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88-655: Dravo Corporation was an American shipbuilding company with shipyards in Pittsburgh and Wilmington, Delaware . It was founded by Frank and Ralph Dravo in Pittsburgh in 1891. The corporation went public in 1936 and in 1998 it was bought out by Carmeuse for $ 192 million ($ 358.9 million today). On March 5, 1942, it became the first corporation to receive the Army-Navy "E" Award for outstanding war time production. Dravo ranked 72nd among United States corporations in

176-615: A solar barque . Early Egyptians also knew how to fasten the planks of this ship together with mortise and tenon joints. The oldest known tidal dock in the world was built around 2500 BC during the Harappan civilisation at Lothal near the present day Mangrol harbour on the Gujarat coast in India . Other ports were probably at Balakot and Dwarka . However, it is probable that many small-scale ports, and not massive ports, were used for

264-588: A Hanseatic cog were discovered in the estuary sediment of the Pärnu River in Estonia which has been dated to 1300. In 2012, a cog dating from the early 15th century was discovered preserved from the keel up to the decks in the silt of the River IJssel in the city of Kampen , Netherlands . During its excavation and recovery an intact brick dome oven and glazed tiles were found in the galley as well as

352-426: A broad beam and heavily curved at both ends. Another important ship type was the galley, which was constructed with both sails and oars. The first extant treatise on shipbuilding was written c.  1436 by Michael of Rhodes, a man who began his career as an oarsman on a Venetian galley in 1401 and worked his way up into officer positions. He wrote and illustrated a book that contains a treatise on shipbuilding,

440-410: A curved, progressive joint could not be achieved. One study finds that there were considerable improvements in ship speed from 1750 to 1850: "we find that average sailing speeds of British ships in moderate to strong winds rose by nearly a third. Driving this steady progress seems to be the continuous evolution of sails and rigging, and improved hulls that allowed a greater area of sail to be set safely in

528-589: A given wind. By contrast, looking at every voyage between the Netherlands and East Indies undertaken by the Dutch East India Company from 1595 to 1795, we find that journey time fell only by 10 percent, with no improvement in the heavy mortality, averaging six percent per voyage, of those aboard." Initially copying wooden construction traditions with a frame over which the hull was fastened, Isambard Kingdom Brunel 's Great Britain of 1843

616-508: A high degree of commercialization and an increase in trade. Large numbers of ships were built to meet the demand. The Ming voyages were large in size, numbering as many as 300 ships and 28,000 men. The shipbuilders were brought from different places in China to the shipyard in Nanjing , including Zhejiang , Jiangxi , Fujian , and Huguang (now the provinces of Hubei and Hunan ). One of

704-406: A range of sailing rigs that included the crab claw sail . The origins of this technology is difficult to date, relying largely on linguistics (studying the words for parts of boats), the written comments of people from other cultures, including the observations of European explorers at the time of first contact and the later more systematic ethnographic observations of the types of craft in use. There

792-472: A sea fight, which made them safer from pirates. Cogs were a type of round ship, characterized by a flush-laid flat bottom at midships which gradually shifted to overlapped strakes near the posts. They were propelled by a single, large, rectangular sail. Typical seagoing cogs ranged from about 15 to 25 meters (49 to 82 ft) in length with a beam of 5 to 8 meters (16 to 26 ft) and were 40–200 tons burthen . Cogs were rarely as large as 300 tons, although

880-477: A significant number of workers, and generate income as the shipbuilding market is global . Cog (ship) A cog is a type of ship that was used during the Middle Ages , mostly for trade and transport but also in war. It first appeared in the 10th century, and was widely used from around the 12th century onward. Cogs were clinker-built , generally of oak . Cogs were fitted with a single mast and

968-891: A similar design. Austronesians established the Austronesian maritime trade network at around 1000 to 600 BC, linking Southeast Asia with East Asia, South Asia, the Middle East, and later East Africa. The route later became part of the Spice trade network and the Maritime Silk Road . The naval history of China stems back to the Spring and Autumn period (722 BC–481 BC) of the ancient Chinese Zhou dynasty . The Chinese built large rectangular barges known as "castle ships", which were essentially floating fortresses complete with multiple decks with guarded ramparts . However,

