digitalmodel — Engineering Intelligence

Deepwater Mudmat Installation Analysis

180 parametric cases: 2 vessels x 6 depths x 3 mudmats x 5 sea states
180 parametric cases analysed overnight
Generated 2026-04-15 04:04 UTC · demo_03
Live walkthrough of deepwater mudmat installation engineering across 180 parametric cases — vessel RAO, sea-state, mudmat geometry
Live walkthrough — deepwater mudmat installation across 180 parametric cases (DNV H103-coupled, OrcaFlex-driven, vessel-RAO sensitivity).

Download Capability Summary (PDF, 1 page)

Methodology

This analysis screens deepwater mudmat installations across a parametric matrix of vessels, water depths, structure sizes, and sea states. Each case evaluates five installation phases per DNV-RP-H103 and DNV-ST-N001 methodology.

Phase 1: Lift-off

Hook load = massair × g × DAFlift (1.10). Checked against crane SWL at operating radius via interpolation of the crane capacity curve.

Phase 2: In-air Transit

Tilt check for 4-point lift with spreader beam. CoG offset / hook height gives tilt angle, checked against 5° limit. Symmetric mudmats always pass.

Phase 3: Splash Zone (Critical)

Slamming force: Fslam = 0.5 × ρ × Cs × Ap × vrel2, where vrel = vlowering + vwave. Additional varying buoyancy and drag forces. DAFsplash = 1.30. This phase typically governs for large mudmats in higher sea states.

Phase 4: Lowering through Water Column

Cable tension = Wsub + Wcable(depth) + snap load. Snap load from dynamic cable response using vessel heave RAO. Checked against 85% of wire MBL. Becomes critical at extreme depths due to cable self-weight.

Phase 5: Landing

Bearing pressure = Wsub / Abase. Checked against 50 kPa soft clay bearing capacity. Rarely governs for typical mudmat proportions.

Go/No-Go Criteria

  • GO: All phases pass AND max utilisation < 0.85
  • MARGINAL: All phases pass AND max utilisation in [0.85, 1.00]
  • NO-GO: Any phase fails (utilisation > 1.00)

Applicable Codes & Standards

  • DNV-RP-H103 (2011) — Modelling and Analysis of Marine Operations
  • DNV-ST-N001 (2021) — Marine Operations and Marine Warranty
  • DNV-RP-C205 (2010) — Environmental Conditions and Environmental Loads

Installation Screening Summary

All cases at Hs = 2.0 m reference sea state

Vessel Structure Depth (m) Max Util. Governing Phase Status
Large CSV Mudmat-S-50te 500 24.7% Landing GO
Large CSV Mudmat-M-100te 500 21.5% Landing GO
Large CSV Mudmat-L-200te 500 20.6% Splash zone GO
Large CSV Mudmat-S-50te 1000 24.7% Landing GO
Large CSV Mudmat-M-100te 1000 21.5% Landing GO
Large CSV Mudmat-L-200te 1000 20.6% Splash zone GO
Large CSV Mudmat-S-50te 1500 24.7% Landing GO
Large CSV Mudmat-M-100te 1500 21.5% Landing GO
Large CSV Mudmat-L-200te 1500 20.6% Splash zone GO
Large CSV Mudmat-S-50te 2000 24.7% Landing GO
Large CSV Mudmat-M-100te 2000 21.5% Landing GO
Large CSV Mudmat-L-200te 2000 20.6% Splash zone GO
Large CSV Mudmat-S-50te 2500 24.7% Landing GO
Large CSV Mudmat-M-100te 2500 21.5% Landing GO
Large CSV Mudmat-L-200te 2500 20.6% Splash zone GO
Large CSV Mudmat-S-50te 3000 24.7% Landing GO
Large CSV Mudmat-M-100te 3000 21.5% Landing GO
Large CSV Mudmat-L-200te 3000 20.6% Splash zone GO
Medium CSV Mudmat-S-50te 500 24.7% Landing GO
Medium CSV Mudmat-M-100te 500 34.8% Splash zone GO
Medium CSV Mudmat-L-200te 500 71.5% Splash zone GO
Medium CSV Mudmat-S-50te 1000 24.7% Landing GO
Medium CSV Mudmat-M-100te 1000 34.8% Splash zone GO
Medium CSV Mudmat-L-200te 1000 71.5% Splash zone GO
Medium CSV Mudmat-S-50te 1500 24.7% Landing GO
Medium CSV Mudmat-M-100te 1500 34.8% Splash zone GO
Medium CSV Mudmat-L-200te 1500 71.5% Splash zone GO
Medium CSV Mudmat-S-50te 2000 24.7% Landing GO
Medium CSV Mudmat-M-100te 2000 34.8% Splash zone GO
Medium CSV Mudmat-L-200te 2000 71.5% Splash zone GO
Medium CSV Mudmat-S-50te 2500 24.7% Landing GO
Medium CSV Mudmat-M-100te 2500 34.8% Splash zone GO
Medium CSV Mudmat-L-200te 2500 71.5% Splash zone GO
Medium CSV Mudmat-S-50te 3000 24.7% Landing GO
Medium CSV Mudmat-M-100te 3000 34.8% Splash zone GO
Medium CSV Mudmat-L-200te 3000 71.5% Splash zone GO

Take This Analysis Live During Operations

This report used design sea states to screen parametric cases overnight. During the actual operation, digitalmodel can feed your vessel's measured motion data — VMMS, IMMS, MRU — directly into the same engineering models for real-time go/no-go decisions.

Instead of relying on forecasted Hs limits, the installation screening updates continuously with actual crane tip motions, hook loads, and dynamic amplification factors measured on your vessel.

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Assumptions & Limitations

  • Crane SWL evaluated at maximum capacity radius (most favourable position)
  • DAF lift-off = 1.10, DAF splash zone = 1.30 per DNV-ST-N001
  • JONSWAP peak period approximation: Tp = 4 * sqrt(Hs)
  • Slamming coefficient Cs = 5.0 for flat-bottom structures per DNV-RP-H103 Table 4-1
  • Added mass coefficient Ca = 1.0, drag coefficient Cd = 2.0 for flat plate geometry
  • Wire rope MBL safety factor = 0.85 (max tension / MBL)
  • Bearing capacity limit = 50 kPa (soft clay, undrained)
  • Vessel heave at crane tip uses simplified single-frequency RAO peak
  • No current loads or wind loads on structure during lowering
  • Rigging weight excluded from hook load calculations
  • Seabed assumed flat — no slope corrections for landing
  • Seawater density = 1025 kg/m3 throughout water column
Chart 1: Go/No-Go Installation Matrix
Side-by-side vessel comparison at Hs = 2.0 m reference sea state.
Chart 2: Crane Utilisation vs Water Depth
Max utilisation across all phases. Solid = Large CSV, dashed = Medium CSV.
Chart 3: Phase Utilisation vs Water Depth — Splash & Lowering
Shows how splash zone dominates shallow cases while lowering governs at depth.
Chart 4: Operability Envelope — Max Hs vs Structure Weight
Maximum sea state where all depths pass. Defines weather window requirements.
Chart 5: Vessel Head-to-Head — Structures Installable per Depth
Number of mudmat sizes (out of 3) each vessel can install at Hs = 2.0 m.

These results are preliminary engineering estimates generated by automated parametric analysis. All outputs require review by a qualified engineer before use in design or operational decisions.

References: DNV-RP-H103 (2011) — Modelling and Analysis of Marine Operations · DNV-ST-N001 (2021) — Marine Operations and Marine Warranty · DNV-RP-C205 (2010) — Environmental Conditions and Environmental Loads

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