Hydrofoil Gearbox Integration for Drag Reduction
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Solution Overview
Problem
Conventional hydrofoil systems in boats face inefficiencies due to mechanical distance between the engine/gearbox and propeller, leading to energy losses and increased hydrodynamic drag, while also requiring manual control that is prone to human error.
Innovation Solution
The gearbox and engine are integrated within a housing provided by the hydrofoil, reducing the wetted area and drag, and utilizing a thermally conductive gearbox casing for passive heat transfer cooling, eliminating the need for mechanical cooling systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the engine and gearbox are located beneath the hull with mechanical linkage to the propeller, then the propulsion system is mechanically connected, but hydrodynamic drag increases and system integrity becomes challenging due to foil deformation
Solution Approach 1:
The patent combines the engine, gearbox, and propeller into a single integrated propulsion unit that is mounted on the hydrofoil structure itself. This merging eliminates the need for separate mechanical linkages (propeller shafts and bearings) that would otherwise extend from the hull beneath the hydrofoil, thereby removing the source of hydrodynamic drag while maintaining structural integrity through direct mounting on the foil.
Solution Approach 2:
The propulsion system is extracted from the traditional hull-mounted configuration and relocated to be mounted directly on the hydrofoil structure. This extraction removes the mechanical linkage components (propeller shaft, bearings) that cause drag when submerged, while the propulsion unit remains intact and functional on the foil where it does not interfere with hydrodynamic performance.
2Power
If mechanical linkage is used between engine/gearbox and propeller, then power transmission is achieved, but efficiency losses occur due to mechanical distance and friction
Solution Approach 1:
The engine, gearbox, and propeller are merged into a single integrated unit with direct coupling. The propeller is mounted directly on the output shaft of the gearbox, eliminating intermediate mechanical linkages, propeller shafts, and bearings. This direct coupling minimizes mechanical distance and friction losses, maximizing power transmission efficiency from the engine to the propeller.
3Ease of operation
If manual control with mechanical lever arm is used, then flap control is achieved, but human error increases and control accuracy requires extensive experience
Solution Approach 1:
The patent replaces the manual mechanical lever arm control system with an electric actuation system. Electric motors or actuators are used to control the flaps, eliminating the need for manual mechanical linkages. This substitution provides more precise and reliable control without requiring extensive human experience, as the electric system can be programmed and controlled with greater accuracy through electronic means.
4Stability of the object's composition
If wider and longer hull is used, then stability of sailing hydrofoil increases, but hydrodynamic drag and packaging space increase
Solution Approach 1:
The patent addresses stability without increasing hull dimensions by utilizing the vertical dimension through hydrofoils. The hydrofoils generate lift that raises the hull out of the water, providing stability through the underwater foil structures rather than requiring a wider or longer hull. This dimensional approach maintains stability while minimizing hydrodynamic drag on the hull form.
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
This configuration enhances efficiency and reduces fuel/energy usage by minimizing hydrodynamic drag and mechanical losses, while enabling autonomous control and improved ride comfort through optimized vessel positioning.
Implementation Method 1
utilizing a thermally conductive gearbox casing for passive heat transfer cooling
Data Source
Figure 1
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Figure 4~5
AI summary
The present invention relates to a gearbox system for mounting on a hydrofoil (18) for a waterborne vessel (10), the gearbox system comprising: a housing (60) having an interior surface defining an interior space of defined dimension; a gearing system comprising a gear box (44) located within the interior of the housing; a propeller shaft (33) engagement portion (35), the gearing system located within the interior of the housing; and an engine (42) located within the interior space of the housing and in mechanical communication with the gear box; wherein the housing is water-tight and wherein the gearing system and engine are in thermal contact with the interior surface of the housing. Further provided is a hydrofoil system including such a gearbox system and a waterborne vessel including such a hydrofoil system.