5.2.2 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 15, Ch 3, 6.4 Lubricating oil contamination 6.4.5.
-
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.
5.2.3 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 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 11, Ch 2, 4.14 Corrosion resistant 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 2.5.2 Alarm and safeguard for water
lubricated bearings.
-
Alternative arrangements
are subject to special consideration.
Table 2.5.2 Alarm and safeguard for water
lubricated bearings