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101-407: A sail is any type of surface intended to move a vessel, vehicle or rotor by being placed in a wind. Sail or SAIL may also refer to: Sail A sail provides propulsive force via a combination of lift and drag, depending on its angle of attack , its angle with respect to the apparent wind . Apparent wind is the air velocity experienced on the moving craft and is the combined effect of

202-878: A clay sealing with a cord impression that might have come from rope spun from wool fibers. The animal bone assemblage at this site had a large percentage of domesticated sheep/goat, with changes in the assemblage suggesting that the production of secondary products (such as wool and milk) became more important toward the late Ubaid and the Uruk period. The spindle whorls from Kosak Shamali, and also those from Telul eth-Thalathat II (northern Iraq), gradually decreased in weight, which could indicate that more and more finer-quality or softer fibers were spun. At Tell Surezha (Iraqi Kurdistan), evidence from animal bones also suggests that wool production may have been important. Stamp seals had been in use in Upper Mesopotamia since

303-558: A wetland environment . As a result of changes in sea-level, the shoreline of the Persian Gulf during the Ubaid was different from that of today. At the beginning of the Ubaid, around 6500 BC, the shoreline at Kuwait may have run slightly further south. During the subsequent 2.5 millennia, the shoreline moved further northward, up to the ancient city of Ur around 4000 BC. Date palms were present in southern Mesopotamia since at least

404-423: A council of one's peers, were no longer sufficient for the needs of the local community. Ubaid culture originated in the south, but still has clear connections to earlier cultures in the region of middle Iraq. The appearance of the Ubaid folk has sometimes been linked to the so-called Sumerian problem, related to the origins of Sumerian civilisation . Whatever the ethnic origins of this group, this culture saw for

505-442: A distinctive fine quality buff or greenish colored pottery decorated with geometric designs in brown or black paint. Tools such as sickles were often made of hard fired clay in the south, while in the north stone and sometimes metal were used. Villages thus contained specialised craftspeople, potters, weavers and metalworkers, although the bulk of the population were agricultural labourers, farmers and seasonal pastoralists. During

606-420: A domestic activity to a more specialized activity carried out by dedicated craftspeople . This may have been associated with the introduction of Canaanean blade technology, which became common in the 4th millennium BC and may itself have been linked to increased mass-production and intensification of agricultural strategies. Evidence for metallurgy comes from several sites in Upper Mesopotamia, all dating to

707-487: A high degree of cultural continuity is evident throughout the Ubaid and Uruk periods, and it seems that there is some agreement that "the relation between three categories, linguistic, racial and ethnic, is exceedingly complex in Mesopotamia and still far from being sufficiently investigated". Scarce DNA analysis of human skeletal material from various archaeological sites in Upper Mesopotamia (none of which dated to

808-405: A lateral force, resisted by the underwater foils, ice runners, or wheels of the sailing craft. For apparent wind angles aligned with the entry point of the sail, the sail acts as an airfoil and lift is the predominant component of propulsion. For apparent wind angles behind the sail, lift diminishes and drag increases as the predominant component of propulsion. For a given true wind velocity over

909-414: A line or a hook may pass, as on Bermuda mainsails. Fore-and-aft sails may have tell-tales —pieces of yarn, thread or tape that are affixed to sails—to help visualize airflow over their surfaces. The lines that attach to and control sails are part of the running rigging and differ between square and fore-and-aft rigs. Some rigs shift from one side of the mast to the other, e.g. the dipping lug sail and

1010-439: A mast to support the airfoil and are beyond the scope of this article. Sailing craft employ two types of rig, the square rig and the fore-and-aft rig . The square rig carries the primary driving sails on horizontal spars , which are perpendicular or square , to the keel of the vessel and to the masts. These spars are called yards and their tips, beyond the lifts , are called the yardarms . A ship mainly so rigged

1111-561: A mast. They are typically raised by a line, called a halyard , and their angle with respect to the wind is usually controlled by a line, called a sheet . In use, they may be designed to be curved in both directions along their surface, often as a result of their curved edges. Battens may be used to extend the trailing edge of a sail beyond the line of its attachment points. Other non-rotating airfoils that power sailing craft include wingsails , which are rigid wing-like structures, and kites that power kite-rigged vessels , but do not employ

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1212-652: A precursor of the beveled rim bowl from the Uruk period. As with many other aspects of Ubaid material culture, it is possible to distinguish different geographical traditions in the production of the coba bowl during the Ubaid period. Flint was widely available in Mesopotamia and could be sourced from outcrops in the Zagros and the Jebel Sinjar , from limestone and river terraces in northern Mesopotamia and from alluvial deposits in southern Mesopotamia. Different qualities of flint were used, depending on what kind of tool

1313-533: A result of downward social mobility . Morton Fried and Elman Service have hypothesised that Ubaid culture saw the rise of an elite class of hereditary chieftains , perhaps heads of kin groups linked in some way to the administration of the temple shrines and their granaries, responsible for mediating intra-group conflict and maintaining social order. It would seem that various collective methods, perhaps instances of what Thorkild Jacobsen called primitive democracy , in which disputes were previously resolved through