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1056-484: A single square sail . They were used primarily for trade in north-west medieval Europe, especially by the Hanseatic League . Typical seagoing cogs were from 15 to 25 meters (49 to 82 ft) long, 5 to 8 meters (16 to 26 ft) wide, and were of 30–200 tons burthen . Cogs were rarely as large as 300 tons although a few were considerably larger, over 1,000 tons. Although the name cog is recorded as early as

1144-411: A single piece of hollowed-out log. At the sides were two planks, and two horseshoe-shaped wood pieces formed the prow and stern . These were fitted tightly together edge-to-edge with dowels inserted into holes in between, and then lashed to each other with ropes (made from rattan or fiber) wrapped around protruding lugs on the planks. This characteristic and ancient Austronesian boatbuilding practice

1232-526: A treatise on mathematics, much material on astrology, and other materials. His treatise on shipbuilding treats three kinds of galleys and two kinds of round ships. Shipbuilders in the Ming dynasty (1368~1644) were not the same as the shipbuilders in other Chinese dynasties, due to hundreds of years of accumulated experiences and rapid changes in the Ming dynasty. Shipbuilders in the Ming dynasty primarily worked for

1320-564: A very small number were considerably larger, over 1,000 tons. A rule of thumb for crew size was that one sailor, exclusive of any dedicated fighting men, was required for every 10 tons burthen of the cog, although this may generate a suggested crew size on the low side of Medieval practice. Crews of up to 45 for civilian cogs are recorded, and 60 for a 240 ton cog being used for military transportation. Cogs were typically constructed largely of oak , and had full lapstrake, or clinker , planking covering their sides, generally starting from

1408-514: A vessel identified by contemporary sources as a cog is the Lübeck city seal from 1223. The early cogs were fitted with a side-mounted rudder oar that also functioned as a leeboard and was rigged with a single broad square sail that functioned similar to a lug sail . Around 1200, the side rudder began to be replaced with a centerline rudder attached to a sternpost and developed in the typical medieval cog. Cogs could carry more cargo than knarrs;

1496-467: Is a famous example). Later Great Britain ' s iron hull was sheathed in wood to enable it to carry a copper-based sheathing . Brunel's Great Eastern represented the next great development in shipbuilding. Built-in association with John Scott Russell , it used longitudinal stringers for strength, inner and outer hulls, and bulkheads to form multiple watertight compartments. Steel also supplanted wrought iron when it became readily available in

1584-663: Is a possibility that they may have reached the Americas . After the 11th century, a new type of ship called djong or jong was recorded in Java and Bali. This type of ship was built using wooden dowels and treenails, unlike the kunlun bo which used vegetal fibres for lashings. The empire of Majapahit used jong, built in northern Java, for transporting troops overseas. The jongs were transport ships which could carry 100–2000 tons of cargo and 50–1000 people, 28.99–88.56 meter in length. The exact number of jong fielded by Majapahit

1672-492: Is an advantage in North Atlantic rollers , provided the vessel has a small overall displacement . A limitation of cogs is that they lack points to mount additional masts: at least some fore-and-aft sails are desirable for maneuverability but clinker-built cogs were effectively limited to a single sail. This made them unhandy, limiting their ability to tack in the harbour and making them very reliant on wind direction at

1760-431: Is done. The keel , or keel-plank, was only slightly thicker than the adjacent garboards and had no rabbet . Both stem and stern-posts were straight and rather long, and connected to the keel-plank through intermediate pieces called hooks . The lower plank hoods terminated in rabbets in the hooks and posts, but upper hoods were nailed to the exterior faces of the posts. Caulking was generally tarred moss that

1848-641: Is from the 6th to 5th millennium BC of the Ubaid period of Mesopotamia . They were made from bundled reeds coated in bitumen and had bipod masts. They sailed in shallow coastal waters of the Persian Gulf . Evidence from Ancient Egypt shows that the early Egyptians knew how to assemble planks of wood into a ship hull as early as 3100 BC. Egyptian pottery as old as 4000 BC shows designs of early fluvial boats or other means for navigation. The Archaeological Institute of America reports that some of

