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The mass and centre of gravity of the whole system are input for the intact stability calculation. For this tutorial a very simplified stability calculation is used. The only input value that is required is the moment of area inertia of the waterline area.

Create a new class in the Knowledge Browser alongside the others that you have made so far: Intact stability calculation.

Create the following parameters in the Knowledge Browser:

Parameter name	Dimension	Determined by	Reference	In Class
`BM`	[m]	USR: User or system/equation	Distance between center of buoyancy and metacenter	`Intact stability calculation`
`GM`	[m]	USR: User or system/equation	Metacentric height	`Intact stability calculation`
`KB`	[m]	USR: User or system/equation	Distance between keel and center of buoyancy	`Intact stability calculation`
`KG`	[m]	USR: User or system/equation	Distance between keel and center of gravity	`Intact stability calculation`
`Moment_of_Inertia`	[m^4]	USR: User or system/equation	Moment of inertia of the water plane area, For this tutorial give a rough estimate	`Intact stability calculation`

Include the following parameters inentityIntact stability calculation: Loa,Boa,BM, COGX, COGY, COGZ, Displacement, GM, KB, KG, Moment_of_Inertia, Rho, and T_design.
Create the following relations (either entity relations or normal relations, it does not matter here):

Loa = ENTITY#(xx).Loa where “xx” is the QEntityID value of entity Main Dimensions.

Boa = ENTITY#(xx).Boa where “xx” is the QEntityID value of entity Main Dimensions.

GM = KB + BM – KG

BM = Moment_of_Inertia / (Displacement/Rho)

KG = COGZ

KB = 0.7*T_design

T_design = ENTITY#(xx).T_design where “xx” is the QEntityID value of entity Hydrostatics.

Displacement = ENTITY#(xx).Mass where “xx” is the QEntityID value of entity Mass calculation.

COGX = ENTITY#(xx).COGX where “xx” is the QEntityID value of entity Mass calculation.

COGY = ENTITY#(xx).COGY where “xx” is the QEntityID value of entity Mass calculation.

COGZ = ENTITY#(xx).COGZ where “xx” is the QEntityID value of entity Mass calculation.

Rho = ENTITY#(xx).Rho where “xx” is the QEntityID value of entity Hydrostatics.

To show computed values set attribute @SHOW on QEntityData.

QUAESTOR > Intact stability calculation > IntactStabilityCalculation.png

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