Ballast is weight placed low in ships to lower their centre of gravity , which increases stability (more technically, to provide a righting moment to resist any heeling moment on the hull ). Insufficiently ballasted boats tend to tip or heel excessively in high winds. Too much heel may result in the vessel filling with water and/or capsizing . If a sailing vessel needs to voyage without cargo, then ballast of little or no value will be loaded to keep the vessel upright. Some or all of this ballast will then be discarded when cargo is loaded.
29-579: Rozelle Bay is a bay located to the south of Glebe Island and the west of Blackwattle Bay , on Sydney Harbour . The naming of the bay is derived from either the Rosella bird or the Rosella plant , with the latter being more likely, due to the other names in the area that have botanic origins. A light rail station on the Dulwich Hill Line is named after the bay. Rozelle Bay is fed by Johnstons Creek and Whites Creek . The dockyard of
58-464: A causeway was laid in the 1840s. Surveyor William Wells created a subdivision for the Balmain end of the island in 1841, with four intended streets and six sections containing a total of 86 lots. The subdivision did not eventuate. In 1850–1854, Colonial Architect Edmund Blacket designed stone buildings for a public abattoir on the island. According to Joan Kerr , Blacket's chosen architecture
87-439: A bulb of ballast on a long, thin keel that can tilt from side to side to create a canting keel . This lets the ballast be placed on the windward side, providing a far greater righting moment with a lower angle of heel. Tilting the keel, however, greatly reduces its lift, so canting keels are usually combined with a retractable centerboard or daggerboard that is deployed when the keel is tilted, and retracted (to reduce drag) when
116-399: A bulk cement terminal. These are now heritage-listed. In the 1990s a high-level, cable-stayed, reinforced concrete six-lane bridge spanning 345 metres between two 120-metre towers was built above the older Allan-designed Glebe Island Bridge. The new bridge opened on 3 December 1995, and was also named Glebe Island Bridge. It was renamed Anzac Bridge in 1998. Until November 2008, the island was
145-548: A capacity of 7,500,000 bushels (202,500 tonnes ). During World War II much of the island was commandeered for the main United States Army depot in Sydney. Bulk handling of grain continued until 1990 when the wheat terminal was transferred to Port Kembla and the wharfage remodelled for containerised cargo. Some silos were demolished, while from 1991 Australian Cement (now Cement Australia) used 16 of them as
174-546: A cargo vessel (such as a tanker, bulk carrier or container ship) wishes to travel empty or partially empty to collect a cargo, it must travel "in ballast". This keeps the vessel in trim and keeps the propeller and rudder submerged. Typically, being "in ballast" will mean flooding ballast tanks with sea water. Serious problems may arise when ballast water is discharged, as water-borne organisms can create havoc when deposited in new environments. Ballast takes many forms. The simplest form of ballast used in small day sailers
203-404: Is so-called "live ballast", or the weight of the crew. By sitting on the windward side of the hull , the heeling moment must lift the weight of the crew. On more advanced racing boats, a wire harness called a trapeze is used to allow the crew to hang completely over the side of the hull without falling out; this provides much larger amounts of righting moment due to the larger leverage of
232-779: The Sydney Harbour Bridge in order to reach the facility. On New Year's Eve 2011–12, the large empty space, conveniently located with a good view of the Sydney Harbour Bridge fireworks, was used for a major televised concert with headliners Jamiroquai , Culture Club and Pet Shop Boys . The old Glebe Island Bridge was included on the heritage list in 2013, lending more weight to calls for its retention as an active transport link. In August 2013, construction began on an interim exhibition facility Sydney Exhibition Centre @ Glebe Island , which opened on 15 February 2014. The venue offered 20,000 square metres of space for large trade and consumer exhibitions and operated throughout
261-543: The Sydney Heritage Fleet is located on the western shore of Rozelle Bay. This article related to the geography of Sydney is a stub . You can help Misplaced Pages by expanding it . Glebe Island Glebe Island was a major port facility in Sydney Harbour and, in association with the adjacent White Bay facility, was the primary receiving venue for imported cars and dry bulk goods in
290-431: The leeward ballast tank and fill the windward tank as the boat tacks, and the quantity of ballast can be varied to keep the boat at the optimum angle of heel. A disadvantage of water ballast is that water is not very dense and therefore the tanks required take up more space than other forms of ballast. Some manufacturers offer flexible ballast bags that are mounted outboard of the hull on both sides, and pumps that use
319-667: The Australian Amalgamated Terminals (AAT) facility for imported motor vehicles. Discussions for rejuvenation of the now disused site are ongoing. In 2008 it was suggested by the Government of New South Wales that a tennis centre could be created to host the Australian Open tournament after Melbourne 's existing contract expired in 2016. This plan was short-lived and in 2009 it was announced that White Bay Cruise Terminal would be renovated at
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#1732800908459348-543: The NSW Department of Public Works, opened. Like the ground-breaking Pyrmont Bridge being built at the same time, the second Glebe Island Bridge was a swing bridge swivelling on a massive central stone pivot-pier with timber-trussed side spans. The two bridges "are among the structures standing as monuments" to Allan's skill. Under the Local Government Act 1906 , the 14-hectare (34-acre) Glebe Island
377-424: The ballast needs to be as low as possible, it is often placed into a centerboard or retracting keel, requiring a heavy-duty mechanism to lift the massive foil . The simplest solution is to use a fixed ballasted keel, but that makes the boat nearly incapable of sailing in very shallow water, and more difficult to handle when out of the water. While prohibited by most class racing rules, some cutting-edge boats use
406-406: The boat's speed through the water for power. When under way, the pump can be used to fill the windward side, while the lee side is allowed to drain. This system, while not very attractive, does allow significant gains in righting force with no modifications to the hull. A trick commonly used on boats with water ballast is to link port and starboard tanks with a valved pipe. When preparing to tack,
