Twin Rudder Steering Device for Marine Vessel Slipstream Control
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Solution Overview
Problem
Conventional rudder configurations in marine vehicles face limitations in propulsive performance, especially at slow speeds, and struggle to maintain turning ability without increasing fuel consumption or underwater noise, while existing solutions either hinder propulsive efficiency or require additional engine power.
Innovation Solution
A steering device with two rudder plates positioned laterally to the propeller, rotating in opposite directions to deflect the propeller slipstream, allowing for high propulsive efficiency and turning performance without being in the propeller slipstream during cruising, and capable of blocking the slipstream for emergency stopping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the rudder is positioned in the propeller slipstream, then the stopping ability is enhanced, but the propulsive performance deteriorates due to additional resistance
Solution Approach 1:
The rudder is designed to dynamically change its position relative to the propeller slipstream. During normal cruising, the rudder is positioned laterally to minimize resistance and maximize propulsive efficiency. During emergency stopping, the rudder rotates to block the slipstream, utilizing the dynamic repositioning capability to switch between opposing performance requirements.
Solution Approach 2:
The rudder system operates in periodic cycles between two distinct states: a cruising state where the rudder is positioned laterally for efficient propulsion, and a stopping state where the rudder blocks the slipstream for rapid deceleration. This periodic switching allows the system to optimize performance for the current operational phase.
2Loss of energy
If the rudder is arranged lateral to the propeller for high propulsive efficiency, then the propulsive performance is improved, but the turning ability at slow speeds deteriorates
Solution Approach 1:
The rudder system dynamically repositions itself based on operational requirements. At slow speeds during maneuvering, the rudder can rotate to engage with the propeller slipstream, providing sufficient turning ability. During high-speed cruising, the rudder positions laterally to minimize drag and maximize propulsive efficiency.
3Use of energy by moving object
If two rudders are arranged in front of or aside the propeller to improve propulsive performance, then the fuel consumption is reduced, but the stopping ability deteriorates
Solution Approach 1:
The twin rudder system is designed with rotational capability around vertical axes, allowing each rudder to dynamically reposition. During normal operation, the rudders are positioned laterally to reduce resistance and improve fuel efficiency. During emergency stopping, the rudders rotate to block the propeller slipstream, providing powerful stopping force.
4Device complexity
If the rudder plate rotates around a steering shaft included in the rudder plate face, then the steering mechanism is simplified, but the ability to block the propeller slipstream deteriorates
Solution Approach 1:
The rudder plate is designed to rotate around a vertical axis rather than a horizontal axis within the plate face. This dynamic repositioning capability allows the rudder to achieve a blocking position perpendicular to the propeller slipstream during emergency stopping, while maintaining a streamlined lateral position during normal cruising for reduced complexity operation.
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 enhances propulsive efficiency during cruising, maintains high turning performance, and reduces underwater noise, while enabling effective emergency stopping without increasing fuel consumption or noise pollution.
Implementation Method 1
two rudder plates, whereby the two rudder plates simultaneously rotate in mutually opposite directions
Implementation Method 2
the two rudder plates exceeding a rudder angle of 70°, and the two rudder plates cooperate to almost block the propeller slipstream
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A ship hull (10) having a propeller (20), a screw shaft (5) for the propeller (20) and a steering device (1) having: - two steering shafts (40), - a driving mechanism (90) for rotating the two steering shafts (40), - a power mechanism for driving the steering shafts (40), - two rudder plates (30), - whereby an upper portion of each of the rudder plates (30) is connected and suspended to one of the steering shafts (40), - whereby the steering shafts (40) are biaxially arranged rotatably to have a vertical rotation axis located on both sides of said screw shaft (5), - wherein the two rudder plates (30) are arranged such that they are located lateral to said propeller (20) at the time of the ship straight travelling, - wherein each of the two rudder plates (30) is arranged such that turns around the rotation axis of the corresponding steering shaft (40) between a side propeller position corresponding to the situation when the ship is travelling straight and a position corresponding to the situation when the ship performing a stop maneuver, - wherein the steering device (1) is arranged such that the two rudder plates (30) simultaneously rotate in mutually opposite directions.