Port
A port is a maritime facility comprising one or more wharves or loading areas, where ships load and discharge cargo and passengers. Although usually situated on a sea coast or estuary, ports can also be found far inland, such as Hamburg, Manchester and Duluth; these access the sea via rivers or canals. Because of their roles as ports of entry for immigrants as well as soldiers in wartime, many port cities have experienced dramatic multi-ethnic and multicultural changes throughout their histories.
Ports are extremely important to the global economy; 70% of global merchandise trade by value passes through a port. For this reason, ports are also often densely populated settlements that provide the labor for processing and handling goods and related services for the ports. Today by far the greatest growth in port development is in Asia, the continent with some of the world's largest and busiest ports, such as Singapore and the Chinese ports of Shanghai and Ningbo-Zhoushan. As of 2020, the busiest passenger port in Europe is the Port of Helsinki in Finland. Nevertheless, countless smaller ports do exist that may only serve their local tourism or fishing industries.
Ports can have a wide environmental impact on local ecologies and waterways, most importantly water quality, which can be caused by dredging, spills and other pollution. Ports are heavily affected by changing environmental factors caused by climate change as most port infrastructure is extremely vulnerable to sea level rise and coastal flooding. Internationally, global ports are beginning to identify ways to improve coastal management practices and integrate climate change adaptation practices into their construction.
Historical ports
Wherever ancient civilisations engaged in maritime trade, they tended to develop sea ports. One of the world's oldest known artificial harbors is at Wadi al-Jarf on the Red Sea. Along with the finding of harbor structures, ancient anchors have also been found.Other ancient ports include Guangzhou during Qin dynasty China and Canopus, the principal Egyptian port for Greek trade before the foundation of Alexandria. In Ancient Greece, Athens' port of Piraeus was the base for the Athenian fleet which played a crucial role in the Battle of Salamis against the Persians in 480 BCE. In ancient India from 3700 BCE, Lothal was a prominent city of the Indus valley civilisation, located in the Bhal region of the modern state of Gujarāt. Ostia Antica was the port of ancient Rome with Portus established by Claudius and enlarged by Trajan to supplement the nearby port of Ostia. In Japan, during the Edo period, the island of Dejima was the only port open for trade with Europe and received only a single Dutch ship per year, whereas Osaka was the largest domestic port and the main trade hub for rice.
Ostia Antica is an ancient Roman city and the port of Rome located at the mouth of the Tiber. It is near modern Ostia, southwest of Rome. Due to silting and the invasion of sand, the site now lies from the sea. The name Ostia derives from Latin os 'mouth'. Ostia is now a large archaeological site noted for the excellent preservation of its ancient buildings, magnificent frescoes and impressive mosaics. The city's decline after antiquity led to harbor deterioration, marshy conditions, and reduced population. Sand dunes covering the site aided its preservation. Its remains provide insights into a city of commercial importance. As in Pompeii, Ostia's ruins provide details about Roman urbanism that are not accessible within the city of Rome itself. Post-classical Swahili kingdoms are known to have had trade port islands and trade routes with the Islamic world and Asia. They were described by Greek historians as "metropolises". Famous African trade ports such as Mombasa, Zanzibar, Mogadishu and Kilwa were known to Chinese sailors such as Zheng He and medieval Islamic historians such as the Berber Islamic voyager Abu Abdullah ibn Battuta.
Many of these ancient sites no longer exist or function as modern ports. Even in more recent times, ports sometimes fall out of use. Rye, East Sussex, was an important English port in the Middle Ages, but the coastline changed and it is now from the sea, while the ports of Ravenspurn and Dunwich have been lost to coastal erosion.
File:Maritime republics map - IT.png|thumb|A map with the locations and coats of arms of the maritime republics of medieval Italy: Amalfi, Genoa, Pisa, and Venice, Noli, Ancona, Ragusa, Gaeta.
