Marine construction vessels are generally of four types: heavy-lifting barges (with cranes attached); dredging ships for construction or land reclamation; jackup rigs or barges; and floating platforms. While marine construction vessels may not seem particularly interesting in themselves, they are used for a number of interesting and forward-thinking projects. Three examples of these remarkable projects are the Dubai Palm Islands, artificial reefs, and offshore windfarms.

The Dubai Palm Islands

The Dubai Palm Islands were constructed using dredging ships to pump sand up from the sea floor. The sand was then sprayed out to create a breakwater where the island was to be built. This sand was covered with layers of rocks stacked on top, and more sand was pumped up to create the 16 palm fronds. Dredging ships work in a similar way to a vacuum cleaner, by using suction to pull sand and water up from the sea floor. The water is then drained out through the bottom of the ship, and the sand remains on board - it can then be dumped or sprayed where it is needed. The Palm Islands were a unique and ambitious construction venture, and are now one of the most highly-sought-after tourist destinations in Dubai.

Artificial Reefs

Artificial reefs are man-made underwater structures, built with the aims of promoting increased marine life, controlling erosion, blocking passages for ships, or improving surfing in the region. Marine construction vessels are used to build artificial reefs by sinking them, also called "scuttling", with oil rigs in particular being used for this purpose. The Rigs-to-Reefs initiative creates artificial reefs by capping the oil wells in decommissioned oil rigs, then towing, toppling, or removing the upper portion of the oil rig platform. The underwater portion is then managed as a reef to support the restoration of the marine life in the area.

Offshore Windfarms

Windfarms are becoming increasingly prevalent as a renewable energy source, but offshore locations often have better wind speeds than onshore locations. The first offshore windfarm was built by Denmark in 1991, which paved the way for other European countries to take up this new technology. Offshore windfarms are built by using marine construction vessels to install what are called "monopiles" or "gravity based structures". This is essentially sinking large concrete structures into the ocean, which the wind turbines then sit upon - the monopile is one thin shaft that sinks into the ocean floor, while the gravity based structures have a "skirt" or foot at the bottom that spreads out along the seabed. Large floating cranes, barges, and tugboats are used to install gravity based structures, as the structure can usually be constructed and then floated to the location. In contrast, monopiles are typically built using a jack-up (a floating barge that deploys legs down to the sea floor for stability), and associated drilling equipment.

Marine construction vessels are an important component in the development of marine structures, many of which are interesting and cutting-edge developments. Without marine construction vessels made by companies like Andro Charters, remarkable projects such as artificial islands and reefs, and offshore windfarms would simply not be able to be made. 

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