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Case Study
Borkum Riffgrund 1 OWF (2014) – 43 ICC cables
This task was the first project in German waters for CT Offshore. The company’s cable installation vessel SIA
was supported by survey vessel MV SANDER 2, also owned and operated by CT Offshore, installing a total
number of 43 cables at DONG Energy’s 277MW wind farm project.
1. Scope of Work
Installation and burial of 43 inter-array cables, using CPS system Seaproof.
 Cable load-out
 Pre-lay Multibeam survey (MBES)
 Pre-lay grapnel run (PLGR)
 Rigging of towers and messenger wire work
 Array cable installation
 Post-lay inspection (PLI)
 Optical time delay reflection (OTDR) test
 Post-lay burial (PLB)
 Post-burial inspection (PLI)
 ROV post-burial survey
Additional works (1 cable)
 1 cable to be installed at DONG Energy’s test suction bucket foundation
 Recovery and replacement of 1 PCC cable
Vessels and equipment utilized
Cable Installation: CLV SIA
MBES / TSS Survey: MV SANDER 2
Trenching vessel: VOS SYMPATHY
Trencher ROV: CTO 103
Crew Transfer Vessels: Njord Skua, Njord Avocet, Marineco Stingray, Fob Lady
Execution period, free surface cable laid
Start-up 4 July 2014
Completed 2 September 2014
Preparing for cable load out at harbour
“Client says…
DONG Energy – Sam Gardner, Offshore Client Representative, Cable Installation,
Borkum Riffgrund 1…
“Throughout the project your team on board the Sia showed good
knowledge, experience and confidence in cable installation. They
maintained a professional attitude at all times and successfully
surface laid 44 cables without incident. This is a huge achievement
and one you should all be very proud of. Congratulations on a job
well done and I look forward to working with you all in the future.
Good luck with the burial campaign.”

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2. Cable load out – self designed harbour set up
For this project the cables protection system Seaproof was chosen.
To ensure an optimum cable load and handling, CT Offshore designed our own load out arrangement, which
allowed us to mount the Seaproof onshore and load it onto the CLV SIA in a quick and safe way.
Nordenham in Germany was chosen for cable load out.
3. Raw Installation Time
It was the first time for CT Offshore to install cables with the CPS system Seaproof. Despite the limited practical
knowledge with this specific type, the learning curve improved satisfactory.
3.1 raw installation time of 43 inter-array cables (green = Raw Installation Time)

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3.2 Min. / Average installation time (hrs.) of 43 cable 3.3. Duration of time vs. number of cables

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Cable Protection System Seaproof
The experienced team on board CLV SIA at work on the Bridge.

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Beautiful sun set while MV SANDER 2 is running a pre-lay MBES survey.