OrcaFlex Jumper Analysis Skill
Description
Rigid and flexible jumper modelling in OrcaFlex — covers installation analysis (crane lift, lowering, landing), in-place analysis (VIV, fatigue, extreme response), and parametric studies across environmental headings and sea states.
When to Use
- Jumper installation analysis (SZ/DZ, AHC on/off)
- Rigid jumper stress analysis and VIV screening
- Flexible jumper fatigue assessment
- Multi-section pipe modelling with buoyancy modules
- Three-point lift rigging design
- Parametric heading/sea-state studies
Key Concepts
Multi-Section Pipe
- Jumpers typically have 15-25 OrcaFlex line sections with alternating line types
- Line types: bare coated pipe, buoyancy modules, strake sections, insulation
- Each section has distinct OD, wall thickness, mass, and bending stiffness
- Section lengths vary: short connector sections (1-2m) to long pipe runs (50-100m)
M-Shape Buoyancy Layout
- Mid-span buoyancy modules create characteristic M-shape in water column
- Module dimensions: typically 10m blocks, density ~0.694 te/m3
- Buoyancy placement defined by arc-length ranges along jumper
- Net buoyancy per module determines equilibrium shape
Rigid End Connectors
- Modelled as separate short OrcaFlex lines with very high bending stiffness
- Typical: OCS 200-V connectors, OD ~1.8m, length ~0.5-1.0m
EndBxBendingStiffness: 1.0e+307 (effectively rigid)- Connected to main jumper via end connections
Installation Rigging Chain
The full lift system from vessel to jumper, modelled as linked OrcaFlex objects:
- Vessel — Installation vessel with RAOs
- Crane Pedestal — 6DBuoy at vessel crane location
- Crane Boom — Constraint object (boom geometry)
- Crane Wire — Winch object (main hoist)
- Sling — Line from winch to masterlink
- Masterlink — 3DBuoy (central connection point)
- Slings — Lines from masterlink to spreader bar ends
- Spreader Bar — 6DBuoy (~120ft / 36.6m)
- Lift Slings + Turnbuckles — Lines from spreader bar to clamp points
- Clamps — Attached to jumper at pickup arc lengths
Three-Point Lift
- Spreader bar with asymmetric pickup at 3 arc-length positions
- Pickup points determined by jumper COG and weight distribution
- Typical: 5 clamps (10-inch jumper clamps, ~0.26 te each) at sling points
- COG calculation considers all KIT weights (~46 te total for 4 KITs)
AHC System (Active Heave Compensation)
- Modelled via Winch + ExternalFunction (DLL)
- Two analysis variants: AHC-on (DZ) and AHC-off (SZ)
- ExternalFunction64.dll provides real-time heave compensation
- AHC reduces dynamic tension variation during lowering
Dual-Zone Analysis
| Zone |
Depth |
Wave Theory |
Typical Hs |
Focus |
| SZ (Splash Zone) |
Surface |
JONSWAP |
1.5m |
Sling loads, vessel motion |
| DZ (Deep Zone) |
Near seabed |
Dean Stream |
2.0m |
Landing loads, clearance |
Coatings & Insulation
| Type |
Density (te/m3) |
Thickness (mm) |
Purpose |
| Insulation |
0.979 |
76.2 |
Thermal |
| Buoyancy |
0.694 |
343 |
Net uplift |
| Strake |
1.128 |
5 |
VIV suppression |
Two-Step Statics
- Step 1: User-specified starting positions (rigging geometry)
- Step 2: Full statics solve (catenary + equilibrium)
- Critical for installation models where initial geometry is non-trivial
Parametric Studies
- Environmental headings: 0, 30, 60, 90, 120, 150, 165, 180 degrees
- Sea states: Hs = 0.75, 1.0, 1.25, 1.5, 1.75, 2.0, 2.5m
- Seeds: 20+ random seeds per (heading, Hs) combination
- Total runs per jumper: 200-1000+ simulations
Model Library
Available Models
| Model |
Location |
Description |
| Manifold-to-PLET |
docs/modules/orcaflex/jumper/manifold_to_plet/ |
Full installation rigging |
| PLET-to-PLEM |
docs/modules/orcaflex/jumper/plet_to_plem/ |
Shorter jumper variant |
| SUT/MM |
docs/modules/orcaflex/jumper/sut_mm/ |
SZ/DZ/resonance variants |
File Structure
docs/modules/orcaflex/jumper/<model>/
├── monolithic/ # Sanitized original OrcaFlex YAML
│ ├── DZ_AHCoff.yml
│ ├── SZ.yml
│ └── ...