1414-420: A sail is defined by its edges and corners in the plane of the sail, laid out on a flat surface. The edges may be curved, either to extend the sail's shape as an airfoil or to define its shape in use. In use, the sail becomes a curved shape, adding the dimension of depth or draft . Sail characteristics derive, in part, from the design, construction and the attributes of the fibers, which are woven together to make

1515-471: A sail to reinforce it, or to fix the sail into a groove in the boom, in the mast, or in the luff foil of a roller-furling jib. They may have stiffening features, called battens , that help shape the sail, when full length, or just the roach, when present. They may have a variety of means of reefing them (reducing sail area), including rows of short lines affixed to the sail to wrap up unused sail, as on square and gaff rigs, or simply grommets through which

1616-582: A shape that does not lie flat. Conventional sail panels are sewn together. Sails are tensile structures, so the role of a seam is to transmit a tensile load from panel to panel. For a sewn textile sail this is done through thread and is limited by the strength of the thread and the strength of the hole in the textile through which it passes. Sail seams are often overlapped between panels and sewn with zig-zag stitches that create many connections per unit of seam length. Whereas textiles are typically sewn together, other sail materials may be ultrasonically welded ,

1717-411: A site as, for example, purely Ubaid or purely Halaf. In northern Mesopotamia, Ubaid characteristics only start to appear in Ubaid 2-3, i.e. toward the end of the sixth millennium BC, so that the entire Ubaid period would be much shorter. For Syria , a range of 5300-4300 BC has been suggested. However, some scholars have argued that the interaction between the originally southern Mesopotamian Ubaid and

1818-451: A slender body, long, reptilian head with incised eyes and mouth and a threedimensional small nose. This particular rendering of the face may be a representation of a mask or possibly headshaping . The hands are placed before the stomach, sometimes with incised fingers. They are thought to be naked. Paint is sometimes used to indicate hair or other details. The majority of these figures is female, but male and sexless figurines exist as well. In

1919-401: A technique whereby high frequency ultrasonic acoustic vibrations are locally applied to workpieces being held together under pressure to create a solid state weld . It is commonly used for plastics , and especially for joining dissimilar materials . Sails feature reinforcements of fabric layers where lines attach at grommets or cringles . A bolt rope may be sewn onto the edges of

2020-412: Is called a square-rigger . A fore-and-aft rig consists of sails that are set along the line of the keel rather than perpendicular to it. Vessels so rigged are described as fore-and-aft rigged . The invention of the sail was a technological advance of equal or even greater importance than the invention of the wheel. It has been suggested by some that it has the significance of the development of

2121-464: Is complex and not yet fully understood, including how and when exactly the Ubaid started to appear in northern Mesopotamia. To resolve these issues, modern scholarship tends to focus more on regional trajectories of change where different cultural elements from the Halaf, Samarra, or Ubaid - pottery, architecture, and so forth - could co-exist. This makes it increasingly hard to define an occupation phase at

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2222-407: Is extremely rare. The "Burnt Village" at Tell Sabi Abyad could be suggestive of destruction during war but it could also have been due to other causes, such as wildfire or accident. Ritual burning is also possible since the bodies inside were already dead by the time they were burned. A mass grave at Tepe Gawra contained 24 bodies apparently buried without any funeral rituals, possibly indicating it

2323-428: Is unclear. There is some evidence for emerging wool production in the fifth millennium BC, i.e. late Ubaid. Some of the earliest evidence comes in the form of an animal figurine from Iran dated to c. 5000 BC with incised decorations that might possibly represent wool. At Kosak Shamali , an Ubaid site in northern Syria, indirect evidence for wool production has been found in the form of spindle whorls , clay scrapers, and

2424-471: Is usually a "flow through" structure) and a number of intervisible islands create both an invitation to travel and an environment where advanced navigation techniques are not needed. Alongside this, the Nile has a northward flowing current with a prevailing wind in the opposite direction, so giving the potential to drift in one direction and sail in the other. Many do not consider sails to have been used before

2525-433: Is very little stress at the tack, whereas head sails (spinnakers and jibs) are more likely to be tri-radial, because they are tensioned at their corners. Higher performance sails may be laminated, constructed directly from multiple plies of filaments , fibers , taffetas , and films , instead of woven textiles that are adhered together. Molded sails are laminated sails formed over a curved mold and adhered together into

2626-760: The Shahrizor Plain and the Hamrin area further south were stronger than those with the north. Mesopotamia does not have local, high-resolution climate proxy records such as the Soreq Cave . This makes it difficult to reconstuct the region's past climate. Even so, it is known that the environment during the sixth and fifth millennium BC was not the same as today. A more temperate climate settled in around 10,000 BC. Marshy and riverine areas transformed into floodplains and finally river banks with trees. The area south of Baghdad may have been inhabitable by humans in

