AMENDMENTS TO THE INTERNATIONAL CONVENTION FOR THE SAFETY OF LIFEAT SEA, 1974
AMENDMENTS TO THE INTERNATIONAL CONVENTION FOR THE SAFETY OF LIFEAT SEA, 1974
[Adopted on 25 May 1990 by Resolution MSC. 19(58)]
Whole document
TABLE OF CONTENTS
CHAPTER II-1 CONSTRUCTION-SUBDIVISION AND STABILITY, MACHINERY AND
ELECTRICAL INSTALLATIONS
Addition of new Part B-1
PART B-1 SUBDIVISION AND DAMAGE STABILITY OF CARGO SHIPS
25-1 Application
25-2 Definitions
25-3 Required subdivision index "R"
25-4 Attained subdivision index "A"
25-5 Calculation of the factor "P "
i
25-6 Calculation of the factor "S "
i
25-7 Permeability
25-8 Stability information
25-9 Openings in watertight bulkheads and internal decks in cargo
ships.
25-10 External openings in cargo ships
AMENDMENTS TO THE INTERNATIONAL CONVENTION FOR THE SAFETY OF LIFE AT SEA,
1974
[Adopted on 25 May 1990 by Resolution MSC ¡¤19(58)]
CHAPTER II-1 CONSTRUCTION-SUBDIVISION AND STABILITY, MACHINERY ANDELECTRICAL INSTALLATIONS
Insert the following new part B-1, comprising Regulations 25-1 to
25-10, after existing part B: "PART B-1 SUBDIVISION AND DAMAGE STABILITY
OF CARGO SHIPS *
[* The Maritime Safety Committee, in adopting the Regulations
contained in part B-1, invited Administrations to note that the
Regulations should be applied in conjunction with the explanatory notes
developed by the Organization in order to ensure their uniform
application.] (This part applies to cargo ships constructed on or after 1
February 1992)
Regulation 25-1 Application
1 The requirements in this part shall apply to cargo ships over 100 m
in length ("Ls") but shall exclude those ships which are shown to comply
with subdivision and damage stability regulations in other instruments **
developed by the Organization.
[** Ships shown to comply with the following Regulations may be
excluded from the application of part B-1:
.1 annex 1 to MARPOL 73/78;
.2 International Bulk Chemical Code (resolutions MSC. 4(48) and
MSC. 10(54)), as amended;
.3 International Gas Carrier Code (resolution MSC. 5(48));
.4 Guidelines for the Design and Construction of Offshore Supply
Vessels (resolution A. 469 (XII));
.5 Code of Safety for Special Purpose Ships (resolution A. 534
(13));
.6 damage stability requirements of Regulation 27 of the 1966 Load
Line Convention as applied in compliance with resolutions A. 320(IX) and
A. 514(13), provided that in the case of ships to which Regulation 27(9)
apply, main transverse watertight bulkheads, to be considered effective,
are spaced according to paragraph (12) (f) of resolution A. 320(IX).]
2 Any reference hereinafter to Regulations refers to the set of
Regulations contained in this part.
3 The Administration may for a particular ship or group of ships
accept alternative arrangements, if it is satisfied that at least the
same degree of safety as represented by these Regulations is achieved. Any
Administration which allows such alternative arrangements shall
communicate to the Organization particulars there of.
Regulation 25-2 Definitions
For the purpose of these Regulations, unless expressly provided
otherwise:
1.1 Subdivision load line is a waterline used in determining the
subdivision of the ship.
1.2 Deepest subdivision load line is the subdivision load line which
corresponds to the summer draught to be assigned to the ship.
1.3 Partial load line is the light ship draught plus 60% of the
difference between the light ship draught and deepest subdivision load
line.
2.1 Subdivision length of the ship ("Ls") is the greatest projected
moulded length of that part of the ship at or below deck or decks limiting
the vertical extent of flooding with the ship at the deepest subdivision
load line.
2.2 Mid-length is the mid point of the subdivision length of the ship.
2.3 Aft terminal is the aft limit of the subdivision length.
2.4 Forward terminal is the forward limit of the subdivision length.
3 Breadth ("B") is the greatest moulded breadth of the ship at or
below the deepest subdivision load line.
4 Draught ("d") is the vertical distance from the moulded baseline at
mid-length to the waterline in question.
