Misplaced Pages

#591408

57-425: Lofting is particularly useful in boat building , when it is used to draw and cut pieces for hulls and keels . These are usually curved, often in three dimensions . Loftsmen at the mould lofts of shipyards were responsible for taking the dimensions and details from drawings and plans, and translating this information into templates, battens , ordinates , cutting sketches, profiles, margins and other data. From

114-519: A US aircraft company, North American Aviation , took the practice into the purely mathematical realm. One of that war's outstanding warplanes, the North American P-51 Mustang , was designed using mathematical charts and tables rather than lofting tables. Lofting is the transfer of a Lines Plan to a Full-Sized Plan . This helps to assure that the boat will be accurate in its layout and pleasing in appearance. There are many methods to loft

171-496: A builder should choose the most appropriate one for the boat's intended purpose. For example, a sea-going vessel needs a hull which is more stable and robust than a hull used in rivers and canals. Hull types include: Teak Teak ( Tectona grandis ) is a tropical hardwood tree species in the family Lamiaceae . It is a large, deciduous tree that occurs in mixed hardwood forests. Tectona grandis has small, fragrant white flowers arranged in dense clusters ( panicles ) at

228-410: A covering of paint). Modern steel components are welded or bolted together. As the welding can be done very easily (with common welding equipment), and as the material is very cheap, it is a popular material with amateur builders. Also, amateur builders which are not yet well established in building steel ships may opt for DIY construction kits. If steel is used, a zinc layer is often applied to coat

285-514: A depletion of remaining natural hectares of teak forests, growth in plantations in Latin America is expected to rise. Hyblaea puera , commonly known as the teak defoliator, is a moth native to southeast Asia. It is a teak pest whose caterpillar feeds on teak and other species of trees common in the region of Southeast Asia. Teak's high oil content, high tensile strength, and tight grain make it particularly suitable where weather resistance

342-455: A part of ship lofting; "lofting" means drawing full-sized patterns, so-called because it was often done in large, lightly constructed mezzanines or lofts above the factory floor. When aircraft design progressed beyond the stick-and-fabric boxes of its first decade of existence, the practice of lofting moved naturally into the aeronautical realm. As the storm clouds of World War II gathered in Europe,

399-503: A set of plans. Generally, boat building books have a detailed description of the lofting process, beyond the scope of this article. Plans can be lofted on a level wooden floor, marking heavy paper such as Red Rosin for the full-sized plans or directly on plywood sheets. The first step is to layout the grid, mark the Base Line along the length of the paper or plywood sheet. Then nail Battens every 12 inches (or more in some cases) where

456-469: A smooth finish. In the 1960s and 1970s, particularly in Australia and New Zealand, the cheapness of ferro construction encouraged amateur builders to build hulls larger than they could afford, not anticipating that the fitting-out costs of a larger boat can be crippling. The advantages of a ferro hull are: The disadvantages are: See also : concrete ship , concrete canoe . There are many hull types, and

513-417: A somewhat dull finish. Finally, teak may also be varnished for a deep, lustrous glow. Teak is also used extensively in boat decks , as it is extremely durable but requires regular maintenance. The teak tends to wear into the softer 'summer' growth bands first, forming a natural 'non-slip' surface. Any sanding is therefore only damaging. The use of modern cleaning compounds, oils or preservatives will shorten

570-411: A very effective antifouling metal. Cupronickel may be found on the hulls of premium tugboats , fishing boats and other working boats ; and may even be used for propellers and propeller shafts . Fiberglass ( glass-reinforced plastic or GRP) is typically used for production boats because of its ability to reuse a female mould as the foundation for the shape of the boat. The resulting structure

627-400: A wooden hull provided the risk of galvanic corrosion was minimised. Fast cargo vessels once were copper-bottomed to prevent being slowed by marine fouling. GRP and ferrocement hulls are classic composite hulls, the term "composite" applies also to plastics reinforced with fibers other than glass. When a hull is being created in a female mould, the composite materials are applied to the mould in

SECTION 10

#1732883985592

684-545: Is 2.5–3 mm long with 2 mm wide obtuse lobes. Tectona grandis sets fruit from September to December; fruits are globose and 1.2–1.8 cm in diameter. Flowers are weakly protandrous in that the anthers precede the stigma in maturity and pollen is shed within a few hours of the flower opening. The flowers are primarily entomophilous (insect-pollinated), but can occasionally be anemophilous (wind-pollinated). A 1996 study found that in its native range in Thailand,

