What are intact stability criteria for passenger ship and cargo ship?

The following   criteria are recommended   for  passenger and cargo  ships.

  • The area under the righting lever  curve   (GZ curve)   should not be less than 0.055  metre-radian  up to e = 30° angle of heel and not  less than 0.09  metre-radian  up to 9 = 40°  or the angle of flooding θf if this angle is less than 40°.   Additionally,   the area under  the righting  lever  curve   (GZ curve)   between  the angles of heel of 30°  and 40°  or between  30°  and θf ,   if this angle  is less than 40°,  should  not  be less than 0.03 metre-radian.
  • The righting  lever   GZ  should  be at least 0.20  m at an angle of heel equal  to or greater  than 30°.
  • The maximum  righting  arm should  occur  at an angle of heel preferably  exceeding  30° but not less than  25°.
  • The initial  metacentric   height  GMo    should  not  be less than 0.15 
  • In addition, for passenger ships, the angle of heel on account  of crowding  of passengers to one side as defined   should  not exceed  10 degree.
  • Where anti-rolling  devices  are installed  in a ship,  the Administration    should  be  satisfied  that  the above  criteria  can be maintained  when  the devices   are in operation.
  • In addition,   for  passenger ships, the  angle  of  heel on  account  of turning  should  not  exceed  10 degree when  calculated  using the following   formula.