5 Permeability (" ¦Ì") of a space is the proportion of the immersed
volume of that space which can be occupied by water.
Regulation 25-3 Required subdivision index "R"
1 These Regulations are intended to provide ships with a minimum
standard of subdivision.
2 The degree of subdivision to be provided shall be determined by the
required subdivision index "R", as follows:
|-------|
| 1/3 |
| R=(0.002+0.0009Ls) | where "Ls" is in metres.
|-------|
Regulation 25-4 Attained subdivision index "A"
1 The attained subdivision index "A", calculated in accordance with
this Regulation, shall not be less than the required subdivision index
"R", calculated in accordance with paragraph 2 of Regulation 25-3.
2 The attained subdivision index "A" shall be calculated for the ship
by the following formula:
|----|
| A=¡Æp s |
| i i |
|----|
where:
"i" represents each compartment or group of compartments under
consideration,
"p " accounts for the probability that only the compartment or group
i of compartments under consideration may be flooded, disregarding
any horizontal subdivision,
"s " accounts for the probability of survival after flooding the
i compartment or group of compartments under consideration,
including the effects of any horizontal subdivision.
3 In calculating "A", level trim shall be used.
4 This summation covers only those cases of flooding which contribute
to the value of the attained subdivision index "A".
5 The summation indicated by the above formula shall be taken over the
ship's length for all cases of flooding in which a single compartment or
two or more adjacent compartments are involved.
6 wherever wing compartments are fitted, contribution to the summation
indicated by the formula shall be taken for all cases of flooding in which
wing compartments are involved; and additionally, for all cases of
simultaneous flooding of a wing compartment or compartments and the
adjacent inboard compartment or compartments, assuming a rectangular
penetration which extends to the ship's centreline, but excludes damage to
any centreline bulkhead.
7 The assumed vertical extent of damage is to extend from the baseline
upwards to any watertight horizontal subdivision above the waterline or
higher. However, if a lesser extent will give a more severe result, such
extent is to be assumed.
8 If pipes, ducts or tunnels are situated within assumed flooded
compartments, arrangements are to be made to ensure that progressive
flooding cannot there by extend to compartments other than those assumed
flood. However, the Administration may permit minor progressive flooding
if it is demonstrated that its effects can be easily controlled and the
safety of the ship is not impaired.
9 In the flooding calculations carried out according to the
Regulations, only one breach of the hull need be assumed.
Regulation 25-5 Calculation of the Factor "Pi "
1 The factor "p " shall be calculated according to paragraph 1.1 as
i
appropriate, using the following notations:
X =the distance from the aft terminal of "L " to the foremost
1 s
portion of the aft end of the compartment being considered;
X =the distance from the aft terminal of "L " to the aftermost
2 s
portion of the forward end of the compartment being considered;
E =X /L
1 1 s
|----|
| E =X /L |
| 2 2 s |
|----|
E=E +E -1
1 2
|----|
| J=E - E |
| 2 1 |
|----|
J'=J-E, if E¡Ý0
J'=J+E, if E£¼0
The maximum nondimensional damage length
|-----------|
| J =48/L , but not more than 0.24. |
| max s |
|-----------|
The assumed distribution density of damage location along the
ship's length
a=1.2+0.8E, but not more than 1.2.
The assumed distribution function of damage location along the
ship's length
F=0.4+0.25E(1.2+a)
|-----|
| y=J/J |
| max |
|-----|
P=F * J
1 max
|------|
| 2 |
| q=0.4F (J ) |
| 2 max |
|------|
|--------|
| 3 |
| 2 y |
| F = y - --, if y£¼1, |
| 1 3 |
|--------|
1
F =y- --, otherwise;
1 3
|--------|
| 3 4 |
| y y |
| F =-- - --, if y£¼1, |
| 2 3 12 |
|--------|
2
y y 1
F =-- - -- + --, otherwise.