└── spec.yml # Extracted spec for modular builder
Commands
Generate from spec
uv run python -m digitalmodel.solvers.orcaflex.modular_generator --spec docs/modules/orcaflex/jumper/manifold_to_plet/spec.yml
Validate round-trip
uv run python scripts/semantic_validate.py \
--mono docs/modules/orcaflex/jumper/manifold_to_plet/monolithic/SZ.yml \
--modular output/generated_model.yml
Run benchmark
uv run python scripts/benchmark_model_library.py --library-only --three-way --skip-mesh
Implementation Notes
- Jumper models use the
generic field in ProjectInputSpec (not dedicated jumper schema)
- The
MonolithicExtractor handles arbitrary OrcaFlex object types including 3DBuoys, 6DBuoys, Constraints, Winches
- Vessel RAO data round-trips through the extractor (verify RAO table sizes)
- ExternalFunction DLL references will cause benchmark failures — add to skip list
- For parametric studies, use the campaign generator pattern with seed/heading/Hs variations
Related Skills
/orcaflex-extreme-analysis — General installation modelling/orcaflex-model-generator — Modular YAML generation from spec/orcaflex-modeling — Core OrcaFlex modelling patterns/orcaflex-specialist — Advanced OrcaFlex specialist workflows
1---2name: orcaflex-jumper-analysis-23description: Rigid and flexible jumper modelling in OrcaFlex covering installation analysis, in-place analysis, VIV screening, and fatigue assessment.4---56# OrcaFlex Jumper Analysis Skill78## Description9Rigid and flexible jumper modelling in OrcaFlex — covers installation analysis (crane lift, lowering, landing), in-place analysis (VIV, fatigue, extreme response), and parametric studies across environmental headings and sea states.1011## When to Use12- Jumper installation analysis (SZ/DZ, AHC on/off)13- Rigid jumper stress analysis and VIV screening14- Flexible jumper fatigue assessment15- Multi-section pipe modelling with buoyancy modules16- Three-point lift rigging design17- Parametric heading/sea-state studies1819## Key Concepts2021### Multi-Section Pipe22- Jumpers typically have 15-25 OrcaFlex line sections with alternating line types23- Line types: bare coated pipe, buoyancy modules, strake sections, insulation24- Each section has distinct OD, wall thickness, mass, and bending stiffness25- Section lengths vary: short connector sections (1-2m) to long pipe runs (50-100m)2627### M-Shape Buoyancy Layout28- Mid-span buoyancy modules create characteristic M-shape in water column29- Module dimensions: typically 10m blocks, density ~0.694 te/m330- Buoyancy placement defined by arc-length ranges along jumper31- Net buoyancy per module determines equilibrium shape3233### Rigid End Connectors34- Modelled as separate short OrcaFlex lines with very high bending stiffness35- Typical: OCS 200-V connectors, OD ~1.8m, length ~0.5-1.0m36- `EndBxBendingStiffness: 1.0e+307` (effectively rigid)37- Connected to main jumper via end connections3839### Installation Rigging Chain40The full lift system from vessel to jumper, modelled as linked OrcaFlex objects:411. **Vessel** — Installation vessel with RAOs422. **Crane Pedestal** — 6DBuoy at vessel crane location433. **Crane Boom** — Constraint object (boom geometry)444. **Crane Wire** — Winch object (main hoist)455. **Sling** — Line from winch to masterlink466. **Masterlink** — 3DBuoy (central connection point)477. **Slings** — Lines from masterlink to spreader bar ends488. **Spreader Bar** — 6DBuoy (~120ft / 36.6m)499. **Lift Slings + Turnbuckles** — Lines from spreader bar to clamp points5010. **Clamps** — Attached to jumper at pickup arc lengths5152### Three-Point