741-511: Is also a major producer of teak and is home to the world's oldest teak plantation. Teak consumption raises several environmental concerns, such as the disappearance of rare old-growth teak. However, its popularity has led to growth in sustainable plantation teak production throughout the seasonally dry tropics in forestry plantations . The Forest Stewardship Council offers certification of sustainably grown and harvested teak products. Propagation of teak via tissue culture for plantation purposes

798-450: Is also prized for the trim work on boat interiors. Due to the oily nature of the wood, care must be taken to properly prepare the wood before gluing. When used on boats, teak is also very flexible in the finishes that may be applied. One option is to use no finish at all, in which case the wood will naturally weather to a pleasing silver grey. The wood may also be oiled with a finishing agent such as linseed or tung oil. This results in

855-411: Is applied by a team of plasterers. The cement:sand ratio is a very rich 4:1. As the hull thickness is typically 2.5 to 3 cms, ferrocement is unsuitable for boats less than about 15 metres LOA as there is a weight penalty; above that length there is no penalty. Properly plastered ferrocement boats have smooth hulls with fine lines, and amateur builders are advised to use professional plasterers to produce

912-589: Is commercially viable. Teak plantations were widely established in Equatorial Africa during the Colonial era . These timber resources, as well as the oil reserves, are at the heart of the current (2014) South Sudanese conflict. Much of the world's teak is exported by Indonesia and Myanmar . There is also a rapidly growing plantation-grown market in Central America ( Costa Rica ) and South America . With

969-410: Is desired. It is used in the manufacture of outdoor furniture and boat decks . It is also used for cutting boards , indoor flooring , countertops , and as a veneer for indoor finishings. Although easily worked, it can cause severe blunting on edged tools because of the presence of silica in the wood. Over time teak can weather to a silvery-grey finish, especially when exposed to sunlight. Teak

1026-525: Is laid to the mould, but before the inner skin is laid. This is similar to the next type, composite, but is not usually classified as composite, since the core material in this case does not provide much additional strength. It does, however, increase stiffness, which means that less resin and fiberglass cloth can be used in order to save weight. Most fibreglass boats are currently made in an open mould, with fibreglass and resin applied by hand ( hand-lay-up method). Some are now constructed by vacuum infusion where

1083-550: Is more susceptible to colour change from UV exposure. The vast majority of commercially harvested teak is grown on teak plantations found in Indonesia and controlled by Perum Perhutani (a state-owned forest enterprise) that manages the country's forests. The primary use of teak harvested in Indonesia is in the production of outdoor teak furniture for export. Nilambur in Kerala , India,

1140-453: Is most commonly found in yachts, pontoon and power boats that are not kept permanently in the water. Aluminium yachts are particularly popular in France. A relatively expensive metal used only very occasionally in boatbuilding is cupronickel . Arguably the ideal metal for boat hulls, cupronickel is reasonably tough, highly resistant to corrosion in seawater, and is (because of its copper content)

1197-558: Is native to south and southeast Asia , mainly Bangladesh , India , Indonesia , Malaysia , Myanmar , Thailand , and Sri Lanka , but is naturalised and cultivated in many countries in Africa and the Caribbean . Myanmar 's teak forests account for nearly half of the world's naturally occurring teak. Molecular studies show that there are two centres of the genetic origin of teak: one in India and

SECTION 20

#1732883985592

1254-477: Is noted for its dense yellowish tomentose hairs on the lower surface of the leaf. The English word teak comes via the Portuguese teca from Malayalam tekka (cognate with Tamil tekku , Telugu teku , and Kannada tegu ) via Sanskrit "shaka" and "saka" . Central Province teak and Nagpur teak are named for those regions of India. Tectona grandis is one of three species in

1311-625: Is propagated mainly from seeds. Germination of the seeds involves pretreatment to remove dormancy arising from the thick pericarp. Pretreatment involves alternate wetting and drying of the seed. The seeds are soaked in water for 12 hours and then spread to dry in the sun for 12 hours. This is repeated for 10–14 days and then the seeds are sown in shallow germination beds of coarse peat covered by sand. The seeds then germinate after 15 to 30 days. Clonal propagation of teak has been successfully done through grafting, rooted stem cuttings, and micropropagation. While bud grafting onto seedling root stock has been

