*** EN draft 2 ***
Explanatory Notes to the SOLAS Chapter II-1 Subdivision and
Damage Stability regulations
Contents
Page
Part A – Background
To be developed
Part B – Guidance on individual regulations
Regulation 2 ………………………………………………………………......
Regulation 4 ………………………………………………………………......
Regulation 6 ………………………………………………………………......
Regulation 7 ………………………………………………………………......
Regulation 7-1 ……………………………………………………………......
Regulation 7-2 ……………………………………………………………......
Regulation 7-3 ……………………………………………………………......
Regulation 8 ………………………………………………………………......
Regulation 9 ………………………………………………………………......
Regulation 10 …………………………………………………………….......
Regulation 13 …………………………………………………………….......
Regulation 13-1 …………………………………………………………........
Regulation 15 …………………………………………………………….......
Regulation 15-1 ………………………………………………………...........
Regulation 16 …………………………………………………………...........
Regulation 17 …………………………………………………………….......
Regulation 19 …………………………………………………………….......
Regulation 21 …………………………………………………………….......
Regulation 22 …………………………………………………………….......
Regulation 35-1 ………………………………………………………….......
Appendices
Appendix 1 – Presentation of damage stability calculation results ……….....
Appendix 2 – Guidelines for damage control plans and information to
the Master …………………………………………………….
Appendix 3 – Guidance used for the determination of the impact of open
watertight doors on survivability under regulation II-1/22.4….
Annexes
Annex 1 – Resolution MSC.194(80) – (adopted 20 May 2005) ……………..
Annex 2 – SOLAS chapter II-1, parts A, B, B-1, B-2, B-3 and B-4 …………
-1*** EN draft 2 ***
Part A
To be developed
Action item: Request a volunteer to draft the Part A section *
* Any yellow highlighted text in this document is Co-ordinators’ comments / editorial
notes; it is not part of the Explanatory Notes draft text.
-2*** EN draft 2 ***
Part B
Regulation 2 – Definitions
Paragraph 1
Subdivision length (Ls) – Different examples of Ls showing the buoyant hull and the
reserve buoyancy are provided in the figures below. The limiting deck [for the reserve
of buoyancy] may be partially watertight with defined openings.
-3*** EN draft 2 ***
Figure xx
Paragraph 6
Freeboard deck – See regulation 13-1 for the treatment of a stepped freeboard deck with
regard to watertightness and construction requirements.
Paragraph 11
Light service draught (dl) – The light service draught (dl) represents the lower draught
limit of the minimum required GM curve. It corresponds, in general, to the ballast arrival
condition with 10% consumables for cargo ships. For passenger ships it corresponds, in
general, to the arrival condition with 10% consumables, a full complement of passengers
and crew and their effects, and ballast as necessary for stability and trim. The 10%
arrival condition is not necessarily the specific condition that must be used for all ships,
but represents in general a suitable lower limit for all loading conditions. [This is
understood to not include docking conditions or other non-service conditions.]
Paragraph 19
Bulkhead deck – See regulation 13 for the treatment of a stepped bulkhead deck with
regard to watertightness and construction requirements.
Regulation 4 – General
Paragraph 1
[ Regarding the footnote; those cargo ships excluded from the application of Part B-1
should comply with the provisions of Parts B-2 through B-4 as follows:
Part B-2: all cargo ships except tankers (reg 9.8 needs additional consideration)
Part B-4: all cargo ships except tankers ]
- alternative proposal below
[ Cargo ships complying with the regulations listed in the footnote are excluded from the
-4*** EN draft 2 ***
application of Part B (including Parts B-2 through B-4). ]
- alternative proposal below
[ Cargo ships shown to comply with the regulations listed in the footnote to Regulation
4.1 are excluded from the application of the probabilistic stability requirements of Part B1 but may be required to comply with Parts B-2 to B-4 and Part C Regulation 35-1 as
appropriate according to ship type. ]
- alternative proposal below
[
Reg
5
5-1
9
10
11
12
13-1
15
15-1
16
16-1
19
22
24
25
35-1
For cargo ships
complying with
damage stability
regulations in other
IMO instruments
Applies
Part B-1
x
x
Part B-2
x (1) (3)
x
x
x
x
x
x
x
x
Part B-4
x
x
x
x (2)
x
(1) Only applies to ships other than tankers
(2) Only applies to single hold cargo ships other than bulk carriers
(3) Paragraph 8 of regulation 9 not to be applied to this type of ships? ]
Paragraph 4
See regulation 7-2, paragraph 2, for information and guidance related to these provisions.
-5*** EN draft 2 ***
Regulation 5-1 – Stability information to be supplied to the master*
Paragraphs 3 and 4 (also see regulation 7, paragraph 2)
[ In cases where the operational trim range is intended to exceed +/- 0.5% of LS, the
original GM limit line is to be designed in the usual manner with the deepest subdivision
draught and partial subdivision draught calculated at level trim and actual service trim
used for the light service draught. Then another set of GM limit lines should be
constructed on the basis of the maximum envisaged trim applied to all three draughts.
The two sets of GM limit lines are combined to give one overall limiting set of values.
If the actual service trim for the light service draught deviates more than 0.5% LS and is
the largest trim envisaged then this will be the trim used for the second set of values.
a
Limit
Lines
a
b
b
GM
Draught
l
Actual
Max
Trim
>±
0.5%L
p
Level
Max
Trim
>±
0.5%L
s
Level
Max
Trim
>±
0.5%L
Draught
]
[The GM values for the three loading conditions could, as a first attempt, be taken from
the intact stability GM limit curve. If a required index A is not obtained, the GM values
could be increased but still taken into account that the intact loading conditions from the
intact stability book should meet the GM limit curve from the damage stability (linear
interpolation between the three GMs).] note: this text is also under reg 7, para 1
Regulation 6 – Required subdivision index R
Paragraph 1
To demonstrate compliance with these provisions, see the guidelines in Appendix 1
regarding the presentation of damage stability calculation results.
Regulation 7 – Attained subdivision index A
Paragraph 1
The probability of surviving after a damage to the ship hull is expressed by the index A.
-6*** EN draft 2 ***
Producing an index A requires calculation of various damage scenarios defined by the
extent of damage and the initial loading conditions of the ship before damage. Three
loading conditions are to be considered and the result weighted as follows:
A = 0.4As + 0.4Ap + 0.2Al
where the indices s, p, l represents the three loading conditions and the factor to be
multiplied to the index, indicates how the index A from each loading condition is
weighted.
The method of calculating the A for a loading condition is expressed by the formula:
i=t
Ac =  pi [vi si ]
i=1
The index c represents one of the three loading conditions, index i represents each
investigated damage or group of damages and t is the number of damages to be
investigated to calculate A for the particular loading condition.
To obtain a maximum index A for a given subdivision, t has to be equal to T: the number
of damage zones plus the maximum number of combined adjacent zones.
In practice the damage combinations to be considered are limited either by significantly
reduced survivability possibility (i.e. flooding of substantially larger volumes) or by
exceeding the maximum possible damage length
The index A is divided into part factors as follows:
pi
The p factor is solely dependent on the geometry of the watertight arrangement of
the ship.
vi
Accounts for the probability of survival after flooding the compartment or group
of compartments under consideration, and includes the effect of any horizontal
subdivision, as defined in regulation 7-2. The v factor is dependent on the geometry of
the watertight arrangement (decks) of the ship and the draught of the initial loading
condition. [It represents the probability that the spaces above the horizontal subdivision
will not be flooded.] - the response was split on this [ ] item; 2 to include and 2 to delete.
Please indicate your preference on this item.
si
The s factor is dependent on the calculated stability of the ship after damage in a
specific initial condition.
Three initial loading conditions are to be used for calculating the index A. The loading
conditions are defined by their mean draught d, trim and GM.
ds
dp
Level trim
Level trim
100%
60%
Service trim
Mean draught dl
dl
The mean draught and trim are illustrated in the figure above.
-7*** EN draft 2 ***
The GM values for the three loading conditions could, as a first attempt, be taken from
the intact stability GM limit curve. [Stability information should include curves of
minimum operational metacentric height (GM) from reg. 5-1.2.1. Therefore the presented
limiting curve should correspond to GM-values, which will give attained index equal to
required index.] If [an attained index A greater than the required index R is not obtained,
the GM values could be increased but still taken into account that the [GM from] intact
loading conditions from the intact stability book [must meet or exceed ] the GM limit
curve from the damage stability (linear interpolation between the three [ draughts]).]
- or alternative proposal below
[ The GM values for the three loading conditions could, as a first attempt, be taken from
the intact stability GM limit curve. If the required index R is not obtained, the GM
values may be increased implying that the intact loading conditions from the intact
stability book must now meet the GM limit curve from the damage stability calculations
derived by linear interpolation between the three GM’s.]
Paragraph 2
The calculations for differing trims should be carried out with the same initial trim for the
partial and deepest subdivision drafts. For the light service draft, the actual service trim
may be used. The GM values should be as close as possible to the GM values used for
level trim calculation.
Each combination of the index within the formula given in regulation 7.1 should not be
less than the requirement given in regulation 6.2. Each partial index A shall comply with
the requirements of regulation 6.1.
Example:
Ls = 175 m
ds = 7.9 m; dp = 7.14 m; dl = 6 m
Trim up to 1.575 (0.9% Ls) m aft
The calculation for the index A is carried out for even keel. This allows for
varying of the [ship’s operating] trim for each draught within the trims of
+0.875m (0.5%Ls) and -0.875m (0.5%Ls) without any change of the GM
requirements. In order to show the influence of the trim [in excess of (0.5%Ls)]
the calculation of the index A will be repeated for all draughts [at a new trim].
[New Trim, minimum = Max trim (1.575m) – Even Keel trim (0.5%Ls = 0.875 m)
= 0.70 m]
The attained index has to be at least so high as to meet the requirements and is to
be calculated for the trim 0.7 m aft according to the formula:
A = 0.4As (trim = 0.7) + 0.4Ap (trim = 0.7) + 0.2Al []
Each A should be not less than 0.9R for passenger ships and 0.5R for cargo ships.
-8*** EN draft 2 ***
The GM for each A can be increased by the smallest possible change to comply
with the requirements for the index and causing contingently the increase of the
GM requirement within the trim of 0.875 m (0.5%Ls) and 1.575 m (0.9%). []
A @ Trim=0.7m
A @ Trim=0.0m
Max
Allowable
Trim range
- alternative proposal for Paragraph 2 below
[For trims between +/-0.5% Ls use the "even keel" calculation (and actual trim on light
service draught); for trims between 0.5% and 1.5% Ls make a calculation using a trim of
1.0% Ls; for trims between 1.5% and 2.5% Ls make a calculation using a trim of 2.0%
Ls; etc. In this case you will get several GM limit curves but you will not have to
interpolate between the trims as the GM limit curves are covering a trim interval. This
means that if you have a loading condition with a trim of 0.49% Ls you should use the
GM limit curve for "even keel" and when you have a loading condition with a trim of
0.51% Ls you should use the GM limit curve covering the trim interval between 0.5%
and 1.5% Ls.]
