Jumbo Offshore"s engineers and the crew of DP2 vessel Jumbo Javelin have successfully installed their first transition piece (TP) at a wind farm off the UK"s southeast coast.
Jumbo says this is the first time that a TP has been transported and installed with only one DP2 vessel. The installation trial included leveling and grouting operations and even the removal of the TP. With a workability for critical lifts in significant wave heights up to at least 1.5m, Jumbo Offshore is now able to deliver various installation services for offshore wind farms.
After loading the 255 tonnesTP in Flushing, it was transported to the offshore location. There, the Jumbo Javelin positioned itself on DP next to the monopile and lifted the TP from its lower hold onto the monopile. After leveling the TP to its final position, the grouting procedure was tested.
To give crew safe access from the Jumbo Javelin to the installed TP as well as efficiently guiding the grout hoses, the Ampelmann II was used. This ship based, self stabilizing platform actively compensates all vessel motions to make offshore access safe and easy. In 20 landings, a total of 72 transfers were made to and from the TP. The Ampelmann also supported the grout hose, providing access and support in significant wave heights up to 2.5 m.
This was the first time that a TP was placed on a monopile from a free floating vessel on DP. The whole operation was completed in approximately 24 hours and was performed as planned with respect to every detail of the transportation, installation, accessibility of the TP, grouting and, importantly, safety.
The Jumbo Javelin isable to carry 9 TP"s at a time, each with weights up to 300 tons. All the TPs can be stowed vertically in the hold of the vessel and transported to the offshore location. The ship is free floating and uses its DP2 system to create a working environment in which TP"s can be installed in significant wave heights up to 1.5 m. With a high transit speed of up to 17 knots, the vessel is well equipped for wind farm installation work.
Using a DP positioned heavy lift vessel compared to the conventional method of moving and installing TPs means that the DP vessel is used for transporting a considerable load and also provides rapid transit to the installation site and the rapid installation itself. Also, the relocation from one position to the next is relatively fast as the vessel does not need to reposition anchors or jack up and down again.
Jumbo Offshore has access to 14 heavy lift vessels, two of which have DP2, the Jumbo Javelin and the Fairplayer. These DP2 vessels can be used for subsea installation work including the installation of subsea structures and the installation of moorings for floating production systems.
In August, deep water installation winches were installed in the Fairplayer, enabling Jumbo Offshore to lift large and heavy structures from the deck and place them on the seabed without the need for subsea transfer. Typical weights which can be installed are 600t in 1,500m depth and 200t at 3,000m.