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1936-600: Is known as the " lashed-lug " technique. They were commonly caulked with pastes made from various plants as well as tapa bark and fibres which would expand when wet, further tightening joints and making the hull watertight. They formed the shell of the boat, which was then reinforced by horizontal ribs. Shipwrecks of Austronesian ships can be identified from this construction as well as the absence of metal nails. Austronesian ships traditionally had no central rudders but were instead steered using an oar on one side. Austronesians traditionally made their sails from woven mats of

2024-571: Is noted in the works of Ibn Jubayr . The ships of Ancient Egypt's Eighteenth Dynasty were typically about 25 meters (80 ft) in length and had a single mast , sometimes consisting of two poles lashed together at the top making an "A" shape. They mounted a single square sail on a yard , with an additional spar along the bottom of the sail. These ships could also be oar propelled. The ocean- and sea-going ships of Ancient Egypt were constructed with cedar wood, most likely hailing from Lebanon. The ships of Phoenicia seem to have been of

2112-499: Is only a small body of archaeological evidence available. Since Island Southeast Asia contained effective maritime transport between its very large number of islands long before Austronesian seafaring, it is argued that Austronesians adopted an existing maritime technology from the existing inhabitants of this region. Austronesian ships varied from simple canoes to large multihull ships. The simplest form of all ancestral Austronesian boats had five parts. The bottom part consists of

2200-556: Is the settlement of Australia between 50,000 and 60,000 years ago. This almost certainly involved rafts , possibly equipped with some sort of sail . Much of the development beyond that raft technology occurred in the "nursery" areas of the Mediterranean and in Maritime Southeast Asia . Favoured by warmer waters and a number of inter-visible islands, boats (and, later, ships) with water-tight hulls (unlike

2288-411: Is unknown, but the largest number of jong deployed in an expedition is about 400 jongs, when Majapahit attacked Pasai, in 1350. Until recently, Viking longships were seen as marking an advance on traditional clinker -built hulls where leather thongs were used to join plank boards. This consensus has recently been challenged. Haywood has argued that earlier Frankish and Anglo-Saxon nautical practice

2376-589: The ghe mành . Early Egyptians also knew how to assemble planks of wood with treenails to fasten them together, using pitch for caulking the seams. The " Khufu ship ", a 43.6-meter vessel sealed into a pit in the Giza pyramid complex at the foot of the Great Pyramid of Giza in the Fourth Dynasty around 2500 BC, is a full-size surviving example which may have fulfilled the symbolic function of

2464-579: The k'un-lun po or kunlun bo ("ship of the k'un-lun [dark-skinned southern people]"). These ships used two types of sail of their invention, the junk sail and tanja sail . Large ships are about 50–60 metres (164–197 ft) long, had 5.2–7.8 metres (17–26 ft) tall freeboard , each carrying provisions enough for a year, and could carry 200–1000 people. The Chinese recorded that these Southeast Asian ships were hired for passage to South Asia by Chinese Buddhist pilgrims and travelers, because they did not build seaworthy ships of their own until around

2552-724: The Abbasid period. Mughal Empire had a large shipbuilding industry, which was largely centred in the Bengal Subah . Economic historian Indrajit Ray estimates shipbuilding output of Bengal during the sixteenth and seventeenth centuries at 223,250 tons annually, compared with 23,061 tons produced in nineteen colonies in North America from 1769 to 1771. He also assesses ship repairing as very advanced in Bengal. Documents from 1506, for example, refer to watercraft on

2640-547: The Napoleonic Wars were still built more or less to the same basic plan as those of the Spanish Armada of two centuries earlier, although there had been numerous subtle improvements in ship design and construction throughout this period. For instance, the introduction of tumblehome , adjustments to the shapes of sails and hulls, the introduction of the wheel, the introduction of hardened copper fastenings below

2728-459: The Sierra Leone river carrying 120 men. Others refer to Guinea coast peoples using war canoes of varying sizes – some 70 feet in length, 7–8 feet broad, with sharp pointed ends, rowing benches on the side, and quarterdecks or forecastles build of reeds. The watercraft included miscellaneous facilities, such as cooking hearths, and storage spaces for the crew's sleeping mats. From

