Condition of Equilibrium
Clasification Society 2024 - Version 9.40
Statutory Documents - IMO Publications and Documents - Resolutions - Assembly - IMO Resolution A.320(IX) Regulation Equivalent to Regulation 27 of the International Convention on Load Lines,1966 (Adopted on 12 November 1975)Amended by Resolution A.514(13) - Annex - Regulation Equivalent to Regulation 27 of the International Convention on Load Lines, 1966 - Condition of Equilibrium

Condition of Equilibrium

  (13) The condition of equilibrium after flooding shall be regarded as satisfactory provided:

  • (a) The final waterline after flooding, taking into account sinkage, heel and trim, is below the lower edge of any opening through which progressive downflooding may take place. Such openings shall include air pipes, ventilators and openings which are closed-by means of weathertight doors (even if they comply with regulation 12) or hatch covers (even if they comply with regulation 16 or 19(4)), and may exclude those openings closed by means of manhole covers and flush scuttles (which comply with regulation 18), cargo hatch covers of the type described in regulation 27(2), remotely operated sliding watertight doors, and side scuttles of the non-opening type (which comply with regulation 23). However, in the case of doors separating a main machinery space from a steering gear compartment, watertight doors may be of a hinged, quick acting type kept closed at sea, whilst not in use, provided also that the lower sill of such doors is above the summer load waterline.

  • (b) If pipes, ducts or tunnels are situated within the assumed extent of damage penetration as defined in paragraph 12(b) of this Regulation, arrangements are to be made so that progressive flooding cannot thereby extend to compartments other than those assumed to be floodable in the calculation for each case of damage.

  • (c) The angle of heel due to unsymmetrical flooding does not exceed 15 degrees. If no part of the deck is immersed, an angle of heel of up to 17 degrees may be accepted.

  • (d) The metacentric height in the flooded condition is positive.

  • (e) When any part of the deck outside the compartment assumed flooded in a particular case of damage is immersed, or in any case where the margin of stability in the flooded condition may be considered doubtful, the residual stability is to be investigated. It may be regarded as sufficient if the righting lever curve has a minimum range of 20 degrees beyond the position of equilibrium with a maximum righting lever of at least 0.1 metre (4 inches) within this range. The area under the righting lever curve within this range shall be not less than 0.0175 metre-radians (0.689 inch-radians). The Administration shall give consideration to the potential hazard presented by protected or unprotected openings which may become temporarily immersed within the range of residual stability.

  • (f) The Administration is satisfied that the stability is sufficient during intermediate stages of flooding.


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