Jumbo Offshore has completed its TP-installation project for the Greater Gabbard Offshore Wind Farm (GGOWF), off the UK’s south-east coast. For client Fluor, Jumbo’s DP2 Heavy Lift Vessel Jumbo Javelin installed 131 TP’s (out of 140 in the field) with a record-breaking installation speed of more than one TP per day. The job included leveling and grouting operations and was done without any serious accidents or incidents. This is the first time that TP’s have been transported and installed using a free floating vessel on Dynamic Position.
Jumbo’s scope included transport, installation, leveling and grouting of the TP’s. During the mobilization in March 2010 the Jumbo Javelin was outfitted with job-specific equipment, amongst others Temporary Living Quarters (Ferguson), a grout plant (Densit) and an access system (Ampelmann). The Ampelmann is a ship-based, self stabilizing access system that actively compensates all vessel motions. It was used to give crew safe access from the vessel to the installed TP as well as efficiently guiding the grout hoses.
In addition, Jumbo developed and built its own passive lifting compensators (with a 2.5 m stroke and a Safe Working Load of 300 t) and two job-specific, remote release operated, spreader bars to lift the TP’s.
Each time after loading nine 280 t TP’s in the Port of Flushing, the Jumbo Javelin sailed to the offshore location where she positioned herself on DP and started overboading the first TP onto the monopile. Every TP was placed in the specified orientation and then leveled to its final position. Next, the annulus (the space between TP and monopile) was filled with grout to fix it permanently. After the final survey the TP was handed over to client Fluor.
The Jumbo Javelin is able to carry nine TP’s at a time, stowed vertically in the hold and each with weights up to 300 tonnes. The vessel is well-equipped for wind farm installation work: it is free floating, uses its DP2 system to create an efficient and safe working environment, has a transit speed of 17 knots and sails with open hatches. This means a large transport capacity, fast transit times to the installation site, fast installation and fast relocation from one position to the next.