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123-516: With an area of 119 square miles (308.17 square km), the group lies north of Nias and 18 miles (29 km) west of Sumatra in the Indian Ocean . The islands have long been noted for the existence of substantial offshore coral reefs, though problems with overharvesting , damage from explosives, and recent geological disturbances have threatened these underwater resources. The islands vary in their land cover; most are sandy with limited vegetation, while

246-560: A "cheap and dirty" sharpie hull made of two 32-foot (9.8 m) planks, a couple of bulkheads and a crossplanked bottom. By lucky accident he may have been the first sailor to plane his boat. Robert Barnwell Roosevelt , uncle of American President Theodore Roosevelt , also built a proa at about the same time. He used it sailing from Long Island . It was significantly different but equally creative, and at 50 feet (15 m), much longer. From his 1898 article in The Rudder , it appeared

369-413: A 1900 issue of The Rudder included more details on the construction of his second proa. A 1948 book of sailboat plans published by The Rudder includes the following specifications for the 1900 proa: From the drawings, the distance from the center of the main hull to the center of the aka is about 12 feet (3.7 m). Western designers often feel the need to tinker with the proa. They are attracted by

492-408: A centered mast. The sail was symmetric across the yard, and to shunt, what was previously the top end of the yard was lowered and became the bottom end, reversing the direction of the sail. Proa enthusiast Gary Dierking modified this design further, using a curved yard and a boom perpendicular to the yard. This allows a greater control of the sail shape than the traditional Gibbons rig, while retaining

615-462: A global rise in sea level. Sea level also increases in the Indian Ocean, except in the south tropical Indian Ocean where it decreases, a pattern most likely caused by rising levels of greenhouse gases . Among the tropical oceans, the western Indian Ocean hosts one of the largest concentrations of phytoplankton blooms in summer, due to the strong monsoon winds. The monsoonal wind forcing leads to

738-408: A greater righting moment. Perhaps the most extreme variants of the proa are the ones designed for pure speed. These often completely discard symmetry, and are designed to sail only in one direction relative to the wind; performance in the other direction is either seriously compromised or impossible. These are "one way" proas, such as world record speed holding Yellow Pages Endeavour , or YPE . While

861-530: A key role in early human migrations and the spread of civilizations. In modern times, it remains crucial for global trade, especially in oil and hydrocarbons. Environmental and geopolitical concerns in the region include the effects of climate change , piracy, and strategic disputes over island territories. The Indian Ocean has been known by its present name since at least 1515, when the Latin form Oceanus Orientalis Indicus ( lit.   ' Indian Eastern Ocean ' )

984-406: A long, thin hull to lee, and a short, fat hull, containing the cabin, to windward. This would normally be more like an Atlantic proa, but the rig is on the lee hull, leaving it technically a Pacific design. This and other similar proas place the bulk of the passenger accommodations on the ama, in an attempt to make the vaka as streamlined as possible, and put much of the mass in the lee side to provide

1107-723: A maximum depth of 7,290 m (23,920 ft). All of the Indian Ocean is in the Eastern Hemisphere and the centre of the Eastern Hemisphere, the 90th meridian east , passes through the Ninety East Ridge . Within these waters are a number of islands. These include those controlled by surrounding countries, and independent island states and territories. Of the non-coastal islands, there are two broad clusters: one around Madagascar, and one south of India. A few other oceanic islands are scattered elsewhere. In contrast to

1230-500: A maximum speed of about 7.3 knots (13.5 km/h); Munroe's proa could reach nearly 2.5 times that speed. This accomplishment was the nautical equivalent to the X-1 breaking the sound barrier. It is not clear that traditional proas of the Pacific islanders could plane, though the long, slender hull would have a much higher speed/length ratio than other contemporary designs. Munroe was building

1353-531: A member of the Royal Mersey Yacht Club in England built a copy of a Micronesian proa. He used the traditional asymmetric hull, flat on the lee side, and a decked dugout ama (outrigger). While no quantitative record was made of its speed, it was noted that the proa would run at speeds that would bury the bows of any other vessel. It carried three times the ratio of sail area to immersed midships section than

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1476-433: A period of interest in the design by sports sailors . Working from the drawings and descriptions of explorers, western builders often took liberties with the traditional designs, merging their interpretation of native designs with Western boat building methods. Thus this Western "proa" often diverged radically from the traditional "proa" to the point that the only shared feature was the windward/leeward hull arrangement. In

1599-463: A period of six years, except for debris that gets indefinitely stuck in the centre of the gyre. The garbage patch in the Indian Ocean will, according to a 2012 study, decrease in size after several decades to vanish completely over centuries. Over several millennia, however, the global system of garbage patches will accumulate in the North Pacific. There are two amphidromes of opposite rotation in

1722-522: A proa type configuration equipped with lifting foils. In a non-traditional variant, first seen among Western yacht racers, the "Atlantic proa" has an ama which is always to the lee side to provide buoyancy for stability, rather than ballast as in a traditional proa. Because the Atlantic ama is at least as long as the main hull, to reduce wave drag, this style can also be thought of as an asymmetric catamaran that shunts rather than tacking. The first Atlantic proa

1845-787: A process of aridification began in the southwest Indian Ocean began around 4,000 years ago. Mammalian megafauna once widespread in the MPA was driven to near extinction in the early 20th century. Some species have been successfully recovered since then — the population of white rhinoceros ( Ceratotherium simum simum ) increased from less than 20 individuals in 1895 to more than 17,000 as of 2013. Other species still depend on fenced areas and management programs, including black rhinoceros ( Diceros bicornis minor ), African wild dog ( Lycaon pictus ), cheetah ( Acynonix jubatus ), elephant ( Loxodonta africana ), and lion ( Panthera leo ). This biodiversity hotspot (and namesake ecoregion and "Endemic Bird Area")

1968-478: A small book called The Canoe and the Flying Proa .) This proa was one of several either captured or seen under sail when Anson stopped at Tinian during a Pacific crossing. Brett, the draughtsman of the plan, is thought by some to have misinterpreted one key element, showing the mast fixed vertically in the center of the boat. This view as based on the fact that other Micronesian proa masts were raked end-to-end as

