CSL OWL Subsea Rock Installation, a newly formed partnership between The CSL Group (CSL) and Offshore Wind Logistics (OWL), announced the construction of two subsea rock installation vessels tailored for the offshore renewable energy sector.
Each vessel will have a cargo capacity of 17,500 metric tonnes and will be equipped with dynamic positioning (DP2). They will be able to operate on marine gas oil (MGO) and/or methanol, providing a pathway to zero emission operations.
Purpose-built for optimal flexibility, these vessels will deliver efficient and cost-effective subsea rock installation services in water depths up to 100 metres.
Capable of installing rock material up to the 60/300 kg grading, with the option of handling rocks weighing up to 450 kg. A Tremie Pipe with active motion compensation ensures precise placement at water depths between 30 and 100 metres. The transport belts are designed to handle rocks weighing up to 1,500 kg, with a side chute available for larger armour gradings. Excavators can be used to handle larger amour rock.
CSL OWL SRI is an independent marine contractor specializing in subsea rock installation services, dedicated to delivering safe, sustainable and cost-effective solutions for the installation and maintenance of subsea rock. Based in Rotterdam, the company combines OWL’s extensive experience in the offshore marine construction sector with CSL’s expertise as a leading provider of complex marine solutions.
The first subsea rock installation vessel is scheduled for delivery from the shipyard in August 2026, followed by the second vessel in November 2026.