2 2 3 12
1.1 The factor "p " is determined for each single compartment:
i
1.1.1 Where the compartment considered extends over the entire ship
length, "L ":
s
p =1
i
1.1.2 Where the aft limit of the compartment considered coincides with
the aft terminal:
p =F+0.5ap+q
i
1.1.3 Where the forward limit of the compartment considered coincides
with the forward terminal:
p =1-F+0.5ap
i
1.1.4 When both ends of the compartment considered are inside the aft
and forward terminals of the ship length, "L ":
s
p =ap
i
1.1.5 In applying the formulae of paragraphs 1.1.2, 1.1.3 and 1.1.4,
where the compartment considered extends over the "mid-length", these
formulae values shall be reduced by an amount determined according to the
formula for "q", in which "F " is calculated taking "y" to be J'/J
2 max
2 Wherever wing compartments are fitted, the "p " -value for a wing
i
compartment shall be obtained by multiplying the value, as determined in
paragraph 3, by the reduction factor "r" according to subparagraph 2.2,
which represents the probability that the inboard spaces will not be
flooded.
2.1 The "P "-value for the case of simultaneous flooding of a wing and
i adjacent inboard compartment shall be obtained by using
the formulae of paragraph 3, multiplied by the factor (1-r).
2.2 The reduction factor "r" shall be determined by the following
formulae:
For J ¡Ý0.2b/B:
b 0.08
r=-(2.3 + --) + 0.1, if b/B ¡Ü0.2
B J+0.02
0.016 b
r=(--- + - + 0.36), if b/B£¾0.2
J+0.02 B
For J £¼0.2 b/B the reduction factor "r" shall be determined by linear
interpolation between
r=1, for J=0
and
r=as for the case where J ¡Ý0.2b/B, for J=0.2b/B,
where:
b=the mean transverse distance in metres measured at right
angles to the centreline at the deepest subdivision load line between the
shell and a plane through the outermost portion of and parallel to that
part of the longitudinal bulkhead which extends
between the longitudinal limits used in calculating the factor "p ".
i
3 To evaluate "p" for compartments taken singly the formulae in
paragraphs 1 and 2 shall be applied directly.
3.1 To evaluate the "p"-values attributable to groups of compartments
the following applies:
for compartments taken by pairs:
|----|
| p =p -p -p |
| i 12 1 2 |
|----|
p =p -p -p , etc.
i 23 2 3
for compartments taken by groups of three:
p =p -p -p +p
i 123 12 23 2
p =p -p -p +p , etc.
i 234 23 34 3
for compartments taken by groups of four:
p =p -p -p +p
i 1234 123 234 23
p =p -p -p +p , etc.
i 2345 234 345 34
Where:
p , p , p , etc.,
12 23 34
p , p , p , etc. and
123 234 345
p , p , p , etc.
1234 2345 3456
shall be calculated according to the formulae in paragraphs 1 and 2
for a single compartment whose nondimensional length "J" corresponds to
that of a group consisting of the compartments indicated by the indices
assigned to "p".
3.2 The factor "P " for a group of three or more adjacent compartments
i equals zero if the nondimensional length of such a
group nines the nondimensional length of the aftermost and foremost
compartments in the group is greater than "J ".
max
Regulation 25-6 Calculation of Factor "Si"
1 The factor "s ", shall be determined for each compartment or group
i
of compartments ac cording to the following:
1.1 in general for any condition of flooding from any initial loading
condition "s" shall be
s=C ¡Ì0.5(GZ )(range)
max
with C=1, if ¦Èe ¡Ü25¡ã
C=0, if ¦Èe £¾30¡ã
C= ¡Ì 30-¦Èe
-- otherwise
5
GZ =maximum positive righting lever (in metres) within the
max range as given below but not more than 0.1 m;
range=range of positive righting levers beyond the angle of
equilibrium (in degrees) but not more than 20 ¡ã; however, the range shall
be terminated at the angle where openings not capable of being closed
weathertight are immersed;
¦Èe=final equilibrium angle of heel (in degrees);
1.2 s=0 where the final waterline taking into account sinkage, heel
and trim, immerses the lower edge of openings through which progressive
flooding may take place. Such opening shall include air-pipes, ventilators
and openings which are closed by means of weathertight doors or hatch
covers, and may exclude those openings closed by means of watertight
manhole covers and flush scuttles, small watertight hatch covers which
maintain the high integrity of the deck, remotely operated sliding
watertight doors, access doors and access hatch covers, of watertight
integrity, normally closed at sea and sidescuttles of the non-opening
type. However, if the compartments so flooded are taken into account in
the calculations the requirements of this Regulation shall be applied.
