Ship-Moorings

It is a sophisticated computer program designed to simulate the dynamic behaviour of single or multiple floating bodies moored to fixed structures (quays, jetties) as well as floating structures (single point or spread mooring systems, pontoons) under the influence of wind, waves, and currents.

It is a fully dynamic, 6-degree-of-freedom, time-domain, and nonlinear model (real deformation curves of mooring lines, catenaries, and fenders). It stands out for its versatility:

  • Deep and shallow waters
  • Vertical and pile-supported piers
  • Anchored vessels, single-point mooring buoys, MBM, spread systems, and ship-to-ship configurations
  • Floating structures other than conventional vessels

Developed by: Alkyon-Arcadis, Hydraulic Consultancy & Research (Holanda). Since 2024, transfer of ownership to Siport21.

More information




    It solves the impulse response function for ship motions as derived by Cummins (1962). The equation describes the motion of the ship in 6 degrees of freedom (x, y, z, Φ, θ, ψ) in the time domain. The hydrodynamic response characteristics of the ship are based on 3D diffraction theory in the frequency domain. The transfer into the time domain is according to Oortmerssen (1976). The low frequency second order wave exciting forces on shallow water are modelled according to Pinkster (1980).

    External forces include wave exciting forces, hydrodynamic reaction forces, hydrostatic reaction forces, hydrodynamic viscous forces, wind forces, current forces and mooring/fender forces. Wave exciting forces include irregular first order waves and second order (bound) long waves (important for large vessels) and mean wave drift forces (important for ships moored at buoys). Coefficients for the higher frequency hydrodynamic reaction forces are applied using retardation functions as described by Cummins. These enable the associated forces to be computed in terms of the motions of each mode up to that moment.

    Solutions

    • Predicts ship motions at berth under operational or extreme weather conditions.
    • Evaluates forces on mooring lines and fenders to ensure safety and efficiency.
    • Reduces reliance on physical scale models, saving time and cost in project development.
    • Supports decision-making for berth operability and design under complex environmental conditions.
    • Helps to optimize mooring configurations for harbours and offshore terminals.

    How it works

    • Uses a time-domain simulation with 6 degrees of freedom (surge, sway, heave, roll, pitch, yaw).
    • Each time step evaluation of:
      • Environmental conditions, dependent on the ship’s actual position.
      • External forces like line forces, fender forces, wave forces, wind forces.
      • Generating output data at fixed time intervals.
    • Models ship behaviour based on:
      • 3D form description for the ship-fender interaction.
      • Hydrostatic and mass/inertial properties.
      • Dynamic flow force coefficients.
      • Wind force coefficients.
      • Ship dynamic characteristics added mass, wave force transfer function.
      • Added mass and wave force transfer functions (via 3D diffraction models).
    • Avails an integrated Static Analyzer Module for the fast execution and simplified analysis of static scenarios.
    • Allows input of multiple wave systems (e.g., sea, swell, long waves) with directional variation.
    • Includes mooring line and fender configurations, accounting for linear or nonlinear elasticity.
    • Outputs include:
      • Motion time series (exursions, velocities, accelerations).
      • Mooring forces (line forces and extensions, total bollard forces and anchor and chain forces) and fender forces and deflections.
      • Statistical and spectral analyses.
      • Exceedance distributions, using post-processing tools.
      • Animated visualizations from top-view and cross section.
    • Validated through extensive simulations and comparisons with physical model tests.