Paragraph 4
[In cases of unsymmetrical arrangements, “mean value of A” means that complete
attained indices are calculated for all damages on each side.]
Paragraph 5
In the forward and aft ends of the ship where the sectional breadth is less than the ship’s
breadth B, transverse damage penetration can extend beyond the centreline bulkhead.
-9*** EN draft 2 ***
This application of the transverse extents of damage is consistent with the methodology
to account for penetrations of a centreline bulkhead at such positions.
- alternative proposal below
In the forward and aft ends of the ship where the sectional breadth is less than the ship’s
breadth B, the transverse damage penetration need not extend to the ship’s centerline if
such penetration does not provide any contribution to the attained index.
Coordinators’ note: unclear to us whether this proposal meets the SLF 48 agreed action /
intent (see SLF 48/21, paragraph 3.22). Please comment.
Where corrugated bulkheads are fitted at the centreline they may be treated as [ordinary
stiffened bulkheads] or [equivalent plane bulkheads] as long as the corrugation is of the
same order as the stiffening structure [ and the total corrugation width does not exceed
1.0m [B/30] ]. - the response was split / mixed on this [ ] item. Please indicate your
preference on this item. [A “b” value equal to B/2 can be used in these cases.]
- alternative proposal below
[A ccorrugated bulkhead may be treated as a mean plane bulkhead if corrugations doesn’t
exceed [ +/- 0.5m or 2% of B ] ]
Paragraph 7
[ In determining what constitutes minor progressive flooding the capacity of bilge pumps
and the diameter of the bilge main as required by regulation 35-1 should be taken into
consideration. ]
- alternative proposal below
Minor flooding is considered as the flooding of the chain lockers and spaces no larger
than 0.15% of the volumetric displacement at the subdivision draught. This refers to
progressive flooding via openings such as air pipes and service piping systems that are
not solely constructed for cross flooding and equalisation purposes. Instances of
progressive flooding should be limited to a maximum of two instances of flooding per
damage case.
- alternative proposal below
[ Use IACS SC156 for reference.]
Co-ordinators’ note: the response was mixed making conclusions difficult. Please
review the comments and indicate your preference on this item.
- 10 *** EN draft 2 ***
Regulation 7-1 – Calculation of the factor pi
General
Compartment – an onboard space within watertight boundaries. Ordinary (in SOLAS
Part B-1) spaces between hull main transverse watertight bulkheads reaching from keel to
the freeboard deck / bulkhead deck, and from ship side to ship side, are named
compartments. Above the bulkhead deck, compartments may be limited by partially
watertight bulkhead or decks, openings being defined at the limits of non-watertight
places. In these Guidance Notes the “compartment” is replaced by zone, damage and
rooms as more suitable definitions.
Zone – a longitudinal interval of the ship within the subdivision length.
[ Damage volume – a damage volume to the ship is defined as a number of rooms in a
watertight arrangement opened to the sea, or connected to rooms opened to the sea, in
case of damage in a zone. The damage may be limited by transverse, longitudinal and/or
vertical structure. ]
- alternative proposal below
[ Damage – a damage corresponds to the extent of flooding and is defined by the number
of rooms opened to the sea or connected to other rooms opened to the sea. These rooms
may be flooded in successive stages. The extent of flooding is limited by transverse,
longitudinal and vertical watertight boundaries. ]
[ Room – a space within the watertight arrangement having a specific permeability,
defined by bulkheads and decks. ]
- alternative proposal below
[ Room – an elementary volume having a specific permeability and which can be
considered as flooded in a single stage. ]
- alternative proposal below
[ Room – a part of the ship, limited by bulkheads and decks, having a specific
permeability. ]
- new proposal below
[ For the calculation of p, v, r, b only the damaged area should be considered, for the
calculation of the s-value the flooded space has to be considered. The figures below
illustrate the difference.
Damaged space shown as the red square:
- 11 *** EN draft 2 ***
Flooded space shown in blue, damaged space shown as the red square:
]
Paragraph 1
The last line of paragraph 1 is an independent condition that is not related to how many
adjacent zones are damaged, and the words “where r(x1, x2, b0) = 0” mean that where
[k = 0, r(x1j, x2j, b) = 0] or [k=1, r(x1,x2,bk-1) = 0].
- alternative proposal for r factor with k included in the formula
- 12 *** EN draft 2 ***
r  f ( x1 j , x 2 j , bk )
If k  0 follows b0  0
And from this follows: r ( x1 j , x 2 j ,0)  0
Paragraph 1.1
The longitudinal subdivision
In order to prepare for the calculation of Index A the ship’s subdivision length Ls is
divided into a fixed discrete number of damage zones. These damage zones will
determine the damage stability investigation in the way of specific damages to be
calculated.
There are no rules for the subdividing except that the length Ls defines the extremes for
the actual hull. However, it is important to consider a strategy carefully to obtain a good
result (that is a large attained index A.) All zones and combination of adjacent zones may
contribute to the index A.
Z1
Z1
Z2
Z2
Z3
Z4
Z5
Z6
Z3
Z7
Ls
- alternative proposal for figure
[
- 13 *** EN draft 2 ***
Z8
Z9
Z10
Z11
Z1
Z1
Z2
Z2
Z3
Z4
Z5
Z6
Z3
Z7
Z8
Z9
Z10
Z11
Ls
]
The figure shows different longitudinal divisions of the length Ls.
The first example is a very rough division into 3 zones at approximately same size with
limits where transverse subdivision is established. The probability that the ship will
survive a damage in one of the three zones is expected to be low (s-factor = 0) and
therefore the total attained index A will be lost.
In the second example the zones have been placed in accordance to the watertight
arrangement, including minor subdivision (as in double bottom etc.). The chances of
getting good s-factors in this case should be good.
The triangle in the figure below illustrates the possible single and multiple zone damages
in a ship with a watertight arrangement suitable for a seven-zone division. The triangles
at the bottom line indicate single zone damages and the parallelograms indicate adjacent
zones damages.
- 14 *** EN draft 2 ***
Max damage length
Ls
Z1
Z2
Z3
Z4
Z5
Z6
Z7
Ls
Figure illustrates the possible single and multiple zone damages in a ship
As an example the triangle illustrates a damage opening the rooms in zone 2 to the sea
and the parallelogram illustrates a damage where rooms in the zones 4, 5 and 6 are
flooded simultaneously.
The shaded area illustrates the effect of the maximum absolute damage length: the pfactor for a combination of three or more adjacent zones equals zero if the length of the
combined adjacent damage zones minus the length of the foremost and the aft most
damage zones in the combined damage zone is greater than the maximum damage length.
Having this in mind when subdividing the LS could limit the number of zones defined to
optimise the attained index A. Co-ordinators’ note: the response was mixed on this
paragraph making a conclusion difficult. Please review the comments and indicate your
preference on this item.
- alternative proposal for figure / text
[
- 15 *** EN draft 2 ***
A damage can be defined by its tri-dimensional extension and it is assumed that the
compartments located within the damage limits are open to see. Damages shall be
assumed as being box-shaped. This principle is valid for one-zone damages as well as for
multi-zone damages.
The concept of a gap is not defined or considered in SOLAS. In principle a gap can be
treated as a special zone defined as a discontinuity in the subdivision along the
longitudinal extension. For one-zone damages, the gaps are not relevant. A box-shaped
damage leads to the flooding of the compartments located inside the relevant zone and
the pi values reflect correctly the damage extension on the longitudinal direction. For
multi-zone damages a box-shaped damage does not only lead to the flooding of the
compartments situated inside the relevant zones, but also to the flooding of the gap fitted
- 16 *** EN draft 2 ***
between the relevant zones. In this case, the pi values correspond to the extension of the
damage in the longitudinal direction. The gap is to be assessed in terms of openings and
compartment connections and has to be correctly reflected in the damage stability
calculations (multiple damages are not considered in SOLAS).
The damage stability calculation can be performed with gaps in the subdivision as long as
the gap’s connections to other compartments such as air pipes, ventilators, doors, hatches,
are described in detail in the damage stability documentation. If progressive flooding is
likely to occur beyond the damaged area in question, this needs to be accounted for when
calculating the residual stability. ]
- 17 *** EN draft 2 ***
As the p-factor is related to the watertight arrangement by the longitudinal limits of
damage zones and the transverse distance from the ship side to any longitudinal barrier in
the zone the following indices are introduced:
Examples of pj,n,k
j:
the damage zone number starting with
no.1 at the stern.
[N]: the total number of defined damage zones
n:
the number of adjacent damage zones in
question where j is the aft zone.
k:
the number of a particular longitudinal
bulkhead as a barrier for transverse
penetration in a damage zone
counted from shell towards the
centreline. The shell has No 0.
K:
total number of transverse barriers
[ comment noted that index
should not have both k and K ]
p j,n,k: the p-factor for a damage in
zone j and next (n-1) zones
forward of j damaged to the
longitudinal bulkhead k
P5,3
P4,2
P3,1
X13
X23
n=1
X14
X15
Zone
j =1
X25
n=2
j =2
j =3
j=
X27
n=3
j=
j=
j =J
ds
Z1
Z2
Z3
Z4
Z5
Z6
Z7
Ls
k=0
k=1
k=2
k=K
- 18 *** EN draft 2 ***
P3,1,0
P3,1,1
P3,1,2
P3,1,K
ds waterline
Pure transverse subdivision
Single damage zone, pure transverse subdivision:
pj,1 = p(x1j,x2j)
Co-ordinators’ note: in the figure x1j+1 should be x2j
Pj,1
X1j
X1j+1
Zones
J
n =1: damage to 1 Zone
Already taken
into account
Pj,2
Two adjacent zones, pure transverse subdivision:
pj,2 = p(x1j,x2j+1) - p(x1j,x2j) - p(x1j+1,x2j+1)
X1j
X2j
X1j+1
Zones
J
X2j+1
J+1
n =2: damage to 2 Zones
Already taken
into account
Pj,3
Three or more adjacent zones, pure transverse
subdivision:
pj,n = p(x1j,x2j+n-1) - p(x1j,x2j+n-2) p(x1j+1,x2j+n-1) + p(x1j+1,x2j+n-2)
X1j
Zones
X1j+1
J
J+1
n =3: damage to 3 Zones
Paragraph 1.2
The transverse subdivision in a damage zone
- 19 *** EN draft 2 ***
X2j+n-2 X2j + n -1
J+n-1
Damage to the hull in a specific damage zone may just penetrate the ship’s watertight
hull or penetrate further towards the centreline. To describe the probability of penetrating
only a wing compartment, a probability factor r is used, based mainly on the penetration
depth b. The value of r is equal to 1, if the penetration depth is B/2 where B is the
maximum breadth of the ship at the deepest subdivision draught ds, and r = 0 if b = 0.
The penetration depth b is measured at level subdivision draught ds as a transverse
distance from the ship side right-angled to the centreline to a longitudinal barrier.
Where the actual watertight bulkhead is not a plane parallel to the shell, b should be
determined by means of a fictive line, dividing the zone to the shell in a relationship b1/b2
with [ ½ ≤ b1/b2 ≤ 2 ] or [ 1/3 < b1/b2 < 3 ]. In no case should b be greater than [2 x b2]
or [twice min(b1 ; b2 )]. Co-ordinators’ note: there was also a proposal to delete this
paragraph. Please review the comments and indicate your preference on this item.
