5.1.1 For
assignment of DP(AAA) notation, the applicable requirements
of Pt 7, Ch 4, 2 Class notation DP(CM), Pt 7, Ch 4, 3 Class notation DP(AM) and Pt 7, Ch 4, 4 Class notation DP(AA),
together with Pt 7, Ch 4, 5.1 Requirements 5.1.2 to Pt 7, Ch 4, 5.1 Requirements 5.1.3 are to be complied with.
5.1.2 The
DP system is to be arranged such that failure of any component or
system necessary for the continuing correct functioning of the DP
system, or the loss of any one compartment as a result of fire or
flooding, will not result in a loss of position. This is to be verified
by means of a FMEA. See
Pt 7, Ch 4, 1.3 Information and plans required to be submitted 1.3.6.
5.1.3 Thruster
units are to be installed in separate machinery compartments, separated
by a watertight A-60 class division.
5.1.4 Generating
sets, switchboards and associated equipment are to be located in at
least two compartments separated by an A–60 class division,
so that at least half of the equipment will be available following
a fire or similar fault in one of the compartments. If the equipment
is located below the operational waterline, the division is also to
be watertight. There is to be provision to connect the switchboard
sections together by means of circuit-breakers.
5.1.5 Duplicated
cables and pipes for services essential for the correct functioning
of the DP system are not to be routed through the same compartments.
If this is not practicable, then they are to be carried in A-60 protected
ducts. The termination arrangements are also to take due account of
the degree of protection. Alternative arrangements will be considered.
5.1.6 Where
duplicated cables and pipes for services essential for the correct
functioning of the DP system are installed in adjacent compartments,
A-60 rated fire protection is to be provided between the spaces. Details
of alternative arrangements which demonstrate essential equipment
located in an adjacent space will continue to operate satisfactorily
and essential services will continue to be available in the event
of a fire in the adjacent space may be submitted for consideration.
5.1.7 An additional/emergency
automatic control unit is to be provided at an emergency control station,
in a compartment separate from that for the main control station,
and is to be arranged to operate independently from the working and
standby control units required by Pt 7, Ch 4, 4.1 Requirements 4.1.8.
5.1.8 Arrangements
are to be provided such that, in the event of a failure of the working
and standby control units, a smooth transfer of control to the emergency
control unit may be effected from the emergency control station by
manual means.
5.1.9 Arrangements
are to be provided at the emergency control station so that changes
in the resultant vectorial thrust output may be readily effected by
a single operator action.
5.1.10 The
control/indication unit of one of the position reference systems required
by Pt 7, Ch 4, 4.1 Requirements 4.1.9 is to be located
at the emergency control station. A repeater control/indication unit
from this system is to be located at the main control station.
5.1.12 One
wind sensor is to directly supply the additional/emergency control
unit.