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2816-464: The logarithm (invented in 1615) to generate the curves used to produce the shape of a hull , especially when scaling up these curves accurately in the mould loft . Shipbuilding and ship repairs, both commercial and military, are referred to as naval engineering . The construction of boats is a similar activity called boat building . The dismantling of ships is called ship breaking . The earliest evidence of maritime transport by modern humans

2904-522: The "flow through" structure of a raft) could be developed. The ships of ancient Egypt were built by joining the hull planks together, edge to edge, with tenons set in mortices cut in the mating edges. A similar technique, but with the tenons being pinned in position by dowels, was used in the Mediterranean for most of classical antiquity . Both these variants are "shell first" techniques, where any reinforcing frames are inserted after assembly of

2992-536: The 17th century, some kingdoms added brass or iron cannons to their vessels. By the 18th century, however, the use of swivel cannons on war canoes accelerated. The city-state of Lagos , for instance, deployed war canoes armed with swivel cannons. With the development of the carrack , the west moved into a new era of ship construction by building the first regular oceangoing vessels. In a relatively short time, these ships grew to an unprecedented size, complexity, and cost. Shipyards became large industrial complexes, and

3080-701: The 5,000-year-old ship may have even belonged to Pharaoh Aha . The Austronesian expansion , which began c.  3000 BC with migration from Taiwan to the island of Luzon in the Philippines , spread across Island Southeast Asia . Then, between 1500 BC and 1500 AD they settled uninhabited islands of the Pacific, and also sailed westward to Madagascar. This is associated with distinctive maritime technology: lashed lug construction techniques (both in outrigger canoes and in large planked sailing vessels), various types of outrigger and twin-hulled canoes and

3168-606: The 8–9th century AD. Austronesians (especially from western Island Southeast Asia ) were trading in the Indian Ocean as far as Africa during this period. By around 50 to 500 AD, a group of Austronesians, believed to be from the southeastern coasts of Borneo (possibly a mixed group related to the modern Ma'anyan , Banjar , and/or the Dayak people ) crossed the Indian Ocean and colonized Madagascar . This resulted in

3256-501: The 9th century, the seagoing vessel of that name seems to have evolved on the Frisian coast during the 12th century. Cogs progressively replaced Viking -type vessels such as knarrs in northern waters during the 13th century. Cogs could carry more cargo than knarrs of a similar size. Their flat bottoms allowed them to settle on a level in harbour, making them easier to load and unload. Their high sides made them more difficult to board in

3344-764: The Admiral Zheng He . Six voyages were conducted under the Yongle Emperor's reign, the last of which returned to China in 1422. After the Yongle Emperor's death in 1424, his successor the Hongxi Emperor ordered the suspension of the voyages. The seventh and final voyage began in 1430, sent by the Xuande Emperor . Although the Hongxi and Xuande Emperors did not emphasize sailing as much as the Yongle Emperor, they were not against it. This led to

3432-507: The Chinese vessels during this era were essentially fluvial (riverine). True ocean-going Chinese fleets did not appear until the 10th century Song dynasty . There is considerable knowledge regarding shipbuilding and seafaring in the ancient Mediterranean. Large multi-masted seafaring ships of Southeast Asian Austronesians first started appearing in Chinese records during the Han dynasty as

3520-654: The Chinese, from the Old Javanese parahu , Javanese prau , or Malay perahu – large ship. Southern Chinese junks showed characteristics of Austronesian ships that they are made using timbers of tropical origin, with keeled, V-shaped hull. This is different from northern Chinese junks, which are developed from flat-bottomed riverine boats. The northern Chinese junks were primarily built of pine or fir wood, had flat bottoms with no keel, water-tight bulkheads with no frames, transom (squared) stern and stem, and have their planks fastened with iron nails or clamps. It

3608-570: The Han dynasty junk ship design in the same century. The Chinese were using square sails during the Han dynasty and adopted the Austronesian junk sail later in the 12th century. Iconographic remains show that Chinese ships before the 12th century used square sails, and the junk rig of Chinese ships is believed to be developed from tilted sails . Southern Chinese junks were based on keeled and multi-planked Austronesian ship known as po by