1.3 For each compartment or group of compartments "s " shall be
i
weighted according to draught consideration as follows:
s =0.5s +0.5s
i l p
where
"s " is the "s"-factor at the deepest subdivision load line;
l
"s " is the "s"-factor at the partial load line.
p
2 For all compartments forward of the collision bulkhead, the
"s"-value, calculated assuming the ship to be at its deepest subdivision
load line and with assumed unlimited vertical extent of damage is to be
equal to 1.
3 Wherever a horizontal subdivision is fitted above the waterline in
question the following applies.
3.1 The "s"-value for the lower compartment or group of compartments
shall be obtained by multiplying the value as determined in subparagraph
1.1 by the reduction factor "v " ac cording to subparagraph 3.3, which
i
represents the probability that the spaces above the horizontal
subdivision will not be flooded.
3.2 In cases of positive contribution to index "A" due to simultaneous
flooding of the spaces above the horizontal subdivision, the resulting
"s"-value for such a compartment or group of compartments shall be
obtained by an increase of the value as determined by subparagraph 3.1 by
the "s"-value for simultaneous flooding according to subparagraph 1.1,
multiplied by the factor (1-v ).
i
3.3 The probability factor "v " shall be calculated according to:
i
H-d
v = ---, for the assumed flooding up to the horizontal
i H -d
max
subdivision above the subdivision load line, where "H" is to be restricted
to a height of
"H ",
max
v =1, if the uppermost horizontal subdivision in way of the
i
assumed dam aged region is below "H ",
max
where:
"H" is the height of the horizontal subdivision above the baseline (in
metres) which is assumed to limit the vertical extent of damage,
"H " is the maximum possible vertical extent of damage above the
max
baseline (in metres), or
|----------|
| L |
| s |
| H =d+0.056L (1- --), if L ¡Ü250m; |
| max s 500 s |
| H =d+7, if L £¾250m |
| max s |
|----------|
whichever is less.
Regulation 25-7 Permeability
For the purpose of the subdivision and damage stability calculations
of the Regulations, the permeability of each space or part of a space
shall be as follows:
Spaces Permeability
Appropriated to stores 0.60
Occupied by accommodation 0.95
Occupied by machinery 0.85
Void spaces 0.95
Dry cargo spaces 0.7
Intended for liquid 0 or 0.95*
[* whichever results in the more severe requirements.]
Regulation 25-8 Stability Information
1 The master of the ship shall be supplied with such reliable
information as is necessary to enable him by rapid and simple means to
obtain accurate guidance as to the stability of the ship under varying
conditions of service. The information shall include:
.1 a curve of minimum operational metacentric height (GM) versus
draught which assures compliance with the relevant intact stability
requirements and the requirements of Regulations 25-1 to 25-6,
alternatively a corresponding curve of the maximum allowable vertical
centre of gravity (KG) versus draught, or with the equivalents of either
of these curves;
.2 instructions concerning the operation of cross-flooding
arrangements; and
.3 all other date and aids which might be necessary to maintain
stability after damage.
2 There shall be permanently exhibited, or readily available on the
navigating bridge, for the guidance of the officer in charge of the ship,
plans showing clearly for each deck and hold the boundaries of the
watertight compartments, the openings therein with the means of closure
and position of any controls thereof, and the arrangements for the
correction of any list due to flooding. In addition, booklets containing
the aforementioned information shall be made available to the officers of
the ship.
3 In order to provide the information referred to in 1.1, the limiting
GM (or KG) values to be used, if they have been determined from
considerations related to the subdivision index, the limiting GM shall be
varied linearly between the deepest subdivision load line and the partial
load line. In such cases, for draughts below the partial load line if the
minimum GM requirement at this draught results from the calculation of the
subdivision index, then this GM value shall be assumed for lesser
draughts, unless the intact stability requirements apply.
Regulation 25-9 Openings in watertight bulkheads and internaldecks in cargo ships
1 The number of openings in watertight subdivision is to be kept to a
minimum compatible with the design and proper working of the ship. Where
penetrations of watertight bulkheads and internal decks are necessary for
access, piping, ventilation, electrical cables, etc., arrangements are to
be made to maintain the watertight integrity. The Administration may
permit relaxation in the water-tightness of openings above the freeboard
deck, provided that it is demonstrated that any progressive flooding can
be easily controlled and that the safety of the ship is not impaired.