2727-834: The Tigris . In general, copper objects seem to be very rare, and gold has not been found at Ubaid sites either. The Ubaid period provides the first evidence for boating in the ancient Near East. Ceramic boat models have been recovered from numerous sites across Mesopotamia, from Zeidan and Tell Mashnaqa in modern-day northern Syria to Eridu and 'Oueili in the south and Abada in the Hamrin. These models date from Ubaid 1-4 but become more common from Ubaid 3 onwards. The models indicate that different boat types may have been in use, including reed boats , and boats with masts. It has been noted that no evidence for boats has been recovered from Halaf sites in northern Mesopotamia, and that Ubaid 3, from which more boat models have been recovered, coincides with

2828-572: The caravel in Northern European waters from about 1440 made lateen sails familiar in this part of the world. Additionally, lateen sails were used for the mizzen on early three-masted ships, playing a significant role in the development of the full-rigged ship . It did not, however, provide much of the propulsive force of these vessels – rather serving as a balancing sail that was needed for some manoeuvres in some sea and wind conditions. The extensive amount of contemporary maritime art showing

2929-399: The linear mass density of fibers). Cross-cut sails have the panels sewn parallel to one another, often parallel to the foot of the sail, and are the least expensive of the two sail constructions. Triangular cross-cut sail panels are designed to meet the mast and stay at an angle from either the warp or the weft (on the bias ) to allow stretching along the luff, but minimize stretching on

3030-546: The "Sumerian problem" or "Sumerian question". The starting point of this debate was that the oldest cuneiform tablets were written in Sumerian, and that earlier pictographical tablets from the Late Uruk and Jemdet Nasr periods (3200-3000 BC) were likely written in the same language. Based on this evidence, Henri Frankfort proposed in the 1930s that the people who wrote and presumably spoke Sumerian, originally came from

3131-504: The 11th into the 19th centuries. Materials used in sails, as of the 21st century, include nylon for spinnakers, where light weight and elastic resistance to shock load are valued and a range of fibers, used for triangular sails, that includes Dacron , aramid fibers including Kevlar , and other liquid crystal polymer fibers including Vectran . Woven materials, like Dacron, may specified as either high or low tenacity , as indicated, in part by their denier count (a unit of measure for

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3232-618: The 5th millennium BCE. Others consider sails to have been invented much earlier. Archaeological studies of the Cucuteni-Trypillian culture ceramics show use of sailing boats from the sixth millennium BCE onwards. Excavations of the Ubaid period (c. 6000–4300 BCE) in Mesopotamia provide direct evidence of sailing boats. Sails from ancient Egypt are depicted around 3200 BCE, where reed boats sailed upstream against

3333-424: The 7th millennium BC. By the time of the Ubaid period, a wide range of motifs had developed, including geometric patterns and depictions of animals and occasional humans. The Ubaid period saw the first depictions of ibex-headed and bird-headed humans. The majority of Ubaid figurines represented various animals, including sheep, cattle and dogs. Human figurines were already present in previous periods. Those from

3434-513: The Eridu and Hajji Muhammed styles were not distinct at all. Instead, they were part of the greater Ubaid phenomenon. She proposed a chronological framework that divides the Ubaid period in 4 phases. Other scholars later proposed phases 0 and 5. Scholars in the 1930s only knew a few Ubaid sites. These included the type site of Tell al-'Ubaid itself, Ur , and Tepe Gawra in the north. Since then, archaeologists found Ubaid material culture all over

3535-655: The Gulf coast, notably the sites in Kuwait. Conversely, there is also evidence for Arabian Neolithic material in southern Mesopotamia. It has been noted that certain types of flint arrowheads found at Ur show clear resemblance with the Arabian Bifacial Tradition. Arabian Coarse Ware has been found at the sites of 'Oueili and Eridu. As at the sites in Kuwait, it may have been possible that Arabian Neolithic groups lived in southern Mesopotamia. The Ubaid period

3636-594: The Iranian highlands and settled Mesopotamia at the start of the Ubaid period. Speiser , on the other hand, thought that the Sumerians entered Mesopotamia during the Uruk period and interpreted the regional styles that existed before that time, i.e. Ubaid, Hassuna, Halaf, as evidence of distinct ethnic groups . More recent discussion has taken a more careful approach, taking pains not to equate pots with people or language with ethnicity. Archaeologists have stressed that

3737-632: The Late Chalcolithic period . The excavators of Eridu and Tell al-'Ubaid found Ubaid pottery for the first time in the 1910-20s. In 1930, the attendees at a conference in Baghdad defined the concept of an "Ubaid pottery style". This characteristic pottery of this style was a black-on-buff painted ware. This conference also defined the Eridu and Hajji Muhammed styles. Scholars at this conference thought that these pottery styles were so different that "[...] they could not have developed out of

