Stability Calculator (A003)

Given a subdivided solid model of a ship or submarine, this module provides all the functionality necessary for a designer to perform general stability analyses. This module is normally used in conjunction with one or more of the three advanced stability modules, which provided more specific stability calculations and GZ criteria for warships, commercial ships and submarines.

The functionality includes the following:

• Loading conditions (surfaced and submerged) including normal or compensated tanks
• GZ curves: intact, damaged or balanced on a wave
• Cross-flooding time based simulation and analysed against criteria
• Damage definition
• Floodable length calculations
• Freeboard calculations
• One and two point grounding analysis and assessing float off
• Limiting KG curves for stability management
• Deadweight moment curves for operation use
• Tank calibrations
• Define the watertight subdivision

All of the stability has been completely written from scratch in parallel with the development of a Systems Requirement Document (SRD). This was then used by DERA (now QinetiQ) to independently validate all of the stability from first principles. The use of objects minimises the amount of input data, which reduces risk of errors and inconsistencies. As the objects are wired together any changes will force dependant objects to recalculate (when next viewed) such that all the results are up to date. When the stability calculator is combined with one of the advanced stability modules, it provides the functionality to analyse the stability of any vessel from initial design, though life, until disposal.