1.
Stavros S Niarchos
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Stavros S Niarchos is a British brig-rigged tall ship owned and operated by the Tall Ships Youth Trust. She is primarily designed to provide people with the opportunity to undertake voyages as character-building exercises. She is also used for adult voyages and holidays, which help subsidise the operation of the ship, in the late 1990s the two schooners then owned by the Tall Ships Youth Trust were showing their age and becoming increasingly expensive to maintain. The hulls for the two new brigs were obtained half-completed from another project in Germany and these were transported to Appledore Ship Yards in Devon, where they were modified to the TSYTs requirements, and fitted out. She was completed in January 2000, the rig was designed by Michael Willoughby, who wrote a few comments on the overall design of the brigs. Following completion of sea trials she was handed over to the STA at Avonmouth Docks and she sailed for her maiden voyage, a training voyage for permanent and volunteer crew, on 13 February 2000. She arrived in Weymouth, UK three days later, during that trip she encountered a south westerly gale as she came round Lands End. She achieved an indicated speed through the water of 14 knots under lower topsls, in January 2006 Stavros S Niarchos rescued the two women crew from a vessel taking part in the 2005 Atlantic Rowing race. The rescue was made in heavy weather, with the assistance of a USCG Lockheed C-130 Hercules aircraft, in late 2006 TSYT Captain Darren Naggs was awarded the Thomas Gray Silver Medal of the Marine Society, for exemplary seamanship during the rescue. Stavros S Niarchos is a brig, that is a two masted vessel with square sails on both masts and she carries five yards on each mast, and a total of 18 sails. In good conditions she has managed speeds of just over 13 knots, Stavros S Niarchos normally sail with a crew of up to 67 people. The crew consists of 6 permanent salaried crew,11 to 13 volunteer crew, the voyage crewmembers, those paying to sail on the ship, are divided into three watches of 16. Each of these watches has a Watch Leader from the volunteer crew and they are usually professionally qualified teachers or youth workers. The 2 or 3 deckhands act as assistants to the bosun and as such are mostly concerned with the cleaning, in November 2011, the Tall Ships Youth Trust announced plans to sell Stavros S Niarchos, its last remaining tall ship, to focus on smaller vessels. Much of this is due to the high cost of running a vessel of such size due to pilotage charges and this has become a contentious issue with the trust and its supporters where some see this as the abandonment of the tall ships for yachts within the trust. Although the schooners were smaller, they ran a better programme and fulfilled the mandate of the former Sail Training Association. The ship will continue in operation until a buyer is found, archived from the original on 2011-07-18
2.
Sailing
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Sailing employs the wind—acting on sails, wingsails or kites—to propel a craft on the surface of the water, on ice or on land over a chosen course, which is often part of a larger plan of navigation. A course defined with respect to the wind direction is called a point of sail. Conventional sailing craft cannot derive power from sails on a point of sail that is too close into the wind, on a given point of sail, the sailor adjusts the alignment of each sail with respect to the apparent wind direction to mobilize the power of the wind. In the 21st century, most sailing represents a form of recreation or sport, recreational sailing or yachting can be divided into racing and cruising. Cruising can include extended offshore and ocean-crossing trips, coastal sailing within sight of land, until the end of the 19th century, sailing ships were the primary means for marine commerce. The earliest representation of a ship under sail appears on a painted disc found in Kuwait dating between 5000 and 5500 BCE, polynesian oceanfarers traveled vast distances of open ocean in outrigger canoes using navigation methods such as stick charts. Advances in sailing technology from the Middle Ages onward enabled Arab, Chinese, Indian and European explorers to make longer voyages into regions with extreme weather and climatic conditions. There were improvements in sails, masts and rigging, improvements in marine navigation including the tree and charts. Sailing has contributed to many great explorations in the world, the air interacting with the sails of a sailing vessel creates various forces, including reaction forces. If the sails are properly oriented with respect to the wind, however, boats propelled by sails cannot sail directly into the wind. They must tack back and forth in order to progress directly upwind, sails are airfoils that work by using an airflow set up by the wind and the motion of the boat. Sails work in two modes to use the wind to force, PUSH, when the boat is going in the same direction as the wind. The force on the sail is mostly aerodynamic drag, and sails acting in this way are aerodynamically stalled. This force manifests itself as pressure differences between the two sides of the sail - there is a region of low pressure on the front side of the sail and a region of high pressure on the back. Another way to say this is that sails generate lift using the air flows around them in the same way as an aircraft wing. The wind that a boat experiences is the combination of the true wind and this combination is the apparent wind, which is the relative velocity of the wind relative to the boat. When sailing upwind the apparent wind is greater than the true wind, iceboats can typically sail at 5 times the speed of the wind. Where there is a difference in motion, then there is energy to be extracted at the interface, the sailboat does this by placing the sail in the air and the hull in the water
3.