Examples of such fictive division lines are illustrated in the figure below. Each sketch
represents a single damage zone at a water line plane level ds and the longitudinal
bulkhead represents the outermost bulkhead position below ds + 12.5m.
centreline
centreline
b1 ( 2b2)
b
b
b2
shell
=
=
=
centreline
b1 (=2b2)
b
=
b2
centreline
b1 ( 2b2)
b
b2
shell
=
=
b
=
b2
shell
=
centreline
b1 (=2b2)
shell
=
centreline
b1 ( 2b2)
b
b2
shell
=
=
shell
=
centreline
centreline
b1 (=2b2)
b2
b
b
b1 (=2b2)
b2
shell
=
=
=
shell
=
Co-ordinators’ note: figures above will need updating if limit is changed to 1/3 < b1/b2 <
3 as proposed.
- 20 *** EN draft 2 ***
Calculating pi for combined damage zones having different values of b has to be
calculated as damage zones having uniform b values. As an example: a pi for the
combined damage zones based on the smallest b in the group of damage zones may be
calculated and the pi for the combined damage zones based on the second smallest b in
the group etc. for all values of b in the group of damage zones.
In calculating r-values for a group of two or more adjacent compartments, the b-value is
common for all compartments in that group, and equal to the smallest b-value in that group:
b= min {b1,b2….. bn}
where
n = number of wing compartments in that group;
b1, b2, … bn are the mean values of b for individual wing compartments contained in the
group.
When determining the factor p for simultaneous flooding of space 1 (in figure A-4 and
A5) and adjacent side compartment(s) the values r1, r12 etc, should be calculated taking
b for space 1 equal to the breath of the adjacent side compartment(s).
Co-ordinators’ note: there was a proposal to delete these figures. Please review the
comments and indicate your preference on this item.
Accumulating p
The accumulated value of p for one zone or a group of adjacent zones is determined by:
- 21 *** EN draft 2 ***
k=Kj,n
pj,n = pj,n,k
k=1
j+n-1
where Kj,n =  Kj the total number of bk’s for the adjacent zones in question.
j
ds waterline
bj,1
bj,2
bj+1,1
bj+n-1,1
bj,K
J
J+n-1
J+1
The figure illustrates b’s for adjacent zones. The zone j has 2 penetration limits and one
to the centre, the zone j+1 has 1 b and the zone j+n-1 has 1 value for b. The multiple
zones will have (2+1+1) 4 values of b, and sorted in increasing order they are:
(bj,1 ; bj+1,1 ; bj+n-1,1 ; bj,2 ; bK)
Because of the expression for r(x1,x2,b) only one bK is to be considered.
To minimize the number of calculations, b’s of the same value may be deleted.
As bj,1 = bj+1,1 the final b’s will be
(bj,1 ; bj+n-1,1 ; bj,2 ; bK)
The total accumulated p
j=T
p = pj,n
j=1
where T is the number of damage zones plus the maximum number of combined adjacent
zones.
Examples of multiple zones having a different b
Examples of combined damage zones and damage definitions are given in the figures.
Rooms are identified by R10, R12, etc.
centreline
R10
*** EN draft 2 ***
R32
- 22
R20
R31
b3
shell
Zone 1
Zone 2
Zone 3
centreline
R32
R10
R20
Figure: combined
damage of zones
1 + 2 + 3 includes a limited penetration to b3,
R31
b3
taken into account generating two damages:
shell
1)
to b3 with R10, R20 and R31 damaged
2) Zone
to 1[B/2] with R10,Zone
R20 2R31and R32 damaged
Zone 3
centreline
centreline
R12
R32
R22
R10
R20
R11
R21
b1
R31
b2
=
=
Zone 2
Zone 2
Zone 1
Zone 1
R31
R32
b3
b3
shell
shell
Zone 3
Zone 3
centreline
Figure: R12
combined damage ofR22
zones 1 + 2 + 3 includes 3 different limited
damage
centreline
R32
R22
penetrationsR12
generating four damages:
R32
R11 1) b1
R21
to
b
R11,
R21
and
R31
damaged
3 with
R11
R31
b2
b3
b1 b2 with R11, R21,
2)
to
and R32R31
damaged
2
shell
R21
bR31
b3
shell
3)
to b1 with R11,
= R21, R31,
= R32, and R22 damaged
=
=
=
=
4)
R31, R32, R22
Zone 1 to [B/2] with R11,
ZoneR21,
2
Zoneand
3 R12 damaged
Zone 1
Zone 2
Zone 3
centreline
R12
R11
R22
b1
R32
b2
R21
R31
b3
shell
=
=
Zone 1
=
=
Zone 2
Zone 3
Figure: combined damage of zone 1 + 2 + 3 including 2 different limited damage
penetrations (b1 < b2 = b3) generating three damages:
1)
to b1 with R11, R21 and R31 damaged
2)
to b2 with R11, R21, R31 and R12, damaged
3)
to [B/2] with R11, R21, R31, R12, and R22, R32 damage
Co-ordinators’ note: the response was mixed on these “Examples of combined transverse
and longitudinal bulkheads” – with proposals to delete and also to revise. Please review
the comments and indicate your preference on this item.
- 23 *** EN draft 2 ***
- new proposal below
- 24 *** EN draft 2 ***
[ A damage having a horizontal extension b and a vertical extension H2 leads to a
flooding of both wing compartment and Hold; for b and H1 only the wing compartment.
b
b
H2
H1
subdivison
draught
Th.”
be necessary.
The same is valid if b-values are calculated for arrangements with sloped walls. ]
Co-ordinators’ note: the comments on paragraph 1.2 were extensive and mixed, making
any conclusions difficult. Please review the comments; comprehensive / full / single
author proposals are needed and strongly encouraged for this important topic.
Regulation 7-2 – Calculation of the factor si
General
[ Damage case – a combination of a damage [volume] and an initial condition. ]
Initial condition – an intact loading condition to be considered in the damage analysis
described by the mean draught, vertical centre of gravity and the trim. Or alternative
parameters from where the same may be determined. (ex. displacement, GM and trim)
[There are three initial conditions corresponding to the three draughts ds, dp and dl.]
Immersion limits – immersion limits are an array of points that are not to be immersed at
various stages of flooding as indicated in paragraphs 5.2 and 5.3. [Openings fitted with
weathertight means of closure are to be considered as immersion limits.]
- 25 *** EN draft 2 ***
Openings – all openings need to be defined: [both weathertight and unprotected].
Openings are the most critical factor to preventing an inaccurate index A.
If the final waterline immerses the lower edge of any opening through which progressive
flooding take place, the factor “s” may be recalculated taking such flooding into account.
However in this case, s value shall also be calculated without taking into account
progressive flooding and corresponding opening. The smallest s value shall be retained
for the contribution to the attained index.
Paragraph 2
Intermediate stages of flooding
The case of instantaneous flooding in open spaces does not require intermediate stage
flooding calculations. Where intermediate stages of flooding calculations are necessary
in connection with progressive flooding of several spaces, they should reflect the
sequence of filling as well as filling stages. Calculations for intermediate stages of
flooding should be performed whenever equalization is not instantaneous, i.e.
equalization is of a duration greater than 60 s. Such calculations consider the progress
through one or more floodable (non-watertight) spaces. Bulkheads surrounding
refrigerated spaces, incinerator rooms and longitudinal bulkheads fitted with nonwatertight doors are typical examples of structures that may significantly slow down the
equalization of main compartments.
Flooding boundaries and non-watertight compartments: If a compartment contains
decks, inner bulkheads, structural elements and doors of sufficient tightness and strength
to seriously restrict the flow of water, for intermediate stage flooding calculation
purposes it should be divided into corresponding non-watertight spaces. It is assumed
that the non-watertight divisions considered in the calculations are limited to “A” class
fire-rated bulkheads and does not apply to “B” class fire-rated bulkheads normally used
in accommodation areas (e.g. cabins and corridors). Consideration should be given to
large volumes [25m3] only. This guidance also relates to regulation 4, paragraph 4.
Sequential flooding computation: For each damage scenario the damage extent and
location determine the initial stage of flooding. Calculations shall be performed in
stages, each stage comprising at least [two filling phases (half full and full)] or [two
intermediate filling phases in addition to the full phase] per flooded space. Spaces in way
of damage should be considered as flooded immediately. Every subsequent stage
involves all connected spaces being flooded simultaneously until an impermeable
boundary or final equilibrium is reached. If due to the configuration of the subdivision in
the ship it is expected that other intermediate stages of flooding are more onerous, then
those should be investigated.
[Cross-flooding / equalization: The cross-flooding time should be calculated in
accordance with IMO resolution A.266(VIII). If complete fluid equalization occurs in 60
s or less, it should be treated as instantaneous and no intermediate stage calculations need
to be carried out. Only passive open cross-flooding arrangements without valves should
be considered effective for instantaneous flooding cases.
- 26 *** EN draft 2 ***
If complete fluid equalization can be finalized in 10 minutes or less, the assessment of
survivability can be carried out for passenger ships as the smallest values of sintermediate,i or
sfinal. In any cases where complete fluid equalization exceeds 10 minutes, the value of
sfinal,i used in the formula in paragraph 1.1 should be the minimum of sfinal,i at 10 minutes
or at final equalization. ]
- alternative proposal for “Cross-flooding / equalization” text above
[Cross-flooding / equalisation: The cross-flooding time should be calculated in
accordance with IMO resolution A.266(VIII). If complete fluid equalisation occurs in 60
s or less, it should be treated as instantaneous and no further calculations need to be
carried out. Only passive open cross-flooding arrangements without valves should be
considered effective for instantaneous flooding cases.
In all cases cross-flooding fittings are taken into account, the equilibrium after
equalisation is considered as the final equilibrium i.e. the equalisation is calculated after
all possible intermediate flooding stages, and the formulae for sfinal is to be used.
If complete fluid equalisation can be finalised in 10 minutes or less, the assessment of
survivability can be carried out for passenger ships as the smallest values of sintermediate,i or
sfinal.
In case the equalisation time is longer than 10 minutes, sfinal is calculated for the floating
position achieved after 10 minutes of equalisation. This floating position is computed by
calculating the amount of flood water according to A.266(VIII) using linear interpolation,
where the equalisation time is set to 10 minutes i.e. the interpolation of the flood water
volume is made between the case before equalisation (T=0) and the total calculated
equalisation time.
In any cases where complete fluid equalisation exceeds 10 minutes, the value of sfinal used
in the formula in paragraph 1.1 should be the minimum of sfinal at 10 minutes or at final
equalisation.]
- alternative proposal for Paragraph 2 text
[1- Definition of compartment limits:
The first point is to define the basic compartments and rooms necessary to proceed to
damage stability calculations. In hydrostatic calculations, a basic assumption is that all
parts of a “room” will be considered as a space flooded with a common horizontal free
surface (instantaneous flooding of the room). If in a given compartment, there are
restrictions to the progression of flooding water, it may be necessary to split this
compartment in 2 or more rooms which will be flooded at different stages to simulate
more correctly the progress of flooding. Principal for justification of “instantaneous
flooding of a compartment” may be the following:
Restrictions to be considered are those which are between a part of the compartment
which will be within the breach extent and part of the compartment out of breach extent.
