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Cross curves of stability

  • The Cross Curves Of Stability are used to determine the length of the righting arm at any angle of inclination for a given displacement.
  • To draw the curve of statical stability, we need GZ values for various angles of heel.
  • For this we use the GZ cross curves of stability.
  • These curves are provided for an assumed KG, tabulating GZ values for various displacements and angles of list.
  • Called cross curves because the various curves actually ‘cross’ each other.
  • Since the curves are plotted for an assumed KG, if the actual KG differs from this a correction (GG1Sineθ) needs to be applied.
  • This correction is positive if the actual KG is less than the assumed KG and vice-versa.
  • After obtaining the GZ values at various angles, the curve of statical stability is prepared

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