3838-585: The River Nile 's current. Ancient Sumerians used square rigged sailing boats at about the same time, and it is believed they established sea trading routes as far away as the Indus valley . Greeks and Phoenicians began trading by ship by around 1200 BCE. V-shaped square rigs with two spars that come together at the hull were the ancestral sailing rig of the Austronesian peoples before they developed

3939-528: The Ubaid Period (5000–4000 BC), the movement towards urbanization began. "Agriculture and animal husbandry [domestication] were widely practiced in sedentary communities". There were also tribes that practiced domesticating animals as far north as Turkey, and as far south as the Zagros Mountains . The Ubaid period in the south was associated with intensive irrigated hydraulic agriculture , and

4040-443: The Ubaid period) provides some evidence for genetic links with other regions, but also provides evidence for continuity in Mesopotamia itself. Most importantly, the dating of genetic influxes that have been detected, has not been refined up to the point that it can be assigned to the Ubaid period - or any other period earlier than the one from which the skeletal material came. In other words, this genetic influx could have happened during

4141-606: The Ubaid period. It has been interpreted as a marker for socio-cultural group affiliation during the Ubaid. Labrets and/or ear-spools were likewise recovered from many archaeological Ubaid sites across Mesopotamia and its border regions. In at least one case from southwestern Iran, a labret was found in situ in a burial, located at the mandible of the buried individual and with associated tooth wear indicating that it had been worn. Labrets were absent from Halaf sites in northern Mesopotamia, again indicating that they may have been important markers of socio-cultural identity during

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4242-411: The Ubaid than during the preceding Halaf period and the subsequent Uruk period. Obsidian could be transported over hundreds of kilometers. For example, obsidian tools found along the Gulf coast at sites such as Dosariyah ( Saudi Arabia ) and Wadi Debayan ( Qatar ) came from sources in southeastern Turkey. The Ubaid may have witnessed a shift in the production of flint tools from being carried out as

4343-465: The Ubaid. Their use seems to have declined again during the Uruk period. The modern excavations at Tell Zeidan have revealed a wealth of information on the subsistence economy of a large northern Mesopotamian Ubaid settlement. Cultivated species included barley , wheat , lentil , ervil , and flax . There is some evidence that the inhabitants of Zeidan practiced a form of floodwater irrigation on agricultural lands. The excavators have suggested that

4444-610: The ancient Near East. There are now Ubaid sites in the Amuq Valley in the northwest all the way to the Persian Gulf coast in the southeast. Important research includes the many excavations in the Hamrin area in the 1970s. There, archaeologists found a complete Ubaid settlement at Tell Abada , and a really well-preserved house at Tell Madhur . The excavation at Tell el-'Oueili in the 1980s revealed occupation layers that were older than those from Eridu . This discovery pushed back

4545-410: The angle of attack diverges from the apparent wind as a sailing craft turns downwind, the more drag increases and lift decreases as propulsive forces, until a sail going downwind is predominated by drag forces. Sails are unable to generate propulsive force if they are aligned too closely to the wind. Sails may be attached to a mast , boom or other spar or may be attached to a wire that is suspended by

4646-536: The animal bone assemblage from Zeidan changed considerably from the Halaf to the Ubaid period. During the Halaf, some 50% of the animal bones came from wild species (indicative of hunting), whereas during the Ubaid over 90% represented domesticated species (indicative of herding and keeping animals). Common animals were sheep, goat, cattle, and pigs. A comparison with other Ubaid sites in northern Mesopotamia showed that, in general, pastoralism became more important and reliance on wild fauna decreased somewhat, but this pattern

4747-550: The central Gulf coast at sites like Ain Qannas , suggesting that the pottery may have been traded and valued in and of itself, rather than just being a container for some other commodity. This suggestion is reinforced by locally-produced pottery imiting Ubaid wares found at Dosariyah. It is unclear which products were exchanged for the pottery. Suggestions include foodstuffs (dates), semi-precious materials, jewellery (made from pearl and shell ), animal products, and livestock. Notably,

4848-494: The complete body. During Ubaid 4, some 80% (adults) and 94% (infants) of the burials consisted of primary inhumations. The dead were often accompanied by personal adornments such as beads, necklaces, and headdresses. Pots (presumably) containing foodstuffs were also common. Pieces of red ochre have also been recovered from graves. Burials have been excavated at many Ubaid sites, with exceptionally large numbers coming from Tell Abada (127 infant burials) and Eridu (193 burials). By

4949-641: The date for the earliest human occupation of southern Mesopotamia. Excavations along southcoast of the Persian Gulf provided a lot of evidence for contacts with Mesopotamia. The site of H3 in Kuwait , for example, provided the earliest evidence in the world for seafaring. The explosion of archaeological research in Iraqi Kurdistan since the 2010s also led to a lot of new data on the Ubaid. For example, this research showed that cultural links between

5050-455: The degree of cultural interaction between the Ubaid and local Neolithic communities is much stronger in the area of Kuwait than further south, up to the point that it has been suggested that Mesopotamians may have actually lived (part of the year) at sites like H3 and Bahra 1. Small objects such as labrets, tokens, clay nails and small tools that may have had cosmetic use, and that are known from southern Mesopotamian sites also occur on sites along