2 Doors provided to ensure the watertight integrity of internal
openings which are used while at sea are to be sliding watertight doors
capable of being remotely closed from the bridge and are also to be
operable locally from each side of the bulkhead. Indicators are to be
provided at the control position showing whether the doors are open or
closed, and an audible alarm is to be provided at the door closure. The
power, control and indicators are to be operable in the event of main
power failure. Particular attention is to be paid to minimize the effect
of control system failure. Each power-operated sliding watertight door
shall be provided with an individual hand-operated mechanism. It shall be
possible to open and close the door by hand at the door itself from both
sides.
3 Access doors and access hatch covers normally closed at sea,
intended to ensure the watertight integrity of internal openings, shall be
provided with means of indication locally and on the bridge showing
whether these doors or hatch covers are open or closed. A notice is to be
affixed to each such door or hatch cover to the effect that it is not to
be left open. The use of such doors and hatch cover shall be authorized by
the officer of the watch.
4 Watertight doors or ramps of satisfactory construction may be fitted
to internally subdivide large cargo spaces, provided that the
Administration is satisfied that such doors or ramps are essential. These
doors or ramps may be hinged, rolling or sliding doors or ramps, but
shall not be remotely controlled. Such doors or ramps shall be closed
before the voyage commences and shall be kept closed during navigation;
the time of opening such doors or ramps in port and of closing them before
the ship leaves port shall be entered in the logbook. Should any of the
doors or ramps be accessible during the voyage, they shall be fitted with
a device which prevents unauthorized opening.
5 Other closing appliances which are kept permanently closed at sea to
ensure the watertight integrity of internal openings shall be provided
with a notice which is to be affixed to each such closing appliance to the
effect that it is to be kept closed. Manholes fitted with closely bolted
covers need not be so marked.
Regulation 25-10 External openings in cargo ships
1 All external openings leading to compartments assumed intact in the
damage analysis, which are below the final damage waterline, are required
to be watertight.
2 External openings required to be watertight in accordance with
paragraph 1 shall be of sufficient strength and, except for cargo hatch
covers, shall be fitted with indicators on the bridge.
3 Openings in the shell plating below the deck limiting the vertical
extent of damage shall be kept permanently closed while at sea. Should any
of these openings be accessible during the voyage, they shall be fitted
with a device which prevents unauthorized opening.
4 Notwithstanding the requirements of paragraph 3, the Administration
may authorize that particular doors may be opened at the discretion of the
master, if necessary for the operation of the ship and provided that the
safety of the ship is not impaired.
5 Other closing appliances which are kept permanently closed at sea to
ensure the watertight integrity of external openings shall be provided
with a notice affixed to each appliance to the effect that it is to be
kept closed. Manholes fitted with closely bolted covers need not be so
marked.
+0.02 B
For J £¼0.2 b/B the reduction factor "r" shall be determined by linear
interpolation between
r=1, for J=0
and
r=as for the case where J ¡Ý0.2b/B, for J=0.2b/B,
where:
b=the mean transverse distance in metres measured at right
angles to the centreline at the deepest subdivision load line between the
shell and a plane through the outermost portion of and parallel to that
part of the longitudinal bulkhead which extends
between the longitudinal limits used in calculating the factor "p ".
i
3 To evaluate "p" for compartments taken singly the formulae in
paragraphs 1 and 2 shall be applied directly.
3.1 To evaluate the "p"-values attributable to groups of compartments
the following applies:
for compartments taken by pairs:
|----|
| p =p -p -p |
| i 12 1 2 |
|----|
p =p -p -p , etc.
i 23 2 3
for compartments taken by groups of three:
p =p -p -p +p
i 123 12 23 2
p =p -p -p +p , etc.
i 234 23 34 3
for compartments taken by groups of four:
p =p -p -p +p
i 1234 123 234 23
p =p -p -p +p , etc.
i 2345 234 345 34
Where:
p , p , p , etc.,
12 23 34
p , p , p , etc. and
123 234 345
p , p , p , etc.
1234 2345 3456
shall be calculated according to the formulae in paragraphs 1 and 2
for a single compartment whose nondimensional length "J" corresponds to
that of a group consisting of the compartments indicated by the indices
assigned to "p".