2091-464: A strong coastal and open ocean upwelling , which introduces nutrients into the upper zones where sufficient light is available for photosynthesis and phytoplankton production. These phytoplankton blooms support the marine ecosystem, as the base of the marine food web, and eventually the larger fish species. The Indian Ocean accounts for the second-largest share of the most economically valuable tuna catch. Its fish are of great and growing importance to

2214-403: A total cancellation of heeling forces. Inclined rigs are also well suited to the proa, as the direction of incline remains constant during shunting. Another use of foils is to provide lift, turning the boat into a hydrofoil . Hydrofoils require significant speeds to work, but once the hull is lifted out of the water, the drag is significantly reduced. Many speed sailing designs have been based on

2337-440: A vertical position. 500 Sails also found that the mast could be raked to advantage in many situations and noted that the mast step depicted in the "Anson" drawing could be interpreted as depicting a rotational point rather than a rigid mast step that would not allow raking. 500 Sails canoes employ rotational mast steps that allow mast raking. Munroe, however, was a talented boat designer who was able to work around any problems with

2460-471: Is a foil that provides a lateral resistance with zero heeling moment by placing the foil to either or both of the leeward and the windward sides, angled so the direction of the force passes through the center of effort of the sail. Since proas already have an outrigger to the windward side, a simple angled foil mounted on the ama becomes a Bruce foil, making the already stable proa even more stable. Bruce foils are often combined with inclined rigs, which results in

2583-464: Is a patchwork of small forested areas, often with a unique assemblage of species within each, located within 200 km (120 mi) from the coast and covering a total area of c. 6,200 km (2,400 sq mi). It also encompasses coastal islands, including Zanzibar and Pemba, and Mafia. This area, one of the only two hotspots that are entirely arid, includes the Ethiopian Highlands ,

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2706-894: Is artificially connected to the Mediterranean Sea without ship lock through the Suez Canal , which is accessible via the Red Sea. The Arabian Sea is connected to the Persian Gulf by the Gulf of Oman and the Strait of Hormuz . In the Persian Gulf, the Gulf of Bahrain separates Qatar from the Arabic Peninsula. Along the west coast of India, the Gulf of Kutch and Gulf of Khambat are located in Gujarat in

2829-700: Is attested, named after India, which projects into it. It was earlier known as the Eastern Ocean , a term that was still in use during the mid-18th century, as opposed to the Western Ocean ( Atlantic ) before the Pacific was surmised. In modern times, the name Afro-Asian Ocean has occasionally been used. The Hindi name for the Ocean is हिंद महासागर ( Hind Mahāsāgar ; lit. transl.  Ocean of India ). Conversely, Chinese explorers (e.g., Zheng He during

2952-412: Is called "lead." In a proa hull, and in all fore and aft symmetric foils, the center of resistance is not at or even near the center of the boat, it is well forward of the geometric center of area. Thus the center of effort of the sails needs to also be well forward, or at least needs to have a sail which is well forward which can be sheeted in to start the boat moving, allowing the rudders to bite and keep

3075-426: Is ecologically diverse, with important marine life and ecosystems like coral reefs, mangroves, and sea grass beds. It hosts a significant portion of the world's tuna catch and is home to endangered marine species. It faces challenges like overfishing and pollution , including a significant garbage patch . Historically, the Indian Ocean has been a hub of cultural and commercial exchange since ancient times. It played

3198-579: Is most famously used for the sakman ships of the Chamorro people of the Northern Marianas , which were known as the "flying proas" for their remarkable speed. In Island Southeast Asia, the term proa may also sometimes be used, but the terms perahu , prau , prahu , paraw and prow are more common. These differ from the Pacific proas in that they are not double-ended and have a trimaran configuration with two outriggers . These are widely used in

3321-464: Is projected to push the tropical Indian Ocean into a basin-wide near-permanent heatwave state by the end of the 21st century, where marine heatwaves are projected to increase from 20 days per year (during 1970–2000) to 220–250 days per year. South of the Equator (20–5°S), the Indian Ocean is gaining heat from June to October, during the austral winter, while it is losing heat from November to March, during

3444-610: Is spread throughout the main islands, but divided administratively into villages, listed below with their areas and their populations at the 2010 Census and 2020 Census, together with the official estimates as at mid 2022: The Banyak Islands lie within the Aceh Singkil Regency in Aceh Province, and are divided into two districts ( kecamatan ): Banjak Islands District ( Kecamatan Pulau Banyak ) and Western Banjak Islands District ( Kecamatan Pulau Banyak Barat ). The latter district

3567-507: Is the only ocean named after a country. It has an average depth of 3,741 m. All of the Indian Ocean is in the Eastern Hemisphere . Unlike the Atlantic and Pacific, the Indian Ocean is bordered by landmasses and an archipelago on three sides, making it more like an embayed ocean centered on the Indian Peninsula. Its coasts and shelves differ from other oceans, with distinct features, such as a narrower continental shelf . In terms of geology,

3690-539: Is tropical; August to January are the rainy season, followed by a dry season from approximately February to July. The island group had a population of 6,570 persons at the 2010 Census and 7,640 at the 2020 Census. The majority of the population resides in villages on the islands of Pulau Tuangku , Pulau Baguk and Pulau Balai . Most of the dozens of small islands in the area have no permanent homes but are used instead for gardening and leisure, with small pondoks and bungalows constructed for temporary visits. The population

3813-661: The Arabian Peninsula in the Northern Hemisphere and north of the trade winds in the Southern Hemisphere. The Indonesian Throughflow is a unique Equatorial connection to the Pacific. The climate north of the equator is affected by a monsoon climate. Strong north-east winds blow from October until April; from May until October south and west winds prevail. In the Arabian Sea, the violent Monsoon brings rain to

