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The initial stability (GM) of the ships can also be calculated using numerical integration.

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• Add a new class,

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• called Stability, as sub-class of 

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• Geometry

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• . Add the following relation to this class:

GM = KB + BM - KG

The dimension dimensions of all new parameters is must be meters, and they are defined by a relation (which follows). GM  SYS parameters. Their relations follow. GM is a Top Goal and should be moved to Top Goals/Undefined.

In the class Stability, enter the following relations.

Distance between keel K and center of buoyancy B, select KB and right click Image Removed " , right-click and select New Relation..." (or press Ctrl+N). By selecting KB it is automatically presented as left side part of the relation:

KB = 0.7 * T

Distance between keel K and center of gravity G, KG, in meters:

KG = 0.8 * T

Distance between center of buoyancy B and metacenter M, BM, in meters:

BM = Moment_of_Inertia / (DISP * 1000/ Rho)

Moment of inertia of the waterplane area in m^4:

Moment_of_Inertia = 1/12 * INTEGR(Hull(@X, @B3_Frame, Lpp, B), 2, @X, @B3_Frame, 2, 0, Lpp)

Please note (and you might have experienced this in the previous tutorial too) that the parameter Moment_of_Inertia might still have a red cross and an Error warning in the knowledge base although you have provided the relation and a dimension. When this is the case, for sure you still have the Hull object in focus in a solution of the Workbase. When this is the case, Quaestor communicates that the relation you have provided cannot be used inside this object (and thus you have a red cross for Moment_of_Inertia). When you select a top node of a solution, you will see that the Moment_of_Inertia parameter is properly defined.

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