Offshore Marine Technology: 4th Quarter 2016
HeavyLift@Sea’s new Floating Foundation Installation (FFI) 1700 vessel concept – which was unveiled in August this year, just in time for September’s SMM exhibition and conference in Hamburg – is intended to provide some serious muscle when it comes to offshore wind farm construction contracts.
Designed specifically to undertake deepwater installation of turbine array components such as monopiles, jackets and tripods, the FFI 1700 measures 165m x 43.5m, has a deadweight of 14,500tonnes and incorporates a high-strength and unobstructed working deck, spanning some 130m in length. The deck is capable of storing four XL-sized monopiles, each measuring 100m in length and 10m in diameter and weighing 1,500tonnes, as well as transition pieces and towers. The area below deck, meanwhile, is dedicated to the stowage of grouting equipment.
In addition to deck capacity, the FFI 1700 incorporates a heavy-lift offshore crane, developed by HeavyLift@Sea’s engineering and production subsidiary Mate@Sea.
The wire-luffing crane has a capacity of 1,700tonnes SWL at up to 30m, 1,000tonnes at up to 50m and 500tonnes at up to 100m. Should the customer request it, a second, auxiliary crane can be installed.
Pile gripper
Additional equipment includes a ‘pile gripper’ system. This comprises a lifting frame, welded to the deck, and hydraulically driven arms. The pile gripper’s main remit is to ensure that the monopile remains in a fixed vertical position when it is lifted into position, via vessel crane, at the wind farm construction site – thereby avoiding the likelihood of the monopile being driven into the seabed whilst it is in an inclined position.
To limit the frequency of costly ship-to-shore transfers, the vessel will also function as a floating accommodation block for its workers. The FFI 1700 class factors in 80 single cabins for its complement, and station-keeping is made possible via a dynamic positioning 2 (DP2) system working in conjunction with three 1,750kW bow thrusters and three 3,350kW azimuth thrusters.
As befits a vessel operating in the renewable energy sector, HeavyLift@Sea has opted for a relatively green means of powering the vessel. The FFI 1700 will incorporate a diesel-electric propulsion system, including the aforementioned azimuth thrusters and six gensets; three gensets rated 5,000kW each and three rated 595kW apiece, resulting in a total installed power rating of 16,785kW for the diesel-electric propulsion system, crane and hotel load.