- 27 *** EN draft 2 ***
Several breach extent may be considered which will be related to different restrictions. A
first approach may be to compare the cross section area Ar in the restricted part with the
maximum cross section area Am of the cross flooded part of the compartment. If ratio Ar /
Am is less than [0.2], a flooding time calculation has to be done. If compartment extend
above the waterline, only cross sections below waterline have to be considered. If
flooding time exceeds 60s, compartment will be subdivided in way of restricted sections.
If restricted section extends over a significant length, partition will be defined at the mid
length of this restricted section. If volume of this restricted section is significant in
comparison with total volume of the compartment ( > 0.2 ), this restricted part may be
defined as a room.
As this calculation must be done before damage stability calculations, and as there is a
large uncertainty on the behaviour of the ship during the first minute after damage, this
calculation may be done from a simplified simulation, assuming that ship remain in
upright position and neglecting draft increase due to the flooded water.
Flooding time calculation has to be done for the worst initial condition, and depending on
the situation of the compartment relatively to the deepest subdivision waterline:
- If compartment is entirely below the deepest subdivision waterline, calculation will be
done from the light service condition. In this case, cross flooding time will be calculated
from following formula:
T = 2 W / ( S F ) * [1 – √ ( hf / H0 ) ]/ √2g H0 * 1 / ( 1 – hf / H0 )
With:
W = Volume of part of the compartment to be cross flooded
S: reference cross section
F=1/√Σk+1
k: frictional coefficient of the cross connecting area referred to S
(corrected to take into account loss of head in air vents if necessary)
H0 = dl – hcs
dl = light service draft
hcs = Height of the centre of cross section above base line
hf = dl - hmax, but not less than 0
hmax = Height of the upper part of the compartment to be cross flooded
above base line
- If compartment extend from below to above the deepest subdivision waterline,
calculation will be done from the deepest subdivision draft. In this case, cross flooding
time will be calculated from following formula:
T = 2 W / ( S F ) * [1 / √2g H0 ]
With:
W = Volume of part of the compartment to be cross flooded up to deepest
subdivision waterline
S: reference cross section
F = 1 / √Σ k + 1
k: frictional coefficient of the cross connecting area referred to S (
corrected to take into account loss of head in air vents if necessary )
H0 = ds – hcs
- 28 *** EN draft 2 ***
ds = deepest subdivision draft
hcs = Height of the centre of cross section, limited to the waterline, above
base line
- If the compartment is entirely above the deepest subdivision waterline, it will be
subdivided in way of restricted sections.
This also supposes that air may escape from the cross flooded part of the compartment
which implies that a section of about 10% of the cross section in the restricted part is
available to evacuate the air without restraining the water flow significantly. If air vents
have a smaller cross section, F factor for calculation of the flooding time must take into
account drop of head in the air vents. If cross section extends above the water level, air
may evacuate partly through the same cross section as water.
A typical situation is the case of a compartment which is subdivided by internal
bulkheads which however non watertight, will restrain the progression of flooding water.
These bulkheads may be neglected if it is demonstrated that they will collapse
immediately under water pressure. If not, compartment has to be subdivided in rooms
according to position of bulkheads. In practice, it will be necessary to take into account
steel bulkheads (Class A fire bulkheads). However, rooms may be gathered in a single
room, if it is demonstrated that this has no influence or a negative influence on the
calculation results. Consideration should be given to large volumes only.
2 - Flooding stages definition:
All rooms within the damage extent will be considered as flooded in the first stage. Minor
damages may also be considered if they can lead to a worst situation. However, minor
damages which would correspond to the flooding generated by a damage of lesser extent
(penetration or length) already taken into account have not to be considered.
If flooding through openings or non watertight boundary may lead to the flooding of
rooms connected to flooded compartments, successive stages have to be studied.
Different cases have to be considered depending on the cross flooding time:
- If cross flooding time is less than 60s, cross flooded rooms may be considered as
flooded in the first stage (Instantaneous flooding)
- If cross flooding time is more than 60s, cross flooded rooms have to be considered as
flooded in a second stage.
If successive flooding of connected compartments are possible, same principle has to be
applied until an impermeable boundary is reached:
- If cross flooding time is less than 60s, corresponding cross flooded rooms may be
considered as flooded in the previous stage (Instantaneous flooding)
- If cross flooding time is more than 60s, cross flooded rooms have to be considered as
flooded in a successive stage.
If the total cross flooding time to reach a given stage, taking into account all previous
flooding stages, is of more than 600s, this stage and also the previous stage and all
- 29 *** EN draft 2 ***
possible successive stages have to be considered as “final stage” for calculation of “s”
factor. (Final stage criteria have to be applied to the last stage within the 600s).
If cross flooding time between the first and second stages is of more than 600s, first stage
is to be considered as a final stage. For these cases, an alternative solution may be
applied: To define an intermediate stage corresponding to the situation reached after 10
minutes (minus a few seconds), and then calculate:
sint for the damage case with only rooms directly within the breach extent.
sfinal for the intermediate stage after 10 minutes and for the successive stages of
flooding (smallest sfinal to be retained )
In case of rooms subdivided by non watertight bulkheads it may be difficult to calculate a
cross flooding time unless special flooding devices are fitted. In this case, cross flooding
time has to be considered as greater than 600s.
3 - Intermediate phases:
Intermediate phases between stages have to be studied.
For the first stage, if only compartments in way of damage are involved, flooding of these
compartments may be considered as instantaneous, so intermediate phase has not to be
considered. For successive stages, one intermediate phase has to be studied,
corresponding to half filling of rooms flooded during this stage. These intermediate
phases are to be considered as intermediate stages for “s” calculation, if they occur before
the first stage considered as a final stage. Phases which occur after the first stage
considered as “final” have to be considered as “final stages”.
4 – GZ calculation:
In all stages in equilibrium situation, level of water in flooded compartment will be
considered at the same level as external water level: GZ curve will be calculated with lost
buoyancy method.
For intermediate phases, two types of rooms have to be considered:
Rooms which was flooded at the previous stages, are considered as fully flooded
(lost buoyancy method for calculation of the GZ curve)
Rooms which are flooded during the current stage, are gathered in a single
compartment which is flooded up to half of its final flooding volume in these rooms. This
volume is kept constant when calculating the GZ curve.
Note: It can be considered that risk to capsize is when the ship is heeling on the side of
the damage, so for determination of the “s” factor GZ curve should be calculated on the
side of the damage. More usual method is to calculate the GZ curve on the heel side.
However, if heel at equilibrium is on the side opposite to the damage, it may be
considered as necessary to calculate the GZ curve on both sides and retain the worth “s”
value. This point has to be clarified.
5 - Basic principals for “s” calculation:
“s” factor is associated to a “p” factor. “p” factor is linked to a longitudinal extent (from
an aft transverse bulkhead to a forward bulkhead), transverse extent (limited by a
longitudinal boundary) and a vertical extent (limited by an upper horizontal boundary)
- 30 *** EN draft 2 ***
limiting possible damages. “s” factor must be calculated for damage cases associated to
“p” factor.
First damage case is the damage of all rooms within the maximum extent of damage. All
rooms within this extent of damage will be considered as immediately flooded in the first
stage. If flooded rooms are limited by non watertight bulkhead, or if cross flooding
devices are fitted, following stages are to be investigated.
“sfinal” defined in regulation 7-2 is supposed to apply to the final stage of flooding.
However, “sintermediate” is defined with less stringent criteria, assuming that intermediate
stages have a limited duration. When cross flooding devices are used, this duration is
defined as maximum of 10 minutes. So it can be considered that situation of the ship may
be evaluated by sintermediate if this situation doesn’t (dure) more than 10 minutes; otherwise,
“sfinal” should be applied. If subsequent stage is generated by progressive flooding
through non watertight bulkhead, weathertight opening submerged at equilibrium, broken
pipe, unprotected opening submerged within the range beyond equilibrium, and if it
cannot be demonstrated that this progressive flooding will take less than 10 minutes, it
should be logical to apply “sfinal” to the situation before progressive flooding.
So basic principle for “s” calculation may be:
Apply “intermediate” formulation if stage occurs within 10 minutes from the beginning
of the flooding process.
Apply “final” formula for the last stage within the 10 minutes and to all subsequent
stages or phases. If it is not possible to define a flooding time, duration shall be assumed
to be longer than 10 minutes.
In paragraph 5.2.1 of regulation 7-2, it is specified that immersion of opening closed by a
weathertight of closing is not allowed (“s” = 0) if flooding through this opening is not
accounted for. So on the contrary, immersion of such opening is permitted if flooding of
connected room is taken into account. If this weathertight opening is the only way of
flooding, progressive flooding will have an undefined but long duration, so it is not
sufficient to study the damage case including the progressively flood compartment.
Damage case without progressive flooding has also to be studied and an intermediate
situation with half of the progressive flooding. These situations may be defined as
different damage cases or different stages and phases of the same damage case, but “s”
factor has to be calculated using sfinal formula for all these cases.
The same assumption should be possible if any part of piping or ventilation duct (or any
unprotected opening) carried through a watertight boundary and if progressive flooding
of room connected to this opening is taken into account.
It can be consider that this is the intention of paragraph 5.4 of regulation 7-2, however, in
this paragraph, it is specified that “multiple values of sintermediate,i may be calculated
assuming equalisation in additional flooding phases”. If progressive flooding will last
more than 600s or is of undetermined time, sintermediate should be replaced by sfinal.]
- new proposal for Paragraph 2 text
- 31 *** EN draft 2 ***
[Intermediate Stages and Progressive Flooding
Intermediate stages and progressive flooding can be dealt similarly, as no further
requirement is described and in any case the minimum of sint is relevant.
This sequential flooding in separate stages should be used wherever non-watertight
boundaries delay the flooding significantly. No time limit is to be considered.
Cross Flooding
For cross flooding equalization time of 600 seconds is required. “Cross-flooding” for the
purpose of this regulation is defined as follows:
In general cross flooding is meant as a flooding of an undamaged space on the other side
of the ship to reduce the heel in the final equilibrium condition. In particular crossflooding is assumed if:
1. two separate tanks are connected by one or more pipes (with or without valves),
or
2. two parts of a void space are only connected via a small duct, where the volume
of the duct is less than [5%] of the total volume of the space.
Examples:
Connection between tanks:
Cross-flooding pipe
Small duct between both sides:
Small cross-flooding duct
Arrangements such as the following can be considered as instantaneously flooded
common spaces:
1. typical void spaces below engine rooms to separate lubricating tanks from the
shell
2. void spaces above the double bottom, which separate consumable tanks like fuel
oil or potable water from the shell
- 32 *** EN draft 2 ***
3. open spaces above the double bottom, where both sides of a compartment are
accessible by an open passage way.
Instantaneous Flooding
For spaces for which instantaneous flooding is assumed, it has to be proven that the cross
flooding will take place in 60 seconds. It is considered to be sufficient to base the
calculation of the flooding time on the initial condition only.]
