4.1.2 Oil
lubricated bearings:
-
Arrangements are
to be provided to allow analysis of the lubricating oil. Oil samples
are to be taken under service conditions and are to be representative
of the oil within the sterntube, sampling arrangements are to meet
the requirements of Pt 5, Ch 14, 8.12 Lubricating oil contamination 8.12.6.
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Bearing temperature
sensor arrangement is to be designed with either:
-
sufficient redundancy
in the event of failure of one sensing element and/or its associated
cabling; or
-
means to allow
replacement of a damaged sensor without requiring dry-docking or divers.
-
Facilities are
to be provided for measurement of bearing weardown.
-
Approved oil glands
that are capable of being replaced without removal of the propeller
or withdrawal of the screwshaft are to be fitted.
4.1.3 Water
lubricated bearings:
-
An approved means
of monitoring and recording variations in the flow rate of lubricating
water using two independent sensors is to be provided.
-
An approved means
of monitoring and recording variations in the shaft power transmission
is to be provided.
-
The maximum permitted
weardown of the sternbush is to be indicated by the manufacturer.
The maximum weardown allowance is to include both the absolute maximum
permitted weardown and the weardown at which it is recommended to
carry out an inspection and maintenance. An approved means of monitoring
bearing wear is to be provided. An alignment analysis considering
both the newly installed clearance and the proposed absolute maximum
allowable weardown, demonstrating that the system will operate satisfactorily
within these two limits, is to be submitted and approved.
-
For open loop
systems the manufacturer is to submit information regarding the required
standard of lubricating water filtration and lubricating water filters
or separators are to be fitted which are able to achieve this requirement.
The lubricating water supply is to be fitted with either continuous
water sediment measuring equipment; turbidity monitoring equipment
or an LR approved extractive sampling and testing procedure.
-
Where a closed
cycle water system is used, arrangements are to allow analysis of
the water for at least the following parameters:
-
Chloride content.
-
Bearing material
and metal particles content.
Water samples are to
be representative of the water circulating within the sterntube.
-
The shaft is
to either be constructed of corrosion resistant material or protected
with a corrosion resistant protective liner or coating approved by
LR. Where a protective liner or coating is used, this is to meet the
requirements of Pt 5, Ch 6, 3.9 Bronze or gunmetal liners on shafts and
a means of assessing the condition of this liner is to be submitted
and approved.
-
Glands are to
be capable of being replaced without withdrawal of the screwshaft.
-
There is to be
a shaft starting/clutch engagement block to inhibit starting the shaft
until lubricating water flow has been established. This is to only
act as a starting block; for lubricating water flow alarm see
Table 6.4.1 Alarm and safeguard for water
lubricated bearings.
-
Alternative arrangements
are subject to special consideration.
Table 6.4.1 Alarm and safeguard for water
lubricated bearings