5151-427: The earlier Ubaid, ophidian figures were only used in domestic contexts, whereas in Ubaid 3-4, they appear in graves as well, indicating a shift in how these figures were used. The rarity of ophidian figures as grave gifts may indicate differential treatment of the dead, possibly based on age, kinship or social standing. The most common burial practice during the Ubaid seems to have been primary inhumation; i.e. burial of

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5252-531: The earliest evidence for actual boats in Western Asia , and the earliest evidence for seagoing vessels in the world. Evidence for the production of wool is ambiguous and mostly indirect. Wool-bearing sheep have been clearly attested in Uruk-period sites, and the domestication of sheep and goat started in the ninth millennium BC, but exactly when wool-production emerged between those two fixed points

5353-498: The early Ubaid reflect a continuation of earlier traditions. A single, painted figurine from the Ubaid 0 levels at Tell el-'Oueili has been interpreted as an early representation of the so-called "ophidian figurines", which became common in the later Ubaid. Both seating and standing figurines were made, with paint being used to detail body parts, clothing, or body modifications . "Ophidian figures" have been exclusively found at various southern Mesopotamian sites. They are characterised by

5454-400: The eleventh millennium BC, predating the earliest evidence for domesticated dates from Eridu by several millennia. Date palms require a perennial water source, again indicating that this period may have been wetter than today. Similarly, oak was present from the eighth millennium, but disappeared at around the same time that Ubaid material culture spread outward from southern Mesopotamia during

5555-441: The eleventh millennium BC. Humans could have lived south of Uruk as early as the eighth millennium BC. This is much earlier than the oldest evidence of human occupation in this area. The oldest known site in southern Mesopotamia (Tell el-'Oueili) dates to the Ubaid 0 period. Archaeobotanical research in the Ubaid 0 levels at 'Oueili (6500-6000 BC) has indicated the presence of Euphrates poplar and sea clubrush , both indicative of

5656-418: The expansion of the Ubaid towards the north and into the Persian Gulf. At the site of H3 in modern-day Kuwait, a ceramic boat model and a ceramic disc with an image of a two-masted boat were recovered. The latter is the oldest evidence for the use of masts and sails. At the same site, pieces of bitumen with barnacles attached to one side and reed-impressions on the other sides were recovered. These pieces are

5757-462: The fifth millennium BC, children and adults were given differential treatment in death. The available evidence indicates that infants were primarily buried inside the settlement, often near larger, presumably more important dwellings, and often in pots. The association of children's burials with larger buildings is well-illustrated at the sites of Tell Abada and Tepe Gawra. It has been suggested that this pattern of children's burials near larger dwellings

5858-401: The final stages of the Ubaid period. At Mersin , Level XVI (5000-4900 BC), unalloyed copper pins and chisels were found. At southeastern Anatolian sites like Değirmentepe and Norşuntepe , metallurgical production was practiced during the Ubaid 3, as evidenced by furnaces, and related finds. At late fifth millennium Tell Nader , northern Iraq, kilns were excavated that may have been used for

5959-521: The first time a clear tripartite social division between intensive subsistence peasant farmers, with crops and animals coming from the north, tent-dwelling nomadic pastoralists dependent upon their herds, and hunter-fisher folk of the Arabian littoral, living in reed huts. Stein and Özbal describe the Near East oecumene that resulted from Ubaid expansion, contrasting it to the colonial expansionism of

6060-536: The following. Sails on high-performance sailing craft. Sails on craft subject to low forward resistance and high lateral resistance typically have full-length battens. Ubaid period The Ubaid period (c. 5500–3700 BC) is a prehistoric period of Mesopotamia . The name derives from Tell al-'Ubaid where the earliest large excavation of Ubaid period material was conducted initially in 1919 by Henry Hall , Leonard Woolley in 1922-1923, and later by Pinhas Delougaz in 1937. In South Mesopotamia

6161-444: The force component in the direction of the apparent wind and lift , the force component normal (90°) to the apparent wind. Depending on the alignment of the sail with the apparent wind, lift or drag may be the predominant propulsive component. Total aerodynamic force also resolves into a forward, propulsive, driving force, resisted by the medium through or over which the craft is passing (e.g., through water, air, or over ice, sand) and

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6262-503: The fore-and-aft crab claw , tanja and junk rigs . The date of introduction of these later Austronesian sails is disputed. Lateen sails emerged by around the 2nd century CE in the Mediterranean. They did not become common until the 5th century, when there is evidence that the Mediterranean square sail (which had been in wide use throughout the classical period ) was undergoing a simplification of its rigging components. Both

6363-480: The increasing popularity of the lateen and the changes to the contemporary square rig are suggested to be cost saving measures, reducing the number of expensive components needed to fit out a ship. It has been a common and erroneous presumption among maritime historians that lateen had significantly better sailing performance than the square rig of the same period. Analysis of voyages described in contemporary accounts and also in various replica vessels demonstrates that

