Shipyard

A shipyard (also called a dockyard) is a place where ships are built and repaired. These can be yachts, military vessels, cruise liners or other cargo or passenger ships. Dockyards are sometimes more associated with maintenance and basing activities than shipyards, which are sometimes associated more with initial construction. The terms are routinely used interchangeably, in part because the evolution of dockyards and shipyards has often caused them to change or merge roles. A shipyard (also called a dockyard) is a place where ships are built and repaired. These can be yachts, military vessels, cruise liners or other cargo or passenger ships. Dockyards are sometimes more associated with maintenance and basing activities than shipyards, which are sometimes associated more with initial construction. The terms are routinely used interchangeably, in part because the evolution of dockyards and shipyards has often caused them to change or merge roles. Countries with large shipbuilding industries include Australia, Brazil, China, Croatia, Denmark, Finland, France, Germany, India, Ireland, Italy, Japan, the Netherlands, Norway, the Philippines, Poland, Romania, Russia, Singapore, South Korea, Sweden, Taiwan, Ukraine, the United Kingdom, the USA and Vietnam. The shipbuilding industry is more fragmented in Europe than in Asia where countries tend to have fewer, larger companies. Many naval vessels are built or maintained in shipyards owned or operated by the national government or navy. Shipyards are constructed near the sea or tidal rivers to allow easy access for their ships. The United Kingdom, for example, has shipyards on many of its rivers. The site of a large shipyard will contain many specialised cranes, dry docks, slipways, dust-free warehouses, painting facilities and extremely large areas for fabrication of the ships. After a ship's useful life is over, it makes its final voyage to a shipbreaking yard, often on a beach in South Asia. Historically shipbreaking was carried on in drydock in developed countries, but high wages and environmental regulations have resulted in movement of the industry to developing regions. Welding, sandblasting, painting, and other maintenance work contribute pollution. Ship hulls are made of steel and have many layers of anti-fouling and anti-corrosion paint. Shipyards around the world paint ships, usually by airtight spraying or by thermal spraying. Studies have shown that painting generates almost half of the dangerous waste at a shipyard due to using high-pressure equipment to wash or remove any unwanted material that is on it like rust. This material will eventually make its way to the water as water pollution. In a study in 2011 samples of sediments were collected from two sites in coastal marine area of Yongho Bay, one from the shipyard and the other 500m away. Both samples contained metals that included Al, Fe, Li, V, Cr, Mn, Ni, Cu, Zn, As, Cd, Sn, and Pb. In addition, it had been confirmed that the concentration was higher in the first sample that was by the shipyard then the sample taking 500m away and was due to paint fragments applied to the steel ship hulls. Ship breaking can release excessive amounts of pollution. Paints used for hulls are anti-fouling paints and most contain triphenyl tetrazolium (TPT) and can be treated by using dolomitic sorbents. Over time weathering from ships will eventually sink to the bottom of the seabed. In 2005, a study showed the high level of toxicity of TBT compounds to organisms in the ocean and what can be done to reduce the pollution by using dolomitic sorbents. In the study, a sample of shipyard water was used in the experiment in a period over 14 days. At the end the experiment it was concluded that dolomites were successful in reducing the contaminants from the shipyard wastewater. Welding is the most important factor in ship building and should be performed by qualified welders in order to protect the ship structure. It is achieved by heating the surfaces to the point of melting using oxy-acetylene, electric arc, or other means, and uniting them by pressing, hammering, etc. But in shipyards, there are times when the welder has to crawl into a confined space and weld. Welding can produce toxic fumes such as Nitric Oxide, Nitrogen Dioxide, Carbon Monoxide, Phosgene, Hydrogen Fluoride, Carbon Dioxide can also result in serious damage to human health or death if ventilation is not present. A case study was performed to see where would be most effective place to exhaust the hull cells on the bulkhead in between two spaces using an air horn versus air with an electric blower. They used welders who were employees of the shipyard and asked them to weld in a specific space. One that had shipyard dilution ventilation(DV) and the other had local exhaust ventilation(LEV) then recorded to see which typed of ventilation worked the best. In the results, they found that local exhaust ventilation reduced particulate concentrations but also the efficiency of either method depended on equipment maintenance and their own work practices because everyone has a different way of getting things done. The world's earliest known dockyards were built in the Harappan port city of Lothal circa 2600 BC in Gujarat, India. Lothal's dockyards connected to an ancient course of the Sabarmati river on the trade route between Harappan cities in Sindh and the peninsula of Saurashtra when the surrounding Kutch desert was a part of the Arabian Sea.