Installation ship
A construction vessel (short for offshore wind turbine installation vessel , including installation vessel called) is in contrast to the jack-up platform , a special, for the creation and development of offshore wind turbines built workboat suitable with heavy-duty crane and own for propulsion and dynamic positioning, powerful engines - and propulsion systems. It also has lifting devices so that it can work independently of the sea .
development
Offshore wind energy developed slowly, beginning in Denmark and led to the use of jack-up rigs (1st generation) and, in the case of greater water depths and distances from the coast, occasionally also to converting freighters into first installation vessels (2nd generation). These were better suited than the jack-up platforms, but as conversions they were only to be viewed as a compromise.
The development of offshore wind energy in Germany has been accelerating since around 2005. Offshore wind farms were built close to the coast around Great Britain , similar to Denmark. The German decision to phase out electricity generation by nuclear power plants and the requirements to approve offshore wind power plants in the German EEZ only at great distances from the coast is the background to the fact that these wind power plants are to be built in great water depths of 15–40 m. With the experience of the "conversions", drafts for the third generation installation ships with high load capacity (cranes up to 1500 t load capacity) and ship speeds of up to 15 knots were created. These installation ships have thus developed into their own type of ship and can no longer be called jack-up rigs, but also belong to the category Heavy Lift Vessel ( heavy transport ship).
The 4th generation of offshore wind turbine installation vessels does not have a jack-up system, but as a semi-submersible is as independent of sea conditions as possible. Because of the untested installation concept and the resulting increased investment risk, no such ships have yet been built.
The 5th generation of OWT installation vessels is now being planned. The task of transporting the individual elements for the construction of the systems from the port on the mainland to the construction site on site is to be transferred from the installation ship to several barges moved by tugs . Several barges commute between the loading port and the construction site and carry out the material transport. Because the installation ship can remain on the construction site and the installation of the components does not have to be interrupted for the transport to the site, it is hoped that considerable time and cost savings will be achieved. Instead of having their own loading deck area , such installation ships have a floating dock that can be flooded on site in a slightly raised, ballasted state. In this state, the feeder barges can swim in with the material. The legs of the installation ship are now extended further while the ballast tanks and the loading dock are drained. The installation vessel can then begin installing the cargo it has brought with it. The fact that the feeder barges can also call at the ports of the production sites of the wind farm elements due to their significantly smaller size means that further cost savings are hoped for by avoiding base ports.
features
Features include a large deck area , ship's bridge, superstructures to accommodate crew and fitters and, most importantly, a powerful board crane with a load capacity of 500–1500 t, which is used to erect the offshore wind turbines, and a helicopter platform. In addition, there are devices for dynamic positioning (DP) so that the installation ship can position itself at the respective locations via GPS without external help, and then use the jack-up legs to get up exactly at this location.
The ships are so-called jack-up ships, which can be set up in a fixed position in the sea with the help of four to six hydraulically or electrically operated legs (so-called jack-up legs). Ships in semi-submersible or SWATH design were only used in the early days , as they are less stable in the water.
Working method
The legs are raised while driving. Only when they are in the intended position are they gradually lowered and placed on the seabed. Then the ship is lifted out of the water (usually 10 to 20 m high depending on the waves) and firmly anchored by its own weight. This results in the necessary stable work platform.
The installation vessels are equipped with a large heavy-duty crane for the tasks that arise . In addition, there is a large superstructure with accommodation for the crew and a helideck for changing teams and quick help or transport options in the event of an accident.
See also
literature
- Christian Mueller: Holistic solution concepts for offshore special ships . In: Schiff & Hafen , Issue 7/2011, pp. 44-46, Seehafen-Verlag, Hamburg 2011, ISSN 0938-1643
- Philipp Mucha, Antje Fleischhauer: Intact stability criteria for offshore installation vessels . In: Schiff & Hafen , Issue 9/2011, pp. 180–111, Seehafen-Verlag, Hamburg 2011, ISSN 0938-1643
- Ralf Witthohn: First German offshore installation ships delivered . In: Schiff & Hafen , Heft 5/2012, pp. 54–57, Seehafen-Verlag, Hamburg 2012, ISSN 0938-1643
- Henning von Wedel: Third generation offshore wind installation vessels . In: Hansa , Heft 5/2012, special part Wind & Maritim 2012, pp. 19-22, Schiffahrts-Verlag Hansa, Hamburg 2012, ISSN 0017-7504
- Ralf Witthohn: Workhorses for challenging offshore operations . In: Ship & Offshore , Issue 5/2012, pp. 10–15, DVV Media Group, Hamburg 2012, ISSN 2191-0057 (about Heavy Lift Vessels, in English)
- "Required tonnage must be secured in good time" . Interview by Anne-Katrin Wehrmann with Philippe Schönefeld, in: Hansa , Heft 1/2013, pp. 38–40, Schiffahrts-Verlag Hansa, Hamburg 2013, ISSN 0017-7504
- Henning von Wedel, Carsten-S. Wibel: loading dock instead of loading deck . In: Hansa , issue 6/2013, pp. 124–127
- Docking for service ship. Special construction for offshore supply with a new type of installation system - delivery 2014 . In: Daily port report of September 18, 2013, p. 3
- Andreas Fieber: The Netherlands as a location for offshore ships? In: Hansa , Heft 10/2013, pp. 23-25 (about preferential treatment of ships registered in the Netherlands compared to those in Germany)
Web links
Individual evidence
- ^ Henning von Wedel , Carsten-S. Wibel: loading dock instead of loading deck . In: Hansa , issue 6/2013, pp. 124–127