6464-432: The islands of Maritime Southeast Asia , then later sailed further onwards to Micronesia , Island Melanesia , Polynesia , and Madagascar , eventually settling a territory spanning half the globe. The proto- Austronesian words for sail, lay(r) , and some other rigging parts date to about 3000 BCE when this group began their Pacific expansion. Austronesian rigs are distinctive in that they have spars supporting both

6565-533: The lateen mizzen on 16th and 17th century ships often has the sail furled. Practical experience on the Duyfken replica confirmed the role of the lateen mizzen. Austronesian invention of catamarans , outriggers , and the bi-sparred triangular crab claw sails enabled their ships to sail for vast distances in open ocean. It led to the Austronesian Expansion . From Taiwan, they rapidly settled

6666-401: The lateen. The lines can be categorized as those that support the sail, those that shape it, and those that control its angle to the wind. Fore-and-aft rigged vessels have rigging that supports, shapes, and adjusts the sails to optimize their performance in the wind, which include the following lines: Square-rigged vessels require more controlling lines than fore-and-aft rigged ones, including

6767-422: The later Uruk period . "A contextual analysis comparing different regions shows that the Ubaid expansion took place largely through the peaceful spread of an ideology, leading to the formation of numerous new indigenous identities that appropriated and transformed superficial elements of Ubaid material culture into locally distinct expressions." There is some evidence of warfare during the Ubaid period although it

6868-422: The luff and foot, where the fibers are aligned with the edges of the sail. Radial sails have panels that "radiate" from corners in order to efficiently transmit stress and are typically of higher performance than cross-cut sails. A bi-radial sail has panels radiating from two of three corners; a tri-radial sail has panels radiating from all three corners. Mainsails are more likely to be bi-radial, since there

6969-403: The most common patterns. The slow potter's wheel became in use during Ubaid 3-4, which may have played a role in the decrease in decoration. The coarse, plant-tempered coba bowl , found at many Late and Post-Ubaid sites in northern Mesopotamia from, has been interpreted as some kind of vessel for handing out rations or as evidence of more specialized production, and as such may have been

7070-482: The neolithic lifestyle or the first establishment of cities. Yet it is not known when or where this invention took place. Much of the early development of water transport is believed to have occurred in two main "nursery" areas of the world: Island Southeast Asia and the Mediterranean region. In both of these you have warmer waters, so that use of rafts is possible without the risk of hypothermia (a raft

7171-574: The north started already during Ubaid 1-2. Ubaid pottery started to appear along the Persian Gulf coast toward the end of the sixth millennium BC, reaching a peak around 5300 BC and continuing into the fifth millennium. Coastal sites where Ubaid pottery has been found include Bahra 1 and H3 in Kuwait, Dosariyah in Saudi Arabia, and Dalma Island in the United Arab Emirates . Ubaid pottery has also been found further inland along

7272-430: The old, as is the case with the Uruk ware after the al-'Ubaid ware [...]". For many attendants of the conference, "this sequence based largely on pottery represented a series of different 'ethnic elements' in the occupation of southern Mesopotamia." These ideas about the nature of the Ubaid phenomenon did not last. The term Ubaid itself is still used, but its meaning has changed over time. Joan Oates showed in 1960 that

7373-585: The performance of square rig and lateen were very similar. Lateen provided a cheaper rig to build and maintain, with no degradation of performance. The lateen was adopted by Arab seafarers (usually in the sub-type: the settee sail ), but the date is uncertain, with no firm evidence for their use in the Western Indian Ocean before 1500 CE. There is, however, good iconographic evidence of square sails being used by Arab, Persian and Indian ships in this region in, for instance, 1519. The popularity of

7474-609: The period is the earliest known period on the alluvial plain although it is likely earlier periods exist obscured under the alluvium . In the south it has a very long duration between about 5500 and 3800 BC when it is replaced by the Uruk period . In Northern Mesopotamia the period runs only between about 5300 and 4300 BC. It is preceded by the Halaf period and the Halaf-Ubaid Transitional period and succeeded by

7575-465: The production of both pottery and metal. Copper objects are also known from the Ubaid levels at Tepe Gawra (XVII-XII) and Tell Arpachiyah . Copper objects were absent in the Ubaid levels at Eridu and 'Oueili, possibly indicating that copper use spread southwards from the north. However, copper may have been traded, as it was present in elite burials of the Susa I (terminal Ubaid) necropolis at Susa east of

7676-537: The rest of Austronesia , crab claw sails were mainly for double-outrigger ( trimarans ) and double-hulled ( catamarans ) boats, which remained stable even leeward. In western Island Southeast Asia , later square sails also evolved from the crab claw sail, the tanja and the junk rig , both of which retained the Austronesian characteristic of having more than one spar supporting the sail. Aerodynamic forces on sails depend on wind speed and direction and

