August – October 2004
M.T. Hojgaard (MTH) awarded the subcontract to MPI Offshore in May 2004 for the load out, transport and installation of 30 WTG Monopiles and Transition Pieces. MTH crews, supported by MPI personnel, operated the foundation installation equipment.
The foundation components were collected from the manufacturer’s works based at Hoboken, Belgium. MPI Resolution’s deck was then loaded with six sets of foundation components – five separate load out operations were needed to complete the 30 foundations. The approximate deck pay load was 2500 tonnes per load out and all components were craned aboard by means of MPI Resolution’s former 300t construction crane.
Monopile weights were in the range of 150 to 185 tonnes and lengths 33 to 41 metres. Transition pieces weighed 70 tonnes and were completely fitted out with all platforms, J-tubes, boat landings and cathodic protection. The transitions pieces were stowed vertically on MPI Resolution’s deck which minimised damage to the finished paint system.
MPI Resolution’s aft deck was fitted with installation equipment which included the pile hammer (160 tonnes) the pile gripper (50 tonnes), grout spread and six 20 feet grout containers, pile up-ending tool and pile tailing frame plus all associated power packs, hydraulic hose reels and other ancillary equipment.
MPI Resolution provided a complete turn-key service for foundation collection, transport, and installation, on board accommodation was provided for the 30 plus construction team members and client representatives working around the clock.
The programme commenced with the first load out at Hoboken and was a demanding 58 days including an allowance of nine days weather down time.
Operational and environmental conditions were extremely onerous throughout the installation period. Detailed planning was essential to maintain smooth, continuous and efficient installation operations. Leg penetrations were regularly seven to eight metres and on occasions as deep as ten to eleven metres. Low water at most monopile locations was nominally four metres; MPI Resolution’s draft fully loaded is also nominally four metres. Hence to maintain the programme, jack-down at one location, moving and jacking-up at the next location had to be achieved within one high water tide.
MPI worked closely with their MTH team partners to achieve this optimum programme, which averaged overall, a foundation installed every two days, including all load out and weather downtime.