Section 7 Control engineering systems
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 4 Propulsion Devices - Chapter 4 Podded Propulsion Units - Section 7 Control engineering systems

Section 7 Control engineering systems

Parent topic: Chapter 4 Podded Propulsion Units

7.1 General

7.1.1 Control engineering arrangements are to be in accordance with Vol 2, Pt 9, Ch 7 Control, Alerts and Safety Systems.

7.1.2 Steering gear control, monitoring and alarm systems are to comply with Vol 2, Pt 6, Ch 1, 6 Steering control systemsand Vol 2, Pt 6, Ch 1, 7 Electrical power circuits and equipment.

7.1.3 Steering control is to be provided for podded drives from the navigating bridge and locally.

7.1.4 An indication of the angular position of the podded propulsion unit(s) and the magnitude of the thrust is to be provided at each station from which it is possible to control the direction of thrust. This indication is to be independent of the steering control system.

7.1.5 Emergency Stop Functions are to be provided at the remote control station(s), independent of the podded drive control system, to stop each podded drive in an emergency. see also Vol 2, Pt 4, Ch 5, 4.4 Propulsion control 4.4.7.

7.1.6 Where programmable electronic equipment is used to prevent loads exceeding those for which the system has been designed (see Vol 2, Pt 4, Ch 4, 2.4 Global loads 2.4.3), then either:

  1. A fully independent hard wired back up is to be provided; or

  2. The software is to be certified in accordance with LR’s Software Conformity Assessment System – Assessment Module GEN1 (1994) and have an independent solution showing redundancy with design diversity, etc. see Vol 2, Pt 9, Ch 8, 5.4 Additional requirements for Mobility category and safety critical systems.

7.1.7 Where a propulsion system which includes a podded propulsor unit is controlled by a series of interactive and integrated programmable electronic systems, then these are to comply with the requirements of Vol 2, Pt 9, Ch 8, 5.5 Additional requirements for integrated systems.

7.1.8 For electronic control systems and electrical actuating systems, an overall quality plan for sourcing, design, installation and testing is to address the following issues:

  1. Standard(s) applied.

  2. Details of the quality control system applied during manufacture and testing.

  3. Details of type approval, type testing or approved type status assigned to the equipment.

  4. Details of installation and testing recommendations for the equipment.

  5. Details of any local and/or remote diagnostic arrangements where assessment and alteration of control parameters can be made which can affect the operation of the podded propulsor unit.

  6. Software lifecycle activities, including configuration management and arrangements for software upgrades.

7.1.9 The quality plan referred to in Vol 2, Pt 4, Ch 4, 7.1 General 7.1.8 is to identify the process for verification of the functional outputs from the electronic control systems with particular reference to system integrity, consistency, security against unauthorised changes to software and maintaining the outputs within acceptable tolerances of stated performance for safe and reliable operation of the podded propulsor unit.

7.1.10 For the permitted range of operating conditions, the control system is to be capable of protecting the podded propulsor from experiencing mechanical loads that may initiate damage while permitting the desired manoeuvres to take place.

7.2 Monitoring and alarms

7.2.1 The requirements for alarms and monitoring arrangements are to be in accordance with Vol 2, Pt 6, Ch 1, 8.1 Monitoring and alarms and Table 4.7.1 Additional alarms and safeguards for podded propulsion units. These alarms are in addition to the requirements of Vol 2, Pt 4, Ch 5, 4 Electric propulsion systems.

Table 4.7.1 Additional alarms and safeguards for podded propulsion units

Item Alarm Note
Podded drive azimuth angle — Indicator, see Vol 2, Pt 4, Ch 4, 7.1 General 7.1.4
Propulsion motors Power supply failure To be indicated on the navigating bridge
Propulsion motor power limitation or automatic reduction Activated See also Vol 2, Pt 4, Ch 5, 4.4 Propulsion control 4.4.9
Hydraulic oil system pressure Low To be indicated on the navigating bridge
Bearing temperature 1st stage high

2nd stage high

For grease lubricated bearings

Actions to prevent damage to propulsion motor are to be instigated.

Motor temperature High See Vol 2, Pt 4, Ch 5, 4.1 General 4.1.5
Lubricating oil supply pressure Low If separate forced lubrication for shaft bearings; to be indicated on the navigating bridge
Lubricating oil temperature 1st stage high See also Vol 2, Pt 4, Ch 5, 4.6 Protection of propulsion system 4.6.9
 

2nd stage high

Actions to prevent damage to propulsion motor are to be instigated.

Lubricating oil tank level for motor bearings Low Independent oil level inspection is required
Water in lubricating oil for motor bearings High Required for single podded propulsion units only
Motor cooling air inlet temperature High  
Motor cooling air outlet temperature High  
Motor cooling air flow Low  
Shaft bearing vibration monitoring High See Vol 2, Pt 4, Ch 4, 5.3 Propulsion shafting 5.3.10. Monitoring is to allow bearing condition to be gauged using trend analysis.
Shaft sealing Water ingress See Vol 2, Pt 4, Ch 4, 5.3 Propulsion shafting 5.3.13
Dry space water pump operation Abnormal Alarm set to indicate a frequency or duration exceeding that which would normally be expected.
Dry space water level 1st stage high
2nd stage high 		—
Propulsion motor is to shut down automatically, See Note
Slip ring forced cooling Failure See Vol 2, Pt 4, Ch 4, 6.2 Slip rings 6.2.2

Note The second stage dry space water level high alarm is not needed where the electrical equipment installed within the pod is suitable for operation in flooded spaces, see Vol 2, Pt 4, Ch 4, 5.8 Pod drainage requirements 5.8.1.

7.2.2 Alarms specified in Table 4.7.1 Additional alarms and safeguards for podded propulsion units are to be in accordance with the alarm system specified by Vol 2, Pt 9, Ch 7, 4.3 Alarm systems, general requirements.

7.2.3 Sensors for control, monitoring and alarm systems required by the Rules and located within the pod are to be duplicated in order that a single sensor failure does not inhibit system functionality.

7.2.4 Pod unit dry space pumping arrangements are to function automatically in the event of a high liquid level being detected in the pod unit.

7.2.5 Spaces intended to be dry are to be provided with arrangements to indicate water ingress in accordance with Vol 2, Pt 4, Ch 4, 7.2 Monitoring and alarms 7.2.6 and Table 4.7.1 Additional alarms and safeguards for podded propulsion units.

7.2.6 The number and location of dry space level detectors are to be such that accumulation of liquids will be detected at all design angles of heel and trim.

7.2.7 Condition monitoring arrangements are not to interface with the operation of safety systems which may cause slow-down or shutdown of the propulsion system. See also Vol 2, Pt 9, Ch 7, 4.6 Bridge control for main propulsion machinery 4.6.8.

7.2.8 Means are to be provided to identify the cause of propulsion motor power limitation or automatic reduction.

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