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3696-713: The Harappan maritime trade. Ships from the harbour at these ancient port cities established trade with Mesopotamia . Shipbuilding and boatmaking may have been prosperous industries in ancient India. Native labourers may have manufactured the flotilla of boats used by Alexander the Great to navigate across the Hydaspes and even the Indus , under Nearchos . The Indians also exported teak for shipbuilding to ancient Persia . Other references to Indian timber used for shipbuilding

3784-653: The Limfjord in northern Jutland offered a fairly protected passage between the North Sea and the Baltic. Due to its unusual geographical conditions and strong currents, the passage was constantly filling with sand and was completely blocked by the early 12th century. This change produced new challenges. The larger ships, which could not be pulled across the sand bars, had to sail around the Jutland peninsula and circumnavigate

3872-401: The Mediterranean, was expensive and required specialist shipwrights . However, their simpler sail setup meant that cogs only required half the crew of similar-sized vessels equipped with lateen sails, as were common in the Mediterranean. A structural benefit of clinker construction is that it produces a vessel that can safely twist and flex around its long axis (running from bow to stern), which

3960-491: The United States in a 15-year period just before the war was a grand total of two. During the war, thousands of Liberty ships and Victory ships were built, many of them in shipyards that did not exist before the war. And, they were built by a workforce consisting largely of women and other inexperienced workers who had never seen a ship before (or even the ocean). After World War II , shipbuilding (which encompasses

4048-404: The bilge strakes , with double-clenched iron nails for plank fastenings. At the stem , chases are formed; that is, in each case, the land of the lower strake is tapered to a feather edge at the end of the strake where it meets the stem or stern-post . This allows the end of the strake to be fastened to the apron with the outside of the planking mutually flush at that point and flush with

4136-462: The crew and tiller up, out of the way. Current archaeological evidence points to the Frisian coast or Western Jutland as the possible birthplace of this type of vessel. The transformation of the cog into a true seagoing trader came not only during the time of the intense trade between West and East but also as a direct answer to the closure of the western entrance to the Limfjord . For centuries,

4224-408: The dangerous Cape Skagen to get to the Baltic. This resulted in major modifications to old ship structures, which can be observed by analyzing the evolution of the earliest cog finds of Kollerup, Skagen, and Kolding. This caused a boom in the number of small cogs, and the need for spacious and seaworthy ships led to the development of the cog as the workhorse of the Hanseatic League . It soon became

4312-468: The development of complex non-maritime technologies, a ship has often represented the most advanced structure that the society building it could produce. Some key industrial advances were developed to support shipbuilding, for instance the sawing of timbers by mechanical saws propelled by windmills in Dutch shipyards during the first half of the 17th century. The design process saw the early adoption of

4400-500: The end of the Ming dynasty in 1644. During this period, Chinese navigation technology did not make any progress and even declined in some aspect. In the Islamic world, shipbuilding thrived at Basra and Alexandria . The dhow , felucca , baghlah , and the sambuk became symbols of successful maritime trade around the Indian Ocean from the ports of East Africa to Southeast Asia and the ports of Sindh and Hind (India) during

4488-594: The government, under command of the Ministry of Public Works . During the early years of the Ming dynasty, the Ming government maintained an open policy towards sailing. Between 1405 and 1433, the government conducted seven diplomatic Ming treasure voyages to over thirty countries in Southeast Asia, India, the Middle East and Eastern Africa. The voyages were initiated by the Yongle Emperor , and led by

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4576-507: The infrastructure required to transport the trees from their point of origin to the shipyards. Shipbuilders were usually divided into different groups and had separate jobs. Some were responsible for fixing old ships; some were responsible for making the keel and some were responsible for building the helm. After 1477, the Ming government reversed its open maritime policies, enacting a series of isolationist policies in response to piracy . The policies, called Haijin (sea ban), lasted until

4664-476: The interpretation as a cog. It was around 16 m long and its wood dated from 1339. The discovery by Modderman was however not well known in the literature. The most famous cog in existence today is the Bremen cog . The artifact originates from the 1380s and was discovered in 1962. Prior to this discovery, the existence of cogs was primarily documented in medieval texts and seals. In 1990 the well-preserved remains of