Square rig
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These spars are called yards and their tips, beyond the last stay, are called the yardarms. A ship mainly so rigged is called a square-rigger, the square rig is aerodynamically the most efficient running rig, and stayed popular on ocean-going sailing ships until the end of the Age of Sail. The last commercial sailing ships, windjammers, were usually square-rigged four-masted barques, square-rigged masts may also have triangular staysails that are deployed fore-and-aft between masts. Square-rigged is also used for the uniform of a rating in the Royal Navy since 1857 and it is slang and refers to anyone wearing the famous blue square collar on the shoulders and bell-bottomed trousers. The name perhaps reflects the fact that it was men who managed the square-rigged sails. The peaked cap worn by Senior Ratings and Officers is known colloquially as fore-and-aft rig. A mast is considered square-rigged if its lowest sail or course is square-rigged, if the course is fore-and-aft, square topsails can still be carried in front of the mast. In their heyday, square-rigged vessels ranged in size from small boats to full rigged ships, but this rig fell from favour to fore-and-aft gaff rigs and bermuda rigs after the development of steam power and new materials. Ocean-going sailing ships stayed mostly square-rigged, Square rigs allowed the fitting of many small sails to create a large total sail area to drive large ships. 18th century warships would often achieve speeds of 12–13 knots. Some clipper ships that had square rigs and for speed was critical could be much faster. The late windjammers were as fast as the clippers, being much bigger, not only could a smaller sail be managed by a smaller crew but also these smaller sails constrained the impact of weapons on them. A hole from a cannonball affected only one area, whilst a hole in a large sail would eventually tear the whole larger area. This reduced running costs and also enlarged the space available in the ship for profitable cargoes, new materials also changed sail designs, particularly on hybrid vessels carrying some square-rigged sails. The low aspect ratio of square-rigged sails produces much drag for the lift produced, so they have poor performance to windward compared to modern yachts, the Bermuda rig is the undisputed champion of windward performance in soft sails, due to its very low drag and high lift-to-drag ratio. One advantage of square rigs is that they are efficient when running, where the high lift to drag is irrelevant. Square-rigged sails are also prone to broaching when running than Bermuda rigs. Ocean-going vessels take advantage of e. g. the trade winds, on a square-rigged mast the sails had names which indicated their vertical position on the mast
4.
Gaff rig
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Gaff rig is a sailing rig in which the sail is four-cornered, fore-and-aft rigged, controlled at its peak and, usually, its entire head by a spar called the gaff. Because of the size and shape of the sail, a gaff rig will have running backstays rather than permanent backstays, the gaff enables a fore and aft sail to be four sided, rather than triangular. A gaff rig typically carries 25 percent more sail than an equivalent bermudian rig for a hull design. A sail hoisted from a gaff is called a gaff-rigged sail, gaff rig remains the most popular fore-aft rig for schooner and barquentine mainsails and other course sails, and spanker sails on a square rigged vessel are always gaff rigged. The gaff is hoisted by two halyards, The throat halyard hoists the throat of the sail at the end of the gaff and bears the main weight of the sail. The peak halyard lifts aft end of the gaff and bears the leech tension. Small craft attach the peak halyard to the gaff with a span with eyes at both ends looped around the gaff and held in place with small wooden chocks, larger craft have more than one span. Peak halyards pull upwards, approaching the gaff at right angles, additionally, a gaff vang may be fitted. It is an attached to the end of the gaff which prevents the gaff from sagging downwind. Gaff vangs are difficult to rig on the aft-most sail, so are only found on schooners or ketches. A triangular fore-and-aft sail called a jib-headed topsail may be carried between the gaff and the mast. Gunter-rigged boats are similar, smaller vessels on which a spar popularly but incorrectly called the gaff is raised until it is vertical, parallel to the mast. Topsails are never carried on gunter rigs, the Spritsail is another rig with a four-sided fore-aft sail. Unlike the gaff rig where the head hangs from a spar along its edge, the forward end of the sprit is attached to the mast but bisects the face of the sail, with the after end of the sprit attaching to the peak and/or the clew of the sail. For a given sail area a gaff rig has a shorter mast than a bermudian rig, because of its low aspect ratio, the gaff rig is less prone to stalling if oversheeted than something taller and narrower. Whilst reaching, the CE being set back, will encourage a small craft to bear up into the wind. The boat builder can compensate for this at design stage, e. g. by shifting the keel slightly aft, the gaff-cutter is in fact a very popular sailplan for small craft. The helmsman can reduce weather helm significantly, simply by sheeting out the mainsail, sheeting out may appear to create an inefficient belly in the sail, but it is often a pragmatic alternative to having a heavy helm
5.
