Section
10 Screwshafts, tube shafts, propellers and water jet units
10.1 Definitions
10.1.1 Adequate means for protection against corrosion. An adequate means for
protection against corrosion is an approved means for full protection of the shaft against
sea water intrusion and subsequent corrosion attack. Such means are used for the protection
of common steel material against corrosion particularly in combination with water lubricated
bearings. Typical means are to be for example:
- continuous metallic, corrosion-resistant liners (Pt 11, Ch 2, 4.14 Corrosion resistant liners on shafts)
- continuous cladding,
- multiple layer synthetic coating,
- multiple layers of fiberglass,
- combinations of above mentioned,
- rubber/elastomer covering coating.
The means for protection against corrosion are to be installed/applied
according to LR approved procedures.
10.1.2 Fresh Water sample test. At the Screwshaft Survey, a sample of the
fresh water in a closed loop fresh water lubricated shaft is to be taken in the presence of
a Surveyor. Fresh Water sample tests are to be carried out at regular intervals not
exceeding six months. The samples are be taken under service conditions and are to be
representative of the water circulating within the sterntube. The Fresh Water sample test
shall include measurement of chloride and sodium content, pH value and presence of particles
from both metallic and synthetic materials. Analysis results are to be retained on board.
10.1.3 Lubricating oil analysis. Lubricating oil analysis is to be carried out
at regular intervals not exceeding six months. The documentation on lubricating oil analysis
is to be available on board. Oil samples, to be submitted for the analysis, should be taken
under service conditions.
10.1.4 Oil sample examination. An oil sample examination is a visual
examination of the sterntube lubricating oil taken in the presence of a Surveyor, with a
focus on water contamination.
10.1.5 Service records. Service records are regularly recorded data showing in-service
conditions of the shaft(s) and are to include:
- For Oil Lubricated Stern Bearings: lubricating oil temperature, bearing temperature
and oil consumption records.
- For Closed Loop System Fresh Water Lubricated Bearings: water flow, water temperature,
salinity, pH, make-up water and water pressure (depending on design).
10.1.6 Survey Methods on Closed Systems. Oil Lubricated Shafts or Closed Loop System Fresh
Water Lubricated Shafts:
- TS Method 1 – Survey of screwshaft, tube shaft and propeller in
accordance with the requirements of TS Method 1, see Table 4.10.3 Shaft survey
methods. Primarily the shaft is withdrawn and the propeller is removed.
- TS Method 2 – Survey of screwshaft, tube shaft and propeller in
accordance with the requirements of TS Method 2, see Table 4.10.3 Shaft survey
methods. Primarily records are reviewed, the propeller is removed but the shaft is not
withdrawn.
- TS Method 3 – Survey of screwshaft, tube shaft and propeller in
accordance with the requirements of TS Method 3, see Table 4.10.3 Shaft survey
methods. Primarily records are reviewed, the shaft is not withdrawn and the propeller is
not removed.
10.1.7 Survey Methods on Open Systems. Water Lubricated Shafts:
- TS Method 4 – Survey of screwshaft, tubeshaft and propeller in
accordance with the requirements of TS Method 4, see Table 4.10.3 Shaft survey
methods. Primarily the shaft is withdrawn and the propeller is removed.
10.1.8 Tube shaft is a shaft placed between the intermediate shaft and propeller shaft,
normally arranged within a stern tube or running in open water. It may also be called a
Stern Tube Shaft.
10.2 Closed Systems – Oil lubricated shafts or
closed loop system fresh water lubricated shafts: Frequency of surveys
10.2.2 Shafts with a keyless propeller connection or a flanged propeller connection
(including controllable pitch propellers for main propulsion purposes) are to be
surveyed at intervals of five years in accordance with TS Method 1, 2 or 3.
10.2.3 Shafts with a keyed propeller connection with a keyway that complies fully with the
present Rules are to be surveyed at intervals of five years in accordance with TS
Method 1 or 2; TS Method 3 is not permitted.
10.2.4 For oil lubricated keyless shafts, the maximum interval between two surveys carried
out according to TS Method 1 or TS Method 2 shall not exceed 15 years, except in the
case when one extension for no more than three months is agreed.
10.2.5 For closed loop system fresh water lubricated shafts, the maximum
interval between two surveys carried out according to TS Method 1 shall not exceed
15 years, except in the case when one extension for no more than three months is
agreed.
10.2.7 TS Method 2 and TS Method 3 are only permitted where the prerequisite service records
and data specified for those methods are to be provided. If at the time of survey
the attending Surveyor is not satisfied with the service records and data presented,
then the shaft may be required to be withdrawn. The service records and data are to
be retained on board and audited by LR at the Annual Survey.
