Trimmable Rudder With Ball-and-Socket Joint for Hull Trim Control
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Solution Overview
Problem
Existing rudder systems for marine vessels have limited control over hull trim and planing, primarily offering single-degree-of-freedom movement, which restricts efficient listing and planing control and increases hydrodynamic drag.
Innovation Solution
A trimmable rudder system with pair of rudder blades providing three rotational degrees of freedom, utilizing a ball-and-socket joint for independent position adjustability, allowing coordinated movements to achieve desired hull trim changes while maintaining alignment with water flow, thus minimizing drag.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single-degree-of-freedom trim tab is used, then the structure is simple, but the hull trim control capability is limited and hydrodynamic drag increases
Solution Approach 1:
The rudder blade is transformed from a fixed single-degree-of-freedom structure to a dynamic multi-degree-of-freedom system capable of independent rotation about three orthogonal axes (transverse, longitudinal, and vertical axes), enabling adaptive positioning for various trim and listing control requirements
Solution Approach 2:
The rudder system is segmented into multiple independently controllable rotational degrees of freedom, with each axis providing separate control capability. The first rotational degree of freedom controls transverse positioning, the second controls longitudinal positioning, and the third controls vertical positioning, allowing versatile hull orientation control
2Adaptability or versatility
If the rudder blade is pivoted down to increase surface area for trim control, then listing and planing control is improved, but hydrodynamic appendage drag increases
Solution Approach 1:
The rudder blade employs dynamic positioning with three rotational degrees of freedom, allowing it to maintain optimal alignment with water flow direction while achieving trim control. By independently adjusting the angle of attack and positioning, the system achieves effective listing and planing control without requiring large downward pivots that would increase drag
Solution Approach 2:
The system changes multiple geometric parameters simultaneously through multi-axis rotation, including the angle of attack, lateral positioning, and longitudinal positioning. This enables effective trim control by optimizing the combination of parameters rather than relying solely on increasing surface area through large downward pivots
3Adaptability or versatility
If a multi-degree-of-freedom rudder system is implemented, then hull trim control capability is improved, but the device complexity increases
Solution Approach 1:
Multiple rotational degree of freedom mechanisms are merged into a single integrated rudder blade assembly. The first, second, and third rotational degrees of freedom are combined in one structure rather than using separate components, reducing overall system complexity while maintaining full control capability
Solution Approach 2:
The rudder blade serves multiple functions simultaneously through its three rotational degrees of freedom: it provides steering control, trim control, and listing control. This multi-functionality reduces the need for separate control surfaces, thereby reducing overall system complexity despite the added degrees of freedom
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
Enables combined steering and trimming capabilities with low-drag, efficient hull orientation control, allowing for infinitely variable adjustments and reduced hydrodynamic appendage drag, enhancing the vessel's stability and maneuverability.
Implementation Method 1
A joint is arranged between a hull of the power boat and the rudder assembly so that the rudder shaft can pivot about an axis that extends in a transverse direction through the joint that is generally perpendicular to the longitudinal axis of the rudder shaft
Data Source
Figure 1
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AI summary
A trimmable rudder system (2) for a marine vessel such as a planing power boat (10), the system including a pair of rudder assemblies (18), each of which includes a mdder blade (20) movably coupled to the hull (12) by way of a ball-and-socket joint (24). Each mdder assembly (18) includes a rudder shaft (22) that extends from the rudder blade (20) through the ball-and-socket joint (24) and can be rotated for rotating the mdder blade (20) to steer the power boat (10). Each rudder shaft (22) may be operably coupled to a pair of actuators (26, 28) configured to control trim and camber positions of the mdder blade (20) so that the pair of rudder blades (20) can collectively achieve a desired hull trim change, including listing control and planing control of the power boat (10). Steering position, trim position, and camber position of the rudder blades (20) may be simultaneously changed.