Rock Dumping Services

1. Introduction The Scope of Work (SoW) defines the requirements, methodologies, and deliverables for the provision of Rock Dumping Services, including the design, supply, installation, and verification of rock berms for the protection and stabilization of subsea cables, CPS, Foundations, and related offshore infrastructure. The services are to be executed at the designated offshore wind farm locations in the German North Sea sector, Baltic Sea Sector or any other european offshore wind farm location.

2. Objectives Protection of Subsea Assets: To protect subsea cables, cable protection systems (CPS), and foundations from environmental and operational risks, such as scouring, freespan, and mechanical damage. Stabilization: To ensure long-term stability and integrity of subsea infrastructure by installing engineered rock berms. Compliance: To execute all works in accordance with applicable international standards, project specifications, and client requirements.

3. Scope of Work 3.1 General Description

The Contractor shall provide a complete service package, including but not limited to: Project management and engineering Design of rock berms and stabilization measures Procurement and supply of rock material Mobilization and demobilization of specialized vessels and equipment Execution of rock installation works Pre- and post-installation surveys Quality assurance and as-built documentation.

3.2 Project Engineering & Management

Project Planning: Develop detailed project schedules, installation plans, and risk assessments. Design Services: Prepare or review CPS berm designs, including cross-sections, material specifications, and installation tolerances. The Contractor may advise on optimal design solutions from an operational perspective. Quality Management: Implement a project-specific Quality Management System (QMS) in line with ISO 9001:2015, ensuring all works meet client and regulatory standards. HSE Management: Develop and enforce a Health, Safety, and Environmental (HSE) plan, including job hazard analysis, toolbox talks, and stop-work authority for all personnel.

3.3 Design Requirements

Example (will be defined case by case by specific project): Berm Geometry: Typical berm dimensions may include heights of ~1.1 m, widths of ~0.3 m, and slopes of 1:3, subject to project-specific requirements. Material Specification: Use freshly crushed rock, grading CP 45/180 or as specified, with a specific density of ~2.65 t/m³ and bulk density of ~1.56 t/m³. All rock must comply with EN 13383-1,2 standards. Tolerances: Vertical tolerance: -0.00/+0.50 m; Horizontal tolerance: -0.00/+2.00 m either side. Tolerances are to be verified by survey. Losses and Settlement: Account for installation losses (e.g., soil penetration, settlement, wash-away, compaction) in the design and quantity calculations.

Execution Accuracy: Capable of precise berm installation according to design profile; Vertical Installation Tolerance -0,00/+0,50m

3.4 Mobilization & Demobilization

Mobilization: Prepare and mobilize the designated rock installation vessel(s) at the port of origin. Calibrate and test all positioning, survey, and installation equipment prior to departure. Demobilization: Upon completion, demobilize all equipment and personnel, ensuring the site is left in a safe and compliant condition.

3.5 Rock Installation Operations 3.5.1 Equipment

Vessels: Use dynamically positioned fall pipe vessels (DPFPV) or equivalent. Fall Pipe Systems: Deploy central and/or inclined fall pipe systems, equipped with ROVs for precise placement and monitoring. Inclined systems are used for close proximity to structures. Survey Systems: Utilize DGNSS, USBL, multibeam echosounders (MBE), and online 3D visualization packages for real-time monitoring and documentation. Vessel Requirement: Minimum DP2 fall pipe vessel

3.5.2 Sequence of Work

Procurement of Rock Material: Source and stockpile rock at the designated quarry, ensuring compliance with design specifications and timely supply. Loading Operations: Load rock onto the vessel using conveyor belts or harbor cranes, with quantities verified by draft survey. Transit to Site: Sail to the offshore site, maintaining communication with client representatives. Pre-Installation Survey: Conduct detailed bathymetric and positioning surveys to establish the as-found condition of the seabed and infrastructure. Rock Placement: Execute rock dumping using DPFPV in auto-track mode, adjusting vessel speed and feeder output to achieve the required berm profile. Use ROVs and real-time monitoring tools to ensure accuracy. Intermediate Surveys: Perform check surveys during installation to monitor progress and adjust methodology as needed. Post-Installation Survey: Conduct final surveys to verify that the installed berm meets design specifications. Demobilization: Recover all equipment and return to port.

3.5.3 Special Operations

Close Proximity Works: For rock placement near structures, use inclined fall pipe or tremie pipe systems, with standoff distances and positioning monitored by echo sounders and sonar. Remedial Works: If required, perform additional passes or remedial installations based on survey results.

3.6 Survey and Documentation

Survey Deliverables: Provide as-built charts (DWG, PDF), DTM ASCII files, and comprehensive as-built reports. All data must be corrected for tide and quality-checked before submission. Acceptance: Survey data and as-built documentation are to be reviewed and accepted by the client’s offshore representative before demobilization.

The exact requirements will be specified by the specific case and project. ___ All companies affiliated with EnBW within the meaning of Sections 15 et seq. of the German Stock Corporation Act (AktG) shall be entitled to place orders.