Section
13 Screwshafts, tube shafts and propellers
13.1 Definitions
13.1.1 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 for example:
- continuous metallic, corrosion-resistant liners,
- 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
the manufacturer’s guidelines, recommendation and procedures.
13.1.2 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.
13.1.3 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,
are to be taken under service conditions.
13.1.4 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.
13.1.5 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, oil consumption records, water content and
flow/viscosity tests.
- For Closed Loop System Fresh Water Lubricated Bearings:
water flow, water temperature, salinity, pH, make-up water and water pressure
(depending on design).
13.1.6 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 3.13.3 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 3.13.3 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 3.13.3 Shaft survey methods.
Primarily records are reviewed, the shaft is not withdrawn and the propeller is
not removed.
13.1.7 Survey methods on open systems. Water lubricated shafts:
- TS Method 4 – Survey of screwshaft, tube shaft and
propeller in accordance with the requirements of TS Method 4, see Table 3.13.3 Shaft survey methods.
Primarily the shaft is withdrawn and the propeller is removed.
13.1.8 Tube shaft is a shaft placed between the intermediate shaft and propeller shaft,
normally arranged within a sterntube or running in open water. It may also be called
a sterntube shaft.
13.2 Closed systems – Oil lubricated shafts or closed loop system fresh water lubricated shafts: Frequency of surveys
13.2.2 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.
13.2.3 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.
13.2.4 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, other than in
the exceptional case when one extension for no more than three months is agreed.
13.2.5 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, other than in the exceptional case when one extension for no more than
three months is agreed.
13.2.7 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 as shown in
Table 3.13.3 Shaft survey methods. 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 onboard and audited by LR at the Annual Survey.
13.2.9 For oil lubricated arrangements, the class notation ShipRightSCM
is not a prerequisite in order to hold TS Method 2 and TS Method 3.
13.2.10 In order to assign and maintain the class notation ShipRightSCM,
the requirements of Vol 2, Pt 3, Ch 2, 5 Control and monitoring and
ShipRight Procedure Machinery Planned Maintenance and Condition Monitoring,
Section 4, 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.
13.2.11 For surveys completed within three months before the Shaft Survey due date, the next
period will start from the Shaft Survey due date.
13.3 Open systems – Water lubricated shafts:
Frequency of surveys
13.3.1 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.
13.3.2 Single shaft configurations other than listed above are to be surveyed every three
years in accordance with TS Method 4.
13.3.3 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.
13.3.4 For surveys completed within three months before the Shaft Survey due date, the next
survey period will start from the Shaft Survey due date.
13.3.5 For shafts with a keyless propeller connection or a flanged propeller connection
(including controllable pitch propellers for main propulsion purposes), and when the
class notation 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.
13.3.6 For shafts with a keyed propeller connection, and when the class notation
ShipRightSCM is assigned to an open loop water lubricated shaft, a TS
Method 4 survey may be replaced by a TS Method 2 survey.
13.3.7 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.
13.4 Survey extensions
13.4.1 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 two and a half years: Only
permitted for closed systems. No more than one extension can be considered. No
further extension, of any 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 ‘two and a half 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 two and a half 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 ‘two and a half 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 two and a half years.
13.4.2 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.
13.4.3 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 3.13.1 Summary of survey intervals and extensions – Closed systems
| Oil Lubricated
|
|
|
Flanged
Propeller Coupling
|
Keyless
Propeller Coupling
|
Keyed
Propeller Coupling (see Note 2)
|
| Every 5
years (see Note 1)
|
TS Method
1 or
TS Method 2 or
TS Method 3
|
TS Method
1 or
TS Method 2 or
TS Method 3 (see Note 3)
|
TS Method
1 or
TS Method 2
|
| Extension
2,5 years
|
Yes
(see Note 4)
|
Yes
(see Note 4)
|
Yes
(see Note 4)
|
| Extension
1 year
|
Yes
(see Note 5)
|
Yes
(see Note 5)
|
Yes
(see Note 5)
|
| Extension
3 months
|
Yes
(see Note 6)
|
Yes
(see Note 6)
|
Yes
(see Note f6)
|
| Closed Loop System Fresh Water Lubricated
|
|
|
Flanged
Propeller Coupling
|
Keyless
Propeller Coupling
|
Keyed
Propeller Coupling (see Note 2)
|
| Every 5 years (see Note 1)
|
TS Method 1 (see Note 7) or
TS Method 2 (see Note 7) or
TS
Method 3
|
TS Method 1 (see Note 7) or
TS Method 2 (see Note 7) or
TS
Method 3
|
TS Method 1 (see Note 7) or
TS Method 2 (see Note 7)
|
| Extension
2,5 years
|
Yes
(see Note 4)
|
Yes
(see Note 4)
|
Yes
(see Note 4)
|
| Extension
1 year
|
Yes
(see Note 5)
|
Yes
(see Note 5)
|
Yes
(see Note 5)
|
| Extension
3 months
|
Yes
(see Note 6)
|
Yes
(see Note 6)
|
Yes
(see Note 6)
|
| 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.
Notes:
Note 1. Unless an
extension (Extension 2,5 years, Extension one year,
Extension three months) is applied in between.
Note 2. TS Method
3 not allowed.
Note 3. 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.
Note 4. No more
than one extension can be considered. No further extension
of other type can be considered.
Note 5. 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.
Note 6. 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.
Note 7. 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, other than in the exceptional case when one
extension for no more than 3 months is agreed.
|
Table 3.13.2 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 types of multiple shaft
arrangements.
|
Other shaft
configurations.
|
|
|
All types of propeller coupling (see Note 4)
|
|
All types
of propeller coupling (see Note 4)
|
| Every 5
years (see Note 1)
|
TS Method 4 (see Note 5)
|
Every 3
years (see Note 1)
|
TS Method
4
|
| Extension
1 year
|
Yes
(see Note 2)
|
Extension
1 year
|
Yes
(see Note 2)
|
| Extension
3 months
|
Yes
(see Note 3)
|
Extension
3 months
|
Yes
(see Note 3)
|
| 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.
Notes:
Note 1.
Unless an extension (Extension 1 year, Extension 3
months) is applied in between.
Note 2. No more than one extension can be considered. No
further extension, of any other type, can be considered.
Note 3. One extension can be considered. In the event an
additional extension is agreed the requirements of the 1
year 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.
Note 4. 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 5. Unless class notation ShipRightSCM is
assigned.
|
13.5 Shaft survey methods
13.5.1 For the survey methods see
Table 3.13.3 Shaft survey methods below.
Table 3.13.3 Shaft survey methods
|
|
TS METHOD 1
|
TS METHOD 2
|
TS METHOD 3
|
TS METHOD 4
|
| GENERAL
|
|
|
|
|
| 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
|
|
| 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 structures 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
|
|
13.6 Other systems
13.6.1 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.
13.6.3 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.
13.6.4 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.
13.6.5 Stationary supporting structure and any erosion protection inserts or doublers are to
be examined in way of any propulsion devices.
13.6.6 Where fitted, a shaft grounding device is to be verified as working satisfactorily
during Annual Surveys and Docking Surveys.
13.7 Alternative arrangements
13.7.1 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.
|