4752-536: The introduction of outrigger canoe technology to non-Austronesian cultures in the East African coast. The ancient Chinese also built fluvial ramming vessels as in the Greco-Roman tradition of the trireme , although oar-steered ships in China lost favor very early on since it was in the 1st century China that the stern -mounted rudder was first developed. This was dually met with the introduction of

4840-432: The keel, the hull was made by overlapping nine strakes on either side with rivets fastening the oaken planks together. It could hold upwards of thirty men. Sometime around the 12th century, northern European ships began to be built with a straight sternpost , enabling the mounting of a rudder, which was much more durable than a steering oar held over the side. Development in the Middle Ages favored "round ships", with

4928-470: The latter half of the 19th century, providing great savings when compared with iron in cost and weight. Wood continued to be favored for the decks. During World War II , the need for cargo ships was so great that construction time for Liberty ships went from initially eight months or longer, down to weeks or even days. They employed production line and prefabrication techniques such as those used in shipyards today. The total number of dry-cargo ships built in

5016-466: The main cargo carrier in Atlantic and Baltic waters. Eventually, around the 14th century, the cog reached its structural limits, and larger or more seaworthy vessels needed to be of a different type. This was the hulk , which already existed but was much less common than the cog. There is no evidence that hulks descended from cogs, but it is clear that a lot of technological ideas were adapted between

5104-401: The mast and to operate the sail. Cordage was usually hemp or flax and the sail hemp-based canvas . From the 13th century cogs would be decked and larger vessels would be fitted with a stern castle, to afford more cargo space by keeping the crew and tiller up, out of the way; and to give the helmsman a better view. A cog, compared with the carvel-built vessels more traditional in

5192-412: The mid-18th century and from the mid-19th century onwards. This was partly led by the shortage of "compass timber", the naturally curved timber that meant that shapes could be cut without weaknesses caused by cuts across the grain of the timber. Ultimately, whole ships were made of iron and, later, steel . The earliest known depictions (including paintings and models) of shallow-water sailing boats

5280-469: The middle of the first millennium AD, transports on the large river estuaries and the sheltered waters of the Wadden Sea was taken over by Frisians who used vessels based on indigenous, flat-bottomed designs that were precursors of later medieval cogs. These had much lower sides than later cogs and would have been very similar to contemporary Scandinavian craft, such as knarrs . The oldest depiction of

5368-568: The most famous shipyards was Long Jiang Shipyard ( zh:龙江船厂 ), located in Nanjing near the Treasure Shipyard where the ocean-going ships were built. The shipbuilders could build 24 models of ships of varying sizes. Several types of ships were built for the voyages, including Shachuan (沙船), Fuchuan (福船) and Baochuan ( treasure ship ) (宝船). Zheng He's treasure ships were regarded as Shachuan types, mainly because they were made in

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5456-465: The oldest ships yet unearthed are known as the Abydos boats . These are a group of 14 ships discovered in Abydos that were constructed of wooden planks which were "sewn" together. Discovered by Egyptologist David O'Connor of New York University , woven straps were found to have been used to lash the planks together, and reeds or grass stuffed between the planks helped to seal the seams. Because

5544-471: The planking has defined the hull shape. Carvel construction then took over in the Mediterranean. Northern Europe used clinker construction , but with some flush-planked ship-building in, for instance, the bottom planking of cogs . The north-European and Mediterranean traditions merged in the late 15th century, with carvel construction being adopted in the North and the centre-line mounted rudder replacing

5632-492: The quarter rudder of the Mediterranean. These changes broadly coincided with improvements in sailing rigs, with the three masted ship becoming common, with square sails on the fore and main masts, and a fore and aft sail on the mizzen. Ship-building then saw a steady improvement in design techniques and introduction of new materials. Iron was used for more than fastenings ( nails and bolts ) as structural components such as iron knees were introduced, with examples existing in

5720-416: The resilient and salt-resistant pandanus leaves. These sails allowed Austronesians to embark on long-distance voyaging. The ancient Champa of Vietnam also uniquely developed basket-hulled boats whose hulls were composed of woven and resin - caulked bamboo, either entirely or in conjunction with plank strakes . They range from small coracles (the o thúng ) to large ocean-going trading ships like

