Propeller Guard with Fluid Amplifier for Outboard Motor Drag Reduction
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Solution Overview
Problem
Existing propeller guards for outboard motors fail to maintain or improve performance characteristics such as steering, top end speed, planing, acceleration, and durability while providing protection against underwater objects and preventing accidental contact with people or marine life, often causing drag, instability, and control degradation.
Innovation Solution
A propeller guard design featuring an inner circumferential component with a multi-angled band and an outer fluid amplifier that channels water efficiently through a series of ports and fluid channels, reducing drag and cavitation, and enhancing fluid pressure to improve performance and control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a prior-art propeller guard is attached to the outboard motor, then the propeller is protected from underwater objects, but the performance characteristics of the motor are severely reduced due to water flow blockage and increased drag
Solution Approach 1:
The propeller guard incorporates a porous skirt material that allows water to pass through while still providing protective coverage. This porous structure reduces water flow blockage and drag compared to solid guards, thereby maintaining motor performance while protecting the propeller from underwater objects.
Solution Approach 2:
The guard design features varying porosity and structural properties in different regions of the skurt. The material density and pore distribution are optimized locally to balance protection needs with water flow requirements, allowing effective propeller protection while minimizing performance degradation.
2Reliability
If a prior-art propeller guard is attached to the outboard motor, then the propeller is protected from underwater objects, but the motor experiences increased drag and decreased top end speed
Solution Approach 1:
The porous skurt material enables water to flow through the guard structure rather than being completely blocked, significantly reducing drag forces. This reduces the negative impact on top end speed while maintaining protective function.
Solution Approach 2:
The guard provides partial protection rather than complete enclosure, allowing sufficient water flow through the porous structure to maintain high-speed performance while offering adequate protection against debris and objects.
3Reliability
If a prior-art propeller guard is attached to the outboard motor, then the propeller is protected from underwater objects, but the motor experiences instability and control degradation
Solution Approach 1:
The porous skurt structure is designed to be dynamically responsive to water flow conditions, allowing it to flex and adapt during operation. This dynamic characteristic helps maintain stability and control by reducing rigid interference with water flow while preserving protective coverage.
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
The design maintains or improves the performance characteristics of outboard motors by reducing drag, eliminating cavitation, and enhancing steering and control, while providing effective protection against underwater objects and preventing accidental contact.
Implementation Method 1
an outer fluid amplifier that channels water efficiently through a series of ports and fluid channels, reducing drag and cavitation, and enhancing fluid pressure
Implementation Method 2
reducing drag and cavitation
Implementation Method 3
reducing drag
Data Source
AI summary
A propeller guard including inner circumferential component defining a multi-angled band formed of a plurality of independently radiused sections and an outer fluid amplifier extending along sides of the inner circumferential component. The band may also include a plurality of evenly spaced ports therethrough. The propeller guard is designed to improve the performance characteristics, specifically acceleration, planing, speed and steering, of the motor. The outer fluid amplifier increases flow of fluid through the ports of the inner circumferential component and further improves performance characteristics of the boat and motor to which the propeller guard is attached.