Asymmetrical Oar Blade Hydrodynamic Self-Feathering
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Solution Overview
Problem
Traditional oar designs require complex self-feathering mechanisms prone to malfunction, as they attempt to keep the oar blade submerged during both power and return strokes, necessitating an improved mechanism that automatically changes orientation in response to water resistance.
Innovation Solution
An oar apparatus with a tubular sheath and rotating shaft, featuring a circumferential slot and pin mechanism, where the oar blade is asymmetrical to remain submerged during both strokes, with water resistance causing it to rotate between deployed and feathered orientations, and adjustable length and operation for left or right-handed use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional self-feathering mechanisms are used to keep the oar blade submerged during both power and return strokes, then the oar blade remains underwater for extended periods, but the complex mechanisms involving hinges and springs are prone to malfunction
Solution Approach 1:
The patent removes the complex self-feathering mechanism (hinges, springs, and other moving parts) entirely from the oar design. Instead, the oar blade is designed with an asymmetrical shape that naturally causes it to rotate and maintain proper orientation in the water through hydrodynamic forces alone, eliminating the need for mechanical self-feathering components.
Solution Approach 2:
The asymmetrical oar blade design allows the water itself to perform the self-feathering function. The unequal surface areas create a natural rotational moment that orients the blade correctly during both power and return strokes without requiring any active mechanical control system.
2Productivity
If the oar blade is designed to remain submerged during both power and return strokes, then propulsion efficiency is improved, but complex self-feathering mechanisms are required that are prone to malfunction
Solution Approach 1:
The patent eliminates complex mechanical self-feathering mechanisms that reduce reliability while attempting to maintain propulsion efficiency. The asymmetrical blade design achieves both goals by using hydrodynamic forces to keep the blade submerged and properly oriented without any moving parts that could fail.
Solution Approach 2:
The water environment itself provides the mechanism for maintaining blade orientation. The asymmetrical shape causes water resistance to automatically rotate and hold the blade in the correct position during both strokes, making the system as reliable as the natural physics governing it.
3Device complexity
If traditional oar designs are used requiring blade removal from water on return stroke, then mechanism complexity is reduced, but coordination and technique requirements increase
Solution Approach 1:
The asymmetrical oar blade automatically performs the feathering action that would otherwise require skilled coordination by the rower. The water resistance acting on the unequal surface areas naturally rotates the blade to the correct orientation, making the system easier to operate while maintaining simple mechanical design.
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 oar apparatus provides reliable, efficient propulsion with reduced skill requirements, as the oar blade remains submerged during both strokes, minimizing energy waste and allowing for simpler operation, with adjustable length and handedness for versatility.
Implementation Method 1
the resistance of the water exerts a first moment onto the oar blade, urging the oar blade to rotate about the pivot axis into a deployed orientation
Implementation Method 2
the sheath comprises a circumferential slot and the shaft comprises a pin configured to reside within the slot, such that the length of the slot limits the predefined angular range of rotation of the shaft relative to the sheath
Data Source
AI summary
An oar apparatus configured to remain submerged under water during the power stroke and the return stroke. The oar apparatus has a sheath and a shaft rotationally disposed within the sheath. An oar blade is affixed to the shaft, such that the oar blade is rotational relative to the sheath. The oar blade has a deployed orientation, in which the oar blade is substantially perpendicular to the movement direction of the vessel, and a feathered configuration, in which the oar blade is substantially parallel to the movement direction of the vessel. The oar blade is asymmetrical relative to the center axis of the shaft, such that resistance of the water exerted onto the oar blade creates a first moment urging the oar blade into the deployed orientation during the power stroke and a second moment urging the oar blade into the feathered orientation on the return stroke.