- new proposal
[Damage Case Flow Chart
- 33 *** EN draft 2 ***
DAMAGE EXTENT DEFINES
PRIMARY FLOODING
FLOOD OPENED
SPACES TO
EQUILIBRIUM
POSITION
ANY CONNECTED
SPACES FROM
PRIMARY FLOODED
SPACES?
YES
NO
USE ‘s’ final FORMULA
TO ASSESS
SURVIVABILITY OF
PRIMARY FLOODING
USE ‘s’ intermediate FORMULA TO
ASSESS SURVIVABILITY OF
PRIMARY FLOODING
END
CROSS-FLOODING
CONNECTION?
INCLUDE CONNECTED
SPACE IN PRIMARY
FLOODING
YES
TIME TO CROSSFLOOD LESS
THAN 1 MINUTE?
YES
NON-WT BHD.
CONNECTION
NO
ASSUME NO FLOODING
THROUGH NON-WT BHD.
USE ‘s’ final FORMULA TO
ASSESS SURVIVABILITY OF
LAST STAGE
ASSUME FLOODING
THROUGH NON-WT
BHD. IN ‘n’ STAGES
ANY CONNECTED
SPACES FROM
THESE FLOODED
SPACES?
NO
YES
TIME TO CROSSFLOOD NOT
MORE THAN 10
MINUTES?
YES
NO
ASSESS CROSSFLOODED STAGE
USING ‘s’ intermediate
AND ‘s’ final AND
USE LOWER OF THE
TWO VALUES
END
NO
ASSESS CONDITION AFTER 10
MINUTES USING ‘s’ final FORMULA
AND CONTINUE CROSS-FLOODING TO
COMPLETION AND ASSESS USING ‘s’
final FORMULA – USE LOWER OF THE
TWO VALUES
ANY NON-WT BHD.
CONNECTION/S?
ANY NON-WT BHD.
CONNECTION/S?
NO
YES
END
ASSESS CROSSFLOODED STAGE
USING ‘s’ intermediate
AND ‘s’ final AND USE
LOWER OF THE TWO
VALUES
AND THEN:
- 34 *** EN draft 2 ***
NO
ASSESS n – 1
STAGES USING ‘s’
intermediate
FORMULA AND nth
STAGE USING ‘s’
final FORMULA
END
ASSESS ALL STAGES
USING ‘s’ intermediate
FORMULA
AND THEN REPEAT:
YES
Notes:
1. Where non-WT bulkhead connections are defined, two scenarios are to be examined;
one that no flooding through the bulkhead occurs and the other that flooding does
occur. The worst ‘s’ factor resulting from the two scenarios is to be used.
2. If any stage / phase of assessment results in ‘s’ = 0, no credit to the attained index is
given and any subsequent stages / phases may be aborted.
3. Credit to attained index is based on the lowest ‘s’ value from all stages / phases
examined for a given damage case, or ‘s’mom,i, if that is lower, ref: Reg. 7-2.1.1.
4. If compartment connections are not compatible with the assumptions used in the flow
chart, the advice of the plan approval office is to be sought and a note advising the
builder of this is to be generated. ]
For cargo ships – where cross-flooding arrangements are fitted, calculations are also to be
carried out in accordance with IMO resolution A.266(VIII). [The time for equalization
shall not exceed 10 min.] or [If the time for equalisation exceeds 10 minutes, the
equalisation stage shall not be taken into account and the “s” factor shall be calculated
from situation at the previous stage.]
Paragraph 4.1.1
The beam B used in this paragraph means breadth as defined in regulation 2.8.
[Paragraph 4.1.2
The parameter A (projected lateral area) used in this paragraph does not refer to the
attained subdivision index.] or delete this paragraph
Paragraph 5.2.1
[Unprotected openings:
The flooding angle will be limited by immersion of such an opening. It is not necessary
to define a criterion for non-immersion of unprotected openings at equilibrium, because if
it is immersed, the range of positive GZ limited to flooding angle will be null so “s” will
be equal to 0.
An unprotected opening connects two rooms or one room and the outside. An
unprotected opening will not be taken into account if the two connected rooms are
flooded or no one of these rooms are flooded. If the opening is connected to the outside,
it will not be taken into account if the connected compartment is flooded. An unprotected
opening has not to be taken into account if it connects a flooded room or the outside to an
undamaged room if this room will be considered as flooded in a subsequent stage.]
[Openings fitted with a weathertight mean of closing (“weathertight openings”):
The survival “s” factor will be “0” if any such point is submerged at a stage which is
considered as “final”. Such points may be submerged during a stage or phase which is
considered as “intermediate”, or within the range beyond equilibrium.
- 35 *** EN draft 2 ***
If an opening fitted with a weathertight means of closure is submerged at equilibrium
during a stage considered as intermediate, it should be demonstrated that this
weathertight means of closure can sustain the corresponding head of water and that the
leakage rate is negligible. A leakage rate of 1/10000th of ship displacement per hour is
considered as acceptable.
These points are also defined as connecting two rooms or one room and the outside, and
same principle as for unprotected openings is applied to take them into account or not.
If several stages have to be considered as “final”, a “weathertight opening” has not to be
taken into account if it connects a flooded room or the outside to an undamaged room if
this room will be considered as flooded in a successive “final” stage.]
Paragraph 5.2.2
Horizontal evacuation routes on the bulkhead deck include only escape routes
(designated as category 2 stairway spaces according to regulation II-2/9.2.2.3 or as
category 4 stairway spaces according to regulation II-2/9.2.2.4 for passenger ships
carrying not more than 36 passengers) used for the evacuation of undamaged spaces.
Horizontal evacuation routes do not include corridors within the damaged space. [There
is no allowance for partial immersion of horizontal evacuation routes, even if there is a
0.9m “dry passage” width.] or [No part of a horizontal evacuation route is to be
immersed.]
- new proposal
[Points limiting horizontal evacuation routes on the bulkhead deck:
Such points will have to be defined at the limits of horizontal evacuation routes in such a
way that non-immersion of evacuation routes may be guarantied if no one of these points
is submerged. Criterion of non-immersion of such points is the same as for “weathertight
openings”. However, same part of an escape route may be used for evacuation of several
compartments. Principle is that a horizontal evacuation route must not to be submerged if
it is used for evacuation of undamaged spaces. So a point of an evacuation route should
connect the space above the bulkhead deck in which it is placed to all spaces for which
escape route pass through this point. If a watertight compartment is subdivided in several
rooms, only rooms in which people are supposed to enter during navigation have to be
considered. Alternatively [If a watertight compartment is subdivided into several rooms,
only rooms directly connected to the access to above the bulkhead deck and rooms above
the bulkhead deck have to be considered . (Spaces in which nobody is supposed to enter
during navigation do not have to be taken into account)]. Such a point will be taken into
account if the space above the bulkhead deck where it is located is flooded and at least
one of the connected spaces is not flooded. (A solution may be to define as many points
as there are spaces for which escape route pass through this point.) If several stages have
to be considered as final, this principle should apply at each stage independently of the
followings.]
- 36 *** EN draft 2 ***
- new proposal
[Subject to certain design principles the provisions for escape in chapter II-2 allows more
than one watertight compartment below the bulkhead deck to be served by a common
stairway within the same main vertical zone (MVZ). As opposed to the previous
passenger ship regulations partial immersion of the bulkhead deck may be accepted at
final equilibrium. The new provision is intended to ensure that evacuation along the
bulkhead deck to the vertical escapes will not be impeded by water on that deck. A
“horizontal evacuation route” in the context of this regulation means a route on the
bulkhead deck connecting spaces located on and under this deck with the vertical escapes
from the bulkhead deck required for compliance with chapter II-2.
The following principles are to be employed:

The horizontal evacuation routes on the bulkhead deck include [only] the
corridors considered part of a stairway enclosure and which are designed as
category 2 spaces according to SOLAS regulation II-2/9 intended for the
evacuation from undamaged spaces.

[Secondary] Corridors such as those connecting cabins to the main and secondary
evacuation routes within the damaged compartments need not be considered.

Where there is more than one route available through the MVZ, for instance
multiple corridors, only one continuous route need to remain unobstructed for the
purpose of this paragraph. (Fig. **)
- 37 *** EN draft 2 ***

No allowance should be given for partial immersion of the escape routes, even if
there would be a 0.9 m “dry passage”. However, immersion of the outer part of
the open deck in lobbies and other wide public spaces within the MVZ may be
accepted if the entrance and exit remains unobstructed and the un-immersed part
of the deck is greater than the immersed part.
In all cases shall no part of the boundary of the stairwell forming the vertical escape be
immersed at the bulkhead deck, also if located in a compartment [zone] considered
damaged.]
Paragraph 5.3.1
[Vertical escape hatches:
The “s” factor will be “0” if such a point is submerged at any stage of flooding. Such
points may be submerged within the range beyond equilibrium. These points have to be
- 38 *** EN draft 2 ***
considered only if they are primary escapes (no other means of escape if watertight doors
are closed.)
These points are defined as connecting the room above the bulkhead deck in which it is
placed and the room below the bulkhead deck. If compartment below the bulkhead deck
is subdivided in several rooms, it may be logical to consider all rooms for which this
escape is used. (rooms in which nobody is supposed to enter during navigation have not
to be taken into account). Such a point will be taken into account if the space above the
bulkhead deck is flooded and at least on of the connected spaces below the bulkhead deck
is not flooded. This assumes that escape from a space not flooded at a stage has to be
considered even if this escape necessitates crossing a flooded space to reach the escape
hatch. An alternative interpretation would be to consider only the space directly below
the escape hatch. If several stages are considered, this principle should apply at each
stage independently of the followings.]
- new proposal
[The purpose of this paragraph is to provide an incentive to ensure that evacuation
through a vertical escape will not be obstructed by water from above. The paragraph is
intended for smaller emergency escapes, typically hatches, where fitting of a water- or
weathertight means of closure would otherwise exclude them from being considered as
flooding points.
Since the probabilistic regulations do not require that the watertight bulkheads be carried
continuously up to the bulkhead deck care should be taken to ensure that evacuation from
intact spaces through flooded spaces below the bulkhead deck will remain possible, for
instance by means of a watertight trunk.
]
Paragraph 5.3.2
[Control stations:
- 39 *** EN draft 2 ***
The criterion is that these control stations remain accessible and operable. Such points are
linked to the space above the bulkhead deck where they are located and these points have
to be taken into account if this space is flooded, independently of the flooding of other
spaces. These points will be defined at the level of the [floor] of the control station.
Criteria for accessibility to any control may be no water in the room. However, if raised
floor is fitted it may be taken into account. Access route from upper decks should also be
dry.
The “s” factor will be “0” if such a point is submerged at any stage of flooding. Such
points may be submerged within the range beyond equilibrium. It may be necessary to
define additional points between the control station and access to upper decks to ensure
that control station will remain accessible. Such points may be located in other spaces
through which it is necessary to pass to have access to a control station. These additional
points will be taken into account in the same manner as control station itself.]
or several comments indicated no guidance necessary for this paragraph.