Bermuda rig
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A Bermuda rig, Bermudian rig, or Marconi rig is a configuration of mast and rigging for a type of sailboat and is the typical configuration for most modern sailboats. Originally developed for smaller Bermudian vessels, and ultimately adapted to the larger, ocean-going Bermuda sloop, the Bermuda rigging has largely replaced the older gaff rigged fore-and-aft sails, except notably on schooners. The traditional design as developed in Bermuda features very tall, raked masts, a long bowsprit, in some configurations such as the Bermuda Fitted Dinghy vast areas of sail are achieved with this rig. Elsewhere, however, the design has omitted the bowsprit, and has become less extreme. A Bermuda rigged sloop with exactly one jib is known as a Bermuda sloop, a Bermuda sloop may also be a more specific type of vessel such as a small sailing ships traditional in Bermuda which may or may not be Bermuda rigged. The foot of a Bermuda sail may be attached to the boom along its length and this modern variation of a Bermuda mainsail is known as a loose-footed main. In some early Bermudian vessels, the mainsails were attached only to the mast and deck and this is the case on two of the three masts of the newly built Spirit of Bermuda, a replica of an 1830s British Royal Navy sloop-of-war. Additional sails were often mounted on traditional Bermudian craft, when running down wind, which included a spinnaker, with a spinnaker boom. The main controls on a Bermuda sail are, The halyard used to raise the head, the outhaul used to tension the foot by hauling the clew towards the end of the boom. The sheet used to haul the boom down and towards the center of the boat, the vang or kicking strap which runs between a point partway along the boom and the base of the mast, and is used to haul the boom down when on a run. The Bermuda rig developed from leg-of-mutton sails in Bermuda during the course of the 17th and 18th cnturies, the design was very useful on the gusty Bermudian waters for the boats that were the mainstay of transport around the archipelago into the 20th century. As Bermuda turned to an economy, after the dissolution of the Somers Isles Company in 1684, the rig was adapted to larger, ocean-going ships. The development of the rig is thought to have begun with fore-and-aft rigged boats built by a Dutch-born Bermudian in the 17th Century, the Dutch were influenced by Moorish lateen rigs introduced during Spains rule of their country. The Dutch eventually modified the design by omitting the masts, with the arms of the lateens being stepped in thwarts. By this process, the yards became raked masts, lateen sails mounted this way were known as leg-of-mutton sails in English. The Dutch called a vessel rigged in this manner a bezaanjacht, a bezaan jacht is visible in a painting of King Charles II arriving in Rotterdam in 1660. After sailing on such a vessel, Charles was so impressed that his successor, the Prince of Orange presented him with a copy of his own. The rig had been introduced to Bermuda some decades before this, Ships with somewhat similar rigs were in fact recorded in Holland during the 17th century
6.