1368-409: Is strong in tension but often needs to be either laid up with many heavy layers of resin-saturated fiberglass or reinforced with wood or foam in order to provide stiffness. GRP hulls are largely free of corrosion though not normally fireproof. These can be solid fiberglass or of the sandwich (cored) type, in which a core of balsa , foam or similar material is applied after the outer layer of fiberglass

1425-407: Is the lightest material for building large boats (being 15–20% lighter than polyester and 30% lighter than steel). Aluminium is relatively cheap in comparison with wood or steel in most countries. In addition it is relatively easy to cut, bend and weld. Galvanic corrosion below the waterline in salt water is a serious concern, particularly in marinas where there are other conflicting metals. Aluminium

1482-405: Is the traditional boat building material used for hull and spar construction. It is buoyant, widely available and easily worked. It is a popular material for small boats (of e.g. 6-metre (20 ft) length; such as dinghies and sailboats). Its abrasion resistance varies according to the hardness and density of the wood and it can deteriorate if fresh water or marine organisms are allowed to penetrate

1539-463: Is used as a food plant by the larvae of moths of the genus Endoclita including E. aroura , E. chalybeatus , E. damor , E. gmelina , E. malabaricus , E. sericeus and E. signifer other Lepidoptera including the turnip moth . Teak has been used as a boatbuilding material for over 2000 years (it was found in an archaeological dig in Berenice Panchrysos , a port on

1596-518: Is used extensively in India to make doors and window frames, furniture, and columns, and beams in homes. It is resistant to termite attacks and damage caused by other insects . Mature teak fetches a very good price. It is grown extensively by forest departments of different states in forest areas. It was also used in the construction of the Kaaba in the Masjid al-Haram of Mecca, which is the holiest structure in

1653-509: The 2021 Myanmar coup d'état , illegal logging of teak and tamalan trees has surged in Sagaing Region, predominantly in key contested battlegrounds, including Kani , Yinmabin , Kantbalu , Indaw , and Banmauk townships . Both the Burmese military and resistance groups have profited from the illegal logging trade. Smugglers transport the wood to India to circumvent economic sanctions and use

1710-456: The D-Day Mulberry harbours . After a buzz of excitement among homebuilders in the 1960s, ferro building has since declined. Ferrocement is a relatively cheap method to produce a hull, although unsuitable for commercial mass production. A steel and iron "armature" is built to the exact shape of the hull, ultimately being covered in galvanised chicken netting. Then, on a single day, the cement

1767-494: The Feet, Inches, and Eighths. The points are plotted at each station then use a small nail and a batten to Fair (draw with a fair curve) the boat's lines. Boat building Boat building is the design and construction of boats (instead of the larger ships ) — and their on-board systems. This includes at minimum the construction of a hull , with any necessary propulsion, mechanical, navigation, safety and other service systems as

Lofting - Misplaced Pages Continue

1824-563: The Indian Roman trade route ). In addition to relatively high strength, teak is also highly resistant to rot, fungi, and mildew. The wood has a relatively low shrinkage ratio, which makes it excellent for applications where it undergoes periodic changes in moisture. Teak has the unusual property of being both an excellent structural timber for framing or planking, while at the same time being easily worked and finished, unlike some otherwise similar woods such as purpleheart . For this reason, it

1881-418: The type specimen : T. grandis f. canescens is distinguished from the type material by being densely canescent or covered in hairs, on the underside of the leaf, T. grandis f. pilosula is distinct from the type material in the varying morphology of the leaf veins, T. grandis f. punctata is only hairy on the larger veins on the underside of the leaf, and T. grandis f. tomentella

1938-410: The "shell-first" method (also called "planking first") and the "frame first" method. With "shell first", the form of the hull is determined by joining shaped planks that are fastened together, followed by reinforcing the structure with the frames (or ribs) that are fitted to the inside. With "frame first", the hull shape is established by setting up the frames on the keel and then fastening the planking on

1995-445: The EU market to ensure they are legally harvested. This regulation specifically applies to teak and other high-risk timber species, particularly those sourced from countries with poor forest governance or illegal logging activities. Myanmar, for example, has been a focus due to concerns over illegal teak harvesting from there. For more detailed information, you can refer to the full text of

