Establish the following principal
| .1 the
subdivision length, Ls||Regulation 1(b)|
| .2 the subdivision breadth, B1
the subdivision breadth, B2 ||Regulation 1(d)(ii)|
| .4 the deepest subdivision
draught, ds ||Regulation
.5 the number of main compartments|
| .6 the ship's maximum
operational KG at the deepest subdivision
For each of the main
compartments establish the following:
| .1 the values X1, X2 || Regulation
the corresponding ksi1, ksi2 and ksi12 values || Regulation
using the values obtained from .1 and .2,
'a' - see regulation 6(b), formula
'p' - see regulation 6(c), formula (IV)|
| 'r' - see regulation
7(b)(ii), formula (X)|
| (where longitudinal
subdivision is concerned).|
The calculation of the 's' factor is by
the use of the formula given in page 3, annex 5, of SLF 35/20. The
s = c x 2.58 x 4
√ GZmax x
Range x Area
When the criteria
for compliance with the requirements of regulation II-1 of the 1974
SOLAS Convention, as amended, are fully met, then s = 1 is to be
assumed. The 's' factor is only to be calculated for the deepest
subdivision draught (ds), rather than for the three draughts
specified for the full resolution A.265(VIII) method. The deepest
subdivision draught in this instance is the subdivision draught
appropriate to the vessel. 2.4
The damage stability results which are used to
obtain the residual stability characteristics, that is, Gzmax, range
and area under the curve, are to be based on the ship's maximum
operational KG at the deepest subdivision draught. Level trim is to
be assumed. 2.5
summary of 'a', 'p', 'r', 's' should now be made for all the main
compartments. The product a×(pr)×s is to be calculated for each
damage case to obtain the contribution to the index 'A' (say, delta
A>0). A summation of the 'delta A' values is then made to obtain
the contribution to the 'A' value from the single compartments
outlined above is now performed for all cases involving the assumed
flooding of two adjacent compartments. 2.7
If the vessel is not fully compliant
with the required residual stability standard, then at least one of
the damage cases appropriate to the subdivision standard will have
an 's' value which is less than 1, i.e:
.1 for a
two-compartment vessel, at least one two-compartment damage case
will have s<_1 br="br" xmlns="http://standaarden.overheid.nl/puc/terms/" xmlns:puc="http://standaarden.overheid.nl/puc/terms/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xhtml="http://www.w3.org/1999/xhtml">.2 for a one-compartment vessel, at least one
one-compartment damage case will have s<_1. br="br">2.8
After this the KG described in
2.4 above is to be modified such that the results of the
worst damage case just meet the required residual stability
standard, i.e. s = 1 for the worst case. 2.9
A subdivision index Amax
is then calculated at the same draught and trim used in 2.4
above but using the modified KG value described in 2.8
above. All single and two-compartment groups contributing to
the index are to be included. For a vessel having a
two-compartment standard, this means that all 's' values
will be equal to 1. For a vessel having a one-compartment
standard, all one-compartment damages will have 's' values
equal to 1.
The use of the probabilistic
concept in assessing the residual stability standards of
existing ro-ro passenger ships.
below contains only the probabilistic parts of IMO
resolution A.265(VIII) which are to be applied for this
The primary objective is
to calculate the attained subdivision index 'A' by modifying
the normal calculation procedure as indicated below, for a
substantial sample of existing ro-ro passenger ships.
Therefore, it is only necessary to
consider those parts of regulations 1 to 8 inclusive which
should apply for the sake of this exercise.
Of these eight regulations, all those which are
deterministic in nature are either ignored or adapted to
conform to probabilistic principles.
Regulation 2 - Subdivision index
For the purposes of this
exercise this regulation is to be ignored.
Regulation 4 - Permeabilities
4(b) Replace the
permeability value for cargo spaces by a constant value of
0.90 for freight/vehicle spaces.
Regulation 5 - Subdivision and
5(c)(i)(1)The requirements for the GM values (in the final
stage of flooding) are to be replaced by the requirements
given in USSR paper SLF 35/4/9 - See later for a full
description of these requirements.