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3936-459: The Austronesian peoples and were the first true ocean-going ships capable of crossing vast distances of water. This enabled the Austronesian peoples to rapidly spread from Taiwan and colonize the islands of both the Pacific and Indian oceans since at least 2200 BC. The first outriggers evolved from the more primitive double-hulled catamarans . There are two types of outrigger ships based on

4059-480: The Crossbow II , owned by Timothy Colman was a proa/catamaran hybrid. Crossbow II was a "slewing" catamaran, able to slew her hulls to allow clear airflow to her leeward bipod sail. Although the hulls appeared identical, the boat had all crew and controls, cockpit etc. in her windward hull; the leeward hull was stripped bare for minimal weight. In March 2009, two new sailing speed records were set by vehicles based on

4182-550: The Dravidian -speaking peoples of Sri Lanka and Southern India as early as 1000 to 600 BC. This is still evident in the terms for "boat" in Tamil , Telugu , and Kannada ( paṭavu , paḍava , and paḍahu , respectively), which are all cognates of Proto-Western-Malayo-Polynesian *padaw. Early contact by Austronesians with Arab sailors may have also influenced the development of the lateen sail in western ship traditions, derived from

4305-560: The East African Rift valley , the Socotra islands, as well as some small islands in the Red Sea and areas on the southern Arabic Peninsula. Endemic and threatened mammals include the dibatag ( Ammodorcas clarkei ) and Speke's gazelle ( Gazella spekei ); the Somali wild ass ( Equus africanus somaliensis ) and hamadryas baboon ( Papio hamadryas ). It also contains many reptiles. In Somalia,

4428-737: The English language via Dutch prauw and Portuguese parau , similar to Spanish proa , meaning " bow ". It is likely ultimately derived from Malay perahu meaning "boat", from the Proto-Western-Malayo-Polynesian doublets *parahu and *padaw, both meaning "sailboat". Its cognates in other Austronesian languages include Javanese prau , Sundanese parahu , Kadazan padau , Maranao padaw , Cebuano paráw , Ngadha barau , Kiribati baurua , Samoan folau , Hawaiian halau , and Māori wharau . Catamarans and outrigger boats were very early innovations of

4551-608: The Malacca , Sunda and Torres Straits . The Gulf of Carpentaria is located on the Australian north coast while the Great Australian Bight constitutes a large part of its southern coast. Several features make the Indian Ocean unique. It constitutes the core of the large-scale Tropical Warm Pool which, when interacting with the atmosphere, affects the climate both regionally and globally. Asia blocks heat export and prevents

4674-534: The Marshall Islands , where the craft were traditionally built, there has been a resurgence of interest in the proa. People hold annual kor-kor races in the lagoon at Majuro , along with events such as a children's riwut race. The kor-kors are built in traditional style out of traditional materials, though the sails are made with modern materials (often inexpensive polyethylene tarpaulins , commonly known as polytarp ). A loose group of individuals from all over

4797-773: The Mascarene Basin the CDW becomes a deep western boundary current before it is met by a re-circulated branch of itself, the North Indian Deep Water. This mixed water partly flows north into the Somali Basin whilst most of it flows clockwise in the Mascarene Basin where an oscillating flow is produced by Rossby waves . Water circulation in the Indian Ocean is dominated by the Subtropical Anticyclonic Gyre,

4920-759: The Ming dynasty ) who traveled to the Indian Ocean during the 15th century called it the Western Oceans. In Ancient Greek geography , the Indian Ocean region known to the Greeks was called the Erythraean Sea . The borders of the Indian Ocean , as delineated by the International Hydrographic Organization in 1953 included the Southern Ocean but not the marginal seas along the northern rim but in 2002

5043-773: The Sea of Zanj is located north of Madagascar. On the northern coast of the Arabian Sea , Gulf of Aden is connected to the Red Sea by the strait of Bab-el-Mandeb . In the Gulf of Aden, the Gulf of Tadjoura is located in Djibouti and the Guardafui Channel separates Socotra island from the Horn of Africa. The northern end of the Red Sea terminates in the Gulf of Aqaba and Gulf of Suez . The Indian Ocean

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5166-417: The double-outrigger boats of Island Southeast Asia , and sometimes ships with no outriggers or sails at all. In its most common usage, the term proa refers to the Pacific proas which consist of two (usually) unequal-length parallel hulls . It is sailed so that one hull is kept to windward , and the other to leeward . It is double-ended, since it needs to " shunt " to reverse direction when tacking . It

5289-680: The parau . They applied the same name to similar ships in their colonies in Southeast Asia. Similarly, the Dutch encountered them when they colonized the islands of Indonesia , calling them prauw . This was rendered as "praw" by the British , later evolving to "proa". In French territories in the Pacific Islands, they were known by the more general term pirogue . Although technically restricted to outrigger sailing vessels, European sources often applied

5412-562: The runoff water to the Indian Ocean. Mainly in summer, this runoff flows into the Arabian Sea but also south across the Equator where it mixes with fresher seawater from the Indonesian Throughflow . This mixed freshwater joins the South Equatorial Current in the southern tropical Indian Ocean. Sea surface salinity is highest (more than 36  PSU ) in the Arabian Sea because evaporation exceeds precipitation there. In

5535-423: The "Hinge zone may represent the relict of continental and proto-oceanic crustal boundary formed during the rifting of India from Antarctica ." Australia, Indonesia, and India are the three countries with the longest shorelines and exclusive economic zones . The continental shelf makes up 15% of the Indian Ocean. More than two billion people live in countries bordering the Indian Ocean, compared to 1.7 billion for

5658-422: The "bow", and leeboards were used. Roosevelt's short article is accompanied by photographs showing his proa Mary & Lamb , at rest and under sail. It is not clear if the boat predated Munroe's 1898 proa. Since Munroe wasn't aware of the raking mast, his 1900 model used two daggerboards set fore and aft of the mast, which would allow adjustment of the center of lateral resistance to provide helm balance. From