2052-626: The Islamic faith. Leaves of the teak wood tree are used in making Pellakai gatti ( jackfruit dumpling), where batter is poured into a teak leaf and steamed. This type of usage is found in the coastal district of Udupi in the Tulunadu region in South India . The leaves are also used in gudeg , a dish of young jackfruit made in Central Java , Indonesia , and give the dish its dark brown colour. Teak

2109-592: The Myanma Timber Enterprise to license the wood as being sourced from permitted areas. EU regulation The regulation that addresses the import of timber, including teak, into the EU from unknown or illegal sources is the EU Timber Regulation (EUTR) No. 995/2010 . This regulation aims to prevent the trade of illegally harvested timber and timber products within the EU market. It places an obligation on operators who place timber and timber products on

2166-532: The annual rainfall in areas where teak grows averages 1,250–1,650 mm with a 3–5 month dry season. Teak's natural oils make it useful in exposed locations and make the timber termite- and pest-resistant. Teak is durable even when not treated with oil or varnish. Timber cut from old teak trees was once believed to be more durable and harder than plantation-grown teak. Studies have shown that plantation teak performs on par with old-growth teak in erosion rate, dimensional stability, warping, and surface checking, but

2223-465: The country's logging industry. In 2014, Myanmar's government imposed a strict ban on exporting wild-grown teak logs. In 2015, 153 Chinese loggers were sentenced to life in prison for illegal logging. Illegal teak logging persists, especially in contested areas. While it is illegal for timber to be exported via land borders, 95% of Myanmar's teak enters China through the China–Myanmar border . Since

2280-478: The craft requires. The boat building industry provides for the design, manufacturing, repair and modification of human-powered watercrafts , sailboats , motorboats , airboats and submersibles , and caters for various demands from recreational (e.g. launches , dinghies and yachts ), commercial (e.g. tour boats , ferry boats and lighters ), residential ( houseboats ), to professional (e.g. fishing boats , tugboats , lifeboats and patrol boats ) . Wood

2337-401: The early 1970s onward computer-aided design (CAD) became normal for the shipbuilding design and lofting process. Lofting was also commonly used in aircraft design before the widespread adoption of computer-generated shaping programs. As ship design evolved from craft to science, designers learned various ways to produce long curves on a flat surface. Generating and drawing such curves became

Lofting - Misplaced Pages Continue

2394-454: The end of the branches. These flowers contain both types of reproductive organs ( perfect flowers). The large, papery leaves of teak trees are often hairy on the lower surface. Teak wood has a leather-like smell when it is freshly milled and is particularly valued for its durability and water resistance. The wood is used for boat building, exterior construction, veneer, furniture, carving, turnings, and various small projects. Tectona grandis

2451-581: The entire hull. It is applied after sandblasting (which is required to have a cleaned surface) and before painting. The painting is usually done with lead paint (Pb 3 O 4 ). Optionally, the covering with the zinc layer may be left out, but it is generally not recommended. Zinc anodes also need to be placed on the ship's hull. Until the mid-1900s, steel sheets were riveted together. Aluminum and aluminum alloys are used both in sheet form for all-metal hulls or for isolated structural members. Many sailing spars are frequently made of aluminium after 1960. It

2508-443: The fibres are laid out and resin is pulled into the mould by atmospheric pressure. This can produce stronger parts with more glass and less resin, but takes special materials and more technical knowledge. Older fibreglass boats before 1990 were often not constructed in controlled temperature buildings leading to the widespread problem of fibreglass pox, where seawater seeped through small holes and caused delamination. The name comes from

2565-410: The form of a thermosetting plastic (usually epoxy , polyester, or vinylester) and some kind of fiber cloth ( fiberglass , kevlar , dynel , carbon fiber , etc.). These methods can give strength-to-weight ratios approaching that of aluminum, while requiring less specialized tools and construction skills. First developed in the mid-19th century in both France and Holland, ferrocement was also used for

2622-672: The genus Tectona . The other two species, T. hamiltoniana and T. philippinensis , are endemics with relatively small native distributions in Myanmar and the Philippines , respectively. Tectona grandis is native to India , Bangladesh , Sri Lanka , Indonesia , Myanmar , northern Thailand , and northwestern Laos . Tectona grandis is found in a variety of habitats and climatic conditions from arid areas with only 500 mm of rain per year to very moist forests with up to 5,000 mm of rain per year. Typically, though,