435-452: The centre of gravity. It is the relationship between centre of gravity and centre of buoyancy that dictates the righting moment. The advantage of water ballast is that the tanks can be emptied, reducing draft or the weight of the boat (e.g. for transport on ground) and water added back in (in small boats, simply by opening up the valves and letting the water flow in) after the boat is launched or cargo unloaded. Pumps can also be used to empty
464-408: The crew's weight, but can be dangerous if the wind suddenly dies, as the sudden loss of heeling moment can dump the crew in the water. On larger modern vessels, the keel is made of or filled with a high density material, such as concrete , iron , or lead . By placing the weight as low as possible (often in a large bulb at the bottom of the keel) the maximum righting moment can be extracted from
493-417: The given mass. Traditional forms of ballast carried inside the hull were stones or sand. There are disadvantages to using high-density ballast. The first is the increased mass of the boat; a heavier boat sits lower in the water, increasing drag when it moves, and is generally less responsive to steering. A heavier boat is also more difficult to put on a trailer and tow behind an automobile. Secondly, since
522-452: The hull (which is, after all, close to the same density as the water outside the hull – fresh vs salt water) would add any stability, the water serves to displace air from the bottom of the hull; adding water ballast below the vertical center of gravity increases stability. The water ballast does not need to be lifted above the waterline to affect stability, as any material having greater bulk density than air will have an effect on
551-445: The island to Pyrmont, and thus to the city, in 1862. The abattoirs featured prominently in the 1882 Royal Commission into noxious and offensive trades, instigated by complaints from Balmain and Glebe Point residents. The commission found that in 1882, 524,415 sheep, 69,991 cattle, 31,269 pigs and 8,348 calves were slaughtered there. On 28 June 1903 the new bridge to Pyrmont, designed by Percy Allan , Assistant Engineer for Bridges in
580-506: The island to make it suitable for wharves. Saunders's firm dumped a great quantity of excavated ballast at the eastern end of the island for wharfage. Many cubic feet of quality dimension stone , however, were carefully cut away and almost certainly used for construction projects. Some 250 of Saunders's men were still working on the island in 1920. Glebe Island was an early success for the Harbour trust. Wharves were built on three sides of
609-455: The keel is returned to the vertical. Some canting keels are designed so that when fully extended to either side they have an angle of attack of about 5° allowing the hydrofoil effect of the blade to lift the boat up and reduce wetted surface area for an increase in boat speed. A common type of ballast for small boats that avoids many of the problems of high-density ballast is water ballast. While it may seem counter-intuitive that placing water in
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#1732800908459638-546: The levelled rocky outcrop from 1912. The reconstructed fourth side was attached to the Rozelle shoreline as part of the extensive reclamation of Rozelle Bay and White Bay which had begun in the 1890s. Glebe Island became the site of a grain elevator and tall concrete silos, operated from 1921 by the Grain Elevators Board of NSW . The 1958 Australian Encyclopaedia records that the bulk wheat terminal had
667-589: The redevelopment of the Sydney Convention & Exhibition Centre . The site was cleared in 2017. In February 2018 Sydney Ports Authority announced plans for a major building materials handling complex. The area forms part of the New South Wales Government's Bays Precinct urban renewal program. 33°52′01″S 151°11′02″E / 33.867°S 151.184°E / -33.867; 151.184 Sailing ballast If
696-609: The region until 2008. It is surrounded by White , Johnstons , and Rozelle Bays . Whilst retaining its original title as an "island", it has long been infilled to the shoreline of the suburb of Rozelle and connected by the Glebe Island Bridge (and its replacement the Anzac Bridge ) to Pyrmont . The rocky outcrop known as Glebe Island was originally accessible from the Balmain shoreline only at low tide, until
725-476: The same time as the Barangaroo development to become a cruise ship terminal to alleviate pressure on the existing facilities at Darling Harbour and Circular Quay . This is a controversial decision with the local community due to largely to traffic concerns and has been called a "good short term solution" by industry groups as most cruise ships currently being constructed would not be able to fit underneath
754-409: The valve is opened, and water in the windward tank, which is higher, is allowed to flow to the lee side, and the sheet is let off to keep the boat from heeling too far. Once as much water as possible has been transferred to the lee side, the boat is brought about and the sail sheeted in, lifting the newly full windward tank. A simple hand pump can then be used to move any remaining water from the lee to
783-577: The windward tank. On empty cargo vessels water is added to ballast tanks to increase propeller immersion, to improve steering, and to control trim and draft. Ballast water discharges by ships can have a negative impact on the marine environment . The discharge of ballast water and sediments by ships is governed globally under the Ballast Water Management Convention , since its entry into force in September 2017. It
812-520: Was Norman in inspiration – round-headed openings and simple decoration. Kerr states that the abattoir was almost certainly based on an American design. On 7 September 1860, Balmain Council resolved to approach the owners of the unsold parts of the Balmain Estate for a grant of land to build a road to the island. The Pyrmont Bridge Company built a low-level timber-framed bridge that connected
841-766: Was added to the Municipality of Balmain. From 1912, the Sydney Harbour Trust (later Maritime Services Board ) planned broadside wharfage at Balmain East and along the southern shore of Balmain, including Glebe Island. Also in 1912 the Metropolitan Meat Industry Board resolved to abolish the abattoirs and build a new facility at Homebush Bay . By 1915 Robert Saunders, the Pyrmont quarry master, had been commissioned to level
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