6.2.1 A Modified Survey may be accepted at alternate five-yearly surveys for
shafts described in of the Rules for Ships, provided they are
fitted with oil lubricated bearings and approved oil glands and also for those in
and provided that:
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The oil glands have
split seals which can be removed/renewed in dry-dock without withdrawing
the shaft.
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In-service sterntube
lubricating oil temperature monitoring has been arranged and is recorded.
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Sterntube lubricating
oil analysis is taken at regular intervals not exceeding six months
and the results are presented to the Surveyors at each annual survey.
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Sterntube lubricating
oil consumption is recorded.
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Facilities are provided
for measurement of bearing weardown.
6.2.2 The Modified
Survey, for keyless propellers or shafts with a solid flange connection
to the propeller, is to consist of a visual examination to confirm
the good condition of the sealing arrangements. All accessible parts
of the screwshaft are to be examined by magnetic particle inspection
methods so far as is practicable. Weardown is to be measured and
found satisfactory. Where a controllable pitch propeller is fitted,
at least one of the blades is to be dismantled completely for examination
of the working parts and the controlgear.
6.2.3 For keyed
propellers, the aft end of the cylindrical shaft and forward one third
of the shaft cone is to be examined by a magnetic particle crack detection
method, for which dismantling of the propeller and removal of the
key is required.
6.2.4 All the
data is to be found within permissible limits. Where any doubt exists
regarding any of the above findings, the shaft is to be withdrawn
to permit an entire examination.