Sloop
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A sloop is a sailing boat with a single mast and a fore-and-aft rig. A sloop has only one head-sail, if a vessel has two or more head-sails, the cutter is used, and its mast may be set further aft than on a sloop. The most common rig of modern sailboats is the Bermuda-rigged sloop, typically, a modern sloop carries a mainsail on a boom aft of the mast, with a single loose-footed head-sail forward of the mast. Sloops are either masthead-rigged or fractional-rigged, on a masthead-rigged sloop, the forestay attaches at the top of the mast. The mainsail may be smaller than the headsail, which is called a genoa jib. On a fractional-rigged sloop, the forestay attaches to the mast at a point below the top, typically 3/4 of the way to top, or perhaps 7/8 or some other fraction. The mast of a fractional-rigged sloop may be placed forward, compared to a masthead-rigged sloop. After the cat rig, which has only a mainsail, the rig is one of the simpler sailing rig configurations. A sloop typically has two sails, a mainsail and a headsail, while the cutter has a mainsail and two or more headsails, next in complexity are the ketch, the yawl and the schooner, each of which has two masts and a minimum of three sails. A sloop has a system of mast rigging — a forestay. By having only two sails, the sails of a sloop are larger than those of an equivalent cutter. Until the advent of lightweight sailcloth and modern sail-handling systems, the sails of a sloop could be a handful. So, until the 1950s, sailboats over 10 metres Length Over All would typically use a rig or a two-mast rig. After the advent of modern winches and light sailcloth, the became the dominant sailing rig type for all. No rig type is perfect for all conditions, sloops, with their paucity of spars and control lines tend to impart less aerodynamic drag. Compared to other rigs, sloops tend to very well when sailing close hauled to windward. Cutters, ketches and yawls are often preferred to sloops when venturing far offshore, because it is easier to reef small sails as the wind increases, while still keeping the boat balanced. To maximize the amount of sail carried, the classic sloop may use a bowsprit, for downwind sailing, the typical foresail may be replaced by larger curved sails known as spinnakers or gennakers
7.
Cutter (boat)
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A cutter is typically a small, but in some cases a medium-sized, watercraft designed for speed rather than for capacity. Traditionally a cutter sailing vessel is a small single-masted boat, fore-and-aft rigged, the cutters mast may be set farther back than on a sloop. In modern usage, a cutter can be either a small- or medium-sized vessel whose occupants exercise official authority, examples are harbor pilots cutters and cutters of the U. S. Coast Guard or UK Border Force. Cutters can also be a small boat serving a one to ferry passengers or light stores between larger boats and the shore. This type of cutter may be powered by oars, sails or a motor, the cutter is one of several types of sailboats. Traditionally the sloop rig was a rig with a single mast located forward of 70% of the length of the sailplan, in this traditional definition a sloop could have multiple jibs on a fixed bowsprit. Cutters had a rig with a single mast more centrally located, which could vary from 50% to 70% of the length of the sailplan, with multiple headsails, a mast located aft of 50% would be considered a mast aft rig. Somewhere in the 1950s or 1960s there was a shift in these definitions such that a sloop only flew one headsail, in this modern idiom, a cutter is a sailing vessel with more than one head sail and one mast. Cutters carry a staysail directly in front of the mast, set from the forestay, a traditional vessel would also normally have a bowsprit to carry one or more jibs from its end via jibstay on travelers. In modern vessels the jib may be set from a permanent stay fixed to the end of a fixed bowsprit, or directly to the stem fitting of the bow itself. In these cases, that may be referred to as the forestay, and the inner one, a sloop carries only one head sail, called either the foresail or jib. These could be managed without the need for crews, winches, or complex tackles, making the cutter especially suitable for pilot, customs. For example, a pilot cutter may only have two people on board for its outward trip—the pilot to be delivered to a ship and an assistant who had to sail the cutter back to port single-handed. The cutter sailing rig became so ubiquitous for these tasks that the modern-day motorised vessels now engaged in these duties are known as cutters, the open cutter carried aboard naval vessels in the 18th Century was rowed by pairs of men sitting side-by-side on benches. The cutter, with its transom, was broader in proportion compared to the longboat, the Watermen of London used similar boats in the 18th Century often decorated as depicted in historical prints and pictures of the River Thames in the 17th & 18th Centuries. The modern Waterman’s Cutter is based on drawings of these boats and they are 34 feet long with a beam of 4 ft 6 in They can have up to six oarsmen either rowing or sculling and can carry a cox and passengers. The organisers of the Great River Race developed the modern version in the 1980s, watermen’s Cutters also compete annually in the Port of London Challenge, and the Port Admirals’ Challenge. Cutter races are also to be found at various town rowing and skiffing regattas, in addition the cutters perform the role of ceremonial Livery Barges with the canopies and armorial flags flying on special occasions
8.
