Stability & Motions Analysis

Stability Analysis.

At MBM we generate the vessel hull form with tanks and compartments to enable both intact and damaged analysis. The environment is predefined to gain results in many formats.

• Integrated compartment definition.
• Complex tanks in the analysis.
• Linked tanks and compartment analysis.
• Integrated load cases.
• Environment options including: grounding, waveform.
• Standard and customisable stability criteria.


The Stability analysis is undertaken with a full set of comprehensive methods.

• Probabilistic damage stability.
• Batch analysis for multiple load and damage cases.
• Upright hydrostatics.
• Large angle stability (GZ / righting lever).
• Equilibrium calculations.
• KN cross curves.
• Limiting KG analysis (maximum VCG).
• Floodable length.
• Longitudinal strength.
• Tank calibration.
• Trim & stability booklet.
• Loading manual.


Example of Hull form with some tanks and compartments in place.



Motions Analysis.

The motion analysis is developed from a direct integration from a surface model.

•Calculation of vessel response amplitude operators.
•Calculation of added resistance response and integration of added resistance for specified sea spectrum.
•Calculation of motion, velocity and acceleration spectra at centre of gravity and specified positions on vessel (absolute and relative motions).
•Integration of significant vessel motions for specified sea spectrum.
•Large number of standard spectra: ITTC/Bretschneider 2 parameter; Bretschneider 1 parameter; JONSWAP; DNV and Peirson Moskowitz
•Graphical and tabular presentation of all data generated by the analysis.
•Interactive results graphs.
•Hull-form design & optimization.
•Propeller & rudder selection.
•Resistance & propulsion calculation.
•Seakeeping & maneuverability studies.
•Tank test coordination & supervision.


This can all be supported with 3D visualisation of ship motions in regular or irregular waves.


Waveform is defined to gain vessel hydrostatics.



Mooring Analysis.

Static mooring analysis generally applies to most cases of wind and current loading in which vesselmotions are not important.Static analysis maybe employed to optimize mooring line arrangements and the size and location of mooring hardware and to determine individual mooring line loads.Static mooring analysis is usally adequate to verify that a vessel can safely moor at a particular terminal or can remain moored in a predicted environment.


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