Paragraph 5.3.2
[Part of piping or ventilation ducts carried through a watertight boundary:
They have to be treated as unprotected openings. (If they are submerged at any stage of
flooding, range of positive GZ will be null, so “s” factor will be “0”). Corresponding
point has to be placed at the lower position of the duct for which, if water level is above,
progressive flooding will occur. If such point is defined differently depending on the
direction of the flow, lower position with mean longitudinal and transverse position will
be retained. If piping or ventilation ducts are fitted with a weathertight mean of closing
at the crossing of the watertight boundary, they will be considered as “weathertight
openings “ (possibility to immerse them during intermediate stages of flooding ).
They will not be taken into account if they are fitted with a watertight mean of closing.]
Paragraph 6
The vertical subdivision in a damage zone
[Damage to the hull might have a limited extent vertically in the form of watertight
structure.] or [The extent of flooding following damage to the hull may be limited
vertically by the presence of watertight decks.] The probability of no impact to a
watertight horizontal subdivision has just one probability factor v. [In case of a
watertight deck above ds + 12.5 m, v = 1. If the damage height H is limited to a lower
extent, the factor v will be reduced.] or [v = 1, if Hm coincides with the uppermost
watertight boundary of the ship.]
The sketches in the figure illustrate the connection between position of watertight decks
in the reserve buoyancy area and the use of factor v for damages below these decks.
- 40 *** EN draft 2 ***
[The damage heights H1 and H2 lead to a factor v < 1
and H3 to a factor v3 = 1.] or [In this example, there
Above the waterline
H3
H2
H1
d
The factor v1 and v2 are the same as above. The
reserve buoyancy above H3 is to be taken undamaged
in all damage cases.
H4
H3
H2
H1
d
Below the waterline
d
R1
R2
R3
Dam. Zone
12.5m
are 3 horizontal subdivisions to be taken into account as
the vertical extent of damage. The example shows the
maximum possible vertical extent of damage d + 12.5m
is positioned between H2 and H3. H1 with factor v1, H2
with factor v2 > v1 but v2 < 1 and H3 with factor v3=1.]
12.5m
The combination of damages into the rooms R1, R2
and R3 positioned below the initial water line must
be chosen so that the damage with the lowest s-factor
is taken into account. That often results in the
definition of alternative damages to be calculated and
compared. If the deck taken as lower limit of damage
is not watertight, down flooding is to be considered.
- another proposal
[
The deck H1 is not taken into account as a limit for the vertical damage extent as H1 < H.
The damage height H2 leads to a factor v2 < 1 and H3 to a factor v3 = 1. ]
- 41 *** EN draft 2 ***
The vi factor
Using the same indices as [previously] and introducing:
m as the index for horizontal subdivision,
M as the maximum number of horizontal subdivisions [below ds + 12.5m,] and
c as the index for the initial loading condition,
the formula below expresses the v-factor:
vj,n,m,c = v(Hj,n,m,d c) - v(Hj,n,m-1,d c)
where
Hm is distance from the baseline to the mth horizontal subdivision in question
v(Hj,n,0,d c) = 0 and v(Hj,n,M,d c) = 1 - v(HM-1,d c)
Important: the same H in all parts of the formula for calculating v.
The Hm’s for adjacent zones should be treated in the same way bk’s in regulation 7-1.
Accumulating v-factor for a damage zone or n adjacent zones
m = Mj,n
vj,n,c = vj,n,m,c
m=1
where:
j+n-1
Mj,n =  Mj the total number of Hm’s for the adjacent zones in question.
j
Accumulating v-factor for a loading condition c
j=T
vc = vj,n
j=1
where:
T is the number of damage zones plus the maximum number of combined
adjacent zones.
- new proposal for
v
and j , n , M 1 :
[
vi
factor as an alternative way to represent the difference of
v j ,n ,m  f ( H j ,n ,m , d c )
- 42 *** EN draft 2 ***
v j ,n ,M
v j ,n ,m  v j ,n ,m  v j ,n ,m 1
v j ,n , 0  0
and
v j ,n , M  1
v j ,n ,M  1  v j ,n ,M 1
]
Paragraph 6.1
The parameters x1 and x2 are the same as parameters x1 and x2 used in regulation 7-1.
Regulation 7-3 – Permeability
Paragraph 2
The following additional cargo permeabilities may be used:
Spaces
Timber cargo in holds
Timber deck cargo
Wood chip cargo
Permeability
at draught ds
0.35
0.25
0.60
Permeability
at draught dp
0.70
[0.6]
0.70
Permeability
at draught dl
0.95
[1.0]
0.95
Paragraph 3
Concerning the use of other figures for permeability “if substantiated by calculations”,
there was a general agreement that such permeabilities should reflect the general
conditions of the ship throughout its service life rather than specific [ loading ]
conditions.
[ When using other figures for permeability:
Non-floodable volume may be determined based on the detailed room configuration.
Alternatively, total weight of equipment within the room may be estimated and
corresponding non-floodable volume to be deducted assuming mean density of material.
If light materials are within the room, no account should be taken for them if it is not
demonstrated that they doesn’t absorb water. If light material of non absorbent type is
used, corresponding volume may be taken into account, but volume of material within the
extent of damage should be excluded.
For liquid cargo, result is very dependant on cargo situation. It can be admitted that
subdivision draft can be achieved only with full cargo. In this case, emptying of liquid
cargo cannot be simulated by adjustment of permeability. The only way to have a correct
simulation is to start from an actual initial condition with cargo filled. At light service
draft, cargo tanks will be considered empty ( permeability 0.95). At partial draft any
combination of cargo filling may be assumed, so a conservative assumption would be to
consider cargo tanks in way of damage as empty ( permeability 0.95).]
Regulation 8 – Special requirements concerning passenger ship stability
- 43 *** EN draft 2 ***
Paragraphs 3.2 to 3.5
The number of persons carried, which are specified in these paragraphs, equals the total
number of persons on board (and not N = N1 + 2 N2 as defined in regulation 6).
Regulation 9 – Double bottoms in passenger ships and cargo ships other than
tankers
Paragraph 2
[An inner bottom should not be located higher than the partial subdivision draught dp.]
[To allow double bottom and margin plate protecting the turn of bilge to a plain plane
parallel to the keel line and which is located not less than a vertical distance 500 mm (or
760 mm) measured from the keel line.]
Paragraph 4
Co-ordinators’ note: a comment indicated that an interpretation of the definition “dry
tanks of moderate size” should be included in the explanatory notes. As noted, this issue
could have a significant impact on survivability in case of grounding damage (see figure
below. Please review the comments and provide proposals on this item.
Paragraph 9
[For the purpose of identifying “large lower holds”, horizontal surfaces having a
continuous deck area of [30] per cent or more in comparison with the waterplane area at
subdivision draft should be taken located anywhere in the affected area of the ship. For
the alternative bottom damage calculation, a vertical extent of B/10 or 3 meters,
whichever is less, should be assumed.]
The increased minimum double bottom height of not more than B/10 or 3 m, whichever
is less, for passenger ships with large lower holds, is applicable to holds in direct contact
with the double bottom. Typical arrangements of ro-ro passenger ships may include a
large lower hold with additional tanks between the double bottom and the lower hold, as
shown in the figure below. In such cases, the vertical position of the double bottom
required to be B/10 or 3 m, whichever is less, shall be applied to the lower hold deck,
- 44 *** EN draft 2 ***
maintaining the required double bottom height of B/20 or 2 m, whichever is less (but not
less than 760 mm).
Figure - Typical arrangement of a modern ro-ro passenger ferry
Regulation 10 – Construction of watertight bulkheads
Paragraph 1
For the treatment of steps in the bulkhead deck of passenger ships see regulation 13. For
the treatment of steps in the freeboard deck of cargo ships see regulation 13-1.
Regulation 13 – Openings in watertight bulkheads below the bulkhead deck in
passenger ships
General – steps in the bulkhead deck
If the transverse watertight bulkheads in a region of the ship are carried to a higher deck
which forms a vertical step in the bulkhead deck, openings located in the bulkhead at the
step may be considered as being located above the bulkhead deck. [Such openings are
then to comply with regulation 17 if progressive flooding might occur ]. or [Such
openings are then to comply with regulation 17 and are to be taken into account when
applying regulation 7-2.]
All openings in the shell plating below the upper deck throughout that region of the ship
should be treated as being below the bulkhead deck and the provisions of regulation 15
should be applied. See figure below.
- 45 *** EN draft 2 ***
1 Bulkhead deck
3 Ship’s side
2 Considered as located above the bulkhead deck
4 Considered as located below the bulkhead deck
Paragraph 7.6
The IEC standard referenced in the footnote (IEC publication 529, 1976) has been
replaced by a newer standard IEC 60529:2003.
Regulation 13-1 – Openings in watertight bulkheads and internal decks in cargo ships
Paragraph 1
If the transverse watertight bulkheads in a region of the ship are carried to a higher deck
than in the remainder of the ship, openings located in the bulkhead at the step may be
considered as being located above the freeboard deck.
All openings in the shell plating below the upper deck throughout that region of the ship
should be treated as being below the freeboard deck and the provisions of regulation 15
should be applied. See figure below.
1 Freeboard deck
3 Ship’s side
2 Considered as located above the freeboard deck
4 Considered as located below the freeboard deck
- 46 *** EN draft 2 ***
Regulation 15 – Openings in the shell plating below the bulkhead deck of passenger
ships and the freeboard deck of cargo ships
General – steps in the bulkhead deck and freeboard deck
For the treatment of steps in the bulkhead deck of passenger ships see regulation 13. For
the treatment of steps in the freeboard deck of cargo ships see regulation 13-1.
Regulation 15-1 – External openings in cargo ships
Paragraph 1
[With regard to air-pipe closing devices, they should be considered weathertight closing
devices (not watertight). This is consistent with their treatment in regulation 7-2.5.2.1.
However in the context of regulation 15-1, “external openings” are not intended to
include air-pipe openings.] Co-ordinators’ note: we drafted this text based on the
submitted comments, and the premise that regulation 15-1 is not intended to require airpipe closing devices to be watertight and fitted with indicators on the bridge.
Regulation 16 – Construction and initial tests of watertight doors, sidescuttles, etc.
Paragraph 2
While this paragraph prescribes the pressure testing of watertight doors to the head of
water they might have to sustain in a final or intermediate stage of flooding, the
watertight bulkhead design requirements in regulation 10.1 implies that a head of water
up to the bulkhead deck (freeboard deck on cargo ships) should be applied if that value is
greater.
However in cases where the door is located in a stepped bulkhead deck or freeboard deck,
the elevation to the lower part of the step may be used in this comparison. A door in such
a position may be considered as being located above the bulkhead deck or freeboard deck
and the testing requirements in regulation 16 need not be complied with. In the case of
passenger ships regulation 17 is to be applied instead. Regulation 13-1 applies to all
watertight doors in cargo ships regardless of location. The principles of [and
MSC/Circ.736 Annex Part B] should be applied.
Note: See regulation 13 for additional information regarding the treatment of steps in the
bulkhead deck of passenger ships. See regulation 13-1 for additional information
regarding the treatment of steps in the freeboard deck of cargo ships.