7777-443: The sail cloth. There are several key factors in evaluating a fiber for suitability in weaving a sail-cloth: initial modulus , breaking strength (tenacity) , creep , and flex strength . Both the initial cost and its durability of the material define its cost-effectiveness over time. Traditionally, sails were made from flax or cotton canvas , although Scandinavian, Scottish and Icelandic cultures used woolen sails from

7878-512: The same phenomenon. Some of these styles, such as Hajji Muhammed (previously thought to be Ubaid 2) are now known to occur in Ubaid 3 contexts as well, thereby limiting their value as chronological markers. The relative chronology is based on the long stratigraphic sequences of sites such as Ur, Eridu and Tepe Gawra. The absolute chronology is harder to establish, mainly due to a lack of abundant radiocarbon dates coming from southern Mesopotamia. (after Pournelle 2003 / after Harris 2021) In

7979-625: The sixth millennium BC. It has been suggested that acquisition of high-quality wood may have played a role in this expansion. The available evidence in northern Mesopotamia points to a cooler and drier climate during the Hassuna and Halaf periods. During the Halaf-Ubaid Transitional (HUT), Ubaid and early Uruk periods, this developed into a climate characterised by stronger seasonal variation , heavy torrential rains and dry summers. Ubaid and Ubaid-like material culture has been found over an immense area. Ubaid ceramics have shown up from Mersin in

8080-434: The south, corresponding to the area that would later be known as Sumer , the entire Ubaid spans an immense period from ca. 6500 to 3800 BC. It is here that the oldest known Ubaid site - Tell el-'Oueili - was found. In southern Iraq , no archaeological site has yet yielded remains older than Ubaid, However, this might be more a result of the fact that such ancient settlements are now buried deep under alluvial sediments. This

8181-445: The speed and direction of the craft. The direction that the craft is traveling with respect to the true wind (the wind direction and speed over the surface) is called the "point of sail". The speed of the craft at a given point of sail contributes to the apparent wind ( V A ), the wind speed and direction as measured on the moving craft. The apparent wind on the sail creates a total aerodynamic force, which may be resolved into drag ,

8282-551: The surface, a sail can propel a craft to a higher speed, on points of sail when the entry point of the sail is aligned with the apparent wind, than it can with the entry point not aligned, because of a combination of the diminished force from airflow around the sail and the diminished apparent wind from the velocity of the craft. Because of limitations on speed through the water, displacement sailboats generally derive power from sails generating lift on points of sail that include close-hauled through broad reach (approximately 40° to 135° off

8383-489: The true wind velocity with the velocity of the sailing craft. Angle of attack is often constrained by the sailing craft's orientation to the wind or point of sail . On points of sail where it is possible to align the leading edge of the sail with the apparent wind, the sail may act as an airfoil , generating propulsive force as air passes along its surface, just as an airplane wing generates lift , which predominates over aerodynamic drag retarding forward motion. The more that

8484-439: The unpredictability of this type of irrigation may have been a factor in increasing social complexity. The relative absence of animal dung , and the common presence of charred wood remains, suggests that wood was used as fuel. At Surezha, dung was commonly used for fuel, and there is some evidence that cattle were used as traction animals for plowing fields. Tell Zeidan again provides a wealth of information. The composition of

8585-545: The upper and lower edges of the sails (and sometimes in between). The sails were also made from salt-resistant woven leaves, usually from pandan plants. Crab claw sails used with single-outrigger ships in Micronesia , Island Melanesia , Polynesia , and Madagascar were intrinsically unstable when tacking leeward. To deal with this, Austronesians in these regions developed the shunting technique in sailing, in conjunction with uniquely reversible single-outriggers. In

8686-412: The use of the plough, both introduced from the north, possibly through the earlier Choga Mami , Hadji Muhammed and Samarra cultures . The Ubaid period as a whole, based upon the analysis of grave goods , was one of increasingly polarized social stratification and decreasing egalitarianism . Bogucki describes this as a phase of "Trans-egalitarian" competitive households, in which some fall behind as

8787-652: The various combinations of sail proposed for a sailing ship . Sail plans may vary for different wind conditions—light to heavy. Both square-rigged and fore-and-aft rigged vessels have been built with a wide range of configurations for single and multiple masts with sails and with a variety of means of primary attachment to the craft, including: High-performance yachts, including the International C-Class Catamaran , have used or use rigid wing sails , which perform better than traditional soft sails but are more difficult to manage. A rigid wing sail

8888-609: The west to Tepe Ghabristan in the east, and from Norşuntepe and Arslantepe in the north to Dosariyah in the south along the Gulf coast of Saudi Arabia . In this area, researchers have discerned considerable regional variation, indicating that the Ubaid was not a monolithic culture through time and space. The Ubaid period is most commonly divided in 6 phases, called Ubaid 0-5. Some of these phases equate with pottery styles that were, in earlier publications, considered to be distinct from Ubaid, but that are now considered to be part of

