Section 7 Control engineering systems
Clasification Society 2024 - Version 9.40
Clasifications Register Rules and Regulations - Rules and Regulations for the Classification of Ships, July 2022 - Part 5 Main and Auxiliary Machinery - Chapter 9 Podded Propulsion Units - Section 7 Control engineering systems

Section 7 Control engineering systems

Parent topic: Chapter 9 Podded Propulsion Units

7.1 General

7.1.1 Control engineering arrangements are to be in accordance with Pt 6, Ch 1 Control Engineering Systems.

7.1.2 Steering gear control, monitoring and alarm systems are to comply with Pt 5, Ch 19, 4 Steering control systems and Pt 5, Ch 19, 5 Electric power circuits, electric control circuits, monitoring and alarms.

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 Pt 6, Ch 2, 16.4 Propulsion control 16.4.7.

7.1.6 Where programmable electronic equipment is used to prevent loads exceeding those for which the system has been designed (see Pt 5, Ch 9, 2.4 Global loads 2.4.3), then either:

  1. A fully independent hard wired backup 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 Pt 6, Ch 1, 2.13 Programmable electronic systems - Additional requirements for essential services and safety critical systems of the Rules.

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 Pt 6, Ch 1, 2.13 Programmable electronic systems - Additional requirements for essential services and safety critical systems of the Rules.

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 Pt 5, Ch 9, 7.1 General 7.1.8 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 Pt 5, Ch 19, 5.3 Monitoring and alarms and Table 9.7.1 Additional alarms and safeguards for podded propulsion units. These alarms are in addition to the requirements of Pt 6, Ch 2, 16 Electric propulsion.

Table 9.7.1 Additional alarms and safeguards for podded propulsion units

Item Alarm Note
Podded drive azimuth angle — Indicator, see Pt 5, Ch 9, 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 Pt 6, Ch 2, 16.4 Propulsion control 16.4.9
Hydraulic oil system pressure Low To be indicated on the navigating bridge
Bearing temperature 1st stage high
2nd stage high 		For grease lubricated bearings. Propulsion motor is to safely shut down automatically to prevent damage.
Motor temperature High See Pt 6, Ch 2, 16.1 General 16.1.3
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
2nd stage high 		See also Pt 6, Ch 2, 16.6 Protection of propulsion system 16.6.9 Propulsion motor is to safely shut down automatically to prevent damage Independent oil level inspection is required
Lubricating oil tank level for motor bearings Low  
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  
Motor cooling air humidity High For closed air systems
Shaft bearing vibration monitoring High See Pt 5, Ch 9, 5.3 Propulsion shafting 5.3.10. Monitoring is to allow bearing condition to be gauged using trend analysis
Shaft sealing Failure See Pt 5, Ch 9, 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 Pt 5, Ch 9, 6.2 Slip ring assemblies 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 Pt 5, Ch 9, 5.8 Pod drainage requirements 5.8.1.

7.2.2 Alarms specified in Table 9.7.1 Additional alarms and safeguards for podded propulsion units are to be in accordance with the alarm system specified by Pt 6, Ch 1 Control Engineering Systems, Pt 6, Ch 2 Electrical Engineering, Pt 6, Ch 3 Refrigerated Cargo Installations.

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 withPt 5, Ch 9, 7.2 Monitoring and alarms 7.2.6 and Table 9.7.1 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 Pt 6, Ch 1, 2.6 Bridge control for main propulsion machinery 2.6.8.

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