Galloper Substation - Seaway Heavy Lifting

Galloper Substation
The Greater Gabbard Offshore Wind Farm is developed by SSE in a joint venture with RWE npower
renewables. The wind farm includes 140 wind turbines and two substations (Gabbard and Galloper),
which are located around two sand banks known as Inner Gabbard and Galloper in the North Sea,
12 nm off the Suffolk Coast. To date, Greater Gabbard is the biggest offshore wind farm, located in
water depths of 22 - 32 m and covering an area of 146 km 2 .
Since 1992, Seaway Heavy Lifting (SHL) has built respected experience in the oil and gas market.
As a marine contractor, SHL has completed over one hundred platform installations and removals
throughout the world. SHL owns and operates the monohull crane vessels “Stanislav Yudin”
(2,500 mt revolving), the “Oleg Strashnov” (5,000 mt
revolving) and all key installation equipment like
piling hammers and handling tools. SHL’s vessels
are able to work under harsh offshore conditions,
and these vessels are perfectly suited for the
installation of substations and different types of
wind turbine foundations. For each project, SHL’s
experienced team develops the most safe, reliable
and economical offshore installation method.
As part of the installation subcontract with Fluor Ltd. (Fluor), SHL transported and installed the
Galloper substation in early June 2010. Both jacket and topside were transported to the offshore
field on cargo barges: the jacket and piles from Methill, and the topside from Hartlepool.
Once the jacket was set on the seabed, the four lead section foundation piles (diameter: 54”,
length: 67.5 m) were stabbed in the designated jacket legs and were driven to penetration by means
of SHL’s IHC S-600 piling hammer. The add-ons (length: 30.0 m) were stabbed in and welded to the
lead sections after which all foundation piles were driven to final penetration of 60 m. After levelling,
using SHL’s levelling tools, the piles were welded to the jacket and the final cut-off was made.
The topside was installed immediately following jacket installation completion. The entire operation,
from receiving the first cargo barge alongside the Stanislav Yudin until completion of the substation
installation, took only 8 days. The topside was installed fully tested and commissioned by the
fabricator at the fabrication yard.
The selection of a conventional platform design installed with a heavy lift vessel (HLV) proved to be the
best choice to meet the project schedule and allowing for flexibility under a lump sum installation contract.

Project details
SCOPE Transport and installation of Galloper substation
DIMENSIONS Topside weight mt 1,650
Jacket weight mt 790
Pile dimensions main piles four in total
Pile weight mt 150
Pile length m 97.5 (lead section + add-on)
Pile diameter in 54
Pile penetration m 57.5
WATERDEPTH m (LAT) 23.0
FABRICATION Topside Newcastle, England
Jacket & piles Methill, Scotland
CLIENT main contractor Fluor Ltd.
INSTALLATION PERIOD June 2010
INSTALLATION SPEED days 8
Key benefits of substation installation with HLV
• Highest offshore workability
• Safe, reliable and proven installation solution
• Full flexibility, capable of maintaining project schedule
• Enable most economical jacket and topside design
• Limit restrictions on fabrication yard and offshore cargo barges
• Topside fully tested and commissioned prior to installation
All specifications are subject to change without notice. No rights can be derived from this information. October 2010.
Seaway Heavy Lifting Engineering B.V.
Albert Einsteinlaan 50, 2719 ER Zoetermeer,
The Netherlands
Tel: +31 (0)79 363 77 00
Fax: +31 (0)79 363 77 99
www.shl.com.cy