Section
15 Navigation and manoeuvring systems
15.1 Steering systems
15.1.2 Two
exclusive circuits, fed from the main source of electrical power and
each having adequate capacity to supply all the motors which may be
connected to it simultaneously are to be provided for each electric
or electrohydraulic steering unit arrangement consisting of one or
more electric motors. One of these circuits may pass through the emergency
switchboard. For high speed craft, one of these circuits is to be
fed either from the emergency source of electric power or from an
independent power source located in such a position as to be unaffected
by fire or flooding affecting the main source of power. See
also
Pt 14, Ch 1, 6 Control, monitoring and electrical equipment.
15.1.3 The
main and auxiliary steering unit motors are to be capable of being
started from a position on the navigating bridge and also arranged
to restart automatically when power is restored after a power failure.
15.1.4 The
motor of an associated auxiliary electric or electrohydraulic power
unit may be connected to one of the circuits supplying the main steering
unit.
15.1.5 Only
short circuit protection is to be provided for each main and auxiliary
steering unit motor circuit.
15.1.6 In craft
of less than 1600 gross tonnage, if an auxiliary steering unit is
not electrically powered or is powered by an electric motor primarily
intended for other services, the main steering unit may be fed by
one circuit from the main switchboard. Consideration would be given
to other protective arrangements other than described in Pt 16, Ch 2, 15.1 Steering systems 15.1.5 for such a motor primarily
intended for other services.
15.1.7 Each
main and auxiliary steering unit electric control system which is
to be operated from the navigating bridge is to be served with electric
power by a separate circuit supplied from the associated steering
gear power circuit, from a point within the steering unit compartment,
or directly from the same section of switchboard busbars, main or
emergency, to which the associated steering unit power circuit is
connected. Each separate circuit is to be provided with short circuit
protection only.
15.2 Thruster systems for manoeuvring
15.2.1 Where
a tunnel or athwartship thruster is fitted solely for the purpose
of manoeuvring, and is electrically driven, its starting and operation
is not to cause the loss of any essential services.
15.2.2 In order
to ensure that the thruster system is not tripped inadvertently whilst
manoeuvring the craft, overload protection in the form of an alarm
is to be provided for the electric motor and any associated supply
converters, in lieu of tripping.
15.2.3 The
thruster electric motor is not to be disconnected as part of a load
management switching operation.
15.3 Navigation lights
15.3.1 Navigation
lights are to be connected separately to a distribution board reserved
for this purpose only and accessible to the officer of the watch.
This distribution board is to be connected directly or through transformers
to the emergency source of electrical power in compliance with, for
passenger craft, Pt 16, Ch 2, 3.2 Emergency source of electrical power in passenger craft and for yachts that are 500 gt or more 3.2.7 and Pt 16, Ch 2, 3.2 Emergency source of electrical power in passenger craft and for yachts that are 500 gt or more 3.2.7.(b).(ii) and Pt 16, Ch 2, 3.2 Emergency source of electrical power in passenger craft and for yachts that are 500 gt or more 3.2.7 or, for cargo craft Pt 16, Ch 2, 3.3 Emergency source of electrical power in craft required to comply with the HSC Code 3.3.7 and Pt 16, Ch 2, 3.3 Emergency source of electrical power in craft required to comply with the HSC Code 3.3.8.(b).(ii) and Pt 16, Ch 2, 3.3 Emergency source of electrical power in craft required to comply with the HSC Code 3.3.8. An alarm is to be activated
in the event of failure of a power supply from the distribution board.
15.3.2 Each
navigation light is to be controlled and protected in each insulated
pole by a switch and fuse or circuit-breaker mounted on the distribution
board.
15.3.3 Provision
is to be made on the navigating bridge for the navigation lights to
be transferred to an alternative circuit fed from the main source
of electrical power.
15.3.4 Each
navigation light is to be provided with an automatic indicator giving
audible and/or visual indication of failure of the light. If an audible
device alone is fitted, it is to be connected to an independent source
of supply, e.g. a battery, with means provided to test this supply.
If a visual signal is used connected in series with the navigation
light, means are to be provided to prevent extinction of the navigation
light due to failure of the signal. The requirements of this paragraph
do not apply to pilot boats, fishing boats and similar small vessels.
15.3.6 To satisfy Pt 16, Ch 2, 15.3 Navigation lights 15.3.5, an audible and visual alarm
is to be activated to notify the Officer of the Watch that the luminous
intensity of the light reduces below the level required by the IMO
Convention on the International Regulations for Preventing Collisions
at Sea. Alternative measures to ensure continuing acceptable performance
of navigation lights using light emitting diodes may be considered
that are in accordance with:
- IMO Res. MSC.253(83), Performance Standards for Navigation
Lights, Navigation Light Controllers and associated Equipment,
and
- EN 14744, Inland navigation vessels and sea-going vessels
– Navigation light, or a relevant National or International
Standard.
Where alternative measures are proposed that require periodic
verification by personnel of the luminous intensity of navigation
lights using light emitting diodes, details of the inspection implementation
in the ships safety management system and acceptance by the National
Administration requirements are to be submitted for consideration.
15.3.7 Navigation
light power supply units installed to convert, control and/or monitor
the distribution board power supply required by Pt 16, Ch 2, 15.3 Navigation lights 15.3.1 above for connection to the
light source(s) (e.g. for LED type navigation lights) are, in the
event of a short-circuit on the unit output, are to disconnect or
limit the supply to prevent further damage and activate an alarm in
the event of a short-circuit on the unit output side.
15.3.8 Navigation
light power supply units are to be selfchecking, detecting failures
of the unit itself and activating an alarm. These are to include:
15.3.9 The
navigation light power supply failure alarms required by Pt 16, Ch 2, 15.3 Navigation lights 15.3.1 are not to be displayed as
a group alarm. Other navigation light alarms may be grouped for each
navigation light where means are provided for personnel to determine
the cause of the alarm. Activation of more than one of the navigation
light alarms as a result of a single failure is to be prevented.
15.3.10 Any
statutory requirements of the country of registration are to be complied
with and may be accepted as an alternative to the above.
15.4 Navigational aids
15.5 Stabilisation
15.5.1 Where
the stabilisation of a craft is essentially dependent upon a single
device which in turn is dependent upon a continuous supply of electrical
power, the supply arrangements are to comply with Pt 16, Ch 2, 5.2 Essential services 5.2.3.
15.5.2 Where
such systems are not dependent upon the continuous availability of
electrical power, but one or more alternative systems not dependent
upon the electrical supply are installed, a single circuit may be
provided, with the protection and alarms required by Pt 16, Ch 2, 5.2 Essential services 5.2.3.
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