10.2.9 For oil lubricated arrangements, the descriptive note ShipRight SCM is not a
prerequisite in order to hold TS Method 2 and TS Method 3.
10.2.10 In order to assign and maintain the descriptive note ShipRight SCM, the
requirements of Pt 11, Ch 2, 5.2 Screwshaft Condition Monitoring (SCM) and
ShipRight Procedure Machinery Planned Maintenance and Condition Monitoring,
Section 6 are to be complied with, including the requirements therein for
onboard maintenance of records and review of them by the attending Surveyor at
Annual Survey.
10.2.11 For surveys completed within three months before the shaft survey due date, the next
period will start from the shaft survey due date.
10.3 Open systems – Water lubricated shafts:
Frequency of surveys
10.3.1 Survey in accordance with TS Method 4 at intervals of five years is
applicable to any of the following:
- Single shaft operating in fresh water only;
- Single shaft provided with approved adequate means of protection against
corrosion or fabricated from corrosion-resistant material;
- Multiple shaft arrangements.
10.3.2 Single shaft configurations other than listed above are to be surveyed
every three years in accordance with TS Method 4.
10.3.3 For shafts subject to five-yearly surveys with keyless connections, at
the Surveyor’s discretion removal of the propeller and NDE of the shaft taper, as
required by TS Method 4, need only be carried out every 15 years, subject to a
satisfactory visual inspection of all accessible parts of the shafting system at the
intervening surveys.
10.3.4 For surveys completed within three months before the shaft survey due
date, the next survey period will start from the shaft survey due date.
10.3.5 For shafts with a keyless propeller connection or a flanged propeller connection
(including controllable pitch propellers for main propulsion purposes), and when the
descriptive note ShipRightSCM is assigned to an open loop water lubricated
shaft, a TS Method 4 survey may be replaced by a TS Method 2 or TS Method 3 survey.
Notwithstanding this, the maximum interval between two surveys carried out according
to TS Method 2 or TS Method 4 shall not exceed 15 years, except in the case when one
extension for no more than three months is agreed.
10.3.6 For shafts with a keyed propeller connection, and when the descriptive note
ShipRightSCM is assigned to an open loop water lubricated shaft, a TS
Method 4 may be replaced by a TS Method 2 survey.
10.3.7 At the discretion of the Classification Committee, consideration may be
given to accept special arrangements to monitor the condition of the screwshaft,
bearings, sealing devices and the sterntube lubricant system so as to allow an
extension to the interval between withdrawals of the Screwshaft required by TS
Method 4. This is subject to the shaft being provided with approved adequate means
of protection against corrosion or being fabricated from corrosion-resistant
material.
10.4 Survey extensions
10.4.1 For all types of propeller connections, consideration can be given at the
discretion of the Classification Committee to an extension of the interval between
two consecutive surveys after the execution of an extension survey as follows:
- Extension up to a maximum of 2,5 years: Only permitted for
closed systems. No more than one extension can be considered. No further
extension, of other type, can be considered.
- Extension up to a maximum of one year: Two consecutive ‘one year
extensions’ can be considered. Where an additional extension is agreed the
requirements of the ‘2,5 year extension’ are to be carried out and the shaft
survey due date, prior to the previous extension(s), is extended for a
maximum of 2,5 years.
- Extension up to a maximum of three months: One ‘three month
extension’ can be considered. In the event an additional extension is agreed
the requirements of the “one year extension” or ‘2,5 years extension’ are to
be carried out and the shaft survey due date, prior to the previous
extension, is extended for a maximum of one year or 2,5 years.
10.4.2 If the extension survey is carried out within one month of the shaft
survey due date then the extension will take effect from the shaft survey due
date.
10.4.3 If the extension survey is carried out more than one month prior to the
shaft survey due date, then the period of extension will take effect from the date
on which the extension survey was completed.
Table 4.10.1 Summary of survey intervals
and extensions – Closed systems
Oil Lubricated
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Flanged Propeller
Coupling
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Keyless Propeller
Coupling
|
Keyed Propeller
Coupling
(see Note b)
|
Every 5 years
(see Note a)
|
TS Method 1 or
TS Method 2 or
TS Method
3
|
TS Method 1 or
TS Method 2 or
TS Method 3
(see Note c)
|
TS Method 1 or
TS Method 2
|
Extension 2,5
years
|
Yes (see
Note d)
|
Yes (see
Note d)
|
Yes (see
Note d)
|
Extension 1
year
|
Yes (see
Note e)
|
Yes (see
Note e)
|
Yes (see
Note e)
|
Extension 3
months
|
Yes (see
Note f)
|
Yes (see
Note f)
|
Yes (see
Note f)
|
|
Closed Loop System Fresh Water Lubricated
|
|
Flanged Propeller
Coupling
|
Keyless Propeller
Coupling
|
Keyed Propeller
Coupling
(see Note b)
|
Every 5 years
(see Note a)
|
TS Method 1
(see Note g) or
TS Method 2 (see
Note g) or
TS Method 3
|
TS Method 1
(see Note g) or
TS Method
2 (see Note g) or
TS Method
3
|
TS Method 1
(see Note g) or
TS Method
2 (see Note g)
|
Extension 2,5
years
|
Yes (see
Note d)
|
Yes (see
Note d)
|
Yes (see
Note d)
|
Extension 1
year
|
Yes (see
Note e)
|
Yes (see
Note e)
|
Yes (see
Note e)
|
Extension 3
months
|
Yes (see
Note f)
|
Yes (see
Note f)
|
Yes (see
Note f)
|
|
General notes:
For surveys (TS Method 1,
or TS Method 2, or TS Method 3) completed within 3 months before
the shaft survey due date, the next period will start from the
shaft survey due date.