The maritime republics, also called merchant republics, were Italian thalassocratic port cities which, starting from the Middle Ages, enjoyed political autonomy and economic prosperity brought about by their maritime activities. The term, coined during the 19th century, generally refers to four Italian cities, whose coats of arms have been shown since 1947 on the flags of the Italian Navy and the Italian Merchant Navy: Amalfi, Genoa, Pisa, and Venice. In addition to the four best known cities, Ancona, Gaeta, Noli, and, in Dalmatia, Ragusa, are also considered maritime republics; in certain historical periods, they had no secondary importance compared to some of the better known cities.
Uniformly scattered across the Italian peninsula, the maritime republics were important not only for the history of navigation and commerce: in addition to precious goods otherwise unobtainable in Europe, new artistic ideas and news concerning distant countries also spread. From the 10th century, they built fleets of ships both for their own protection and to support extensive trade networks across the Mediterranean, giving them an essential role in reestablishing contacts between Europe, Asia, and Africa, which had been interrupted during the early Middle Ages. They also had an essential role in the Crusades and produced renowned explorers and navigators such as Marco Polo and Christopher Columbus.
Over the centuries, the maritime republics — both the best known and the lesser known but not always less important — experienced fluctuating fortunes. In the 9th and 10th centuries, this phenomenon began with Amalfi and Gaeta, which soon reached their heyday. Meanwhile, Venice began its gradual ascent, while the other cities were still experiencing the long gestation that would lead them to their autonomy and to follow up on their seafaring vocation. After the 11th century, Amalfi and Gaeta declined rapidly, while Genoa and Venice became the most powerful republics. Pisa followed and experienced its most flourishing period in the 13th century, and Ancona and Ragusa allied to resist Venetian power. Following the 14th century, while Pisa declined to the point of losing its autonomy, Venice and Genoa continued to dominate navigation, followed by Ragusa and Ancona, which experienced their golden age in the 15th century. In the 16th century, with Ancona's loss of autonomy, only the republics of Venice, Genoa, and Ragusa remained, which still experienced great moments of splendor until the mid-17th century, followed by over a century of slow decline that ended with the Napoleonic invasion.
Modern ports
Whereas early ports tended to be just simple harbours, modern ports tend to be multimodal distribution hubs, with transport links using sea, river, canal, road, rail and air routes. Successful ports are located to optimize access to an active hinterland, such as the London Gateway. Ideally, a port will grant easy navigation to ships, and will give shelter from wind and waves. Ports are often on estuaries, where the water may be shallow and may need regular dredging. Deep water ports such as Milford Haven are less common, but can handle larger ships with a greater draft, such as super tankers, Post-Panamax vessels and large container ships. Other businesses such as regional distribution centres, warehouses and freight-forwarders, canneries and other processing facilities find it advantageous to be located within a port or nearby. Modern ports will have specialised cargo-handling equipment, such as gantry cranes, reach stackers and forklift trucks.Ports usually have specialised functions: some tend to cater mainly for passenger ferries and cruise ships; some specialise in container traffic or general cargo; and some ports play an important military role for their nation's navy. Some third world countries and small islands such as Ascension and St Helena still have limited port facilities, so that ships must anchor off while their cargo and passengers are taken ashore by barge or launch.
In modern times, ports survive or decline, depending on current economic trends. In the UK, both the ports of Liverpool and Southampton were once significant in the transatlantic passenger liner business. Once airliner traffic decimated that trade, both ports diversified to container cargo and cruise ships. Up until the 1950s the Port of London was a major international port on the River Thames, but changes in shipping and the use of containers and larger ships have led to its decline. Thamesport, a small semi-automated container port thrived for some years, but has been hit hard by competition from the emergent London Gateway port and logistics hub.
In mainland Europe, it is normal for ports to be publicly owned, so that, for instance, the ports of Rotterdam and Amsterdam are owned partly by the state and partly by the cities themselves.
Even though modern ships tend to have bow-thrusters and stern-thrusters, many port authorities still require vessels to use pilots and tugboats for manoeuvering large ships in tight quarters. For instance, ships approaching the Belgian port of Antwerp, an inland port on the River Scheldt, are obliged to use Dutch pilots when navigating on that part of the estuary that belongs to the Netherlands.
Ports with international traffic have customs facilities.