5808-425: The rudder made steering easier than did the steering oar of the knarr, especially for larger vessels; and cogs were cheaper to build. The latter was due to the cog's use of sawn rather than split planks which was less wasteful. Fore and stern castles would later be added for defense against pirates , or to enable the use of these vessels as warships. The stern castle also afforded more cargo space below by keeping

5896-410: The same basic shape, but with planking instead of hollowed-out logs. Another development was into Kahnen , flat-bottomed boats , with pointed ends for and aft that were constructed by splitting a hollowed-out log and widening the bottom with planks that were nailed to knee-shaped ribs attached to the sides. The pointed ends (called Block locally) of the log would be cut off and attached separately to

5984-450: The shipbuilder learned the techniques of shipbuilding from his family and is very likely to earn a higher status in the shipyard. Additionally, the shipbuilder had access to business networking that could help to find clients. If a shipbuilder entered the occupation through an apprenticeship, the shipbuilder was likely a farmer before he was hired as a shipbuilder, or he was previously an experienced shipbuilder. Many shipbuilders working in

6072-456: The ships are all buried together and near a mortuary belonging to Pharaoh Khasekhemwy , originally they were all thought to have belonged to him, but one of the 14 ships dates to 3000 BC, and the associated pottery jars buried with the vessels also suggest earlier dating. The ship dating to 3000 BC was about 75 feet (23 m) long and is now thought to perhaps have belonged to an earlier pharaoh. According to professor O'Connor,

6160-429: The ships built were financed by consortia of investors. These considerations led to the documentation of design and construction practices in what had previously been a secretive trade run by master shipwrights and ultimately led to the field of naval architecture , in which professional designers and draftsmen played an increasingly important role. Even so, construction techniques changed only very gradually. The ships of

6248-422: The shipyard were forced into the occupation. The ships built for Zheng He's voyages needed to be waterproof, solid, safe, and have ample room to carry large amounts of trading goods. Therefore, due to the highly commercialized society that was being encouraged by the expeditions, trades, and government policies, the shipbuilders needed to acquire the skills to build ships that fulfil these requirements. Shipbuilding

6336-433: The shipyards, the marine equipment manufacturers, and many related service and knowledge providers) grew as an important and strategic industry in a number of countries around the world. This importance stems from: Historically, the industry has suffered from the absence of global rules and a tendency towards ( state - supported ) over-investment due to the fact that shipyards offer a wide range of technologies, employ

6424-666: The site of Portus in Rome revealed inscriptions in a shipyard constructed during the reign of Trajan (98–117) that indicated the existence of a shipbuilders guild . Roughly at this time is the last migration wave of the Austronesian expansion , when the Polynesian islands spread over vast distances across the Pacific Ocean were being colonized by the (Austronesian) Polynesians from Island Melanesia using double-hulled voyaging catamarans . At its furthest extent, there

6512-404: The start of voyages. The flat bottom permitted cogs to be readily beached and unloaded at low tide when quays were not available; a useful trait when purpose-built jetties were not common. Cogs were expected to have a working life of approximately 40 years. The earliest origins of the cog are believed to be logboats from around northern Germany. These developed into larger craft built in

6600-401: The stem. This means that the boat's passage through the water will not tend to lift the ends of the planking away from the stem. Before the next plank is fitted, the face of the land on the lower strake is bevelled to suit the angle at which the next strake will lie in relation with it. This varies all along the land. The new strake is held in position on the preceding one before the fastening

6688-482: The stronger flushed deck design derived from Indian designs, and the increasing use of iron reinforcement. The flushed deck originated from the Bengal rice ships, with Bengal being famous for its shipbuilding industry at the time. Iron was gradually adopted in ship construction, initially to provide stronger joints in a wooden hull e.g. as deck knees, hanging knees, knee riders and the other sharp joints, ones in which

6776-558: The treasure shipyard in Nanjing. Shachuan , or 'sand-ships', are ships used primarily for inland transport. However, in recent years, some researchers agree that the treasure ships were more of the Fuchuan type. It is said in vol. 176 of San Guo Bei Meng Hui Bian (三朝北盟汇编) that ships made in Fujian are the best ones. Therefore, the best shipbuilders and laborers were brought from these places to support Zheng He's expedition. The shipyard