2679-467: The life of the teak, as it contains natural teak oil a very small distance below the white surface. Wooden boat experts will only wash the teak with salt water, and re- caulk when needed. This cleans the deck and prevents it from drying out and the wood shrinking. The salt helps it absorb and retain moisture and prevents any mildew and algal growth. Over-maintenance, such as cleaning teak with harsh chemicals, can shorten its usable lifespan as decking. Teak

2736-419: The major pollinators were species in the bee genus Ceratina . Wood texture is hard and rings are porous. The density varies according to moisture content: at 15% moisture content it is 660 kg/m . The heartwood is yellowish to golden-brown. Sapwood is whitish to pale yellowish brown. It can easily separate from heartwood. Teak darkens as it ages. There can be a large variation, depending on which region

2793-425: The method used for establishing clonal seed orchards that enables assemblage of clones of the superior trees to encourage crossing, rooted stem cuttings and micro propagated plants are being increasingly used around the world for raising clonal plantations. Illegal logging is prevalent in countries with natural teak forests, including India and Burma. Since 1989, the state-owned Myanma Timber Enterprise has run

2850-446: The multitude of surface pits in the outer gelcoat layer which resembles smallpox. Sometimes the problem was caused by atmospheric moisture being trapped in the layup during construction in humid weather. "Composite construction" involves a variety of composite materials and methods: an early example was a timber carvel skin attached to a frame and deck beams made of iron. Sheet copper anti-fouling ("copper=bottomed") could be attached to

2907-608: The other in Myanmar and Laos . Teak is a large deciduous tree up to 40 m (131 ft) tall with grey to greyish-brown branches, known for its high-quality wood. Its leaves are ovate-elliptic to ovate, 15–45 cm (5.9–17.7 in) long by 8–23 cm (3.1–9.1 in) wide, and are held on robust petioles which are 2–4 cm (0.8–1.6 in) long. Leaf margins are entire. Fragrant white flowers are borne on 25–40 cm (10–16 in) long by 30 cm (12 in) wide panicles from June to August. The corolla tube

SECTION 50

#1732883985592

2964-422: The outside. Some types of wood construction include: Either used in sheet or alternatively, plate for all-metal hulls or for isolated structural members. It is strong, but heavy (despite the fact that the thickness of the hull can be less). It is generally about 30% heavier than aluminium and somewhat more heavy than polyester . The material rusts unless protected from water (this is usually done by means of

3021-473: The regulation here . Ministry of Environmental Conservation and Forestry (Myanmar) found the world's two biggest living teak trees on 28 August 2017 in Homalin Township , Sagaing Region , Myanmar . The biggest one, named Homemalynn 1, is 8.4 m (28 ft) in diameter and 34 m (112 ft) tall. The second biggest one, named Homemalynn 2, is 8.2 m (27 ft) in diameter. Previously,

3078-651: The station lines are to be set as a mark for the perpendicular line, which is marked with a T-square. The previous steps are followed in turn by marking the Top Line and the Water Line. Before continuing make sure to check the lines by using the Pythagorean theorem and make sure the grid is square. The second step is to mark the points from the table of offsets. All measurements off the table of offsets are listed in Millimeters or

3135-473: The teak is from. Old growth has much tighter rings than new growth. There is a leather-like scent in newly cut wood. Tectona grandis was first formally described by Carl Linnaeus the Younger in his 1782 work Supplementum Plantarum . In 1975, Harold Norman Moldenke published new descriptions of four forms of this species in the journal Phytologia . Moldenke described each form as varying slightly from

3192-481: The wood. Woods such as teak , totara and some cedars have natural chemicals which prevent rot whereas other woods, such as Pinus radiata , will rot very quickly. The hull of a wooden boat usually consists of planking fastened to frames and a keel. Keel and frames are traditionally made of hardwoods such as oak while planking can be oak but is more often softwood such as pine , larch or cedar . Traditional wood construction techniques can be classified into

3249-640: The world's biggest recorded teak tree was located within the Parambikulam Wildlife Sanctuary in the Palakkad District of Kerala in India, named Kannimara. The tree is approximately 47.5 metres (156 ft) tall. Its age is between 450 and 500 years and is considered one of the oldest teak trees in the world. In 2017, a tree was discovered in the Ottakallan area of the Thundathil range of

#591408