In American English, dock is technically synonymous with pier or wharf-any human-made structure in the water intended for people to be on. Ī dockyard (or shipyard) consists of one or more docks, usually with other structures. Ships using NAABSA facilities have to be designed for them. NAABSA (Not Always Afloat But Safely Aground) where ships settle on the bottom at low tide.Floating, where there is always sufficient water to float the ship.Where the water level is not controlled berths may be: A floating dry dock (sometimes just floating dock) is a submersible structure which lifts ships out of the water to allow dry docking where no land-based facilities are available.
A drydock is another variant, also with dock gates, which can be emptied of water to allow investigation and maintenance of the underwater parts of ships.The dock reduced ship waiting giving quick turnarounds, greatly improving the throughput of cargo. The world's first commercial enclosed wet dock, with quays and unloading warehouses, was the Old Dock at Liverpool, built in 1715 and held up to 100 ships. The dock was merely a haven surrounded by trees, with no unloading facilities. The world's first enclosed wet dock with lock gates to maintain a constant water level irrespective of tidal conditions was the Howland Great Dock on the River Thames, built in 1703. It works like a lock which controls the water level and allows passage of ships. The level of water in the dock is maintained despite the rising and falling of the tide. A wet dock or impounded dock is a variant in which the water is impounded either by dock gates or by a lock, thus allowing ships to remain afloat at low tide in places with high tidal ranges.There are specific types of dock structures where the water level is controlled: Such a dock may be created by building enclosing harbour walls into an existing natural water space, or by excavation within what would otherwise be dry land. In British English, a dock is an enclosed area of water used for loading, unloading, building or repairing ships. The engineers built a trapezoidal structure, with north–south arms of average 21.8 metres (71.5 ft), and east–west arms of 37 metres (121 ft). This knowledge also enabled them to select Lothal's location in the first place, as the Gulf of Khambhat has the highest tidal amplitude and ships can be sluiced through flow tides in the river estuary. It is speculated that Lothal engineers studied tidal movements and their effects on brick-built structures, since the walls are of kiln-burnt bricks. This is the earliest known dock found in the world equipped to berth and service ships. Modern oceanographers have observed that the ancient Harappans must have possessed great knowledge relating to tides in order to build such a dock on the ever-shifting course of the Sabarmati, as well as exemplary hydrography and maritime engineering. Ī dock from Lothal in India dates from 2400 BC and was located away from the main current to avoid deposition of silt. Archaeologists also discovered anchors and storage jars near the site.
The earliest known docks were those discovered in Wadi al-Jarf, an ancient Egyptian harbor, of Pharaoh Khufu, dating from c.2500 BC located on the Red Sea coast.
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