A trailing suction hopper dredger [1] (TSHD) is a type of ship capable of maintaining navigable waterways, deepening the maritime canals that are threatened to become silted, constructing new land elsewhere or replacing sand eroded by storms or wave action on the beaches. This is made possible by large, powerful pumps and engines able to suck sand, clay, silt and gravel. [2]
A trailing suction hopper dredger is self-loading/unloading and sometimes equipped with a pressurized discharging system.
From the side of the ship one or two suction pipes descend to the bottom of the seabed. On the end of the pipe a so-called trailing drag head is connected. This head is comparable to a large vacuum cleaner and is trailed along the seabed. In the head there are nozzles connected to a high pressure water installation that are capable of loosening the material on the seabed. Due to lower pressure in the pipe, the material will be sucked inward and discharged in the hopper.
The vessel should always have a positive speed over the ground. It is possible to regulate the density of the sucked substance. If the head is lowered, more material will be sucked but this risks damaging the installation because the material can get stuck inside the pipes. Once the mixture is loaded inside the hopper, the substance will sink and the water is discharged overboard, saving on storage space. A trailing suction hopper dredger can only suck relatively loose substance because the steel teeth are not so big. Harder substances such as rock or ironbased rock must be destroyed by a cutter.
There are several ways to discharge a TSHD. The most common way is dumping the material.
A trailing suction hopper dredger is equipped with the following equipment:
A dredging vessel [3] and particularly a TSHD is mostly used for
Dredging is the excavation of material from a water environment. Possible reasons for dredging include improving existing water features; reshaping land and water features to alter drainage, navigability, and commercial use; constructing dams, dikes, and other controls for streams and shorelines; and recovering valuable mineral deposits or marine life having commercial value. In all but a few situations the excavation is undertaken by a specialist floating plant, known as a dredger.
A hose is a flexible hollow tube designed to carry fluids from one location to another. Hoses are also sometimes called pipes, or more generally tubing. The shape of a hose is usually cylindrical.
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Rainbowing is the process in which a dredging ship propels sand that has been claimed from the ocean floor in a high arc to a particular location. This is used for multiple purposes, ranging from building up a beach to prevent erosion to constructing new islands. The name is derived from the appearance of the arc, which closely resembles a brown-colored rainbow.
Queen of the Netherlands is a Dutch trailing suction hopper dredger ship constructed in 1998. After lengthening in 2009, she was the largest and most powerful dredger in the world. The vessel has been used in high-profile salvage and dredging operations including the investigation into the Swissair Flight 111 crash and in the Port Phillip Channel Deepening Project. It has been called "the world's largest floating vacuum cleaner".
A suction excavator, or vacuum excavator, is a construction vehicle that removes heavy debris or other materials from a hole on land using vacuuming. Suction excavators are meant to be more non-destructive than regular excavators. The suction excavator uses suction fans for the airflow to suck up the material that is then transported into the holding tank.
A vacuum truck, vacuum tanker, vactor truck, vactor, vac-con truck, vac-con is a tank truck that has a pump and a tank. The pump is designed to pneumatically suck liquids, sludges, slurries, or the like from a location into the tank of the truck. The objective is to enable transport of the liquid material via road to another location. Vacuum trucks transport the collected material to a treatment or disposal site, for example a sewage treatment plant.
Jan De Nul Group is a Belgian family-owned company, with the financial headquarters in Luxembourg, that provides services relating to the construction and maintenance of maritime infrastructure on an international basis. Its main focus is dredging, which accounts for 85% of its turnover. Other areas include civil engineering and environmental technology.
The TSHD Shoalway is a trailing suction hopper dredger, owned and operated by Royal Boskalis Westminster, originally intended for the British market and built in 2010.
Dredging, Environmental and Marine Engineering NV (DEME) is an international group of specialised companies in the fields of capital and maintenance dredging, land reclamation, port infrastructure development, offshore related services for the oil & gas industry, offshore windfarm installation, and environmental remediation. The group is based in Zwijndrecht, Belgium, and has current operations on five continents.
A Slice of Reality is a work of modern art by Richard Wilson sitting by the Millennium Dome on the north-western bank of the Greenwich Peninsula. It consists of a 9-metre (30 ft) sliced vertical section through the former 800-ton 60-metre (200 ft) sand dredger Arco Trent and exposes portions of the former living quarters of the vessel to the elements.
High-density solids pumps are hydrostatically operating machines which displace the medium being pumped and thus create a flow.
A dredge drag head is used by a trailing suction hopper dredger to collect sand from the sea floor.
The dredge valve is a component of a Cutter Suction Dredge or a Trailing Suction Hopper Dredger that is used control the flow of water and sand in the suction and discharge pipes of one of these types of dredgers.
The TSHD Sospan Dau is a Dutch trailing suction hopper dredger owned by Sosban BV. The vessel has worked on dredging projects, including offshore aggregates, port maintenance, land reclamation, coastal defense and beach replenishment. The name Sospan Dau is Welsh and originates from Sosban Fach and Llanelli's tin plating industry, Sospan being the Welsh for Saucepan and Dau being Welsh for Two as the ship is a successor to the original Sospan.
Dredging Corporation of India Limited, or DCI, is an Indian dredging company which does dredging for Indian seaports exclusively. It occasionally dredges at foreign seaports in countries such as Sri Lanka, Taiwan and Dubai. It is mainly involved in maintenance dredging. Almost all the maintenance dredging in Indian seaports is carried out by DCI due to government regulations. DCI is also involved in capital dredging, beach nourishment, and land reclamation. The main seaports in which DCI does business are Visakhapatnam Port, Haldia, Kandla, Cochin Port and Ennore Port.
MV Tian Kun Hao (天鯤) is a Chinese dredger that has been described variously as “Asia’s most powerful island maker” and "magic island maker" due to its capability to dig 6,000 cubic metres per hour of sand/silt. The ship was launched at Qidong in Jiangsu province in November 2017. The ship is apparently named after "a legendary enormous fish which can turn into a mythical bird".
USAVYaquina is a hopper dredge of the United States Army Corps of Engineers. Her primary mission is to maintain the entrance bars, rivers, and harbors along the coasts of California, Oregon, and Washington. She is assigned to the Portland District of the Army Corps of Engineers. Her homeport is Portland, Oregon. She was launched in 1980 and remains in service.
USAVEssayons is a hopper dredge of the United States Army Corps of Engineers. Her primary mission is to maintain the entrance bars, rivers, and harbors along the coasts of Alaska, Hawaii, California, Oregon, and Washington. In emergencies, she can also be deployed to the Mississippi River. She is assigned to the Portland District of the Army Corps of Engineers. Her homeport is Portland, Oregon. She was launched in 1982 and remains in service.
Miss Katie is a hopper dredge owned by EJE Dredging Service, LLC. Her primary mission is to maintain the channels through Oregon Inlet and nearby Hatteras Inlet in the Outer Banks of North Carolina. Keeping these navigable waterways open is important to local fishing, recreational boating, and other maritime interests.