Regulation 17 – Internal watertight integrity of passenger ships above the bulkhead
deck
General – steps in the bulkhead deck
For the treatment of steps in the bulkhead deck of passenger ships see regulation 13.
Paragraph 1
- 47 *** EN draft 2 ***
[Watertight sliding doors with reduced pressure head complying with the requirements of
MSC/Circ.541 should be in line with regulation 7-2.5.2.1. These types of tested
watertight sliding doors with reduced pressure head could be immersed during
intermediate stages of flooding.]
Paragraph 3
These provisions are generally already accounted for in an alternative probabilistic
manner by paragraphs 5.2.1 and 5.3.3 of regulation 7-2. Therefore instead of the
specified waterline, the waterline from conditions where s = 1 can be used.
Regulation 19 – Damage control information
Paragraph 5
See the Guidelines for damage control plans and information to the Master in appendix 2.
Co-ordinators’ note: regarding the format issue – the majority of those who commented
on this issue preferred a new MSC Circular limited to “information to the Master on ship
survivability” in reg II-1/19.5, which does not incorporate the existing damage control
plan guidance in MSC/Circ.919 (as is currently the case in appendix 2). If this is the
view of the Group, this will be indicated in our SDS CG report to SLF 49. Therefore
please review the comments and specifically indicate your preference on this issue.
Regulation 22 – Prevention and control of water ingress, etc.
Paragraph 4
See the guidance in appendix 3 for determining the impact on survivability of open
watertight doors that are permitted by this paragraph.
Co-ordinators’ note: limited comments were submitted regarding whether the proposed
guidance in appendix 3 is generally acceptable or is too strict / prescriptive (and should
be revised). Therefore it is not possible to summarize the Group view on this issue.
Please carefully review the comments and indicate your preference on this important
item.
Regulation 35-1 – Bilge pumping arrangements
Paragraph 2.6
The drainage from enclosed ro-ro spaces or special category spaces shall be of such
capacity that two-thirds of the scuppers, freeing ports etc. on the starboard or port side
shall be capable of draining off a quantity of water originating from both sprinkler pumps
and fire pumps, taking into account a list of 1 for ships with a breadth of 20 m or more
and 2 for ships with a breadth below 20 m and a trim forward or aft of 0.5.
Scuppers on ro-ro decks shall be provided, over the outlet grate, with a removable grill
with vertical bars, to prevent large obstacles from blocking the drain. The grill may be
placed obliquely against the side of the ship. The grill shall have a height of at least 1 m
- 48 *** EN draft 2 ***
above the deck and shall have a free flow area of at least 0.4 m2, while the distance
between the individual bars shall be not more than 25 mm.
Paragraph 3.1
[The calculation provisions mentioned in last sentence may be interpreted as follows:
Determination of the loading condition derived from the partial subdivision draft
condition by addition of water in the compartment not fitted with drainage (until half
full). Verification that GM of this loading condition is higher than corresponding
required GM.]
- 49 *** EN draft 2 ***
Appendix 1
[ Presentation of damage stability calculation results
1 Documentation
A proposal for a minimum documentation is listed below:
Ship identification and prime parameters
Total number of persons the ship is permitted to carry
Number of persons for whom lifeboats are provided
Subdivision length
Beam at the load line
Beam at the bulkhead deck
Required subdivision index R
Attained subdivision index A
Additional information to be provided:
 the basis for the calculations
 extent of watertight and weather tight integrity
 influence of all piping and AC trunks
 cross flooding and counter filling system
 bilge pumping arrangements
 closing of watertight and weather tight doors and hatches
 scuppers
 extreme floating positions (trim and heel)
 information on what vital systems will be put out of function due to flooding of
certain compartments
Presentation of damage stability calculation results:
Summary of results
Max
Attained
Attained Attained
attainable index at ds index at dp index at dl
index
1 ZONE
2 ZONES
3 ZONES
4 ZONES
……
TOTAL
Global
weighed
index
Table of compressed results [also called summary table in NAPA]:
Initial condition
d
GM
trim
R
A
- 50 *** EN draft 2 ***
A/R
W
A*W
At the end of this table, the total A should be indicated
A list of results for the number of damage zones for each draught.
No. of damage
zones
1
2
3
……..
Total A-index
W*p*v*s
Detailed list of examined damage cases, results and the corresponding factors.
Case
p
v
s
W
W*p*v*s
0.000
0.00000
0.000
0.00000
0.000
0.00000
ds
Subtotal ds
dp
Subtotal dp
dl
Subtotal dl
2 Subdivision matrix
A layout example of a subdivision matrix is made below containing a number of zones
and a number up to four transverse barriers in each zone and up to four vertical barriers
(decks) in each zone (could be expanded if necessary).
Single Zone
(j)
1
2
3
.
.
.
x1
x2
b1
b2
This is one way of presenting the subdivision.
- 51 *** EN draft 2 ***
H1
H2
The subdivision matrix
Having considered the watertight subdivision of the ship, that is longitudinal-,
transverse- and vertical- watertight structure a useful tool to combine the damages
to be examined is a subdivision matrix.
The matrix contains information of all the single zone damages to be considered
for calculating the attained index A that is: the longitudinal zones (x1 x2),
transverse barriers (longitudinal bulkheads in the zones) (b) and vertical barriers
(decks) in the same zones (H).
The data in the matrix is distances measured in metres.
3 Combining the damages to be investigated
Relating the matrix to the watertight rooms in the ship the damages may be defined for all
single zone damages.
Multiple damages are defined by combining adjacent damages respecting the penetrations
for each damage zone in the way that only one value for b is used in a damage to be
investigated. This might lead to the definition of a large number of damages.
The vertical subdivision is treated analog with the transverse when combining multiple
zones.
A Suitable Damage Nomenclature
A proposal for a standard for naming damages are: “PZa-Zf.IB.IHU” where:
P
P for damages on port side, or S for starboard side.
Za
Number of damage zone the only one or the aftermost included
Zf
IB
Number of foremost damage zone if more than one zone involved.
Penetration index, 1 means penetration to 1st. Long. bhd. 2 to 2nd.
Long. bhd. etc. Except that damage to centre line=0.
IHU
Deck number limiting damage upwards, unlimited=0.
IHU-1
-1 means an alternative damage not involving the double-bottom
such damage case will only occur when it requires higher stability
standards.
]
- alternate proposal
[Guidelines for the Preparation of Subdivision and Damage Stability Calculations
- 52 *** EN draft 2 ***
A.
General
1.
Purpose of the Guidelines
1.1
These guidelines serve the purpose of simplifying the process of the damage
stability analysis as experience has shown that a systematically and complete presentation
of the particulars results in considerable saving of time during the approval process.
1.2
A damage stability analysis serves the purpose to provide proof of the damage
stability standard required for the respective ship type. At present, two different
calculation methods, the deterministic concept and the probabilistic concept are applied.
2.
Scope of analysis and documentation on board
The scope of subdivision and damage stability analysis is determined by the required
damage stability standard and aims at providing the ships master with clear intactstability requirements. In general, this is achieved by determining VCG-respective GMlimit curves, containing the admissible stability values for the draught range to be
covered.
Within the scope of the analysis thus defined all potential or necessary damage conditions
will be determined, taking into account the damage stability criteria, in order to obtain the
required damage stability standard. Depending on the type and size of ship, this may
involve a considerable amount of analyses.
Referring to SOLAS II-1, B-4, Reg. 19 the necessity to provide the crew with the relevant
information regarding the subdivision of the vessel is expressed, therefore plans shall be
provided and permanently exhibited for the guidance of the officer in charge. These plans
shall clearly show for each deck and hold the boundaries of the watertight compartments,
the openings therein with means of closure and position of any controls thereof, and the
arrangements for the correction of any list due to flooding. In addition, Damage Control
Booklets containing the aforementioned information shall be available.
B.
Documents for Submission
1.
Presentation of documents
The documentation shall begin with the following details. Principal dimensions, ship
type, designation of intact conditions, designation of damage conditions and pertinent
damaged compartments, VCG-respective GM-limit curve.
2.
General documents
For checking of the input data, the following is to be submitted:
–
main dimensions
–
lines plan, plotted or numerically
–
hydrostatic data and cross curves of stability (incl. drawing of the buoyant hull)
–
definition of sub-compartments with moulded volumes, centres of gravity and
permeability
- 53 *** EN draft 2 ***
–
layout plan (watertight integrity plan) for the sub-compartments with all internal and
external opening points including their connected sub-compartments, and particulars
used in measuring the spaces, such as general arrangement plan and tank plan
–
light service condition
–
load line draught
–
co-ordinates of opening points with their level of tightness (e.g. weathertight,
unprotected)
–
watertight door location with pressure calculation
–
side contour and wind profile
–
cross- and down flooding devices and the calculations thereof according to IMO
Res. A.266 with information about diameter, valves, pipes length and coordinates of
inlet/outlet
–
pipes in damaged area when the destruction of these pipes results in progressive
flooding
–
damage extensions and definition of damage cases
3.
Special documents
The following documentation of results is to be submitted.
3.1
Documentation
Initial data:
–
subdivision length LS
–
initial draughts and the corresponding GM-values
–
required subdivision index R
–
attained subdivision index A with a summary table for all contributions for all
damaged zones
Results for each damage case which contributes to the index A:
–
draught, trim, heel, GM in damaged condition
–
dimension of the damage with probabilistic values p, v and b
–
righting lever curve (incl. GZmax and range) with factor of survivability s
–
critical weathertight and unprotected openings with their angle of immersion
–
details of sub-compartments with amount of inflooded water/lost buoyancy with
their centres of gravity
3.2
Special consideration
For intermediate conditions as stages before cross-flooding or before progressive
flooding an appropriate scope of the documentation covering the aforementioned items is
needed in addition. ]
- 54 *** EN draft 2 ***
- 55 *** EN draft 2 ***
Appendix 2
Co-ordinators’ note: the majority of those who commented on format preferred a new
MSC Circular limited to “information to the Master on ship survivability” in reg II1/19.5, which does not incorporate the existing damage control plan guidance in
MSC/Circ.919 (as is currently the case in appendix 2). If this is the view of the Group,
this will be indicated in our SDS CG report to SLF 49. Therefore please review the
comments and specifically indicate your preference on this issue.
[ Guidelines for damage control plans and information to the Master - under
regulation II-1/19.5
1
Application
These guidelines are intended as advice on the preparation of damage control plans for
passenger and cargo ships and to set a minimum level for the presentation of damage
stability information for the use on board a ship when subject to internal flooding for
passenger and cargo ships to which SOLAS regulations II-1/19 apply.
2
General
2.1
The damage control plan and damage control booklet are intended to provide
ship's officers with clear information on the ship's watertight subdivision and equipment
related to maintaining the boundaries and effectiveness of the subdivision so that, in the
event of damage to the ship causing flooding, proper precautions can be taken to prevent
progressive flooding through openings therein and effective action can be taken quickly
to mitigate and, where possible, recover the ship's loss of stability.
2.2
The damage control plan and damage control booklet should be clear and easy to
understand. It should not include information which is not directly relevant to damage
control, and should be provided in the working language of the ship. If the languages
used in the preparation of the plan and booklet are not one of the official languages of the
SOLAS Convention, a translation into one of the official languages should be included.