8989-405: The wind). Because of low friction over the surface and high speeds over the ice that create high apparent wind speeds for most points of sail, iceboats can derive power from lift further off the wind than displacement boats. Each rig is configured in a sail plan , appropriate to the size of the sailing craft. A sail plan is a set of drawings, usually prepared by a naval architect which shows

9090-421: Was a mass grave from violence. Copper weapons were also present in the form of arrow heads and sling bullets, although these could have been used for other purpose; two clay pots recovered from the era have decorations showing arrows used for the purpose of hunting. A copper axe head was made in the late Ubaid period, which could have been a tool or a weapon. During the late Ubaid period around 4500–4000 BC, there

9191-606: Was also found at the site. Fish may have been a local commodity that was traded for the Mesopotamian pottery that has been found at sites along the Persian Gulf. Ubaid culture is characterized by large unwalled village settlements, multi-roomed rectangular mud-brick houses and the appearance of the first temples of public architecture in Mesopotamia, with a growth of a two tier settlement hierarchy of centralized large sites of more than 10 hectares surrounded by smaller village sites of less than 1 hectare. Domestic equipment included

9292-494: Was also in use during the Ubaid, although the percentage of obsidian tools that was found at archaeological sites fluctuates widely across Mesopotamia. At sites along the middle Euphrates, only few pieces were usually found, and the number of obsidian artefacts was also limited in southern Mesopotamian sites. At sites along the Khabur and the upper Tigris , obsidian was more common. Also, obsidian seems to have been less common during

9393-463: Was detected, it was all of the same type, i.e. one- or two-band circumferential headshaping, which results in an elongated shape of the head. Different types of headshaping were practiced prior to and after the Ubaid period across the Near East, but it seems that the specific technique of circumferential headshaping may have originated in Iran, east of the area of Ubaid influence, and reached its peak during

9494-440: Was first distinguished on the basis of its painted pottery. Ceramics continue to be a main characteristic to determine the chronology and geographical distribution of the period. The paint varies from black to brown, purple and dark green and the pottery fabric itself usually has a buff to red/green brown color. Ubaid 1-2 pottery had dense, geometric and abstract decoration. Later pottery was less decorated, with bands and swags being

9595-558: Was made from it. For example, blades were made from a higher quality flint than other tools, and they may have been produced off-site, indicating that not only raw materials but also finished products were transported over larger distances. Flint was used for a variety of tools, including arrowheads, sickle blades, hoes (which are sometimes considered a hallmark of the Ubaid) and a variety of tools for piercing and drilling. Flint assemblages display both regional and temporal variation. Obsidian

9696-585: Was not as evident at other sites as it was at Zeidan. There was no indication at Zeidan that there was spatial differentiation across the site in how animal products were consumed, suggesting that food stuffs weren't a means to express social differentiation. The Ubaid-related sites along the Persian Gulf coast provide evidence for fishing. The range of species recovered at H3, for example, indicates that fishing probably mainly took place in shallow coastal waters. Tuna, which cannot be caught in Kuwait Bay anymore,

9797-510: Was related to increasing social differentiation between kin groups . Adults, on the other hand, were buried at the edge of the settlement in communal burial grounds in pit burials or inside clay boxes. Such burial grounds have for example been excavated at Eridu. These burial practices represent a clear break from those of the preceding Late Neolithic period. During the Late Neolithic, burials were often secondary and burial treatment

9898-555: Was some increase in social polarization, with central houses in the settlements becoming bigger. But there were no real cities until the later Uruk period . The languages that were spoken during the Ubaid period cannot be determined. Despite the fact that the Ubaid period is prehistorical , it has featured prominently in discussions on the origin and presence of the Sumerian and Akkadian languages in Sumer . This debate has been called

9999-636: Was the case, for example, of the site of Hadji Muhammed , which was discovered only by accident. In central and northern Iraq, the Ubaid was preceded by the Hassuna and Samarra cultures. The Ubaid may have developed out of the latter. In northern Syria and southeastern Turkey, the Ubaid follows upon the Halaf period , and a relatively short Halaf-Ubaid Transitional period (HUT) dating to c. 5500-5200 BC has been proposed as well. HUT pottery assemblages displayed both typically Ubaid and Halaf characteristics. The relations between these periods - or cultures -

10100-424: Was used by Stars and Stripes , the defender which won the 1988 America's Cup , and by USA-17 , the challenger which won the 2010 America's Cup . USA 17' s performance during the 2010 America's Cup races demonstrated a velocity made good upwind of over twice the wind speed and downwind of over 2.5 times the wind speed and the ability to sail as close as 20 degrees off the apparent wind. The shape of

10201-413: Was very diverse. The Ubaid witnessed a marked shift toward primary burial, less diverse burial customs, and less diversity in burial gifts. This shift has been interpreted as a reflection of changing perceptions of personhood . Evidence for cranial modification , i.e. deliberate headshaping, among both men and women, has come from many archaeological sites throughout wider Mesopotamia. Where headshaping

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