5781-694: The Arabian Peninsula) and Limpopo rivers. After the breakup of East Gondwana and the formation of the Himalayas, the Ganges-Brahmaputra rivers flow into the world's largest delta known as the Bengal delta or Sunderbans . Marginal seas , gulfs, bays and straits of the Indian Ocean include: Along the east coast of Africa, the Mozambique Channel separates Madagascar from mainland Africa, while

5904-529: The Atlantic and 2.7 billion for the Pacific (some countries border more than one ocean). The Indian Ocean drainage basin covers 21,100,000 km (8,100,000 sq mi), virtually identical to that of the Pacific Ocean and half that of the Atlantic basin, or 30% of its ocean surface (compared to 15% for the Pacific). The Indian Ocean drainage basin is divided into roughly 800 individual basins, half that of

6027-482: The Atlantic and Pacific, the Indian Ocean is enclosed by major landmasses and an archipelago on three sides and does not stretch from pole to pole, and can be likened to an embayed ocean. It is centered on the Indian Peninsula. Although this subcontinent has played a significant role in its history, the Indian Ocean has foremostly been a cosmopolitan stage, interlinking diverse regions by innovations, trade, and religion since early in human history. The active margins of

6150-569: The Comoros. Although both species represent an order of lobe-finned fishes known from the Early Devonian (410 mya ) and though extinct 66 mya, they are morphologically distinct from their Devonian ancestors. Over millions of years, coelacanths evolved to inhabit different environments — lungs adapted for shallow, brackish waters evolved into gills adapted for deep marine waters. Of Earth's 36 biodiversity hotspots nine (or 25%) are located on

6273-472: The East India Coastal Current to the Arabian Sea from January to April. An Indian Ocean garbage patch was discovered in 2010 covering at least 5 million square kilometres (1.9 million square miles). Riding the southern Indian Ocean Gyre , this vortex of plastic garbage constantly circulates the ocean from Australia to Africa, down the Mozambique Channel , and back to Australia in

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6396-669: The IHO delimited the Southern Ocean separately, which removed waters south of 60°s from the Indian Ocean but included the northern marginal seas. Meridionally , the Indian Ocean is delimited from the Atlantic Ocean by the 20° east meridian , running south from Cape Agulhas , South Africa, and from the Pacific Ocean by the meridian of 146°49'E, running south from South East Cape on the island of Tasmania in Australia. The northernmost extent of

6519-447: The Indian Ocean (including marginal seas) is approximately 30° north in the Persian Gulf . The Indian Ocean covers 70,560,000 km (27,240,000 sq mi), including the Red Sea and the Persian Gulf but excluding the Southern Ocean, or 19.5% of the world's oceans; its volume is 264,000,000 km (63,000,000 cu mi) or 19.8% of the world's oceans' volume; it has an average depth of 3,741 m (12,274 ft) and

6642-405: The Indian Ocean have an average width (horizontal distance from land to shelf break ) of 19 ± 0.61 km (11.81 ± 0.38 mi) with a maximum width of 175 km (109 mi). The passive margins have an average width of 47.6 ± 0.8 km (29.58 ± 0.50 mi). The average width of the slopes (horizontal distance from shelf break to foot of slope) of

6765-505: The Indian Ocean includes beaches and intertidal zones covering 3,000 km (1,200 sq mi) and 246 larger estuaries . Upwelling areas are small but important. The hypersaline salterns in India covers between 5,000–10,000 km (1,900–3,900 sq mi) and species adapted for this environment, such as Artemia salina and Dunaliella salina , are important to bird life. Coral reefs, sea grass beds, and mangrove forests are

6888-532: The Indian Ocean is the youngest of the major oceans, with active spreading ridges and features like seamounts and ridges formed by hotspots . The climate of the Indian Ocean is characterized by monsoons . It is the warmest ocean, with a significant impact on global climate due to its interaction with the atmosphere. Its waters are affected by the Indian Ocean Walker circulation , resulting in unique oceanic currents and upwelling patterns. The Indian Ocean

7011-476: The Indian Ocean region, or almost half of the world's mangrove habitat, of which 42,500 km (16,400 sq mi) is located in Indonesia, or 50% of mangroves in the Indian Ocean. Mangroves originated in the Indian Ocean region and have adapted to a wide range of its habitats but it is also where it suffers its biggest loss of habitat. In 2016, six new animal species were identified at hydrothermal vents in

7134-723: The Indian Ocean, during the past six decades. The tuna catch rates have also declined 50–90% during the past half-century, mostly due to increased industrial fisheries, with the ocean warming adding further stress to the fish species. Endangered and vulnerable marine mammals and turtles: 80% of the Indian Ocean is open ocean and includes nine large marine ecosystems : the Agulhas Current , Somali Coastal Current , Red Sea , Arabian Sea , Bay of Bengal , Gulf of Thailand , West Central Australian Shelf , Northwest Australian Shelf and Southwest Australian Shelf . Coral reefs cover c. 200,000 km (77,000 sq mi). The coasts of

7257-432: The Indian Ocean, probably caused by Rossby wave propagation. Icebergs drift as far north as 55° south latitude , similar to the Pacific but less than in the Atlantic where icebergs reach up to 45°S. The volume of iceberg loss in the Indian Ocean between 2004 and 2012 was 24  Gt . Since the 1960s, anthropogenic warming of the global ocean combined with contributions of freshwater from retreating land ice causes

7380-461: The Indian Ocean. While the Indian Ocean warmed at a rate of 1.2°C per century during 1950–2020, climate models predict accelerated warming, at a rate of 1.7 °C–3.8 °C per century during 2020–2100. Though the warming is basin-wide, maximum warming is in the northwestern Indian Ocean including the Arabian Sea, and reduced warming off the Sumatra and Java coasts in the southeast Indian Ocean. Global warming

7503-495: The Indian subcontinent. In the southern hemisphere, the winds are generally milder, but summer storms near Mauritius can be severe. When the monsoon winds change, cyclones sometimes strike the shores of the Arabian Sea and the Bay of Bengal . Some 80% of the total annual rainfall in India occurs during summer and the region is so dependent on this rainfall that many civilisations perished when

