Oscillating Foil Keel for Boat Stability and Leeway Control
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Solution Overview
Problem
Existing sailing boats with foils face limitations in performance and safety, particularly in low wind conditions, strong winds, and formed waves, due to increased complexity, high costs, and lack of self-righting capabilities.
Innovation Solution
A boat design featuring a double oscillating keel system with hydrodynamic profiles that can rotate and adjust their angle, allowing for traditional and planar sailing modes, enhanced stability, and self-righting capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a single oscillating keel is used to generate righting force, then the boat can achieve form stability and increased sail area, but the boat loses leeway contrast capability when the keel is in horizontal position
Solution Approach 1:
The single oscillating keel is divided into two separate oscillating foils that can operate independently. Each foil can be positioned and oriented separately to provide both righting force and leeway contrast capability, resolving the conflict between these two functions that plagued the single keel design.
Solution Approach 2:
The patent introduces an intermediate structural element (the hull-mounted foil framework) that mediates between the oscillating foils and the hull. This framework provides mounting points and structural support while allowing the foils to oscillate independently, enabling both righting and leeway contrast functions to coexist.
2Reliability
If multiple foils and dagger boards are added to restore leeway contrast, then the boat can maintain directional stability, but the device complexity and cost increase significantly
Solution Approach 1:
Each oscillating foil is designed to perform multiple functions: generating righting force through oscillation, providing leeway contrast through its hydrodynamic profile, and contributing to directional stability. This multi-functionality reduces the need for separate specialized components, simplifying the overall system while maintaining all necessary capabilities.
Solution Approach 2:
The foils are designed to oscillate dynamically rather than remain fixed, allowing them to adapt their position and orientation based on sailing conditions. This dynamic behavior enables a single foil to provide both righting and leeway contrast functions that would otherwise require multiple static components.
3Ease of manufacture
If the oscillating foils are hinged at the bottom of the hull, then the structure is simpler, but the righting moment and leverage are reduced
Solution Approach 1:
The patent moves the hinge point from the bottom (vertical dimension) to the topside (horizontal dimension) of the hull. This dimensional change in hinge positioning increases the lever arm for righting moment while still maintaining structural simplicity through the hull-mounted framework.
4Strength
If fixed hydrodynamic profiles are used, then the structural integrity is higher, but the adaptability to different wind and wave conditions is reduced
Solution Approach 1:
The hydrodynamic profiles are designed to oscillate rather than remain fixed, allowing them to adapt their angle of attack and position based on wind strength, wave conditions, and boat speed. This dynamic capability maintains structural integrity through controlled motion while significantly improving adaptability to varying sailing conditions.
Solution Approach 2:
The oscillating foils change key parameters (position, orientation, angle of attack) in response to varying sailing conditions. This parameter adjustment allows the same structural element to optimize performance across a wide range of wind speeds and wave heights without requiring multiple fixed configurations.
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 solution enables sailing boats to operate safely and efficiently in various wind conditions and wave heights, while maintaining simplicity and reducing costs compared to existing foiled boat designs.
Implementation Method 1
a second portion (23), whose hydrodynamic profile is configured to generate: an upward hydrodynamic thrust in order to lighten the boat and so to contrast friction
Implementation Method 2
a second portion (23), whose hydrodynamic profile is configured to generate: a righting force in order to increase the sail area which can be exposed to the wind
Implementation Method 3
A boat design featuring a double oscillating keel system with hydrodynamic profiles that can rotate and adjust their angle
Data Source
Figure 1(a)~1(c)
Figure 2(a)~2(c)
Figure 3(a)~3(c)
AI summary
Boat comprising at least two oscillating hydrodynamic profiles or foils (20, 30), symmetrical to the longitudinal middle axis of the hull (1) of said boat and hinged in their upper portion, one for each body side, to the topside of said hull (1) so that they can rotate moving away and close to said hull (1), characterized in that each of said foil (20, 30) comprises fastening means (21) positioned at their upper end, by means of which the foil is hinged to the body side of said hull; a first portion (22) having such shape that it can approach the body side of the boat adhering to the same along its whole development; a second portion (23), whose hydrodynamic profile is configured to exert a lift thrust after the boat proceeds in water, said second portion (23) being configured to be vertically positioned when said first portion (22) is approached to the shape of the hull.