Requirements for application of hydrostatic balance loading in cargo tanks as per the Appendix to the IMO Guidelines
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Statutory Documents - IMO Publications and Documents - Circulars - Marine Environment Protection Committee - MEPC/Circular.365 – Interpretation of Requirements for Application of Hydrostatic Balance Loading in Cargo Tanks (Resolution MEPC.64(36)) – (Adopted 26 July 1999) - Annex - IACS Unified Interpretation MPC 7 - Hydrostatic Balance Loading - Requirements for application of hydrostatic balance loading in cargo tanks as per the Appendix to the IMO Guidelines

Requirements for application of hydrostatic balance loading in cargo tanks as per the Appendix to the IMO Guidelines

  .17 The number of tanks to be HBL is determined by the conditions underlined by EOS3 not being greater than EOS2 for the ship arranged with non-cargo side tanks and furthermore not being greater than 85% of the EOS1. Once it has been established that these conditions have been met, with zero trim, adjusted Vi, nominal density and maximum cargo level as per the Appendix formula, the configuration is considered having been validated and there is no need to recalculate EOS3 for the actual loading conditions corresponding to that configuration.

Filling levels in HBL tanks for the actual loading conditions are determined by the HBL formula of the Appendix to the Guidelines using actual density and draught at each HBL tank location.

  .18 Partial filling less than HBL height may alternatively be considered. In such conditions, the cargo height in the selected cargo tanks is to be determined based on EOS3 compliance with the criteria, with zero trim, nominal density, and draught corresponding to adjusted Vi.

Where cargo levels less than maximum cargo level calculated by the HBL formula of the Appendix to the Guidelines are used for EOS3 calculation, the actual filling levels will be calculated as follows:

where
K = is a correction factor h(HBL)/h(PF) with:
h(PF) = maximum cargo height in partial filling condition, leading to a satisfactory EOS3 for the selected configuration (with nominal density, assumed zero trim, corresponding draught d (PF), adjusted Vi).
H(HBL) = maximum HBL cargo height for the selected configuration at draught d(PF).

Thus:

K = ((d (PF) - hi ) x ρsx g - 100 ΔP)/(ρn x g xh (PF)))

Matrix of Parameters

EOS (see Note 1) Assumed trim Draught Density Loaded oil volume Consumables and ballast
EOS 1 0 Maximum assigned summer water line Nominal V1 none
EOS 2 0 Corresponding draught Nominal V2 none
EOS 3 0 Corresponding draught Nominal V3 See Note 2
where
V1 = 98% of cargo and fuel oil tanks volumes within Lt in the original configuration
V2 = V 1 minus 98% volume of side protection tanks corresponding to 13 G(4), in way of cargo tanks
V3 = Oil volume of full cargo and fuel oil tanks within Lt (at 98%) and of HBL and/or partially loaded tanks
Note 1

  Note 2 Ballast may be used to achieve an increased draught only in determining EOS3.

Parent topic: Annex - IACS Unified Interpretation MPC 7 - Hydrostatic Balance Loading
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