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7626-522: The Monsoon failed in the past. The huge variability in the Indian Summer Monsoon has also occurred pre-historically, with a strong, wet phase 33,500–32,500 BP; a weak, dry phase 26,000–23,500 BC; and a very weak phase 17,000–15,000 BP, corresponding to a series of dramatic global events: Bølling–Allerød warming , Heinrich , and Younger Dryas . The Indian Ocean is the warmest ocean in

7749-399: The Pacific, of which 50% are located in Asia, 30% in Africa, and 20% in Australasia. The rivers of the Indian Ocean are shorter on average (740 km (460 mi)) than those of the other major oceans. The largest rivers are ( order 5 ) the Zambezi , Ganges - Brahmaputra , Indus , Jubba , and Murray rivers and (order 4) the Shatt al-Arab , Wadi Ad Dawasir (a dried-out river system on

7872-441: The Southeast Arabian Sea salinity drops to less than 34 PSU. It is the lowest (c. 33 PSU) in the Bay of Bengal because of river runoff and precipitation. The Indonesian Throughflow and precipitation results in lower salinity (34 PSU) along the Sumatran west coast. Monsoonal variation results in eastward transportation of saltier water from the Arabian Sea to the Bay of Bengal from June to September and in westerly transport by

7995-411: The Southwest Indian Ridge, from where it continues into the Mozambique Channel and Prince Edward Fracture Zone . North of 20° south latitude the minimum surface temperature is 22 °C (72 °F), exceeding 28 °C (82 °F) to the east. Southward of 40° south latitude , temperatures drop quickly. The Bay of Bengal contributes more than half (2,950 km or 710 cu mi) of

8118-399: The Southwest Indian Ridge: a "Hoff" crab, a "giant peltospirid" snail, a whelk-like snail, a limpet, a scaleworm and a polychaete worm. The West Indian Ocean coelacanth was discovered in the Indian Ocean off South Africa in the 1930s and in the late 1990s another species, the Indonesian coelacanth , was discovered off Sulawesi Island , Indonesia. Most extant coelacanths have been found in

8241-420: The YPE is often called a trimaran, it would be more correct to call it a Pacific proa, because two of the planing/hydrofoil hulls are in line. This design has been considered by others as well, such as the Monomaran designs by "The 40 knot Sailboat" author Bernard Smith, and these designs been called 3-point proas by some, a reference to the 3 point hulls used in hydroplanes . A previous record holding design,

8364-428: The absolute speed record on water, currently held by l'Hydroptère . Conditions during the record-setting run were less than ideal for the Maquarie Innovation, which is anticipated to have a top speed of 58 knots (107 km/h) – 58 knots (67 mph). On March 27, 2009, Richard Jenkins set a world wind-powered speed record, on land, of 126.1 miles per hour (202.9 km/h) in the Ecotricity Greenbird . This broke

8487-416: The ama to allow the righting moment to be significantly increased if needed. While Brown's proa was designed to be a cruising yacht, not a speed-sailing boat, the newer 36-foot (11 m) Jzerro is capable of speeds of up to 21 knots (39 km/h). One of the issues Western designers have with the proa is the need to manipulate the sail when shunting. Even Munroe's early sails discarded the curved yards of

8610-442: The austral summer. In 1999, the Indian Ocean Experiment showed that fossil fuel and biomass burning in South and Southeast Asia caused air pollution (also known as the Asian brown cloud ) that reach as far as the Intertropical Convergence Zone . This pollution has implications on both a local and global scale. Forty percent of the sediment of the Indian Ocean is found in the Indus and Ganges fans. The oceanic basins adjacent to

8733-422: The better waves being witnessed at Bangkaru due to the larger fetch . Another major sector of the local economy is fishing , which is based on individual small boats, particularly the multi-hulled proa . The islands support limited farming, though this is insufficient to supply the needs of islanders, and a significant quantity of fresh food is brought in from Singkil. Infrastructure projects have worked to restore

8856-431: The boat from heading up when the entire sail area is sheeted in. Jzero, for example, and all of Russell Brown's other designs, use a sloop rig and hoist a jib on whichever end is the current "bow". Other designs use a schooner rig for the same effect. One of the more practical rigs for small proas was invented by Euell Gibbons around 1950 for a small, single handed proa. This rig was a loose footed lateen sail hung from

8979-400: The bordering countries for domestic consumption and export. Fishing fleets from Russia, Japan, South Korea , and Taiwan also exploit the Indian Ocean, mainly for shrimp and tuna. Research indicates that increasing ocean temperatures are taking a toll on the marine ecosystem. A study on the phytoplankton changes in the Indian Ocean indicates a decline of up to 20% in the marine plankton in

9102-686: The centre of the 1,500,000 km (580,000 sq mi) hotspot, the landscape is dominated by Acacia - Commiphora deciduous bushland, but also includes the Yeheb nut ( Cordeauxia edulus ) and species discovered more recently such as the Somali cyclamen ( Cyclamen somalense ), the only cyclamen outside the Mediterranean. Warsangli linnet ( Carduelis johannis ) is an endemic bird found only in northern Somalia. An unstable political situation and mismanagement has resulted in overgrazing which has produced one of

9225-496: The continental shelves are 50.4–52.4 km (31.3–32.6 mi) for active and passive margins respectively, with a maximum width of 205.3–255.2 km (127.6–158.6 mi). In correspondence of the Shelf break , also known as Hinge zone, the Bouguer gravity ranges from 0 to 30 mGals that is unusual for a continental region of around 16 km thick sediments. It has been hypothesized that

9348-541: The continental slopes mostly contain terrigenous sediments. The ocean south of the polar front (roughly 50° south latitude ) is high in biologic productivity and dominated by non-stratified sediment composed mostly of siliceous oozes . Near the three major mid-ocean ridges the ocean floor is relatively young and therefore bare of sediment, except for the Southwest Indian Ridge due to its ultra-slow spreading rate. The ocean's currents are mainly controlled by