3.2 The factor "P " for a group of three or more adjacent compartments
i equals zero if the nondimensional length of such a
group nines the nondimensional length of the aftermost and foremost
compartments in the group is greater than "J ".
max
Regulation 25-6 Calculation of Factor "Si"
1 The factor "s ", shall be determined for each compartment or group
i
of compartments ac cording to the following:
1.1 in general for any condition of flooding from any initial loading
condition "s" shall be
s=C ¡Ì0.5(GZ )(range)
max
with C=1, if ¦Èe ¡Ü25¡ã
C=0, if ¦Èe £¾30¡ã
C= ¡Ì 30-¦Èe
-- otherwise
5
GZ =maximum positive righting lever (in metres) within the
max range as given below but not more than 0.1 m;
range=range of positive righting levers beyond the angle of
equilibrium (in degrees) but not more than 20 ¡ã; however, the range shall
be terminated at the angle where openings not capable of being closed
weathertight are immersed;
¦Èe=final equilibrium angle of heel (in degrees);
1.2 s=0 where the final waterline taking into account sinkage, heel
and trim, immerses the lower edge of openings through which progressive
flooding may take place. Such opening shall include air-pipes, ventilators
and openings which are closed by means of weathertight doors or hatch
covers, and may exclude those openings closed by means of watertight
manhole covers and flush scuttles, small watertight hatch covers which
maintain the high integrity of the deck, remotely operated sliding
watertight doors, access doors and access hatch covers, of watertight
integrity, normally closed at sea and sidescuttles of the non-opening
type. However, if the compartments so flooded are taken into account in
the calculations the requirements of this Regulation shall be applied.
1.3 For each compartment or group of compartments "s " shall be
i
weighted according to draught consideration as follows:
s =0.5s +0.5s
i l p
where
"s " is the "s"-factor at the deepest subdivision load line;
l
"s " is the "s"-factor at the partial load line.
p
2 For all compartments forward of the collision bulkhead, the
"s"-value, calculated assuming the ship to be at its deepest subdivision
load line and with assumed unlimited vertical extent of damage is to be
equal to 1.
3 Wherever a horizontal subdivision is fitted above the waterline in
question the following applies.
3.1 The "s"-value for the lower compartment or group of compartments
shall be obtained by multiplying the value as determined in subparagraph
1.1 by the reduction factor "v " ac cording to subparagraph 3.3, which
i
represents the probability that the spaces above the horizontal
subdivision will not be flooded.
3.2 In cases of positive contribution to index "A" due to simultaneous
flooding of the spaces above the horizontal subdivision, the resulting
"s"-value for such a compartment or group of compartments shall be
obtained by an increase of the value as determined by subparagraph 3.1 by
the "s"-value for simultaneous flooding according to subparagraph 1.1,
multiplied by the factor (1-v ).
i
3.3 The probability factor "v " shall be calculated according to:
i
H-d
v = ---, for the assumed flooding up to the horizontal
i H -d
max
subdivision above the subdivision load line, where "H" is to be restricted
to a height of
"H ",
max
v =1, if the uppermost horizontal subdivision in way of the
i
assumed dam aged region is below "H ",
max
where:
"H" is the height of the horizontal subdivision above the baseline (in
metres) which is assumed to limit the vertical extent of damage,
"H " is the maximum possible vertical extent of damage above the
max
baseline (in metres), or
|----------|
| L |
| s |
| H =d+0.056L (1- --), if L ¡Ü250m; |
| max s 500 s |
| H =d+7, if L £¾250m |
| max s |
|----------|
whichever is less.
Regulation 25-7 Permeability
For the purpose of the subdivision and damage stability calculations
of the Regulations, the permeability of each space or part of a space
shall be as follows:
Spaces Permeability
Appropriated to stores 0.60
Occupied by accommodation 0.95
Occupied by machinery 0.85
Void spaces 0.95
Dry cargo spaces 0.7
Intended for liquid 0 or 0.95*
[* whichever results in the more severe requirements.]
Regulation 25-8 Stability Information
1 The master of the ship shall be supplied with such reliable
information as is necessary to enable him by rapid and simple means to
obtain accurate guidance as to the stability of the ship under varying
conditions of service. The information shall include:
.1 a curve of minimum operational metacentric height (GM) versus
draught which assures compliance with the relevant intact stability
requirements and the requirements of Regulations 25-1 to 25-6,
alternatively a corresponding curve of the maximum allowable vertical
centre of gravity (KG) versus draught, or with the equivalents of either
of these curves;
.2 instructions concerning the operation of cross-flooding
arrangements; and
.3 all other date and aids which might be necessary to maintain
stability after damage.