5(c)(i)(2)The maximum permitted
equilibrium angle after flooding is included in the
requirements of regulation 5(c)(i)(1).
5(c)(i)(3)This is to be interpreted as
non-immersion of the bulkhead deck note that this is not the
margin line - in the final stage of flooding
5(c)(iii) Applies. In
respect of the time for equalisation of cross-connected
spaces, the provisions of resolution A.266(VIII) should be
Applies. A standard of residual stability during the
intermediate stages of flooding, for the purposes of this
exercise only, is to be governed by the heel angle given in
this regulation, i.e. 20 degrees.
5(d) Applies, except that in place of the
final sentence "For each initial trim ... flooded condition"
put "The ship shall be at its design trim (i.e. zero trim in
most cases) at the deepest subdivision loadline".
Regulation 6 -
Attained subdivision index
6(a)(i) Applies, except that the words "In
addition to complying with regulation 5" should be ignored.
except that a full stop should be placed after "... for all
possible pairs of adjacent compartments" and the rest of the
subparagraph should be ignored.
6(a)(iii) Applies, except that the words
"according to Regulation 5" should be ignored.
6(b) Applies, except
that when the end bulkheads of a compartment contains a
step, or steps, then the length of such a compartment is to
be based upon the position of those end bulkheads at the
the formula (VIII) by the formula for 'si' from the paper
SLF 35/4/9 - see below for full details. In respect of GMR,
this should be taken as the GM corresponding to the intact
condition at the deepest subdivision loadline.
6(d)(ii) In place of the
weighted 's' value i.e. s = 0.45s1 + 0.33s2 + 0.22s3, 's'
for the deepest subdivision loadline should be used.
Regulation 7 -
Combined longitudinal and transverse subdivision
The 's' factor to be
used for this exercise only
s = c x 2.58 x
√ GZmax x Range x Area
Gzmax is the
maximum positive residual righting lever (m) within the
range of 15 degrees beyond the angle of equilibrium, but not
more than 0.1 m;
Range is the range of
positive righting levers beyond the angle of equilibrium, in
degrees, but not more than 15 degrees;
Area is the area under the righting lever curve (m.rad),
measured from the angle of equilibrium to the lesser of the
angles at which progressive flooding occurs, or 22 degrees
(measured from the upright) in the case of a one-compartment
flooding, or 27 degrees (measured from the upright) for the
flooding of two or more adjacent compartments, but not more
than 0.015 m.rad.
respect of the 'Area', please note that the allowable area
is up to a heel angle, measured from the upright 22
degrees/27 degrees, depending on whether flooding of a
single compartment or two adjacent compartments is
concerned. and c is determined according to the following:
c = 1 where the final angle of
equilibrium, theta e, is not more than 7 degrees,
c = O where the final angle of
equilibrium, theta e, is more than 20 degrees
else c = square root of (20 degrees-theta
concerning the survival capability of an existing ro-ro
Application of MSC/Circ.574
Ship designation for identification
Principal particulars (in metres)|
|Subdivision length Ls||Breadth B1||Depth|
dk. limiting the allowed buoyancy|
2. Give the number of
compartments - below the bulkhead dk. -bounded by the main
Of the compartments mentioned at 2., how many rely on
longitudinal subdivision (inside B/5) to meet the
deterministic requirements? Give in terms of % Ls.:
4. Year of build:
5. Year of issue of the
initial Passenger Certificate.
6. Lifeboat capacity.
7. The total number of persons
permitted to be on board (passengers and crew)
8. Deepest subdivision
SOLAS regulations which apply.
10. According to 9., what compartment
11. Give the
actual ship KG (in metres) for the loading condition (at
draught ds) used in the damage stability calculations. If
the KG used is not the actual KG, give further details at
12. Is the
freight/vehicle cargo carried below the bulkhead deck? Is
the freight/vehicle cargo carried above the bulkhead deck?
subdivision index 'A'.
14. Give the notional ship KG such that the s-values
appropriate to the compartmental standard at 10. are equal
subdivision index Amax.
16. Ratio A/Amax in %.
17. Additional relevant information.