Mooring Analysis

What is mooring analysis

Verifying mooring integrity and predicting floating unit motion under design environmental conditions.

A mooring analysis verifies the structural adequacy of mooring lines against ultimate limit states and predicts the motion response of a moored floating unit.

For most floating offshore installations, the mooring system is the sole means of station-keeping — making its integrity a safety-critical concern that demands rigorous verification.

Who needs a mooring analysis

• Vessel owners undertaking newbuild projects for floating assets with mooring-based station-keeping
• Offshore contractors relocating an existing moored facility to a new site or reassessing a revised mooring spread
• Project operators planning project or construction where the floating unit must stay within a tight operational envelope

Scope of work of mooring analysis

• Mooring line tension analysis — intact and damaged conditions
• Platform offsets and motion amplitudes — surge, sway, heave, roll, pitch, yaw
• Safety factor checks against classification society criteria
• Motion envelopes for operational planning
• Identification of critical load cases and limiting environmental directions

The analysis uses specialised hydrodynamic software for coupled time-domain or frequency-domain simulation, incorporating vessel RAOs, wind and current drag characteristics, mooring line dynamics, and site-specific metocean data. Classification society rules — including DNV-ST-E301, API RP 2SK, and ISO 19901-7 — govern the safety factors and acceptance criteria.

Project experience

CCS-classed near-shore floating recreation facility — the first of its kind in China. Full mooring analysis including intact and damaged condition checks, approved by CCS.

Temperary mooring of CMIC Gretha — site-specific environmental load assessment and mooring line tension verification for a floating wind deployment study.

Relocation mooring assessment — mooring spread re-evaluation for an existing moored unit moved to a new operational site.

Frequently asked questions

What information do you need to start?

A vessel lines plan or general arrangement, site metocean data, proposed mooring arrangement, and any specific classification society or operational requirements.

How long does a typical mooring analysis take?

A standard calculation (intact condition) for a single-point or spread mooring system typically takes two to four weeks, depending on the number of load cases and environmental directions and the complexity of hull also.

Additional time may be needed for damaged-condition or multi-scenario evaluations.

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