If the extension
survey is carried out within 1 month of the shaft survey due
date then the extension will take effect from the shaft survey
due date. If the extension survey is carried out more than 1
month prior to the shaft survey due date, then the period of
extension counts from the date when the extension survey was
completed.
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Notes:
Note a. Unless an
extension (Extension 2,5 years, Extension 1 year, Extension 3
months) is applied in between.
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Note b. TS Method 3
not allowed.
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Note c. The maximum
interval between two surveys carried out according to TS Method
1 or TS Method 2 shall not exceed 15 years, except in the case
when one extension for no more than 3 months is agreed.
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Note d. No more than
one extension can be considered. No further extension of other
type can be considered.
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Note e. Two
consecutive extensions can be considered. Where an additional
extension is agreed the requirements of the ‘2,5 year extension’
are to be carried out and the shaft survey due date, prior to
the previous extension(s), is extended for a maximum of 2,5
years.
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Note f. Extension up
to a maximum of 3 months: One ‘3 month extension’ can be
considered. In the event an additional extension is agreed the
requirements of the ‘1 year extension’ or ‘2,5 years extension’
are to be carried out and the shaft survey due date, prior to
the previous extension, is extended for a maximum of 1 year or
2,5 years.
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Note g. The maximum
interval between two surveys carried out according to TS Method
1 (or TS Method 2 for arrangements where ShipRightSCM was
assigned) shall not be more than 15 years, except in the case
when one extension for no more than 3 months is agreed.
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Table 4.10.2 Summary of survey intervals
and extensions – Open systems
- Single shaft operating exclusively in fresh
water.
- Single shaft provided with adequate means of
corrosion protection, single corrosion-resistant shaft.
- All kinds of multiple shaft arrangements.
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Other shaft configuration.
|
|
All kinds of
propeller coupling
(see Note d)
|
|
All kinds of
propeller coupling
(see Note d)
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Every 5 years
(see Note a)
|
TS Method 4
(see Note e)
|
Every 3 years
(see Note a)
|
TS Method
4
|
Extension 1
year
|
Yes (see
Note b)
|
Extension 1
year
|
Yes (see
Note b)
|
Extension 3
months
|
Yes (see
Note c)
|
Extension 3
months
|
Yes (see
Note c)
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General notes:
For surveys (TS Method 4)
completed within 3 months before the shaft survey due date, the
next period will start from the shaft survey due date.
If the extension survey is carried out within 1
month of the shaft survey due date then the extension will take
effect from the shaft survey due date. If the extension survey
is carried out more than 1 month prior to the shaft survey due
date, then the period of extension counts from the date when the
extension survey was completed.
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Notes:
Note a. Unless an
extension (Extension 1 year, Extension 3 months) is applied in
between.
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Note b. No more than
one extension can be considered. No further extension, of other
type, can be considered.
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Note c. One
extension can be considered. In the event an additional
extension is agreed the requirements of the one year extension
are to be carried out and the shaft survey due date prior to the
previous extension is extended for a maximum of one year.
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Note d. For keyless
propeller connections the maximum interval between two
consecutive dismantling and verifications of the shaft cone by
means of non-destructive examination (NDE) shall not exceed 15
years.
Note e. Unless descriptive note ShipRightSCM is
assigned.
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10.5 Shaft survey methods
10.5.1 For the survey methods see
Table 4.10.3 Shaft Survey Methods
below.