2 There shall be permanently exhibited, or readily available on the
navigating bridge, for the guidance of the officer in charge of the ship,
plans showing clearly for each deck and hold the boundaries of the
watertight compartments, the openings therein with the means of closure
and position of any controls thereof, and the arrangements for the
correction of any list due to flooding. In addition, booklets containing
the aforementioned information shall be made available to the officers of
the ship.
3 In order to provide the information referred to in 1.1, the limiting
GM (or KG) values to be used, if they have been determined from
considerations related to the subdivision index, the limiting GM shall be
varied linearly between the deepest subdivision load line and the partial
load line. In such cases, for draughts below the partial load line if the
minimum GM requirement at this draught results from the calculation of the
subdivision index, then this GM value shall be assumed for lesser
draughts, unless the intact stability requirements apply.
Regulation 25-9 Openings in watertight bulkheads and internaldecks in cargo ships
1 The number of openings in watertight subdivision is to be kept to a
minimum compatible with the design and proper working of the ship. Where
penetrations of watertight bulkheads and internal decks are necessary for
access, piping, ventilation, electrical cables, etc., arrangements are to
be made to maintain the watertight integrity. The Administration may
permit relaxation in the water-tightness of openings above the freeboard
deck, provided that it is demonstrated that any progressive flooding can
be easily controlled and that the safety of the ship is not impaired.
2 Doors provided to ensure the watertight integrity of internal
openings which are used while at sea are to be sliding watertight doors
capable of being remotely closed from the bridge and are also to be
operable locally from each side of the bulkhead. Indicators are to be
provided at the control position showing whether the doors are open or
closed, and an audible alarm is to be provided at the door closure. The
power, control and indicators are to be operable in the event of main
power failure. Particular attention is to be paid to minimize the effect
of control system failure. Each power-operated sliding watertight door
shall be provided with an individual hand-operated mechanism. It shall be
possible to open and close the door by hand at the door itself from both
sides.
3 Access doors and access hatch covers normally closed at sea,
intended to ensure the watertight integrity of internal openings, shall be
provided with means of indication locally and on the bridge showing
whether these doors or hatch covers are open or closed. A notice is to be
affixed to each such door or hatch cover to the effect that it is not to
be left open. The use of such doors and hatch cover shall be authorized by
the officer of the watch.
4 Watertight doors or ramps of satisfactory construction may be fitted
to internally subdivide large cargo spaces, provided that the
Administration is satisfied that such doors or ramps are essential. These
doors or ramps may be hinged, rolling or sliding doors or ramps, but
shall not be remotely controlled. Such doors or ramps shall be closed
before the voyage commences and shall be kept closed during navigation;
the time of opening such doors or ramps in port and of closing them before
the ship leaves port shall be entered in the logbook. Should any of the
doors or ramps be accessible during the voyage, they shall be fitted with
a device which prevents unauthorized opening.
5 Other closing appliances which are kept permanently closed at sea to
ensure the watertight integrity of internal openings shall be provided
with a notice which is to be affixed to each such closing appliance to the
effect that it is to be kept closed. Manholes fitted with closely bolted
covers need not be so marked.
Regulation 25-10 External openings in cargo ships
1 All external openings leading to compartments assumed intact in the
damage analysis, which are below the final damage waterline, are required
to be watertight.
2 External openings required to be watertight in accordance with
paragraph 1 shall be of sufficient strength and, except for cargo hatch
covers, shall be fitted with indicators on the bridge.
3 Openings in the shell plating below the deck limiting the vertical
extent of damage shall be kept permanently closed while at sea. Should any
of these openings be accessible during the voyage, they shall be fitted
with a device which prevents unauthorized opening.
4 Notwithstanding the requirements of paragraph 3, the Administration
may authorize that particular doors may be opened at the discretion of the
master, if necessary for the operation of the ship and provided that the
safety of the ship is not impaired.
5 Other closing appliances which are kept permanently closed at sea to
ensure the watertight integrity of external openings shall be provided
with a notice affixed to each appliance to the effect that it is to be
kept closed. Manholes fitted with closely bolted covers need not be so
marked.
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