9471-411: The designs of Russell Brown, a boat-fittings maker who designed and built his first proa, Jzero , in the mid-1970s. He has created a number of proa designs, all of which follow the same theme. One of the design elements which Brown used, and a number of other designers have copied, is the lee pod . The akas extend past the main hull and out to the lee side, and provide support for a cabin extending to

9594-401: The drawings, it appears the mast is higher as well, allowing a larger sail. The sail design also changed, with the upper spar now being slightly longer than the upper edge of the sail, and projecting past the apex slightly to allow the apex to be attached to the hull. The sail was loose footed, with the boom attached to the upper spar near the sail apex, and to the clew of the sail. His article in

9717-402: The drawings. His adaptations can be seen in successive proas. Rather than the deep, asymmetric hull of a traditional proa, Munroe created flat-bottomed hulls (similar to the fisolera referred to by Pigafetta), with keels or centerboards for lateral resistance. His first iteration had an iron center fin with a half-oval profile. Rather than the traditional crab-claw sail's spars which meet at

9840-578: The east. To the south it is bounded by the Southern Ocean , or Antarctica , depending on the definition in use. The Indian Ocean has large marginal, or regional seas, such as the Andaman Sea , the Arabian Sea , the Bay of Bengal , and the Laccadive Sea . Once called the Eastern Ocean, it is now named after India , which protrudes into it, and has been known by its current name since at least 1515. It

9963-667: The eastern extension of which is blocked by the Southeast Indian Ridge and the 90°E Ridge. Madagascar and the Southwest Indian Ridge separate three cells south of Madagascar and off South Africa. North Atlantic Deep Water reaches into the Indian Ocean south of Africa at a depth of 2,000–3,000 m (6,600–9,800 ft) and flows north along the eastern continental slope of Africa. Deeper than NADW, Antarctic Bottom Water flows from Enderby Basin to Agulhas Basin across deep channels (<4,000 m (13,000 ft)) in

10086-525: The fastest yachts in the club and yet drew only 15 inches (38 cm). Since Munroe had no direct experience with proas, all he had to work with was the widely distributed and incorrect plan drawing from about 1742, made during Admiral Lord Anson's circumnavigation of the globe. This drawing had been circulated in the press, for example in William Alden's articles in Harper's Magazine . (These were reprinted in

10209-755: The first to describe the Chamorro proas as "flying." The subsequent colonization of the Micronesia and the Philippines provided further references to proas in Spanish records. They also described double-outrigger ships from the Philippines , like the account of the karakoa in Francisco Ignacio Alcina 's Historia de las islas e indios de Bisayas (1668) which describes them as "sailing like birds." During his 1740–1744 circumnavigation , Lord Anson applied

10332-399: The front, Munroe's sails used what could be described as a triangular lug sail or spritsail with a boom, similar to the modern lateen sail with a shorter upper spar. Munroe's first proa was only 30 feet (9.1 m) long, yet was capable of speeds which Munroe estimated at 18 knots (33 km/h). His article in The Rudder describes what can only be planing on the flat hull. As this

10455-536: The harbors and piers of the islands that were damaged in the 2005 tsunami events The island of Bangkaru is a protected area, designated by the Governor of Aceh in 1996 as a "Taman Wisata Alam" (Nature Park). This designation limits fishing and other use of resources around the island, with limited use for research, tourism, and cultural activities. Beaches on Bangkaru are significant turtle rookeries, where green, leatherback, and other sea turtles come to nest and lay eggs. In

10578-557: The island group died as a result of the tsunami. Occurring just three months later, the 2005 Nias–Simeulue earthquake was located slightly east of Bangkaru, which was the closest island to the epicenter. The island was hit by a second tsunami that caused additional flooding and damage to structures. The level of the islands also dropped by as much as a meter in places, plunging coastal areas underwater and making them permanently uninhabitable. There were no reported deaths, but over 3,000 people were reportedly displaced from their homes. Due to

10701-580: The islands of the Indian Ocean are textbook cases of evolutionary processes; the dung beetles , day geckos , and lemurs are all examples of adaptive radiation . Many bones (250 bones per square metre) of recently extinct vertebrates have been found in the Mare aux Songes swamp in Mauritius, including bones of the Dodo bird ( Raphus cucullatus ) and Cylindraspis giant tortoise. An analysis of these remains suggests

10824-449: The larger islands have deep rainforests and are fringed by intertidal mangroves. The Pulau Banyak area contains many varieties of stony Heliopora and branching Acropora types of coral. However, crown-of-thorns starfish are a significant problem. The fringing coral reefs are habitat to diverse species, including green and leatherback sea turtles, pelagic and coral fish, and varieties of octopus, lobster, and other sea life. The weather

10947-490: The lee of the main hull. This is similar to the platform extending to the lee on some Micronesian proas. The lee pod serves two purposes—it can be used for bunk space or storage, and it provides additional buoyancy on the lee side to prevent a capsize should the boat heel too far. Crew can also be moved onto the lee pod to provide additional heeling force in light winds, allowing the ama to lift under circumstances when it would not otherwise. The Jzero also used water ballast in

11070-399: The main hull of Roosevelt's proa was an open 4-foot (1.2 m) wide scow hull; the ama was a smaller, fully decked scow which looked like it could rock on a single aka (supporting beam). The mast was a bipod arrangement with both masts stepped to windward, with a boomed, balanced lugsail suspended from the apex. A balanced rudder at each end managed itself by pivoting 180° when its end was

11193-481: The margins of the Indian Ocean. The origin of this diversity is debated; the break-up of Gondwana can explain vicariance older than 100 mya, but the diversity on the younger, smaller islands must have required a Cenozoic dispersal from the rims of the Indian Ocean to the islands. A "reverse colonisation", from islands to continents, apparently occurred more recently; the chameleons , for example, first diversified on Madagascar and then colonised Africa. Several species on

11316-475: The mid-1930s, when a severe hurricane leveled Munroe's bayside boatshop. At least two of his designs were documented in articles in The Rudder , as was one by Robert B. Roosevelt. Small proas may have been brought back to the United States in the late 19th century, but documentation is sparse. Munroe and Roosevelt appeared to be the first two builders to adapt the proa to Western building techniques. In 1860