Ketch
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A ketch is a sailing craft with two masts. The distinguishing characteristic of a ketch is that the forward of the two masts is larger than the after mast, historically the ketch was a square-rigged vessel, most commonly used as a freighter or fishing boat in northern Europe, particularly in the Baltic and North seas. In modern usage, the ketch is a rigged vessel used as a yacht or pleasure craft. To assist going to windward, a ketch may carry one or more jibs or foresails, if a ketch has no jibs, it is called a cat ketch or a periauger. On older, larger ketches the main mast may in addition one or more square rigged topsails. The large fore-and-aft sail on the mainmast is the mainsail, while the sail on the mizzen mast is the mizzen and these sails may be any type of fore-and-aft sail, in any combination. Most modern ketches are Bermuda rigged, but other possible rigs on a ketch include gunter rigs, the Scots Zulu, for example, had a dipping lug main with a standing lug mizzen. In northern Europe and among long distance cruisers, the ketch is often preferred to a sloop, since the additional sail allows a balance. An advantage of the ketch is when sudden increases in wind strength require a rapid reefing, the ketch rig also allows sailing only on the mizzen and jib, without introducing excessive lee helm, and in an emergency can be quite well steered without use of the rudder. When running before the wind or reaching across the wind, a ketch may set extra sails such as a spinnaker on the main mast, and a spinnaker or mizzen staysail on the mizzen mast. Another advantage of a ketch is at anchor, where the sail may be used to hold the boat steady in the wind. The square-rigged ketch was largely supplanted by the brig, which differs from the ketch by having a forward mast smaller than the after mast, and by the hoy, other similar craft include the snow and the pink. But the balance of sail area can be an overriding characteristic, if 20% or more of the sail area is in the mizzen sail the rig would be termed a ketch. This is particularly true on center cockpit yachts, compared to a ketch, a similar size yawls mizzen sail is much smaller than the main, because of the limitations of the mizzen sheet. So on a ketch, the purpose of the mizzen sail is to both propel and balance the vessel, while on a yawl, the smaller mizzen mainly serves the purpose of trim or balance. Yawls tend to have mainsails almost as large as those of comparable sloops, a ketch may be distinguished from a cutter or a sloop by virtue of having two masts rather than one, though a ketch with two foresails is sometimes called a cutter-rigged ketch. Both the ketch and the yawl differ from the two-masted schooner, if a vessel has two masts of approximately the same height, the rig with the larger sail forward is called a ketch, while the rig with the larger sail aft is a schooner. The American two-masted schooner is rare in Europe, where the rig is preferred
9.
Junk rig
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The junk rig, also known as the Chinese lugsail or sampan rig, is a type of sail rig in which rigid members, called battens, span the full width of the sail and extend the sail forward of the mast. The junk rig is a simple and effective rig, the rig contrasts starkly with the Bermuda rig which is prevalent on Western sail boats. In its most traditional form the junk rig is carried on an unstayed mast however standing rigging of some kind is not uncommon, performance close-hauled is perhaps the strongpoint of the Bermuda rig - key to winning a race with an upwind leg or outmaneuvering an opponent in battle. The junk rig typically produces more drive than a similarly sized Bermuda rig when running downwind without a spinnaker, a junk rigged boat can let its sails out athwartships On a Bermuda rigged boat the shrouds interfere with sails if the sail was let out until it was athwartship. The junk rig is well suited to travel with its working sails. The junk rig appeals to shorthanded sailing crews for many reasons, to lessen sail all that is required is to let out the halyard. It is typical to run the halyards and sheets to the companionway on a junk rigged boat and this means that typical sailhandling can be performed from the relative safety of the cockpit, or even while the crew is below deck. Junk sails are carried on a mast which rakes forward a few degrees from vertical. The forward rake of the sail encourages the sail to swing out, another way to say this is that the sail is stable when swung out and doesnt return to the middle of the ship when the wind drops. Consequently, the airfoil developed in light wind doesnt have enough camber to develop much lift at low wind speeds, perhaps the chief shortcoming of the junk rig is that it typically produces poor drive to windward in light winds. The sail may remain almost entirely flat in light winds and develop unacceptable drive to windward The fully battened sail is much heavier than a sail made entirely of sailcloth with modern battens. The stiff junk battens disturb laminar wind flow over the sail -especially important when sailing to windward, Junk sails are relatively low aspect ratio, resulting in a lower lift-to-drag ratio, consequently the ship cant tack as close to the wind. A junk sail has more running rigging aloft, adding to weight, providing more wind resistance, a junk mast is normally of solid wood and very heavy for its short length. There were two types of ships with Junk Rig in the Malay Archipelago with local hulls instead of the Chinese Junk hull. A light boat used commonly in the early 19th century to carry goods along rivers, twakow, a type of vessel with one mast and junk rig. They were a common sight in the Singapore river in the mid 19th century, among the ships used on the coast of China, Lorcha, a light Chinese sailing vessel. This ship combined a western-style hull of Portuguese influence, with Chinese-style mast, the lorcha were found in the Gulf of Siam and in Philippine waters as well. The Vũng Tàu shipwreck consists of the remains of a late 17th century lorcha from the South China Sea off the islands of Con Dao, about 160 km from Vũng Tàu, each of the traditional sailing rigs can be achieved using the modern junk sail
10.
