Foot-Pedal Flapping Fin Propulsion for Hands-Free Watercraft Steering
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Solution Overview
Problem
Existing hand-powered personal watercrafts are inefficient in utilizing the user's power, as arms are weaker than legs, and require hands for both propulsion and steering, while foot-powered systems like Ketterman's oscillating fin propulsion are prone to damage and inefficient.
Innovation Solution
A flapping manual propulsion system using symmetrical fins driven by foot pedals, with a mechanism that converts foot motion into a continuous scissor-like motion through cranks and cables, allowing efficient propulsion without hands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If hand-powered paddles are used for propulsion, then the watercraft can be propelled, but the user's power is not fully utilized because arms are weaker than legs and hands must be used for both propulsion and steering
Solution Approach 1:
The patent replaces the hand-powered paddle mechanism with a foot-powered oscillating fin mechanism. The user's legs (which are stronger) drive the system through foot pedals that convert leg pumping motion into fin oscillation, substituting the weak arm-hand mechanical system with a stronger leg-foot mechanical system. This resolves the contradiction by fully utilizing leg power while freeing hands for steering operations.
Solution Approach 2:
The patent separates the propulsion function from the steering function. Propulsion is handled by the foot-powered oscillating fin system, while hands are freed to perform steering and other operations. This multi-functionality assignment resolves the contradiction by allowing hands to serve multiple purposes (steering, fishing apparatus operation) while the fin system handles propulsion exclusively.
2Power
If Ketterman's oscillating fin propulsion system is used, then foot power can be utilized, but the fins extend vertically into the water making them prone to damage in shallow water
Solution Approach 1:
The patent changes the fin orientation from vertical extension (Ketterman's design) to horizontal extension. The fins extend horizontally from the sides of the watercraft rather than vertically downward, making them less susceptible to damage in shallow water while still effective for propulsion through oscillating motion.
3Power
If Ketterman's oscillating fin propulsion system is used, then foot power can be utilized, but the mechanism to convert foot pumping motion to fin oscillating is complex and less efficient
Solution Approach 1:
The patent extracts and eliminates the complex motion conversion mechanism from Ketterman's design. Instead of using a complicated system to convert foot pumping motion to fin oscillation, the invention directly couples the foot pedal motion to the fin oscillation through a simplified linkage, removing unnecessary intermediate components and reducing mechanical complexity.
Solution Approach 2:
The patent inverts the conventional approach by having the fin oscillate in response to foot pedal depression rather than using a complex mechanism to translate vertical foot motion into horizontal fin motion. The direct linkage allows the fin to oscillate naturally as the foot pedal moves, simplifying the motion conversion.
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 system effectively utilizes leg power for continuous propulsion, reducing the need for hands and minimizing damage, enhancing the efficiency and usability of personal watercrafts.
Implementation Method 1
A upper end of the left extension 123L is mounted with a left pulley wheel 203L. One end of a cable 412 is attached to the forward end of the left fin 102L, and the other end of the cable 412 is attached to the left pulley wheel 203L
Data Source
AI summary
A manual propulsion system for a watercraft includes an axle horizontally mounted below a bottom surface of the watercraft in a direction perpendicular to a centerline of the watercraft, an elongated fin rotatable around the axle, the elongated fin being oriented along the centerline of the watercraft, a location of the axle dividing the elongated fin into a forward portion in front of the axle and an aft portion behind the axle in reference to a travel direction of the watercraft, the forward portion being shorter than the aft portion, a first foot pedal linked to the forward portion of the elongated fin, a forward motion by the first foot pedal lifting the forward portion of the elongated fin, and a second foot pedal linked to the aft portion of the elongated fin, a forward motion by the second foot pedal lifting the aft portion of the elongated fin.