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1 Every oil tanker
delivered after 31 December 1979, as defined in regulation 1.28.2,
of 150 gross tonnage and above, shall comply with the subdivision
and damage stability criteria as specified in paragraph 3 of this
regulation, after the assumed side or bottom damage as specified
in paragraph 2 of this regulation, for any operating draught reflecting
actual partial or full load conditions consistent with trim and
strength of the ship as well as relative densities of the cargo.
Such damage shall be applied to all conceivable locations along
the length of the ship as follows:
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.1 |
in tankers of more than 225 m in length, anywhere
in the ship's length; |
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.2 |
in tankers of more than 150 m, but not exceeding
225 m in length, anywhere in the ship's length except involving
either after or forward bulkhead bounding the machinery space
located aft. The machinery space shall be treated as a single
floodable compartment; and |
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.3 |
in tankers not exceeding 150 m in length,
anywhere in the ship's length between adjacent transverse bulkheads
with the exception of the machinery space. For tankers of 100
m or less in length where all requirements of paragraph 3 of
this regulation cannot be fulfilled without materially impairing
the operational qualities of the ship, Administrations may allow
relaxations from these requirements. |
Ballast conditions where the tanker is not carrying oil in cargo tanks,
excluding any oil residues, shall not be considered.
SEE INTERPRETATION 46
2 The following provisions
regarding the extent and the character of the assumed damage shall
apply:
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.1 |
Side damage: |
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.1.1 |
Longitudinal extent: |
or 14.5 m, whichever is less |
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.1.2 |
Transverse extent
(inboard from the ship's side at right angles to the centreline
at the level of the summer load line):
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or 11.5 m, whichever is less |
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.1.3 |
Vertical extent: |
From the moulded line of the bottom
shell plating at centreline, upwards without limit |
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.2 |
Bottom damage: |
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For
0.3L from the forward perpendicular
of the ship |
Any other part of the ship |
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.2.1 |
Longitudinal extent: |
or 14.5 m, whichever is less |
or 5 m, whichever is less |
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.2.2 |
Transverse extent: |
or 10 m, whichever is less |
 formula
or 5 m, whichever is less |
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.2.3 |
Vertical extent: |
or 6 m, whichever is less, measured from the moulded line of
the bottom shell plating at centreline |
or 6 m, whichever is less, measured from the moulded line of
the bottom shell plating at centreline |
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.3 |
If any damage of a lesser extent
than the maximum extent of damage specified in subparagraphs
2.1 and 2.2 of this paragraph would result in a more severe
condition, such damage shall be considered. |
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.4 |
Where the damage involving transverse
bulkheads is envisaged as specified in subparagraphs 1.1 and
1.2 of this regulation, transverse watertight bulkheads shall
be spaced at least at a distance equal to the longitudinal extent
of assumed damage specified in subparagraph 2.1 of this paragraph
in order to be considered effective. Where transverse bulkheads
are spaced at a lesser distance, one or more of these bulkheads
within such extent of damage shall be assumed as non-existent
for the purpose of determining flooded compartments. |
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.5 |
Where the damage between adjacent
transverse watertight bulkheads is envisaged as specified in
subparagraph 1.3 of this regulation, no main transverse bulkhead
or a transverse bulkhead bounding side tanks or double bottom
tanks shall be assumed damaged, unless: |
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.5.1 |
the spacing of the adjacent bulkheads
is less than the longitudinal extent of assumed damage specified
in subparagraph 2.1 of this paragraph; or |
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.5.2 |
there is a step or recess in a
transverse bulkhead of more than 3.05 m in length, located within
the extent of penetration of assumed damage. The step formed
by the after peak bulkhead and after peak top shall not be regarded
as a step for the purpose of this regulation. |
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.6 |
If pipes, ducts or tunnels are
situated within the assumed extent of damage, arrangements shall
be made so that progressive flooding cannot thereby extend to
compartments other than those assumed to be floodable for each
case of damage. |
SEE INTERPRETATION 47
3 Oil tankers shall be regarded
as complying with the damage stability criteria if the following
requirements are met:
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.1 |
The final waterline, taking into account sinkage,
heel and trim, shall be below the lower edge of any opening
through which progressive flooding may take place. Such openings
shall include air-pipes and those which are closed by means
of weathertight doors or hatch covers and may exclude those
openings closed by means of watertight manhole covers and flush