Rotor ship
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A rotor ship is a type of ship designed to use the Magnus effect for propulsion. The ship is propelled, at least in part, by large vertical rotors, German engineer Anton Flettner was the first to build a ship which attempted to tap this force for propulsion, and the ships are sometimes known as a Flettner ship. The Magnus effect is a force acting on a body in a moving airstream. This is used in backspin to increase range in ball sports, Rotor ships take advantage of this same effect by spinning a large vertical cylinder, typically using an electric motor, and using the resulting lift for propulsion. Due to the arrangement of forces, rotor ships are able to sail closer to the wind, the rotor ship should not be confused with the similar-looking turbosail. The turbosail also uses a solid vertical sail, but uses airflow within the interior to generate lift conventionally. A rotor/Flettner ship is a type of ship designed to use the Magnus effect for propulsion, the Magnus effect is a force acting on a spinning body in a moving airstream, which acts perpendicularly to the direction of the airstream. Rotor ships typically use rotor sails — spinning bodies that are essentially vertical cylinders — powered by a motor to take advantage of the effect and these types of propulsion cylinders are now commonly called Flettner rotors. Rotor ships have unique points of sail, the German engineer Anton Flettner was the first to build a ship which attempted to use the Magnus effect for propulsion. The vessel was a schooner which carried two cylinders approximately 15 metres high, and 3 metres in diameter, driven by an electric propulsion system of 50 hp power. In 1926, a ship with three rotors, the Barbara, was built by the shipyard A. G. Weser in Bremen. Following completion of its trials, the Buckau set out on her first voyage, from Danzig to Scotland across the North Sea, in February 1925. The rotor ship could tack at 20-30 degrees, while a vessel with a sail rig, cannot tack closer than 45 degrees to the wind, hence. On 31 March 1926, the Buckau, now renamed Baden Baden after the German spa town, sailed to New York via South America, as the Flettner system could not compete economically Flettner turned his attention to other projects, such as his rotor aircraft. The rotors were removed and the Baden Baden returned to screw power, several types of rotor ships can be distinguished. Rotor sail-only ships exist, as do rotor sail-assist ships, wind Ship Development Corporation has two types of sail-assist designs, for use with different sizes of ships. In practice, most rotor ships have a system with a motor that allows the initial start. Rotors rotational speed and direction of spin can also be controlled, there has been renewed interest in the rotor ship concept in the later 20th century
11.
