216-Navigation and Watch Keeping / 748
N
a
v
i
g
ation and
W
atc
h
Kee
p
in
g
BOS-PRD-07.900502
Version 04. Original date: 01/06/2012. Version date: 31/12/2014. Valid version only on QMS site. Uncontrolled document when printed.
Procedure prepared by: BOS Head of Operations. Approved by: BOS Head of Operations. Validated by: BOS Quality Representative.
7 / 17
4
.
3
.
3
R
e
s
t
r
icted
v
i
s
i
b
ilit
y
The
W
atc
h
O
ff
ice
r
in charge of the navigational watch,
additional
B
r
id
g
e
W
atc
h
O
ff
ice
rs
and lookouts
shall
not
perform any other duties except navigational duties during times of restricted visibility.
If the visibility deteriorates, or the
B
r
id
g
e
W
atc
h
O
ff
ice
r
expects visibility to deteriorate, he/she
shall
:
x
Call and inform the
Ma
s
te
r
;
x
Inform the
En
g
ine
W
atc
h
O
ff
ice
r
in order to maintain Engine Room preparedness;
x
Ensure adequate reinforcement of lookouts (including consideration of posting outside lookouts) and
radar monitoring including radar plotting and echo soundings, and
shall
switch to the manual
steering mode;
x
Check and adjust radar settings, turn on navigational lights, and check that the horn/whistle is
working properly;
x
Apply regulations for preventing collisions at sea in a strict and timely fashion (
COLREG
Rule 19);
x
Maintain safe speed at all times in relation to the prevailing visibility;
x
Adjust speed suitably and in good time;
x
Pay special attention for sound signals.
During restricted visibility, Engine Watch Keeping responsibilities are as documented for coastal navigation.
4
.
3
.
4
Sh
allow wate
r
“
S
hallow water”
should
be considered to be any water where a maximum clearance of 2 meters or less
beneath the lowest point of the vessel’s underwater structure (usuall
y the keel) is present.
Ma
s
te
rs
shall
inform the
C
ont
r
act
s
Mana
g
e
rs
whenever any requirement or request is made by charterers
to operate in areas of shallow water; the
Ma
s
te
r
shall
also inform the applicable
O
p
e
r
ation
s
Mana
g
e
r
.
C
ont
r
act
s
Mana
g
e
rs
shall
discuss the requirement with the appropriate client representative and
should
obtain a full site survey, or equivalent, of the subject area, which in turn
shall
be passed to the
Ma
s
te
r
.
C
ont
r
act
s
Mana
g
e
rs
shall
establish maximum operating drafts with the appropriate client representative in
addition to establishing other considerations such as tidal windows to give optimum Under-Keel Clearances
(UKC).
When considering the UKC allowances, the following variable factors and local conditions
shall
include, but
are not be limited to:
x
The squat effect;
x
Environmental conditions; the prevailing weather, height of swell, tidal height and range, atmospheric
pressure, and changes in the density of sea and inland waters, etc.;
x
The nature and stability of the bottom (e.g. sand wave phenomena);
x
The vessel's size and handling characteristics, and increase in draft due to heel;
x
The reliability of ship's draft observations and calculations;
x
The accuracy of hydrographic data and tidal predictions;
x
Reduced depths over pipelines.
Whenever working in shallow water areas, the
Ma
s
te
r
shall
use all available means to gather data and
information concerning the area from other vessels already or previously working the area. Such information
is to be retained onboard and made available for
B
r
id
g
e
W
atc
h
O
ff
ice
rs
at watch handover.
The
Ma
s
te
r
shall
not
operate within shallow water areas unless satisfied by his/her own good judgement and
the practices of good seamanship that it is safe to do so; additionally the
Ma
s
te
r
shall
:
x
Make full consideration for the effects of squat and proceed at a minimum speed suitable to maintain
such effects to an absolute minimum;
x
Ensure that at least two means of position fixing are used to ascertain the vessel’s position.
Wherever possible, these
shall
include fixes from bearings taken of recognised navigation marks,
216