Lift53- Spreader bar with asymmetric pickup at 3 arc-length positions54- Pickup points determined by jumper COG and weight distribution55- Typical: 5 clamps (10-inch jumper clamps, ~0.26 te each) at sling points56- COG calculation considers all KIT weights (~46 te total for 4 KITs)5758### AHC System (Active Heave Compensation)59- Modelled via Winch + ExternalFunction (DLL)60- Two analysis variants: AHC-on (DZ) and AHC-off (SZ)61- ExternalFunction64.dll provides real-time heave compensation62- AHC reduces dynamic tension variation during lowering6364### Dual-Zone Analysis65| Zone | Depth | Wave Theory | Typical Hs | Focus |66|------|-------|-------------|------------|-------|67| **SZ** (Splash Zone) | Surface | JONSWAP | 1.5m | Sling loads, vessel motion |68| **DZ** (Deep Zone) | Near seabed | Dean Stream | 2.0m | Landing loads, clearance |6970### Coatings & Insulation71| Type | Density (te/m3) | Thickness (mm) | Purpose |72|------|----------------|----------------|---------|73| Insulation | 0.979 | 76.2 | Thermal |74| Buoyancy | 0.694 | 343 | Net uplift |75| Strake | 1.128 | 5 | VIV suppression |7677### Two-Step Statics78- **Step 1**: User-specified starting positions (rigging geometry)79- **Step 2**: Full statics solve (catenary + equilibrium)80- Critical for installation models where initial geometry is non-trivial8182### Parametric Studies83- Environmental headings: 0, 30, 60, 90, 120, 150, 165, 180 degrees84- Sea states: Hs = 0.75, 1.0, 1.25, 1.5, 1.75, 2.0, 2.5m85- Seeds: 20+ random seeds per (heading, Hs) combination86- Total runs per jumper: 200-1000+ simulations8788## Model Library8990### Available Models91| Model | Location | Description |92|-------|----------|-------------|93| Manifold-to-PLET | `docs/modules/orcaflex/jumper/manifold_to_plet/` | Full installation rigging |94| PLET-to-PLEM | `docs/modules/orcaflex/jumper/plet_to_plem/` | Shorter jumper variant |95| SUT/MM | `docs/modules/orcaflex/jumper/sut_mm/` | SZ/DZ/resonance variants |9697### File Structure98```99docs/modules/orcaflex/jumper/<model>/100├── monolithic/ # Sanitized original OrcaFlex YAML101│ ├── DZ_AHCoff.yml102│ ├── SZ.yml103│ └── ...104└── spec.yml # Extracted spec for modular builder105```106107## Commands108109### Generate from spec110```bash111uv run python -m digitalmodel.solvers.orcaflex.modular_generator --spec docs/modules/orcaflex/jumper/manifold_to_plet/spec.yml112```113114### Validate round-trip115```bash116uv run python scripts/semantic_validate.py \117 --mono docs/modules/orcaflex/jumper/manifold_to_plet/monolithic/SZ.yml \118 --modular output/generated_model.yml119```120121### Run benchmark122```bash123uv run python scripts/benchmark_model_library.py --library-only --three-way --skip-mesh124```125126## Implementation Notes127128- Jumper models use the `generic` field in `ProjectInputSpec` (not dedicated jumper schema)129- The `MonolithicExtractor` handles arbitrary OrcaFlex object types including 3DBuoys, 6DBuoys, Constraints, Winches130- Vessel RAO data round-trips through the extractor (verify RAO table sizes)131- ExternalFunction DLL references will cause benchmark failures — add to skip list132- For parametric studies, use the campaign generator pattern with seed/heading/Hs variations133134## Related Skills135- `/orcaflex-extreme-analysis` — General installation modelling136- `/orcaflex-model-generator` — Modular YAML generation from spec137- `/orcaflex-modeling` — Core OrcaFlex modelling patterns138- `/orcaflex-specialist` — Advanced OrcaFlex specialist workflows
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