Celtic Sea Floating Offshore Wind – Dynamic Cable Design & Configuration Optimization

Executive Summary

This study establishes the system closure layer of Morie Analytics by transforming system behavior into optimized dynamic cable configurations.

Building on upstream modules, the workflow integrates bathymetry, mooring offsets, and hydrodynamic response to design constraint-compliant dynamic cables.

The result is a constraint-driven optimization framework producing deployable cable designs.

This module represents the final stage where system behavior is translated into infrastructure design.

Site intelligence → Layout generation → Soil reconstruction → Mooring physics → Anchor verification → Cable optimization

Project Scope

• Cable configuration modeling
• Mooring offset integration
• Hydrodynamic motion input
• Constraint-based optimization
• Geometry and performance evaluation

This study converts system behavior into optimized cable design.

Engineering Context

Dynamic cables must accommodate:

• Floater motion
• Cyclic loading
• Seabed interaction
• Strict mechanical constraints

Cable design is a constraint-dominated problem, balancing:

• Geometry
• Curvature
• Tension
• Seabed contact

This workflow ensures cable design reflects true system response, not assumptions.

Inputs and Data Sources

This study builds directly on upstream Morie Analytics outputs:

From morie_site

• Bathymetry grid
• Seabed conditions

From morie_layout

• Floater geometry
• Fairlead position

From morie_mooring

• Platform offset

Additional Inputs

• YAML configuration
• RAFT motion response
• Cable properties and constraints

This provides the boundary conditions for cable design optimization.

Technical Architecture

The workflow is implemented in Python using:

• numpy, scipy → numerical operations
• matplotlib → visualization
• famodel → system definition and data handling
• RAFT → hydrodynamic response input
• CableDesign → dynamic cable modeling and optimization

Core modules:

• system initialization → project and platform extraction
• bathymetry sampling → local water depth evaluation
• geometry definition → fairlead position and span setup
• motion integration → offset and dynamic amplitude computation
• design parametrization → variables, bounds, and constraints definition
• cable model → multi-segment configuration representation
• constraint evaluation → tension, curvature, sag, and touchdown checks
• optimization engine → iterative design convergence

System Flow

Bathymetry → Motion → Cable Geometry → Constraint Evaluation → Optimization

The architecture ensures consistent coupling between system behavior and cable design.

Processing Workflow

1. Load configuration
2. Extract bathymetry
3. Define fairlead geometry
4. Compute mooring offset
5. Extract motion response
6. Define cable model
7. Apply constraints
8. Run optimization
9. Evaluate final configuration

This converts system response into optimized cable design.

Cable System Definition

The cable is modeled as a multi-segment system connecting:

• Seabed touchdown point or range
• Suspended buoyant sections
• Floater fairlead

Fairlead position:

rBFair = [rFair, 0, zFair]

Figure 1 – Initial cable configuration.

Mooring-Derived Offset

The floater offset is computed as:

offset = max( sqrt(dx² + dy²) )

Engineering Interpretation

• Defines quasi-static excursion
• Sets horizontal boundary condition
• Directly influences cable span and touchdown

Hydrodynamic Motion (RAFT)

Dynamic motion is defined as:

x_ampl = sqrt(surge_max² + sway_max²)

Engineering Interpretation

• Captures wave-induced motion
• Defines oscillatory loading
• Expands cable excursion envelope

Cable Design Model

The cable system accounts for:

• Self-weight (marine growth)
• Buoyancy modules
• Seabed interaction
• Dynamic boundary conditions

Engineering Interpretation

Cable behavior is governed by:

• Geometry
• Motion envelope
• Constraint limits

Optimization Problem

Design Variables

• Segment lengths
• Buoyancy distribution
• Lay lengths

Constraints

• Minimum lay length
• Maximum sag and hog heights
• Curvature limits
• Tension safety factors
• Touchdown range limits

Objective

• Minimize cost
• Satisfy all constraints

Optimization Convergence

Figure 2 – Optimization convergence.

Engineering Interpretation

The optimization balances:

• Feasibility (constraint satisfaction)
• Efficiency (cost reduction)

Optimized Configuration

Figure 3 – Optimized cable configuration.

Outputs Generated

• Optimized cable geometry
• Constraint verification
• Tension and curvature profiles
• Sag, hog and touchdown positions
• Optimization history

Engineering Applications

The outputs support:

• Dynamic cable design
• Constraint-driven optimization
• System-level coupling
• Early-stage engineering decisions

This enables:

System Response → Cable Design → Constraint Verification

Relationship to Other Morie Study Cases

This study is the system closure layer of the Morie Analytics workflow.

Receives from

• morie_site → bathymetry context
• morie_layout → geometry and topology
• morie_mooring → static and dynamic offsets
• morie_anchor → validated system constraints

Completes

The cable branch of the system workflow.

It provides the final transition from system behavior to deployable infrastructure design.

Why It Matters Commercially

Dynamic cables are among the most critical and costly components of floating wind systems.

• Reduces overdesign
• Ensures constraint compliance
• Balances cost and reliability
• Supports early-stage decision making

This is where:

• System behavior meets infrastructure design
• Constraints define feasibility
• Final design decisions are made

Aspects to Improve

• Fatigue analysis
• Probabilistic motion
• Multi-cable interaction
• Touchdown abrasion mitigation

Design Philosophy

This study reflects the Morie Analytics approach:

• Physics-informed
• Modular
• Traceable
• Engineering-focused
• Scalable

How to Run

1. Place datasets in celtic_sea_share/

2. Install dependencies:

   • numpy
   • matplotlib
   • FAModel
   • MoorPy
   • RAFT
3. Execute:

python morie_cable.py