Retractable Marine Propulsion Group for Stern Space and Drag Reduction
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Solution Overview
Problem
Existing marine vessel propulsion systems, such as outboard and inboard motorized propulsion groups, face challenges including space constraints, aesthetic compromise, and limited maneuverability, particularly when navigating under sail or in port areas.
Innovation Solution
A propulsion device that can be shifted between a raised position within the vessel's keel and a lowered position in the water, allowing for orientation parallel to the translation direction, enabling steering and auxiliary propulsion, with an electric motor and direct propeller connection for reduced space and emissions, and a threaded shaft mechanism for stable and compact support.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If an outboard propulsion group is mounted in the stern area, then the vessel can be propelled effectively, but it takes up significant space and compromises the external appearance
Solution Approach 1:
The propulsion group is made dynamically positionable between a lowered operational position for propulsion and a raised stowed position within the keel. This dynamic positioning allows the system to occupy space only when needed, resolving the contradiction between propulsion capability and space occupation in the stern area
Solution Approach 2:
The propulsion group is moved from occupying horizontal space in the stern area to being stored vertically within the keel structure. By utilizing the vertical dimension and integrating into the keel's internal volume, the system eliminates the need for dedicated stern space while maintaining propulsion functionality
2Device complexity
If a fixed tail bearing the propeller is used, then the propulsion group can be compact, but the vessel cannot be steered when manoeuvring
Solution Approach 1:
The propulsion group is equipped with orienting mechanisms that allow it to rotate and change its angular position relative to the vessel's longitudinal axis. This dynamic orienting capability enables the propeller to be angled for steering during manoeuvring while maintaining a compact fixed structure when in the neutral position
Solution Approach 2:
The propulsion group serves multiple functions: it provides forward propulsion when aligned with the vessel's longitudinal axis and enables steering when angled relative to the axis. This multi-functionality allows a single compact structure to replace both the fixed tail and separate steering mechanisms
3Power
If the propulsion group is lowered into the water, then auxiliary propulsion can be generated, but it increases drag when navigating under sail
Solution Approach 1:
The propulsion group is designed to be dynamically positioned in either a lowered state when auxiliary propulsion is needed or a raised state when sailing. This on-demand deployment eliminates continuous drag during sailing while providing propulsion when required
Solution Approach 2:
The propulsion group is extracted from a permanent installed position and made removable/stowable within the keel. By taking the propulsion group out of constant service and storing it within the vessel's structure, drag is eliminated during sailing while maintaining the option for auxiliary propulsion when needed
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Facilitates efficient and compact propulsion, enhances maneuverability, reduces space usage, and allows for energy harvesting by converting mechanical energy into electrical energy during sailing, while maintaining a compact and protected mechanical architecture.
Implementation Method 1
The first movement means of the propulsion group comprises a threaded shaft exhibiting an axis of rotation which is parallel to the direction of translation
Implementation Method 2
the motor of the propulsion group can be an electric motor
Implementation Method 3
a marine propeller, which is connected to the motor by a suitable transmission system, such that the propeller can be driven to rotate about the axis thereof
Data Source
AI summary
A device (100) for propelling marine vessels comprising at least a propulsion group (105) provided with a marine propeller (115) and a motor (120) suitable for rotating the propeller (115), first movement means (170, 195, 200, 220, 225) suitable for moving the propulsion group (105) along a translation direction which is perpendicular to an axis of rotation (X) of the propeller (115), and second movement means (210, 280, 285, 310) suitable for moving the propulsion group (105) about an axis (Y) that is parallel to the translation direction.