In order to ensure uniform application of Regulation 7(e)
of Chapter II of the International Convention for the Safety of Life
at Sea and/or Regulation 5(c) of the Regulations on Subdivision and
Stability of Passenger Ships (Resolution A.265(VIII)), Administrations
are recommended to apply the following cross-flooding formulae:
Time required for complete cross-flooding (seconds) 
(I)
Time required to bring vessel from an angle of θ° (or the angle of margin line immersion) to the upright 
(II)
Hence:
Time required from commencement of cross-flooding to θ° heel (or the angle of the margin line immersion) 
(III)
Figure 1 Cross-flooding diagram
The following parameters, in feet or metric units, are used
in formulae (I)-(III):
|
W
|
= |
volume
of water entering the equalizing compartments during the considered
period, |
|
S
|
= |
cross-section
area through the cross-flooding duct, |
|
Ho
|
= |
head of water before commencement of cross-flooding, |
|
Hθ
|
= |
head of water at the time of cross-flooding where the vessel
is heeled θ°, (or at the angle of margin line
immersion),
|
|
hf
|
= |
final head of water after cross-flooding (hf
=0
when the level inside the equalizing compartment is equal to the free
level of the sea),
|
|
F
|
= |
|
|
|
= |
dimensionless
factor of reduction of speed through the duct, being a function of
bends, valves, etc., in the cross-flooding system. |
For guidance some typical values for k are
given in Figures 2 - 12.