FABRICATION SERVICES

FULL PROJECT CYCLE – FROM CONCEPT DESIGN TO

FABRICATION AND CERTIFICATION

SEAFASTENING AND INSTALLATION EQUIPMENT - GODE WIND OWF

UPENDING HINGE & SEAFASTENINGS WWW.TWD.NL

PROJECT HIGHLIGHTS

HYDRAULICALLY DRIVEN SKIDDING SYSTEM FOR

THE LOAD OUT OF MONOPILES, MOVING THE MONO-

PILES INTO THE CRANE CAPACITY LIFTING RANGE

STACKED MONOPILES WITH OPENING CRADLE TO

OPTIMIZE DECK SPACE

SEAFASTENING STRUCTURES ARE ABLE TO AC-

COMMODATE LARGE WEIGHTS AND LENGTHS OF

MONOPILES & TRANSITION PIECES

DESIGN

To install the 97 foundations of the Gode Wind offshore wind farm,

GeoSea used their jack-up installation vessel the Innovation. TWD

provided detailed designs for various seafastening structures on

the Innovation, as well as on three supply barges.

The Innovation and the supply barges were equipped with four

monopile cradles, four transition piece grillages and a seafastening

tower to support four stacked anode cages.

Furthermore, we designed a monopile upending hinge and

seafastening structures for various other items on board of the

Innovation. Additionally, we performed motion studies and

provided a ballast plans for the supply barges.

The installation finished more than a month ahead of schedule,

due to good weather conditions and great performance of the

installation equipment. The crew on board was very pleased with

the excellent functionality of the equipment.

To help streamline the whole project, TWD assisted GeoSea

with the organization and oversight of the fabrication of the

seafastening structures. In this process TWD worked closely with

GeoSea, the fabricators and the marine warranty surveyors to

ensure proper fabrication, testing procedures and verification of

the structures, as well as a safe and efficient mobilization.

TEMPORARY WORKS DESIGN BV

T

W

E

+31 10 294 03 74

www.twd.nl

info@twd.nl

WWW.TWD.NL

Rotterdam Science Tower - Marconistraat 16

3029 AK Rotterdam

The Netherlands

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UPENDING HINGE & SEAFASTENINGS

MONOPILE AND TRANSITION PIECE SEAFASTENING

One of the challenging aspects of this project was to design a structure that was able to carry four monopiles of 67 meter long with a design weight

of 1000 tonne each - some of the longest and heaviest monopiles ever installed in the North Sea. To optimize deck space on the Innovation one of

the monopiles was even stacked above another. To retrieve the bottom one, the top cradle could flip upwards like a draw-bridge.

Three NB90 barges were used to transport foundations from different fabrication yards to the feeder port. Each barge carried four monopiles, two

of which were first lifted and then skid beyond where the quay crane could lift them. This way the need for an additional heavy crane was avoided.

ANODE CAGE SEAFASTENING

In the Gode Wind foundation the anodic protection was

constructed on separate anode cages. To safe deck space, four

anode cages were transported above each other. The cages were

hung on hooks on a lattice tower. Once a cage was lifted off, the

hooks would fold in automatically, allowing lower cages to pass.

UPENDING HINGE

The upending hinge was designed to support the bottom end of

the monopile in a free rotating swing, whilst the crane lifted to top

end. By optimizing its geometry, the upending is stable, smooth

and fast. Access ladders and walkways did not only allow workers

to inspect the hinge and hydraulics, but even provided access

inside the monopile to verify proper insertion of the lifting tool.