Crab claw sail
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The crab claw sail or, as it is sometimes known, Oceanic lateen or Oceanic sprit, is a triangular sail with spars along upper and lower edges. The crab claw sail is used in many traditional Pacific Ocean cultures, as can be seen by the traditional proa, the crab claw sail consists of a sail, approximately an isosceles triangle in shape. The equal length sides are longer than the side, with spars along the long sides. The forward intersection of the spars is placed towards the bow, the sail is supported by a short mast attached near the middle of the upper spar, and the forward corner is attached to the hull. The lower spar, or boom, is attached at the forward intersection, the crab claw is a shunting sail. It is used on a boat which has a permanent windward and leeward side, to tack, or switch directions across the wind, the forward corner of the sail is loosened and then transferred to the opposite end of the boat. While remaining attached to the top of the mast, the upper spar tilts to vertical and beyond as the forward corner moves past the mast, meanwhile, the mainsheet is detached and used to rotate the rearward end of the boom through a horizontal half circle. The forward corner is then re-attached at the new end of the boat. The crab claw is often compared with the tacking lateen sail, while it is possible for the sails to be identical, the two rigs are not identical. The crab claw pivots around the leading edge spar, while a lateen sail on a boat such as a Sunfish pivots around a mast. These features give it its distinct, claw-like shape, modern crab claws generally have straighter spars and a less convex leech, which gives more sail area for a given length of spar. The crab-claw sail is something of an enigma and it has been demonstrated to produce very large amounts of lift when reaching, and overall seems superior to any other simple sail plan. One popular but disputed theory is that the crab-claw wing works like a wing, generating vortex lift. Since the crab claw does not lie symmetric to the airflow, like a delta wing, but rather lies with the lower spar nearly parallel to the water. This can clearly be seen in Marchajs wind tunnel photos published in Sail Performance, the vortex on the top spar of the sail is much larger, covering most of the sail area, while the lower vortex is very small and stays close to the spar. Marchaj attributes the large lifting power of the sail to lift generated by the vortices, while others attribute the power to a mix of aspect ratio, camber. Video Hot Buoys Self-Tacking Crab-Claw Trimaran Polynesian Voyaging Society Wind Tunnel results on effects of crabclaw sail orientation - apex position and consistent camber
12.
Lateen
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A lateen or latin-rig is a triangular sail set on a long yard mounted at an angle on the mast, and running in a fore-and-aft direction. Dating back to Roman navigation, the lateen became the sail of the Age of Discovery. It is common in the Mediterranean, the upper Nile River, and the parts of the Indian Ocean. The lateen is used today in a different form on small recreational boats like the Sailfish and Sunfish. The earliest fore-and-aft rig was the spritsail, appearing in the 2nd century BC in the Aegean Sea on small Greek craft, one theory is that the lateen sail originated during the early Roman empire in the Mediterranean Sea. It evolved out of the dominant square rig by setting the sails more fore-and-aft – along the line of the keel – rather than athwartship, while tailoring the luff and leech. The theory of Roman origin for lateen was begun with Lynn White, John M. H. Brindley.25 The original passage cited from Caesarus is, according to Brindley, no more than an allusion, ‘tres naves, quas Latenas vocant, majores, plenas tritico direxerunt’. The assumption is that labelling these three wheat ships ‘latines’ means that they had lateen sails, there is also reason to doubt Sottas’s interpretation of Procopius’ claim – that three ships of Justinian’s fleet in 533 deployed lateen sails. That the triangular sails refer to triangular top sails, which were standard gear on Roman square-rigged ships after 50 ad’, second, White’s claim that the lateen sail was deployed on a European ship in 880 is problematic. We know that the Persians were sailing to India and beyond via the Persian Gulf from the third, and by the mid-seventh century the Muslims were sailing the length of the Indian Ocean. But even if the Romans had invented the lateen sail, it is important to note that after 50 ce there is no evidence of refinement or further development of sails and rigging. Based on this theory, the lateen sail originated in the Near East, most likely in Persia or Arabia and these sailors were likely responsible for introducing the lateen sails and large three-masted merchant vessels to the Mediterranean. According to the Belgian maritime historian Basch, the earliest true lateen rig appears as early as the 1st century BC, in a Hellenistic wall painting found in a Hypogeum in Alexandria. The earliest archaeologically excavated lateen-rigged ship, the Yassi Ada II, dates to ca.400 AD, the Kelenderis ship mosaic and the Kellia ship graffito from the early 7th century complement the picture. By the 6th century, the lateen sail had largely replaced the square throughout the Mediterranean. It became the standard rig of the Byzantine dromon war galley and was also employed by Belisarius flagship in the 532 AD invasion of the Vandal kingdom. This is also indicated by the terminology of the lateen among Mediterranean Arabs and it has been suggested that the lateen sail was brought to the Indian Ocean by the Alexandrian merchants who sailed the Red Sea in Roman and later Byzantine and Arab times. Such theories have been superseded by unequivocal depictions of lateen-rigged Mediterranean sailing vessels which pre-date the Arab invasion, searches for lateen sails in India were inconclusive