3
Damage control plans
3.1
The damage control plan should be of a scale adequate to show clearly the
required content of the plan.
3.2
Isometric drawings are recommended for special purposes. The plan should
include inboard profile, plan views of each deck and transverse sections to the extent
necessary to show the following:
.1
the watertight boundaries of the ship;
- 56 *** EN draft 2 ***
.2
.3
.4
.5
.6
.7
4
the locations and arrangements of cross-flooding systems, blow-out plugs and
any mechanical means to correct list due to flooding, together with the
locations of all valves and remote controls, if any;
the locations of all internal watertight closing appliances including on ro-ro
ships, internal ramps or doors acting as extension of the collision bulkhead
and their controls and the locations of their local and remote controls, position
indicators and alarms. The locations of those watertight closing appliances
which are not allowed to be opened during the navigation and of those
watertight closing appliances which are allowed to be opened during
navigation, according to SOLAS regulation II-1/13, should be clearly
indicated;
the locations of all doors in the shell of the ship, position indicators, leakage
detection and surveillance devices;
the locations of all weathertight closing appliances in local subdivision
boundaries above the bulkhead deck and on the lowest exposed weather
decks, together with locations of controls and position indicators, if
applicable;
the locations of all bilge and ballast pumps, their control positions and
associated valves; and
pipes, ducts or tunnels, if any, through which limited progressive flooding has
been accepted by the Administration.
Damage control booklets
4.1
The information listed in section 3 should be repeated in the damage control
booklet.
4.2
The damage control booklet should include general instructions for controlling the
effects of damage, such as:
.1
.2
.3
immediately closing all watertight and weathertight closing appliances;
establishing the locations and safety of persons on board, sounding tanks and
compartments to ascertain the extent of damage and repeated soundings to
determine rates of flooding; and
cautionary advice regarding the cause of any list and of liquid transfer
operations to lessen list or trim, and the resulting effects of creating additional
free surfaces and of initiating pumping operations to control the ingress of
water.
4.3
The booklet should contain additional details to the information shown on the
damage control plan, such as the locations of all sounding devices, tank vents and
overflows which do not extend above the weather deck, pump capacities, piping
diagrams, instructions for operating cross-flooding systems, means of accessing and
escaping from watertight compartments below the bulkhead deck for use by damage
control parties, and alerting ship management and other organizations to stand by and to
co-ordinate assistance, if required.
- 57 *** EN draft 2 ***
4.4
If applicable to the ship, locations of non-watertight openings with non-automatic
closing devices through which progressive flooding might occur should be indicated as
well as guidance on the possibility of non-structural bulkheads and doors or other
obstructions retarding the flow of entering seawater to cause at least temporary conditions
of unsymmetrical flooding.
4.5
In case of ships to which damage stability requirements of part B-1 of SOLAS
apply, the damage stability information should be presented in the damage control
booklet.
It should be clearly stated at the beginning of this documentation that the information
provided is only to assist the ship’s officers in estimating the ship's relative survivability
at the first stage.
4.5.1 Damage stability conditions
The damage stability conditions should be classed by the following categories based on
the calculated s-value:
I.
II.
III.
s=1
0<s<1
s=0
reasonable survivability
limited survivability
critical survivability
(green condition)
(yellow condition)
(red condition)
A colour code may also be used to describe the damage condition, though the calculated
s-value should always be documented.
The damage stability should be presented for flooding of each transverse zone/zones of
the ship. [Penetrations of B/10 and B/2 should be included in the presentation of results
for 1, 2 and 3 compartment damages.] These zones should provide the identification for
all conditions. If a longitudinal subdivision is provided in the considered zone/zones the
damage stability should be calculated both for intact and damaged longitudinal bulkhead.
Calculation should be based on an intact condition consistent with the maximum
allowable KG or minimum GM for that condition.
4.5.2 Zones and draughts to be considered
4.5.2.1 Passenger ships
The damage stability should be calculated for [one, two and three flooded main
compartments] or [the maximum damage length plus 1 compartment] and for the initial
conditions corresponding to:
1. Deepest subdivision draught (ds),
2. Partial subdivision draught (dp) and
3. Light service draught(dl)
4.5.2.2 Cargo ships
The damage stability should be calculated for one and two flooded main compartments
- 58 *** EN draft 2 ***
and for the initial conditions corresponding to:
1. Deepest subdivision draught (ds),
2. Partial subdivision draught (dp) and
3. Light service draught (dl).
These are the minimum standards.
4.6
The damage stability information should be divided in chapters that show the
stability for each initial condition. A summary table of all conditions, s-values and
category of condition should be presented for easy reference.
For each condition the following information should be presented: Sketch showing the
damaged area, full listing of damaged compartments/tanks, the final stage of equilibrium
and the GZ-curve for that condition, s-value and category (I, II or III).
Any cross-flooding arrangements should also be thoroughly investigated and presented in
this context. Reference must also be made to any watertight doors that are allowed to be
open at sea according to SOLAS regulation II-1/22.4. The impact on the survivability
caused by open doors should be clearly stated and presented.
4.7
Damage control plans and damage control booklets should be in printed form.
5
Visual guidance to the master
Simple, clear and concise guidance, such as damage consequence diagrams, can provide
the master with a rapid means to evaluate the consequence of damage to the ship.
6
Placement on board the ship
6.1
For passenger ships, the damage control plan should be permanently exhibited on
the navigation bridge, as well as in the ship's control station, safety centre or equivalent.
6.2
For cargo ships, the damage control plan should be permanently exhibited or
readily available on the navigation bridge. Furthermore, the damage control plan should
be permanently exhibited or readily available in the cargo control room.
7
Use of on-board computers
The use of on-board computers (1), with damage stability software developed for the
specific ship, and familiar to properly trained ship's officers can provide a rapid means to
assess damage survivability for effective damage control. Such a computer system may
replace the damage stability conditions in [4.5.1 and 4.6] or [3.1, 4.1, 4.5 and 4.6].
8
1
Shore-based emergency response systems
Refer to the Guidelines for the on-board use and application of computers (MSC/Circ.891).
- 59 *** EN draft 2 ***
8.1
The availability of a shore-based emergency response system [can replace] or
[cannot replace] the damage control booklets in 4. The system could be made available
within the head office technical departments, classification societies or independent
organizations providing this service.
8.2
For this purpose, it should be clearly indicated in the damage stability booklet all
the details as who the master should contact in order to gain access to these facilities and
a list of information required for making damage stability assessments. ]
- 60 *** EN draft 2 ***
Appendix 3
Co-ordinators’ note: limited comments were submitted regarding whether the proposed
guidance in appendix 3 is generally acceptable or is too strict / prescriptive (and should
be revised). Therefore it is not possible to summarize the Group view on this issue.
Please carefully review the comments and indicate your preference on this important
item.
[ Guidance used for the determination of the impact of open watertight doors on
survivability under regulation II-1/22.4
1
Discussion
1.1 Watertight subdivision is vital to the survival of flooding damage. Accordingly,
openings in watertight bulkheads (e.g., doors) are to be kept to a minimum in accordance
with SOLAS regulation II-1/13.1. SOLAS chapter II-1, regulation 22.1 requires that all
watertight doors be kept closed during navigation except that they may be opened during
navigation as specified in certain circumstances. Regulation 22.3 allows a watertight
door to be opened to permit the immediate passage of passenger or crew.
1.2 These regulations reflect sound watertight door practice. There are ship operators
who keep watertight doors closed. These operators address the maintenance issues of
high cycling of watertight doors by incorporating advanced materials into the door’s
working parts and other enhanced reliability/maintainability focused measures.
1.3 Regulation 22.4 permits certain watertight doors “to remain open during
navigation only if considered absolutely necessary; that is, being open is determined
essential to the safe and effective operation of the ship’s machinery or to permit
passengers normally unrestricted access throughout the passenger area.” Further: “Such
determination shall be made by the Administration only after careful consideration of the
impact on ship operations and survivability.” If permitted to remain open, watertight
doors shall be ready at all times to be immediately closed.
1.4 Guidance given herein only addresses how an Administration may make the
determination required by this regulation for the impact on survivability of open
watertight doors.
1.5 Care should be exercised so that no confusion exists between compliance with
SOLAS damage stability criteria compliance, and meeting the floatability criteria for
open watertight door survivability impact.
2
Flooding extent to be examined
2.1
In every case in which a determination has been made that keeping one or more
watertight doors open while underway is absolutely necessary, floatability assessment
- 61 *** EN draft 2 ***
calculations must be performed. The extent of flooding to be assumed in these
calculations is described below.
2.2
Floatability assessment calculations need to be performed for each damage zone
involving damage to compartments that are associated with a watertight door requested to
remain open underway.
2.3
For all floatability assessments, all watertight doors permitted to remain open during
navigation shall be assumed to remain open after damage. In other words, no consideration
is given to any active damage control measures (i.e., no open watertight door is assumed to
close). For example, in Figure 1, if damage is assumed to occur to watertight-bulkhead #d,
the watertight doors in both watertight-bulkhead #c and #e would be assumed to remain
open. Hence, the four compartments bounded by bulkheads #b and #f would be assumed to
be flooded. In Figure 2, if damage is assumed to occur to watertight bulkhead #e, both
watertight doors in bulkheads #c and #d would be assumed to allow flooding to extend into
compartments #B and #C. Therefore, the flooding would extend to the same four
compartments as in Figure 1.
Figure 1 – Two-compartment damage – open WT doors in limiting bulkheads
[in figure 1 - Double bottom parts of #b-#c and #e-#f compartments are not damaged nor
flooded.]
- 62 *** EN draft 2 ***
Figure 2 – Two-compartment damage – open WT doors in one limiting bulkhead
[in figure 2 - Double bottom parts of #b-#c-#d compartments are not damaged nor
flooded.]
2.4
A watertight door should not be permitted to remain open during navigation under
SOLAS regulation II-1/22.4 if the ship does not meet the floatability criteria given in
paragraph 3 for each extent of flooding. When making flooding assessments, the damage
opening should be assumed as both penetrating and not penetrating the double bottom.
3
Criteria for floatability assessment
In each flooded condition described in paragraph 2, the ship must be able to float upright
(i.e., not capsize or founder) in the intermediate and final stages of flooding for every
condition of intact loading with passengers. The following conditions apply:
.1
A transverse moment associated with launching of two fully loaded davitlaunched survival craft on the heeled side (other moments described in
SOLAS regulation II-1/7-2.4.1 are not applied).
.2
The center of gravity is adjusted to consider all persons to be at muster
locations.
.3
The bulkhead deck may be immersed provided that no progressive
flooding occurs (i.e., closed weathertight openings may be immersed
during intermediate stages; only closed watertight opening may be
immersed at the final equilibrium stage of flooding).
.4
The maximum righting arm must not be less than 0.03 m in the final
equilibrium stage.
.5
The range of stability must not be less than 4 degrees in the final
equilibrium stage.
- 63 *** EN draft 2 ***
.6
.7
The maximum heel angle in intermediate stages must not be greater than
20 degrees.
The maximum heel angle in the final equilibrium stage must not be greater
than 15 degrees. ]
- 64 *** EN draft 2 ***