Mooring Fatigue — 8-line R4 120mm chain (deepwater spread)

Engineering analysis, grounded in real-world precedent

Engineering result

Minimum fatigue life 458 yr at Line 1 — above the 25-yr design basis.

Min fatigue life

458 yr

Max damage / line

0.055

Governing line

Line 1

Design basis

25 yr

Live digitalmodel mooring_fatigue — T-N screening (DNV-RP-C203 S-N curve D, seawater with CP), Miner's-rule damage across the tension scatter, DFF 3 · LIVE digitalmodel mooring_fatigue run (subprocess, dm's own venv). Component MC-CH-R4-120 — MBL 11700 kN, Vicinay catalog; geometry + MBL from the mooring component catalog. Tension scatter is a representative spectrum scaled to MBL (illustrative loading; the catalog carries no cyclic history). #768.

Real-world precedent — Mooring / station-keeping failure

Latest on record (circles) and highest-consequence on record (diamonds). Hover for detail.

Latest on record

2020-01-29property_>$25kMC 437 G33733Incident >$25K - Mooring lineBSEE (offshore)
2006-12-24environmentalGoM (unspecified)Pollution - Anchor dragBSEE (offshore)

Highest-consequence on record

2005-09-23catastrophicGC 237 G15563Pollution - Capsized - Mooring FailureBSEE (offshore)
2002-10-03catastrophicSS 126 G12940Pollution - Capsized during Hurricane LiliBSEE (offshore)