line. When a luff rope is attached to a sail it has to be given a small amount of tension in order to take the load that the halyard or Cunningham has applied to it. To slightly raise the aft end of the boom, allowing the extra sailcloth at the luff to roll at a rate that matches the leech. Determine how wide the wedge will be at the head of the sail by measuring up from the tack of the sail to the Final Luff Length. Furling head sails attach to your furling system using luff tape. The LP is then divided by the J measurement and multiplied by 100 to make it a tidy percent. In some cases he might add more luff curve than there is mast bend so that some of that excess curve can be fed into the body of the sail in the form of sail shape. It uses Heron’s Formula to calculate the area of the sail, then uses the basic formula for area of a triangle to calculate the luff perpendicular: area = ½ base × height, solving for height (LP) where the “base” is the luff. Gaff rigged sails, and certain similar rigs, employ two halyards to raise the sails: the throat halyard raises the forward, throat end of the gaff, while the peak halyard raises the aft, peak end. Area = (L x LP)/2, where:~ 'L' is the distance along the forestay from the headstay pin to the front of the mast, and 'LP' is the shortest distance between the clew and the luff of the genoa. Size quantifies the two dimensional aspects of the sail: luff, leech and foot lengths, and the sail’s roach profile. Luff spar Luff spar A slender spar, usually of metal or wood, to which the Luff of a Head­sail is attached. Tie the luff. (noun) Dictionary ! The luff edge of the genoa is probably slightly hollow near the head and slightly convex near the tack. The industry has called it the most significant aero evolution in decades. noun. The fullest part of the bow of a ship. Menu. It is decribed in these FAQs below and also under the relevant products W045, W060 and W075. Luff Specifications: - Furling Head Sail or Hank On. If the entry angle is too high the sail will luff, and if it is too low the sail will stall, since the flow would be required to turn an impossibly sharp corner around the luff. Luff The edge of the sail which is against the mast. Stability, control and lightness in the hands can only be felt when a sail is properly rigged. There is more foam in the bottom third of the luff because that's where the sail has more draft. The LP defines the sail size in terms of percentage increase beyond the J measurement as in the following examples. The peak is the upper aft corner. What does luff mean? Therefore, the foot curve cannot be used to push shape into the sail like the luff is; the foot curve on this sail is almost entirely cosmetic. Roller Furling Used on jibs, genoas and mains. The leech is the trailing edge. Unfold your sail downwind in a gentle surface, like grass or sand. It is a cord or rope warped inside of a tape. With the zipper-luff, you simply zip the sail around the headstay as you hoist the sail using the jib cloth tensioner. noun. The top corner of the luff is the head on the triangular sail and a Throat in a sprit or lug sail. Sail has special luff wire or tape so sail can be rolled, furled and reefed. The solution? Jibs and Genoas have a Luff Perpendicular (LP) that is the perpendicular distance from the luff to the clew. Dictionary Thesaurus Examples ... By easing the halyard, the luff of the sail was made to sag to leeward. For example, the sail designer designs a luff curve on a mainsail that he assumes will match the curve of the mast. When cutting a wedge out of the sail to shorten it, the original luff curve needs to be duplicated. The extra foam makes the roll slightly wider, which flattens that part of the sail. The angle from the mast to the top of the boom has to be 87° to the mast, 3° above perpendicular. Style refers to the material used to build a sail. It's still a simple calculation though, once you know the length of the luff perpendicular (LP), the sail area is:~ Area = (luff x luff perpendicular)/2, or. 0. Luff definition: the leading edge of a fore-and-aft sail | Meaning, pronunciation, translations and examples Its purpose is either to give a clean aerodynamic edge, or to per­mit reefing by rolling the cloth around the spare. Measuring luff lengths of sails also varies, because you might start at the head but at the tack the sail can extend below the tack cringle or pulley. Luff is a see also of leech. It follows that the leading edge entry angle of the sail must be reasonably aligned with the incoming flow angle. Luff-Her To steer the Boat more into the wind, this could have the effect of causing the sails to flap or Luff. What does luff mean? Information and translations of luff in the most comprehensive dictionary definitions resource on the web. The foot is the bottom edge. The tack is … Do I need to flatten the sail with more outhaul? For this reason, mast bend must match the luff curve of the sail. I've tried adding more backstay but the result is the same. Luff Rope Shrinkage One of the biggest causes of the draft position changing is when the rope on the luff of a mainsail or genoa shrinks. the sail. Parts of a headsail Edit. So if you look at it, it weaves back and forth - nylon slide, back to an eye in the sail, nylon slide, and so on. An Interview with Sailmaker and Sail Designer, Dan Kaseler “I’d guess people are over-trimming their spinnakers as much as 80% of the time.” After a few recent races with very smart sailors who were asking an asymmetrical spinnaker trimmer to sail with no luff curl, my wheels were turning. If the sail is set onto a straight mast this results in extra fullness forced back into the sail. Luff curve is also used to control leech twist. The adjustment of sail shape by changing the overlap of panel seams, for improvement. Performance note: Like the foot, the luff of the sail is curved to add depth to the sail. So significant are the developments, that there are many reasons that the Structured Luff technology could transform how yachts are designed and built. Too much luff round results in too much fullness in the sail entry, too little luff round, a flat or distorted entry, commonly known as luff starvation. As nouns the difference between leach and luff is that leach is a quantity of wood ashes, through which water passes, and thus imbibes the alkali while luff is (nautical) the vertical edge of a sail that is closest to the direction of the wind. In context|nautical|lang=en terms the difference between luff and leech is that luff is (nautical) the forward or weather leech of a sail, especially of the jib, spanker, and other fore-and-aft sails while leech is (nautical) the aft edge of a triangular sail. Shelf Foot Very full shaped foot panel, usually of lighter cloth, which can be made fuller or flatter by adjusting outhaul tension. Set the knot and add a half hitch for additional security if needed. Shape describes the three dimensional aerodynamic form built into these perimeter dimensions, which is commonly referred to as the Mold Shape. The Overview page includes the parts of the sail, and that information won't be repeated in detail here. Find the designed luff length for your particular sail type (main, jib, genoa) and sailboat model. I sail a J-22 and I've noticed that often when I'm sailing upwind, the main sail luff luffs, especially in heavy wind and I'm wondering what this is a result of. At the heart of this development is changing the manner in which load in the luff of a sail is distributed and by reducing luff sag it allows the sail to achieve more driving force. The luff is the leading edge of the sail. The sail slides that attach the sail to the mast are loaded up, creating friction, and causing them to twist and toggle in the groove. 0 (nautical) The act of sailing a ship close to the wind. This sail is flown loose-footed, meaning it is not attached to the boom except at the tack and clew. Tie a square knot so that the sail band stays below the top measurement band when the sprit is tensioned. As the sail rolls around the mandrel there is more sail material at the luff than across the rest of the sail. Passagemaker - Foam Luff. 1. Meaning of luff. 0 The luff is the forward or leading edge of a sail. A sail with less luff curve will be easier to downhaul and have a softer profile.