scuttles, small watertight cargo tank hatch covers which maintain
the high integrity of the deck, remotely operated watertight
sliding doors, and sidescuttles of the non-opening type. |
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.2 |
In the final stage of flooding, the angle
of heel due to unsymmetrical flooding shall not exceed 25°,
provided that this angle may be increased up to 30° if no
deck edge immersion occurs. |
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.3 |
The stability in the final stage of flooding
shall be investigated and may be regarded as sufficient if the
righting lever curve has at least a range of 20° beyond
the position of equilibrium in association with a maximum residual
righting lever of at least 0.1 m within the 20° range; the
area under the curve within this range shall not be less than
0.0175 m·rad. Unprotected openings shall not be immersed
within this range unless the space concerned is assumed to be
flooded. Within this range, the immersion of any of the openings
listed in subparagraph 3.1 of this paragraph and other openings
capable of being closed watertight may be permitted. |
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.4 |
The Administration shall be satisfied that
the stability is sufficient during intermediate stages of flooding. |
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.5 |
Equalization arrangements requiring mechanical
aids such as valves or cross-levelling pipes, if fitted, shall
not be considered for the purpose of reducing an angle of heel
or attaining the minimum range of residual stability to meet
the requirements of subparagraphs 3.1, 3.2 and 3.3 of this paragraph
and sufficient residual stability shall be maintained during
all stages where equalization is used. Spaces which are linked
by ducts of a large cross-sectional area may be considered to
be common. |
4 The requirements of paragraph
1 of this regulation shall be confirmed by calculations which take
into consideration the design characteristics of the ship, the arrangements,
configuration and contents of the damaged compartments; and the
distribution, relative densities and the free surface effect of
liquids. The calculations shall be based on the following:
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.1 |
Account shall be taken of any
empty or partially filled tank, the relative density of cargoes
carried, as well as any outflow of liquids from damaged compartments. |
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.2 |
The permeabilities assumed for
spaces flooded as a result of damage shall be as follows: |
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Spaces |
Permeabilities
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Appropriated to stores
Occupied by accommodation
Occupied by machinery
Voids
Intended for consumable liquids
Intended for other liquids
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0.60
0.95
0.85
0.95
0 to 0.95*
0 to 0.95*
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.3 |
The buoyancy of any superstructure
directly above the side damage shall be disregarded. The unflooded
parts of superstructures beyond the extent of damage, however,
may be taken into consideration provided that they are separated
from the damaged space by watertight bulkheads and the requirements
of subparagraph .3.1 of this regulation in respect of these
intact spaces are complied with. Hinged watertight doors may
be acceptable in watertight bulkheads in the superstructure. |
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.4 |
The free surface effect shall
be calculated at an angle of heel of 5° for each individual
compartment. The Administration may require or allow the free
surface corrections to be calculated at an angle of heel greater
than 5° for partially filled tanks. |
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.5 |
In calculating the effect of free
surfaces of consumable liquids it shall be assumed that, for
each type of liquid, at least one transverse pair or a single
centreline tank has a free surface and the tank or combination
of tanks to be taken into account shall be those where the effect
of free surface is the greatest. |
5 The master of every oil tanker to which
this regulation applies and the person in charge of a non-self-propelled
oil tanker to which this regulation applies shall be supplied in
a approved form with:
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.1 |
information relative to loading and distribution
of cargo necessary to ensure compliance with the provisions
of this regulation; and |
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.2 |
data on the ability of the ship to comply
with damage stability criteria as determined by this regulation,
including the effect of relaxations that may have been allowed
under subparagraph 1.3 of this regulation. |
6 For oil tankers of 20,000 tonnes deadweight
and above delivered on or after 6 July 1996, as defined in regulation
1.28.6, the damage assumptions prescribed
in paragraph 2.2 of this regulation shall be supplemented by the
following assumed bottom raking damage:
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.1 |
longitudinal extent: |
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.1.1 |
ships of 75,000 tonnes deadweight and above:
0.6L measured from the forward perpendicular; |
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.1.2 |
ships of less than 75,000 tonnes deadweight:
0.4L measured from the forward perpendicular; |
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.2 |
transverse extent: B/3
anywhere in the bottom; |
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.3 |
vertical extent: breach of the
outer hull. |
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