Marine Propulsion Steering with Trolling Motor

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Solution Overview

Problem

Conventional marine propulsion systems face challenges in achieving both improved turning properties and quiet operation, especially in slow-speed situations where noise is a concern.

Innovation Solution

A marine propulsion system that incorporates a steerable outboard motor and a steerable trolling motor, where the trolling motor is used to enhance turning capabilities without generating propulsion force from the outboard motor, thereby maintaining quietness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the outboard motor is operated to achieve turning, then the turning property is improved, but noise is generated

Engineering Contradiction:
Improveturning propertyVSAvoidnoise
Core Design Contradiction:
Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The patent introduces a trolling motor as an intermediary device to perform the turning function. The trolling motor, being quieter than the outboard motor, serves as a mediator that achieves the steering objective without generating excessive noise. The controller coordinates between the outboard motor and trolling motor, using the trolling motor specifically for turning maneuvers while the outboard motor provides primary propulsion.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-generated harmful factors

If the trolling motor is used for turning, then quietness is achieved, but turning capability may be limited

Engineering Contradiction:
Improvenoise levelVSAvoidturning capability
Core Design Contradiction:
Object-generated harmful factorsVSEase of operation

Solution Approach 1:

The patent merges the functions of two different motors - the outboard motor for propulsion and the trolling motor for steering. By combining these two devices with different strength profiles, the system achieves both quiet operation (from the trolling motor) and adequate turning capability (supplemented by coordinated outboard motor control). The controller integrates the operations of both motors to achieve the desired maneuvering performance.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP4516659A1Marine propulsion system, control method therefor, and marine vessel
Publication Date: 2025.03.05 YAMAHA MOTOR CO LTD
  • EP4516659A1 patent drawingFigure 1
  • EP4516659A1 patent drawingFigure 2
  • EP4516659A1 patent drawingFigure 3

AI summary

A marine propulsion system includes a first propulsion device (4) that is steerable, located at a stern (2A) of a hull (2), and includes a rudder (23), a second propulsion device (5) that is steerable and located in front of the stern (2A) of the hull (2), and a controller (70) configured or programmed to control a propulsion force of the second propulsion device (5) and a steering angle of the rudder (23) without generating a propulsion force of the first propulsion device (4) according to a maneuvering instruction in predetermined modes in which the propulsion force of the second propulsion device (5) is used.