11439-485: The minimalist nature and amazing speeds that proas are capable of (they may still be the fastest sailboats per dollar spent for the home builder) but they often want the proa to do more; adding cabins, different sailing rigs, and bidirectional rudders are common changes made. James Wharram was greatly influenced by the Proa design. For example, unconventional boat and yacht designer Phil Bolger drew at least three proa designs;

11562-400: The monsoon. Two large gyres , one in the northern hemisphere flowing clockwise and one south of the equator moving anticlockwise (including the Agulhas Current and Agulhas Return Current ), constitute the dominant flow pattern. During the winter monsoon (November–February), however, circulation is reversed north of 30°S and winds are weakened during winter and the transitional periods between

11685-602: The monsoons. The Indian Ocean contains the largest submarine fans of the world, the Bengal Fan and Indus Fan , and the largest areas of slope terraces and rift valleys . The inflow of deep water into the Indian Ocean is 11  Sv , most of which comes from the Circumpolar Deep Water (CDW). The CDW enters the Indian Ocean through the Crozet and Madagascar basins and crosses the Southwest Indian Ridge at 30°S. In

11808-461: The more ancient Austronesian crab claw sail . Many of these traditional vessels are now extinct. Either lost during the colonial period or supplanted in modern times by western boat designs or fitted with motor engines. The Portuguese were the first Europeans to encounter the double-outrigger Southeast Asian ships, initially with derivative vessels from the Malabar Coast , which they called

11931-503: The most degraded hotspots where only c. 5 % of the original habitat remains. Proa Proas are various types of multi-hull outrigger sailboats of the Austronesian peoples . The terms were used for native Austronesian ships in European records during the Colonial era indiscriminately, and thus can confusingly refer to the double-ended single-outrigger boats of Oceania ,

12054-535: The most productive ecosystems of the Indian Ocean ;— coastal areas produce 20 tones of fish per square kilometre. These areas, however, are also being urbanised with populations often exceeding several thousand people per square kilometre and fishing techniques become more effective and often destructive beyond sustainable levels while the increase in sea surface temperature spreads coral bleaching. Mangroves covers 80,984 km (31,268 sq mi) in

12177-527: The native ships of Indonesia , Malaysia , and the Philippines , and continue to be used today as traditional fishing, cargo, and transport vessels. Proas are traditionally rigged with the crab claw and tanja sails . The modern proa exists in a wide variety of forms, from the traditional archetype still common in areas described, to high-technology interpretations specifically designed for breaking speed-sailing records. The term "proa" originates from Early Modern English "prow" or "praw". It probably entered

12300-617: The northern end while the Laccadive Sea separates the Maldives from the southern tip of India. The Bay of Bengal is off the east coast of India. The Gulf of Mannar and the Palk Strait separate Sri Lanka from India, while Adam's Bridge separates the two. The Andaman Sea is located between the Bay of Bengal and the Andaman Islands. In Indonesia, the so-called Indonesian Seaway is composed of

12423-702: The number of outriggers : the single-outriggers (which include catamarans with unequal hulls) and the double-outriggers (sometimes called trimarans ). Single-outriggers evolved first and are the dominant form of Austronesians ships in Oceania and Madagascar . They have largely been replaced by the more versatile double-outrigger ships in Island Southeast Asia . Double-outrigger forms, however, are absent entirely in Oceania. Catamaran and outrigger technologies were introduced by Austronesian traders from Southeast Asia to

12546-468: The outrigger layout of the sakman , and ability to switch bow for stern, and also notes its speed and maneuverability, noting, "And although the ships were under full sail, they passed between them and the small boats (fastened astern), very adroitly in those small boats of theirs." Pigafetta likened the sakman to the Venetian fisolere , a narrow variety of gondola . The accounts of Magellan's crew were

12669-498: The past, local people have collected turtle eggs for consumption and sale, and turtles have also been caught by poachers from Sibolga , but this practice is now illegal within the protected area. Turtles are also sometimes hunted for the lucrative export market in turtle meat. Other species in danger from overharvesting include the giant clam and the dugong . Environmental hazards created by climate change, ocean acidification, overfishing and unsustainable practices remain concerns for

12792-486: The proa concept, one on land, and one on the water. On March 26, 2009, Simon McKeon and Tim Daddo set a new C-class speed sailing record of 50.08 knots (92.75 km/h) over 500 meters in the Macquarie Innovation, successor to their previous record holding Yellow Pages Endeavour , with a peak speed of 54 knots (100 km/h). The record was set in winds of 22 to 24 knots (44 km/h), and came close to taking

12915-658: The proa was built in 1898 by Commodore Ralph Middleton Munroe of the Biscayne Bay Yacht Club. Yacht-design giant Nathanael Herreshoff , a friend of Munroe, may have also had an interest in the project. A small model of the Anson-Brett proa is collected at the Herreshoff Marine Museum in Rhode Island ; its maker is uncertain. Over the following years, Munroe built several more. They were all destroyed by

13038-410: The region. 2°10′N 97°15′E  /  2.167°N 97.250°E  / 2.167; 97.250 Indian Ocean The Indian Ocean is the third-largest of the world's five oceanic divisions, covering 70,560,000 km (27,240,000 sq mi) or approximately 20% of the water area of Earth's surface . It is bounded by Asia to the north, Africa to the west and Australia to

13161-474: The simple shunting method, and is often referred to as the Gibbons/Dierking rig . While a proa is fairly efficient at minimizing the amount of wave drag and maximizing stability, there is at least one way to go even further. The use of underwater foils to provide lift or downforce has been a popular idea recently in cutting-edge yacht building, and the proa is not immune to this influence. The Bruce foil

13284-401: The smallest one (20 ft) has been built by several people while the larger two, including his Proa 60, have not been built. For additional examples, see here . The terms ama and aka have been adopted for the modern trimaran . Since trimarans are generally designed to sail with one ama out of the water, they are similar to an Atlantic proa, with the buoyant leeward ama providing the bulk of

