Ship Roll Stabilization with Movable Sub-Element
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Solution Overview
Problem
Existing active roll stabilization systems for ships are ineffective when the ship is stationary, as they rely on water movement past the stabilization elements to generate a counteracting lifting moment, which is absent in this condition, limiting their functionality.
Innovation Solution
The introduction of a movable sub-element within the stabilization system, capable of independent movement relative to the main stabilization element, allows for an additional lifting moment to be imparted to the ship both when sailing and when at anchor, enabling effective roll stabilization by adjusting its position and orientation based on the ship's speed and movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fin-like stabilisation element is used that projects into the water below the waterline, then roll stabilisation is achieved while the ship is sailing through water movement generating a counteracting lifting moment, but the system becomes ineffective when the ship is stationary because there is no functional water movement past the stabilisation element
Solution Approach 1:
The stabilisation element is transformed from a static fin-like structure into a dynamic system by adding a movable sub-element that can be actuated independently. This sub-element is capable of moving relative to the main stabilisation element, allowing the system to generate stabilising forces both when water flows past (sailing) and when the ship is stationary (at anchor), thus resolving the contradiction between adaptability and reliability across different operational conditions
Solution Approach 2:
The stabilisation element is divided into two functional parts: a main stabilisation element and a movable sub-element. This segmentation allows each part to contribute differently to the stabilisation mechanism - the main element works with water flow during sailing, while the sub-element can be actuated to provide additional stabilisation when the ship is stationary, enabling the system to function reliably in both sailing and anchored conditions
2Device complexity
If the stabilisation element is made static and fin-like, then the system structure is simple, but the system cannot provide effective roll stabilisation when the ship is at anchor due to lack of water movement
Solution Approach 1:
A movable sub-element is introduced to the stabilisation element, transforming it from a static structure to a dynamic one. The sub-element can be actuated relative to the main element, enabling the system to generate stabilising forces in both sailing and anchored conditions. This dynamic capability expands the operational range without significantly complicating the overall system structure
Solution Approach 2:
The movable sub-element is positioned within or attached to the main stabilisation element, creating a nested configuration. This allows the sub-element to be accommodated within the overall structure of the stabilisation element, adding functional complexity while maintaining relatively compact and simple system architecture
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 solution allows for effective damping of ship movements both during sailing and when stationary, enhancing the system's functionality and reliability by adapting the stabilization element's dimensions and movement to optimize the Aspect Ratio for different operational conditions.
Implementation Method 1
A reaction force acting on the water can be generated by means of said fin-like stabilisation element while sailing, which reaction force imparts a counteracting lifting or torsional moment to the ship
Implementation Method 2
This makes it possible to impart an additional lifting moment to the ship via the stabilisation element, both while the ship is sailing and while the ship is at anchor
Data Source
AI summary
The invention relates to an active roll stabilization system for ships, including at least one stabilization element extending below the water line, which is mounted on a rotary shaft that extends through the ship's hull, a sensor for sensing the ship's movements and delivering control signals on the basis thereof to rotation member for rotating the rotary shaft for the purpose of damping the ship's movements that are being sensed through the stabilization element.The object of the invention is to provide an active roll stabilization system for ships that can be used both with ships which are underway and with ships that are at anchor. According to the invention, the active roll stabilization system is to that end wherein the stabilization element is provided with a sub-element that is movable with respect to the stabilization element. This makes it possible to impart an additional lifting moment to the ship via the stabilization element, both while the ship is sailing and while the ship is at anchor, for the purpose of effectively damping or countering the ship's movements that are being sensed.