287-Vessel Stability / 748
Vessel Stabilit
y
BOS-PRD-07.900601
Tanks containing slack liquids
should
be kept to a minimum.
Minimise free surface moments by keeping tanks full or dry, whenever possible.
When a tank is to be ballasted at sea, to counteract the loss of consumables it should be noted that:
x
The tanks
shall
have a complete free surface as soon as ballasting commences;
x
The free surface
shall
adversely affect the stability of the vessel before any benefit can be assumed
from the weight of ballast water taken on board.
4
.
2
.
3
Co
n
s
u
m
able ta
n
ks
FO/LO tanks: 90% filling when an overflow system is installed.
If there are no overflow system/tanks and for operation reasons, the filling is limited to 80/85%, FSM
correction
should
be duly taken into account.
Fresh water tanks: 98/100% filling.
4
.
2
.
4
C
a
r
go
ta
n
ks
When liquid cargo is to be loaded or discharged, as soon as pumping has commenced a full free surface
shall
exist in those tanks being pumped and the effect this has on the stability of the vessel taken into
account.
4
.
2
.
5 An
ti
-r
o
ll ta
n
ks/
f
l
u
m
e ta
n
ks
Anti-roll tanks
shall
be filled for standard sea-state operation and taken in to account for all stability
calculations.
50% filling
shall
be assumed in absence of information on the system.
Anti-roll tanks
shall
be dry or filled at 100% for lifting, and/or towing/anchor-handling operations.
4
.
2
.
6 An
ti
-
h
eel ta
n
ks
Unless specified in the approved stability documentation, it is not allowed to ballast the ship during crane
movements.
During the lifting procedure the maximum angle of heel is determined in the approved stability
documentation.
When the maximum crane operating angle is nearly reached the crane operation has to stop and the vessel
needs to ballast in a way that the lifting procedure can proceed, without exceeding the maximum specified
angle of heel to either side.
4
.
2
.
7 B
il
g
es
,
v
o
i
d
s a
nd
o
v
e
r
f
l
o
w ta
n
ks
The vessel bilge, overflow tanks and voids spaces
shall
be kept pumped to a minimum content at all times
consistent with pollution prevention requirements.
4
.
2
.
8 D
e
c
k
c
a
r
go
– e
ff
e
c
t
of
e
n
t
r
a
pp
e
d
wate
r
When pipes are carried on deck (or other cargoes liable to provide a temporary trap for water), a volume of
entrapped water
shall
be assumed.
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.
9 / 13
287