Pivoting Propeller Shield for Boat Safety and Drag Reduction
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Solution Overview
Problem
Conventional propeller guards fail to protect against accidental contact with the distal face of spinning propellers and often compromise boat performance by causing drag, instability, and control issues.
Innovation Solution
A propeller shield that pivots over the distal face of the propeller when the boat is at rest or reversing, and automatically lifts away when the boat moves forward, using a shield member with vents for water flow and hydroplane members to reduce drag, attached via a connection mechanism to the boat's outdrive or lower unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a conventional propeller guard enclosure is used to cover the propeller's lateral edges, then protection against accidental contact is improved, but protection against contact from the distal face remains insufficient
Solution Approach 1:
The shield member is designed to be movable rather than fixed, capable of pivoting between a first position where it covers the distal face of the propeller and a second position where it is removed from the distal face. This dynamic configuration allows the same structure to provide comprehensive protection when needed while avoiding interference with propeller operation during normal forward movement.
Solution Approach 2:
The protective structure is divided into distinct functional zones: a shield member for covering the distal face, lateral guards for side protection, and a vent structure for water flow. This segmentation allows each component to be optimized for its specific function while working together to provide complete protection.
2Object-affected harmful factors
If a fixed propeller guard enclosure is used to cover the distal face, then protection against accidental contact is improved, but boat performance deteriorates due to drag and instability
Solution Approach 1:
The shield member pivots between a first position for protection and a second position for optimal performance. During forward movement, the shield member can be positioned to minimize drag while still providing protection when the boat is stationary or reversing, thus resolving the conflict between safety and performance.
Solution Approach 2:
The position of the shield member is changed based on operating conditions. The system transitions between different configurations depending on whether the boat is moving forward, reversing, or stationary, optimizing both protection and performance for each operational state.
3Object-affected harmful factors
If a propeller guard enclosure is used, then protection against accidental contact is improved, but boat handling and control deteriorate due to drag and instability
Solution Approach 1:
The movable shield member can be positioned to minimize interference with water flow and boat handling. When not in the protective position, the shield member is removed from the distal face of the propeller, eliminating sources of drag and instability that would otherwise degrade boat performance and control.
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
Prevents accidental contact with the propeller's distal face while minimizing drag and maintaining boat performance, as demonstrated by comparative performance measurements showing little to no adverse effect on speed and handling.
Implementation Method 1
the shield member optionally comprises one or more hydroplane members that lift the shield member in the water to reduce drag caused by the shield member as the boat moves forward
Implementation Method 2
the shield member also comprises a plurality of vents that allow water to flow directly through the shield member in a manner that allows the boat to reverse when the propeller shield is engaged
Data Source
AI summary
A propeller shield that is designed to pivot over and away from a distal face of a propeller on a motorized boat. Generally, when the boat is at rest or moving in reverse through water, the propeller shield pivots down over the propeller's distal face and prevents accidental bodily contact with the propeller. As the boat moves forward in the water, the propeller shield pivots up and away from the propeller to allow the boat to move forward without the propeller shield causing an undesirable amount of drag or otherwise adversely affecting the boat's performance. Typically, the propeller shield has a shield member, which is sized and shaped to cover the propeller's distal face, and a connection mechanism, which attaches the shield member to the boat. In some cases, the shield member optionally comprises one or more fluid vents and hydroplane surfaces.