Rock dumping vessels are a category of watercraft that exist for the purpose of dumping rocks on the seabed. They are able to transport and dump rocks of variable sizes. The vessels range from large bulk-carrier style vessels, able to carry out precision operations using fallpipes, to smaller deck-loading vessels mainly used for erosion remediation. [1] [2] [3]
Almost all such vessels are fitted with a dynamic positioning system, which makes it possible to position rocks very accurately. [4]
Large cranes or fall pipes are used to dump the rocks from the vessels. Side-discharging by means of crane is usually done in shallow waters, while fall pipes are more commonly used in deep-water rock-dumping operations.
The most common need for rock dumpers is to provide protection to previously laid pipelines in areas where they may be damaged by fishing gear. Pipelines at risk are not trenched, but remain on the seabed. There are a number of protection methods for such pipelines, including the placement of concrete mattresses, but for areas where a long distance of pipeline has to be protected, a rock-dumping operation may be most cost efficient. [5]
Eclogite is often used because of its high density.
The Belgian dredging companies Jan De Nul and DEME Offshore are two global providers of rock-dumping operations. [6] [7] [8] From the Netherlands Van Oord and Boskalis are also worldwide operators of dump vessels. [3] [9]
An oil platform is a large structure with facilities to extract and process petroleum and natural gas that lie in rock formations beneath the seabed. Many oil platforms will also have facilities to accommodate the workers, although it is also common to have a separate accommodation platform linked by bridge to the production platform. Most commonly, oil platforms engage in activities on the continental shelf, though they can also be used in lakes, inshore waters, and inland seas. Depending on the circumstances, the platform may be fixed to the ocean floor, consist of an artificial island, or float. In some arrangements the main facility may have storage facilities for the processed oil. Remote subsea wells may also be connected to a platform by flow lines and by umbilical connections. These sub-sea facilities may include one or more subsea wells or manifold centres for multiple wells.
Dynamic positioning (DP) is a computer-controlled system to automatically maintain a vessel's position and heading by using its own propellers and thrusters. Position reference sensors, combined with wind sensors, motion sensors and gyrocompasses, provide information to the computer pertaining to the vessel's position and the magnitude and direction of environmental forces affecting its position. Examples of vessel types that employ DP include ships and semi-submersible mobile offshore drilling units (MODU), oceanographic research vessels, cable layer ships and cruise ships.
The Convention on the Prevention of Marine Pollution by Dumping of Wastes and Other Matter 1972, commonly called the "London Convention" or "LC '72" and also abbreviated as Marine Dumping, is an agreement to control pollution of the sea by dumping and to encourage regional agreements supplementary to the convention. It covers the deliberate disposal at sea of wastes or other matter from vessels, aircraft, and platforms. It does not cover discharges from land-based sources such as pipes and outfalls, wastes generated incidental to normal operation of vessels, or placement of materials for purposes other than mere disposal, providing such disposal is not contrary to aims of the convention. It entered into force in 1975. As of September 2016, there were 89 Parties to the convention.
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.
Marine engineering is the engineering of boats, ships, submarines, and any other marine vessel. Here it is also taken to include the engineering of other ocean systems and structures – referred to in certain academic and professional circles as "ocean engineering".
A crane vessel, crane ship, crane barge, or floating crane is a ship with a crane specialized in lifting heavy loads, typically exceeding 1,500 t for modern ships. The largest crane vessels are used for offshore construction.
Great Yarmouth Outer Harbour is a port constructed on the east coast of England at Great Yarmouth. Construction work on the Outer Harbour began in June 2007. The harbour which is built in the South Denes area was planned to bring trade to the area. The plans included a container terminal and a passenger ferry terminal, but with no confirmed contracts these were not built.
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".
Royal Van Oord is a Dutch maritime contracting company that specializes in dredging, land reclamation and constructing man made islands. Royal Van Oord has undertaken many projects throughout the world, including land reclamation, dredging and beach nourishment. The company has one of the world's largest dredging fleets.
MV Rocknes was a 166-metre (545 ft)-long rock discharge vessel that hit shallow water and suddenly capsized south of Bergen, Norway on 19 January 2004, killing 18 members of its 30-person crew. At the time of its sinking, it was the world's largest dynamically positioned flexible fall pipe rock dumping vessel. The ship was repaired during 2004 and 2005 and renamed Nordnes.
A pipelaying ship is a maritime vessel used in the construction of subsea infrastructure. It serves to connect oil production platforms with refineries on shore. To accomplish this goal a typical pipelaying vessel carries a heavy lift crane, used to install pumps and valves, and equipment to lay pipe between subsea structures.
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 Marine Management Organisation (MMO) is an executive non-departmental public body in the United Kingdom established under the Marine and Coastal Access Act 2009, with responsibility for English waters. The MMO exists to make a significant contribution to sustainable development in the marine area, and to promote the UK government's vision for clean, healthy, safe, productive and biologically diverse oceans and seas. The MMO aims to focus all of its activities and resources to meet its mission of enabling sustainable growth in the UK's marine area through 5 strategic outcomes:
Dredging, Environmental and Marine Engineering NV (DEME) is an international group of specialised companies in the field of capital and maintenance dredging, land reclamation, port infrastructure development, offshore related services for the oil & gas industry, offshore windfarm installation, environmental remediation a.o. The group is based in Zwijndrecht, Belgium, and has current operations on the five continents.
A trailing suction hopper dredger is a ship that has a full sailing capacity used to maintain navigable waterways, deepening the maritime canals that are threatened to become silted, to construct new land elsewhere or to replace 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.
Commercial offshore diving, sometimes shortened to just offshore diving, generally refers to the branch of commercial diving, with divers working in support of the exploration and production sector of the oil and gas industry in places such as the Gulf of Mexico in the United States, the North Sea in the United Kingdom and Norway, and along the coast of Brazil. The work in this area of the industry includes maintenance of oil platforms and the building of underwater structures. In this context "offshore" implies that the diving work is done outside of national boundaries. Technically it also refers to any diving done in the international offshore waters outside of the territorial waters of a state, where national legislation does not apply. Most commercial offshore diving is in the Exclusive Economic Zone of a state, and much of it is outside the territorial waters. Offshore diving beyond the EEZ does also occur, and is often for scientific purposes.
A submarine pipeline is a pipeline that is laid on the seabed or below it inside a trench. In some cases, the pipeline is mostly on-land but in places it crosses water expanses, such as small seas, straits and rivers. Submarine pipelines are used primarily to carry oil or gas, but transportation of water is also important. A distinction is sometimes made between a flowline and a pipeline. The former is an intrafield pipeline, in the sense that it is used to connect subsea wellheads, manifolds and the platform within a particular development field. The latter, sometimes referred to as an export pipeline, is used to bring the resource to shore. Sizeable pipeline construction projects need to take into account many factors, such as the offshore ecology, geohazards and environmental loading – they are often undertaken by multidisciplinary, international teams.
A cable protection system (CPS) protects subsea power cables against various factors that could reduce the cable's lifetime, when entering an offshore structure.
Ocean development refers to the establishing of human activities at sea and use of the ocean, as well as its governance.
RFA Proteus is a ship of the Royal Fleet Auxiliary within His Majesty's Naval Service of the United Kingdom. Its roles being a platform for Remotely Operated Underwater Vehicles (ROUVs) and a testbed for new specialist capabilities, required for monitoring waters important to UK interests. Acquired in 2023, the ship entered drydock at Cammell Laird for modification into a Multi-Role Ocean Surveillance Ship (MROSS). She formally entered service in October 2023.