Section 5 Control and monitoring
Clasification Society 2024 - Version 9.40
Clasifications Register Rules and Regulations - Rules and Regulations for the Classification of Naval Ships, January 2023 - Volume 2 Machinery and Engineering Systems - Part 3 Transmission Systems - Chapter 2 Shafting Systems - Section 5 Control and monitoring

Section 5 Control and monitoring

Parent topic: Chapter 2 Shafting Systems

5.1 Unattended machinery

5.1.1 Where sterntube lubrication oil systems are fitted with automatic or remote controls so that under normal operating conditions they do not require any manual intervention by the operators, they are to be provided with the alarms indicated in Table 2.5.1 Alarms.

Table 2.5.1 Alarms

Item Alarm
Sterntube lubricating oil tank level Low
Sterntube bearing temperature (oil lubricated) High

5.1.2 Where shaft systems incorporate a separate thrust block(s) and lubrication oil systems are fitted with automatic or remote controls so that under normal operating conditions they do not require any manual intervention by the operators, they are to be provided with the alarms indicated in Table 2.5.2 Alarms - Thrust block lubrication

Table 2.5.2 Alarms - Thrust block lubrication

Item Alarm
Lubrication oil flow Low
Lubrication oil temperature High
Bearing temperature High

5.2 Screwshaft Condition Monitoring (SCM)

5.2.1 For vessels where the notation SCM (Screwshaft Condition Monitoring) is requested, the requirements in either Vol 2, Pt 3, Ch 2, 5.2 Screwshaft Condition Monitoring (SCM) 5.2.2 or Vol 2, Pt 3, Ch 2, 5.2 Screwshaft Condition Monitoring (SCM) 5.2.3 are to be satisfied.

5.2.2 Oil lubricated bearings:
  1. 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 Vol 2, Pt 7, Ch 3, 8.13 Lubricating oil contamination 8.13.6.
  2. Bearing temperature sensor arrangement is to be designed with either:
    1. sufficient redundancy in the event of failure of one sensing element and/or its associated cabling; or
    2. means to allow replacement of a damaged sensor without requiring dry-docking or divers.
  3. Facilities are to be provided for measurement of bearing weardown.
  4. 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:
  1. An approved means of monitoring and recording variations in the flow rate of lubricating water using two independent sensors is to be provided.
  2. An approved means of monitoring and recording variations in the shaft power transmission is to be provided.
  3. The maximum permitted weardown of the sternbush is to be indicated by the manufacturer. The maximum weardown allowance 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 weardown 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.
  4. 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.
  5. Where a closed cycle water system is used, arrangements are to allow analysis of the water for at least the following parameters:
    1. Chloride content
    2. Bearing material and metal particles content.
      Water samples are to be representative of the water circulating within the sterntube.
  6. 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 Vol 2, Pt 3, 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.
  7. Glands are to be capable of being replaced without withdrawal of the screwshaft.
  8. 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 2.5.3 Alarm and safeguard for water lubricated bearings.
  9. Alternative arrangements are subject to special consideration.

Table 2.5.3 Alarm and safeguard for water lubricated bearings

Item Alarm Note
Lubricating water flow Low See 5.2.3(h)
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