288-Vessel Stability / 748
Vessel Stabilit
y
BOS-PRD-07.900601
The effect of the weight of trapped water on the vertical centre of gravity and trim of vessel
shall
be taken
into account.
The weight of water is included in the cargo dead-weight permitted.
The minimum GM limitations of max VCG limitations
shall
not be exceeded and
shall
include the effect of
entrapped water in deck cargoes in the total VCG for the relevant conditions.
The quantity of water assumed to be trapped in and around the pipes is equal to a certain percentage of the
net volume of the pipe deck cargo. The net volume
shall
be taken as the internal volume of the pipes plus
the volume between the pipes.
The percentage of the net volume used to obtain the quantity of trapped water is based on the freeboard
amidships, as follows:
x
30% if the summer freeboard amidships to the main deck is equal to or less than 0.015*L;
x
10% if the summer freeboard amidships to the main deck is equal to or greater than 0.03*L;
x
For intermediate values of the freeboard amidships, the percentage may be obtained by linear
interpolation.
L is Length (see International Load Line Convention).
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Wate
r
ti
gh
t i
n
te
g
r
it
y
Watertight integrity
shall
be maintained at all time; this includes, but is not limited to the following:
x
Closing external doors;
x
Maintaining internal watertight doors closed at sea at all time;
x
Keeping any openings on the deck always closed; hatch covers, manholes except when necessary
for operations in port;
x
Checking that any devices to prevent progressive flooding are kept closed.
Any other openings that could allow water to enter into the hull or deckhouse, such as air pipes
shall
be kept
closed when rough weather or sea conditions exist or are anticipated.
Any cross connections between port and starboard tank pairs
shall
be kept closed at all times when
underway, the number of partially filled tanks
shall
be kept to a minimum at all times.
All ventilators on cargo deck
shall
be closed unless the operational condition requires some of them to be
open.
Maintenance of all these watertight closing means
shall
be observed.
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e stabilit
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4
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omp
a
ny
i
n
st
ruc
ti
o
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s
fo
r
assessi
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c
o
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seq
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of
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The
Stability Booklet
includes general precautions for prevention of unintentional flooding:
x
Watertight integrity
shall
be maintained at all times, any instruction/recommendation regarding
keeping watertight openings closed
should
be adhered to at all times;
x
Loading condition VCG shall be below damage maximum VCG curve;
x
Damage control plan
should
be available, giving the full list and position of all openings.
Proper assessment has to take place to assess which compartments could be flooded and the points of
ingress that may lead to flooding of nearby compartments.
Version 04. Original date: 22/06/2012. Version date: 31/12/2014. Valid version only on QMS site. Uncontrolled document when printed.
Procedure prepared by: BOS Operations Department Project Coordinator. Approved by: BOS Head of Operations. Validated by: BOS Quality Representative.
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