Counter-Rotating Propeller Pod Layout With Modular Redundancy

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Solution Overview

Problem

Conventional CRP pod propulsion systems are heavy, large, and lack redundancy, with independent operation of two-motor CRP pods failing to provide significant redundancy in the event of a motor or drive failure.

Innovation Solution

A CRP pod propulsion system with two independent, dismountable, and compact propulsion modules fixed to a strut, utilizing a single bearing arrangement and interdependent motor drives for redundancy, allowing simultaneous operation of both modules in case of failure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional CRP pods use two independent shaft lines with two sets of bearings for each shaft, then the system can provide counter-rotating propeller functionality, but the weight and size of the system increase significantly

Engineering Contradiction:
Improvecounter-rotating propeller functionalityVSAvoidpod system weight
Core Design Contradiction:
Adaptability or versatilityVSWeight of moving object

Solution Approach 1:

The patent merges two separate shaft lines into a single shared shaft line, where both counter-rotating propellers are driven from one common shaft. This eliminates the need for two independent bearing sets, reducing both weight and complexity while maintaining the counter-rotating functionality through a unified mechanical structure

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The single shaft line is designed to serve multiple functions: it supports both counter-rotating propellers, provides a common mounting structure for bearings, and enables independent motor control. This multi-functional design reduces the number of dedicated components needed, thereby reducing overall system weight

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Ease of operation

If conventional CRP pods use two independent shaft lines with two sets of bearings for each shaft, then the system can operate independently, but the size of the pod increases

Engineering Contradiction:
Improveindependent motor operationVSAvoidpod system volume
Core Design Contradiction:
Ease of operationVSVolume of moving object

Solution Approach 1:

By combining two separate shaft lines into one shared shaft line, the physical volume required for shaft housings, bearing mounts, and structural support is significantly reduced. The single shaft line design consolidates the mechanical structure, allowing the pod to maintain independent motor operation capability while occupying less space

Inventive Principle:
Principle #5Merging (Combining)

3Power

If conventional CRP pods use conventional motor and drive arrangements, then the system can provide propulsion, but redundancy is lacking in the event of motor or drive failure

Engineering Contradiction:
Improvepropulsion powerVSAvoidsystem redundancy
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The patent segments the propulsion system into two fully independent motor-drive units, each capable of independently controlling one counter-rotating propeller. This segmentation ensures that if one motor or drive fails, the other remains fully operational, providing 100% redundancy. The independent shaft line design for each propeller further reinforces this segmentation and reliability

Inventive Principle:
Principle #1Segmentation

4Force

If conventional pod propulsion systems use larger internal components, then the system can handle higher loads, but the system becomes heavier and larger

Engineering Contradiction:
Improvepropulsion force capabilityVSAvoidpod system weight
Core Design Contradiction:
ForceVSWeight of moving object

Solution Approach 1:

The single shared shaft line design allows for more efficient load distribution and structural optimization. Rather than having two separate heavy shaft assemblies, the unified shaft structure can be engineered to handle the combined loads more efficiently, reducing the total weight of mechanical components while maintaining or improving the propulsion force capability

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP4227204B1Counter rotating propeller pod mechanical arrangement
Publication Date: 2025.12.24 GE ENERGY POWER CONVERSION TECHNOLOGY LTD(GB)
  • EP4227204B1 patent drawingFigure 1A~1B
  • EP4227204B1 patent drawingFigure 2
  • EP4227204B1 patent drawingFigure 3A~3B

AI summary

Provided is a pod propulsion system including first and second counter rotating propellers (318, 822) for propelling a marine vessel, and first and second propeller modules (404, 406), each including an electric motor (314, 316) having a driving-end configured to rotate the first and second propellers (318, 322), respectively. Also included are first and second gondolas (402, 408). Each gondola (402, 408) houses a respective one of the first and second electric motors (314, 316) and includes a boltable interface formed along a lengthwise direction of an extremity of the gondola. A strut (313) connects the first and second gondolas (402, 408) to a hull of the marine vessel and includes first and second boltable interfaces. Each of the boltable interfaces of the strut (313) is configured to form a bolted joint interface (410A, 410B) with a corresponding one of boltable interfaces of the first and second gondolas (402, 408).