13407-531: The speed blowing to leeward. In the late 19th century and early 20th century, many in Europe and America became interested in the proa. Western boat builders such as R. M. Munroe and Robert Barnwell Roosevelt ( Theodore Roosevelt 's uncle) reflected its influence. Into the 20th century, the proa was one of the fastest sailing craft that existed. The proa design is still the basis for many boats involved in speed sailing . The first well-documented Western version of

13530-443: The split between Tuangku and Bangkaru, the earthquake caused Bangkaru to rise and Tuangku to drop. Wells became contaminated by saltwater following the meter-high surge that hit the villages, and the tsunami flowed 100–200 meters into the dense jungle. Fresh sand carried by the tsunami adhered on the seaward side of tree trunks as high as one meter above ground level. The area is popular among tourists on surfing holidays with some of

13653-401: The stability for the long, relatively thin main hull. Some modern proa designers have borrowed trimaran design elements for use in proas. Trimarans often have main hulls that are very narrow at the waterline, and flare out and extend over a significant portion of the akas. This topheavy design is only practical in a multihull, and it has been adapted by some proa designers. Notable examples are

13776-464: The term indiscriminately to any native ships of Southeast Asia. The earliest written accounts of the single-outrigger Pacific proa (though not by name) were by the Venetian scholar Antonio Pigafetta , who was part of Ferdinand Magellan 's 1519–1522 circumnavigation. They encountered the native sakman ships of the Chamorro people in the Islas de los Ladrones ( Mariana Islands ). Pigafetta describes

13899-479: The term proa to the double-ended Micronesian single-outrigger ships. His fleet captured one in 1742, and Lt. Peircy Brett of HMS  Centurion made a detailed sketch of the proa. Rev. Richard Walter, chaplain of HMS Centurion , estimated the speed of the proa at twenty miles per hour (32 km/h). Although aware of earlier Spanish accounts of the boats of the Spanish East Indies , Anson's account

14022-426: The traditional crabclaw for the more familiar straight yards of the lateen and lug sails. Munroe's designs likely lacked the tilting mast because he was unaware of it, but many designers since have used a fixed mast, and provided some other way of adjusting the center of effort. Most sailboats are designed with the center of effort of the sails slightly ahead of the center of area of the underwater plane; this difference

14145-517: The ventilation of the Indian Ocean thermocline . That continent also drives the Indian Ocean monsoon , the strongest on Earth, which causes large-scale seasonal variations in ocean currents, including the reversal of the Somali Current and Indian Monsoon Current . Because of the Indian Ocean Walker circulation there are no continuous equatorial easterlies. Upwelling occurs near the Horn of Africa and

14268-465: The vessel shunted and the fact that a raked mast shifts the center of effort of the sail which would influence helm balance. However, Brett's placing of the mast in a vertical position has found to be accurate when replicas of the "Anson" proa were built and sailed by the Marinas-based organization 500 Sails that found that in many points of sail under many conditions the proa sailed well with the mast in

14391-498: The world has formed from those interested in the proa, including people with a historical perspective and those with a scientific and engineering perspective. Many such individuals are members of the Amateur Yacht Research Society . Sailing is no name for it – flying is better. Out into the bay she skipped, boys yelling with delight on the uplifted outrigger, spray from the lee bow and steering oar riven into vapor by

14514-478: The world. Long-term ocean temperature records show a rapid, continuous warming in the Indian Ocean, at about 1.2 °C (34.2 °F) (compared to 0.7 °C (33.3 °F) for the warm pool region) during 1901–2012. Research indicates that human induced greenhouse warming , and changes in the frequency and magnitude of El Niño (or the Indian Ocean Dipole ), events are a trigger to this strong warming in

14637-493: Was before the advent of planing power boats, this proa was one of the first boats capable of planing. This helped produce its amazing speed when most boats were limited to their hull speed —they had too little power to achieve planing speed, and yet were not designed to exceed hull speed without planing. For example, a 30-foot (9.1 m) boat with too little power to plane, and with a hull form and displacement that didn't permit it to exceed hull speed without planing, would have

14760-1037: Was separated from the former district subsequent to the 2010 Census. Pulau Balai is the seat of the Pulau Banyak District, whose present area had 3,916 inhabitants at the 2010 Census and 4,562 at the 2020 Census, and Haloban is the seat of the Pulau Banyak Barat District, whose present area had 2,654 inhabitants at the 2010 Census and 3,078 at the 2020 Census. The inhabitants of Pulau Banyak consist of 3 ethnicities namely Aneuk Jamee (in Pulau Balai, Pulau Baguk and Teluk Nibung), Haloban (in Haloban and Asantola village) and Nias (in Ujung Sialit and Suka Makmur village). Nias people in Ujung Sialit are Christians while in Suka Makmur they are Muslims. The island group

14883-606: Was significantly affected by the deadly 2004 Indian Ocean earthquake and subsequent tsunami. The quake's epicenter was located only a few hundred kilometres north of the island group. Along with Simeulue and Nias, the Banyak Islands absorbed the shock waves and shielded a lot of damage from the Mentawai Islands . The eastern islands were affected the most due to the poor construction of buildings, as many structures contained timber instead of concrete. As many as 300 residents of

15006-476: Was the Cheers , designed in 1968 by boat designer Dick Newick for the 1968 OSTAR solo transatlantic race, in which it placed third. Newkirk's designs are primarily trimarans, and the Atlantic proa's buoyant outrigger follows naturally from a conversion of a trimaran from a tacking to a shunting vessel. Other proa designers blur the lines between Atlantic and Pacific style proas. The Harryproa from Australia uses

15129-559: Was the first detailed description of a Pacific proa to the English-speaking world. In the subsequent voyages of James Cook in Polynesia , he referred to the similar native single-outrigger canoes there as "proes", differentiating them from the double-hulled catamarans which he called "pahee" (Tahitian pahi ). These accounts fascinated both the British and American public, ushering in

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