Oscillating Fluke Propulsion Device for Marine Efficiency
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Solution Overview
Problem
Conventional rotating propellers for watercrafts suffer from low efficiency, cavitation, entanglement with debris, and harm to marine life, and require significant modifications for fluke propulsion systems to achieve high efficiency.
Innovation Solution
A propulsion device featuring a flexible, pivotable fluke connected to a drive shaft with a gear reduction system that converts rotary motion to oscillatory motion, minimizing thrust loss and enhancing efficiency by directing thrust forward and reducing vibrations, while being adaptable to existing motors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a conventional rotating propeller is used, then the watercraft can be propelled forward, but the propulsion efficiency remains below 20% and cavitation occurs at higher speeds
Solution Approach 1:
The patent applies dynamics by transitioning from a static rotating propeller to a dynamic oscillating fluke system. The fluke oscillates back and forth in a vertical plane, creating alternating thrust forces that push the watercraft forward. This dynamic oscillation mode, rather than continuous rotation, allows the fluke to efficiently move water during each stroke cycle, achieving propulsion efficiencies exceeding 80% while avoiding cavitation that plagues high-speed rotating propellers
Solution Approach 2:
The patent changes key operational parameters by replacing the high-speed rotation (typically thousands of RPM) with low-frequency oscillation (single-digit Hz range). The fluke oscillates at frequencies between 0.5-5 Hz, dramatically reducing the speed parameter compared to conventional propellers. This parameter change from rotational speed to oscillation frequency, combined with large amplitude motion, enables the fluke to move substantial volumes of water efficiently without the cavitation problems that occur at high rotational speeds
2Productivity
If a conventional rotating propeller is used, then propulsion is achieved, but the propeller frequently gets entangled with fishing nets, ropes, and floating debris
Solution Approach 1:
The oscillating fluke's vertical motion pattern and compact underwater profile significantly reduce its interaction with floating debris compared to a rotating propeller. The fluke moves up and down within a limited vertical envelope, making it much less likely to entangle with fishing nets, ropes, or other floating objects that a horizontally rotating propeller would continuously encounter. This dynamic oscillation pattern inherently improves reliability by avoiding the entanglement problem
Solution Approach 2:
The patent transitions the propulsion mechanism from horizontal rotation (conventional propeller) to vertical oscillation (fluke). By changing the dimension of motion from horizontal plane rotation to vertical plane oscillation, the fluke operates in a different spatial domain that minimizes intersection with floating debris. This dimensional change effectively eliminates the entanglement issue while maintaining propulsion capability
3Productivity
If a conventional rotating propeller is used, then the watercraft can be propelled, but it causes harm to swimmers and marine life that come near the propeller
Solution Approach 1:
The oscillating fluke creates a gentler water interaction pattern compared to the high-speed rotation of conventional propellers. The fluke's slow oscillation at single-digit Hz frequencies produces larger, more controlled water displacements that are less likely to violently impact swimmers or marine life. The alternating thrust mechanism pushes water smoothly during each stroke rather than creating the continuous high-velocity water intake and discharge of rotating propellers, thereby reducing harmful effects on nearby organisms
Solution Approach 2:
The patent converts the potential harm of water displacement into a beneficial gentle pushing action. Instead of the harmful high-velocity water jets and suction zones created by rotating propellers, the oscillating fluke generates controlled, alternating thrust that pushes water forward in a more benign manner. The large-amplitude, low-frequency oscillation creates a gentler interaction with water and any organisms nearby, transforming the potentially harmful propulsion mechanism into a safer alternative
4Productivity
If a fluke oscillation drive with gear reduction is implemented, then propulsion efficiency increases significantly, but the device complexity increases due to additional mechanical components
Solution Approach 1:
The patent replaces the complex mechanical gear reduction system with a direct-drive configuration. The oscillating fluke is connected directly to the output shaft of the motor, eliminating the need for intermediate gear trains, belts, or other mechanical transmission components. The motor itself is selected to operate at the appropriate oscillation frequency for the fluke, substituting the mechanical complexity of gear reduction with a simpler direct connection and appropriate motor selection
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 flexible fluke propulsion system achieves high efficiency, reduces environmental impact, and minimizes harm to marine life by directing thrust forward, reducing vibrations, and being compatible with conventional watercraft motors.
Implementation Method 1
The propulsion device comprises a fluke oscillation drive having means for gear reduction of the rotary motion transmitted by the shaft and means for converting the rotary motion transmitted by the shaft to oscillatory motion of the fluke
Implementation Method 2
the counter-acting buoyancy and gravitation of the watercraft keep the watercraft in a vertically more or less locked position
Implementation Method 3
the counter-acting buoyancy and gravitation of the watercraft keep the watercraft in a vertically more or less locked position
Data Source
AI summary
A propulsion device and a watercraft including the propulsion device. The propulsion device comprises a flexible fluke that is pivotable about a horizontal axis, for propelling a floating watercraft. The propulsion device is adapted for connection to an output drive shaft that transmits rotary motion. The propulsion device comprises a fluke oscillation drive having gear reduction of the rotary motion transmitted by the shaft and a mechanism for converting the rotary motion transmitted by the shaft to oscillatory motion of the fluke.