Table 4.10.3 Shaft Survey Methods
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TS
METHOD 1
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TS
METHOD 2
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TS
METHOD 3
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TS
METHOD 4
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GENERAL
|
|
|
|
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Drawing the shaft and examining the entire
shaft (including liners, corrosion protection system and stress
reducing features, where provided), sealing system and
bearings
|
X
|
|
|
X
|
SHAFT
|
|
|
|
|
Visual examination of all accessible parts
of the shafting system in situ
|
|
X
|
X
|
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For keyed and keyless propeller
connections, removing the propeller to expose the forward end of the
taper
|
X
|
X
|
|
X
|
For keyed and keyless propeller
connections, perform a non-destructive examination (NDE) by an
approved surface crack-detection method around the after end of the
cylindrical part of the shaft and the forward one-third of the shaft
cone, including the keyway with the key removed (if fitted); for
shafts provided with liners the NDE shall be extended to the after
edge of the liner
|
X
|
X
|
|
X
|
For flanged connections, whenever the
coupling bolts of any type of flange-connected shaft are removed or
the flange radius is made accessible in connection with overhaul,
repairs or when deemed necessary by the Surveyor, the coupling bolts
and flange radius are to be examined by means of an approved surface
crack detection method
|
X
|
X
|
X
|
X
|
Visual examination of all accessible parts
of the shafting system following re-installation of the
shaft
|
X
|
|
|
X
|
PROPELLER
|
|
|
|
|
Visual examination of the
propeller. Examination of the edges and roots of the propeller’s
blades by an approved surface crack detection method, if deemed
necessary by the Surveyor
|
X
|
X
|
X
|
X
|
Controllable pitch propellers, where
fitted, are to be opened up and the working parts examined, together
with the control gear. Propeller to be examined upon
reassembly
|
X
|
X
|
|
X
|
Operational test of pitch
functionality to its full range, including visual confirmation of no
leakage in the CPP seals
|
X
|
X
|
X
|
X
|
Examination of the propeller following
re-installation
|
X
|
X
|
|
X
|
BEARING CLEARANCES
|
|
|
|
|
Checking, recording and verification of
bearing clearances
|
X
|
|
|
X
|
Recording the bearing weardown measurements
after re-installation, if applicable
|
X
|
|
|
|
Checking and recording the bearing weardown
measurements
|
|
X
|
X
|
|
SEALING SYSTEM
|
|
|
|
|
Examine the inboard and outboard seals with
shaft removed and following the re-installation of the shaft and
propeller
|
X
|
|
|
X
|
Examine the inboard and outboard
seals
|
|
X
|
X
|
|
Examination of seal liner
|
|
X
|
X
|
|
OTHERS
|
|
|
|
|
Stationary supporting structure and any
erosion protection inserts or doublers are to be examined in way of
any propulsion devices
|
X
|
X
|
X
|
X
|
Verification of no unapproved repairs by
grinding or welding of shaft and/or propeller
|
X
|
X
|
X
|
X
|
SERVICE RECORDS
|
|
|
|
|
Review of service records
|
|
X
|
X
|
|
Review of test records of Lubricating Oil
Analysis (for oil lubricated shafts), or Fresh Water Sample Test
(for closed system fresh water lubricated shafts)
|
|
X
|
X
|
|
Oil Sample Examination (for oil lubricated
shafts), or Fresh Water Sample Test (for closed system fresh water
lubricated).
|
|
X
|
X
|
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10.6 Other systems
10.6.1 Directional propeller and podded propulsion units for main propulsion
purposes, inclusive of the propellers, shafts, gearing, control gear and the primary
electrical components including any control and protection devices, are to be
surveyed at intervals not exceeding five years. They are to be dismantled if
considered necessary and generally examined as far as practicable. Non-destructive
examination is to be carried out as considered necessary by the Surveyor on
blade/fin roots. Consideration may be given to condition monitoring schemes for
determining the condition of the unit.
10.6.2 Dynamic positioning and/or thruster-assisted mooring and athwartship
thrust propellers and shaftings are to be surveyed at intervals not exceeding five
years. They are to be generally examined so far as possible in dry dock and tested
under working conditions afloat for satisfactory operation. All accessible parts,
including sealing, locking and bearing faces, and any other moving parts are to be
examined. Non-destructive examination is to be carried out as considered necessary
by the Surveyor on blade/fin roots. Consideration may be given to condition
monitoring schemes for determining the condition of the unit.
10.6.3 Water jet units for main propulsion purposes, including the impeller,
casing, shaft, shaft seal, shaft bearing, inlet and outlet channels, steering
nozzle, reversing arrangements, and control gear are to be surveyed at intervals not
exceeding five years, provided the impeller shafts are made of approved
corrosion-resistant material or have approved equivalent arrangements. They are to
be generally examined so far as practicable.
10.6.4 Stationary supporting structure and any erosion protection inserts or
doublers are to be examined in way of any propulsion devices.
10.7 Alternative arrangements
10.7.1 The Classification Committee will be prepared to give consideration to
the circumstances of any special case upon application by the Owner, where the level
of safety achieved is equivalent to that obtained by the survey methods described in
this Section.
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