6864-491: The two types. The transition from cogs to hulks was not linear, according to some interpretations, both vessels coexisted for many centuries but followed diverse lines of evolution. The first archaeological find that was identified as a cog, was a ship wreck discovered in 1944 by P. J. R. Modderman in the Noordoostpolder near Emmeloord (plot NM 107). The wreck was reburied in situ and a 2008 re-excavation confirmed

6952-402: The value of World War II military production contracts. From 1942 to 1945, Dravo Corporation built Landing Ship, Tank , (LST). LST were built to support amphibious operations able to land tanks , vehicles, cargo, and landing troops on to beaches. No docks or piers were required for these amphibious assaults . The LST had a special bow with a large door that could open. Then a ramp

7040-612: The waterline, the introduction of copper sheathing as a deterrent to shipworm and fouling, etc. In the early decades of the Industrial Revolution (1760 to 1825) western ship design remained largely based on its traditional pre-industrial designs and materials and yet greatly improved in safety as "the risk of being wrecked for Atlantic shipping fell by one-third, and of foundering by two thirds, reflecting improvements in seaworthiness and navigation respectively." The improvement in seaworthiness has been credited to adopting

7128-583: The widened hull which resulted in so-called Blockkahnen , variants of which are still in use. The earliest evidence of a cog-like craft is a clay model found in Leese on the middle Weser from the grave of an adult male who died around 200 BC. Fragments of similar clay models have been found in nearby regions. Trade from Germania in Roman times was mostly carried on Mediterranean-style sailing vessels and controlled by Roman merchants. After Roman power collapsed in

7216-553: Was inserted into curved grooves, covered with wooden laths , and secured by metal staples called sintels . The cog-built structure would be completed with a stern -mounted, hanging, central rudder on a heavy stern-post, which was a uniquely northern development. The single, thick, mast was set forward of amidships, stepped into the keel-plank and equipped with a single large, rectangular, square-rigged sail . The masts of larger vessels would be of composite construction. Complicated systems of rigging were developed to support

7304-523: Was installed for unloading allied vehicles. The LST had a flat keel , so it could be beached and stay upright. The propellers and rudders were protected from grounding damage. Many were used in the Pacific War and in the European theatre , especially on Battle of Normandy . In 1942 and 1943, Dravo Corporation also built Submarine chasers . Shipbuilding Until recently, with

7392-540: Was much more accomplished than had been thought and has described the distribution of clinker vs. carvel construction in Western Europe (see map [1] ). An insight into shipbuilding in the North Sea/Baltic areas of the early medieval period was found at Sutton Hoo , England, where a ship was buried with a chieftain. The ship was 26 metres (85 ft) long and 4.3 metres (14 ft) wide. Upward from

7480-549: Was not the sole industry utilising Chinese lumber at that time; the new capital was being built in Beijing from approximately 1407 onwards, which required huge amounts of high-quality wood. These two ambitious projects commissioned by Emperor Yongle would have had enormous environmental and economic effects, even if the ships were half the dimensions given in the History of Ming . Considerable pressure would also have been placed on

7568-444: Was the first radical new design, being built entirely of wrought iron. Despite her success, and the great savings in cost and space provided by the iron hull, compared to a copper-sheathed counterpart, there remained problems with fouling due to the adherence of weeds and barnacles. As a result, composite construction remained the dominant approach where fast ships were required, with wooden timbers laid over an iron frame ( Cutty Sark

7656-426: Was under the command of Ministry of Public Works . The shipbuilders had no control over their lives. The builders, commoner's doctors, cooks and errands had lowest social status. The shipbuilders were forced to move away from their hometown to the shipyards. There were two major ways to enter the shipbuilder occupation: family tradition, or apprenticeship. If a shipbuilder entered the occupation due to family tradition,

7744-414: Was unknown when the Chinese people started adopting Southeast Asian (Austronesian) shipbuilding techniques. They may have been started as early as the 8th century, but the development was gradual and the true ocean-going Chinese junks did not appear suddenly. The word "po" survived in Chinese long after, referring to the large ocean-going junks. In September 2011, archeological investigations done at

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