For the last five years, Jumbo Offshore has been building its reputation as a solid installation contractor with a clear focus on subsea structures, mooring systems and light weight jackets and topsides. The main installation vessel are the Jumbo Javelin and the Fairplayer. Equipped with two 900 t Huisman mast cranes, fitted with a Konsgberg dynamic positioning system (DP2) and with an enormous deck and large storage capacity, they are versatile installation tools. The OCV Fairplayer is also fitted with a deepwater deployment system (DDS) to facilitate lowering of heavy subsea structures to depths up to 3,000 m.
Ideally, says the company, these heavy lift vessels will be contracted to “Lift, Ship and Install, All in One Go" in one smooth and continuous operation.
After starting out in other offshore industries, Jumbo Offshore has now moved into the offshore wind sector and its crew, engineers and subcontractors have just successfully completed the first leg of their current Transition Piece (TP) installation project. Jumbo’s DP2-vessel Jumbo Javelin installed the TP’s, the first 18 of a series of approx. 110, within schedule. The work for the Greater Gabbard Offshore Wind Farm off the UK’s south-east coast will take up the better part of the rest of the year. This is the first time that TP’s have been transported and installed using a free floating vessel on DP.
After loading the 270 t TP’s in the Port of Flushing, the Jumbo Javelin sailed, with open hold, to the offshore location. There, she positioned herself on DP and lifted the first TP onto the monopile. After levelling the TP to its final position, the space between TP and foundation pile (annulus) was filled with grout to fix it permanently.
A first
It was the first time that TP’s were installed on monopiles from a free floating vessel on DP in one trip. Safety, transport, installation, TP-accessibility and grouting operations were all handled according to plan. 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 stabilising platform actively compensates vessel motions, enabling safe access and support in wave heights up to Hs = 2.5 m (significant wave height).
The Jumbo Javelin uses its DP2-system to create, amongst others, a working environment in which TP’s can be installed in wave heights up to Hs = 1.5 m. With a high transit speed of up to 17 knots, the vessel is well-equipped for wind farm installation work. Installing the 18 TP’s confirmed the suitability of Jumbo’s concept: transportation and installation by the same vessel, fast transit to the installation site and short relocation times from one position to the next.
Jumbo Offshore has access to 14 Heavy Lift Vessels, two of which are DP2-class: 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.
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