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 in entity Intact 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.

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