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Part A Classification and Surveys
Chapter 2 Assignment, maintenance, suspension and withdrawal of class
Section 2 Maintenance of Class
5 Other periodical surveys
5.5 Tailshaft survey
5.5.1 DefinitionTailshaft survey means survey of propeller shafts and
tube shafts (hereafter referred to as tailshafts) as well as survey
of other propulsion systems.
5.5.2 Tailshaft complete
surveyTailshafts are to be submitted to complete examination
at the periodicity specified below and summarised in Fig 1, based
on the type of shaft and its design.
- Where the tailshaft is fitted with continuous liners,
or approved oil sealing glands, or made of corrosion-resistant material,
the periodicity of complete surveys is:
- 3 years for single shafting arrangements
- 4 years for multi-shafting arrangements.
- These periodicities may be increased to 5 years in the following
- where the propeller is fitted keyless to the shaft taper,
the shaft is protected from sea water, the design details are approved,
and a non-destructive examination of the forward part of the aft
shaft taper is performed at each survey by an approved crack-detection
- where the propeller is fitted to a keyed shaft taper the
design details of which comply with the applicable requirements
in Pt C, Ch 1,
Sec 7, and a non-destructive examination of the after end of
the cylindrical part of the shaft (from the after end of the liner, if
any), and of about one third of the length of the taper from the
large end is performed at each survey by an approved crack-detection
- where the propeller is fitted to a solid flange coupling
at the aft end of the shaft, the shaft and its fittings are not
exposed to corrosion, the design details are approved, and a non-destructive
examination of the after flange fillet area of the shaft is performed
at each survey by an approved crack-detection method
- In all other cases the periodicity of complete surveys
is two years and six months (2,5 years).
modified surveyA modified survey of the tailshaft is an alternate way
of examination whose scope is given in Ch 3, Sec 5.
It may be accepted for tailshafts described in [5.5.2] provided
The modified survey is to be carried out five years from the last
complete survey with a window period of plus or minus six months.
- they are fitted with oil lubricated
bearings and approved oil sealing glands
- the shaft and its fittings are not exposed to corrosion
- the design details are approved
- the clearances of the aft bearing are found to be in order
- the oil and the oil sealing arrangements prove effective
- lubricating oil analyses are carried out regularly at intervals
not exceeding six months and oil consumption is recorded at the
The next complete survey is to be carried out ten years from the
last complete survey.
5.5.4 Tailshaft Monitoring
System (MON-SHAFT)Where, in addition to the conditions stated in [5.5.3] for modified
survey, the additional class notation MON-SHAFT is assigned,
the tailshaft need not be withdrawn at both the complete and modified
surveys provided that all condition monitoring data is found to
be within permissible limits and the remaining requirements for
the respective surveys are complied with. Figure 1 : Periodicity
of complete survey of tailshaft
(a) : with shaft withdrawn, subject to modified survey
at 5 years plus or minus 6 months
(b) : with shaft in place, subject to modified survey at 5 years
plus or minus 6 months
Note 1 : Shafts protected against corrosion are those:
Note 2 : Suitable sealing glands are glands which are type approved
by the Society with regard to protection of the sterntube against
ingress of water.
- made of corrosion resistant material, or
- fitted with continuous liners or systems considered as equivalent,
- fitted with oil lubricated bearings and oil sealing glands.
5.5.5 Other propulsion systemsDriving components serving the same purpose as the tailshaft
in other propulsion systems, such as directional propellers, vertical
axis propellers, water jet units, dynamic positioning systems and
thruster assisted mooring systems, are to be submitted to periodical
surveys at intervals not exceeding five years.
5.5.6 Pod propulsion systemsShafting system (including tightness system and connection of
the propeller to the shaft) of pod propulsion systems are to be
submitted to complete or modified surveys, the periodicity of which
is determined in the same principle as for tailshafts described
in [5.5.2], [5.5.3] and Fig 1.
Propulsion motors, orientating devices and other arrangement,
are to be surveyed at each class renewal survey, see Ch 3, Sec 3, [3.2.7].
Next: 5.6 Boiler survey