Hydrojet Rudder Device for Off-Throttle Steering Control
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Solution Overview
Problem
Waterjet-powered vessels face challenges in steering, particularly when throttled back, as existing systems lack effective directional control, leading to accidents due to minimal or non-existent off-throttle steering capabilities.
Innovation Solution
A rudder device with a coupling rod and pivotably coupled rudders that align and pivot in unison with hydrojets and the hull rudder, providing steerage during non-directional thrust, and featuring adjustable rudder elevations and locking mechanisms to enhance maneuverability and response.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If directional control is accomplished by directing the water jet through a moveable nozzle, then the propulsion and steering system is simpler and inherently safer, but off-throttle steering capability is minimal to non-existent
Solution Approach 1:
The patent introduces a rudder assembly as an intermediary component between the water jet nozzle and the vessel hull. This rudder acts as a mediator that can redirect water flow even when the nozzle is in a neutral position, enabling steering control during off-throttle conditions without complicating the primary nozzle-based steering system
Solution Approach 2:
The steering function is segmented into two independent systems: the nozzle-based directional control for normal operation, and the rudder-based auxiliary steering for off-throttle conditions. This segmentation allows each component to specialize in specific operating conditions without requiring the other to be overly complex
2Ease of operation
If a rudder assembly is added to provide off-throttle steering, then steering capability is improved, but device complexity increases
Solution Approach 1:
The rudder assembly is merged with the existing nozzle structure, where the rudder is positioned within or adjacent to the nozzle housing. This integration allows the rudder to utilize the existing water flow path and structural support, reducing the need for separate mounting systems and complex linkages
Solution Approach 2:
The rudder assembly is designed to be automatically actuated by the water flow itself. During off-throttle conditions, the natural water flow from the jet automatically positions the rudder to provide steering assistance, eliminating the need for complex hydraulic or electric actuation systems
3Measurement precision
If the rudder is held in a fixed position, then steering precision is improved, but the system becomes less adaptable to different operating conditions
Solution Approach 1:
The rudder assembly incorporates a spring-loaded mechanism that allows the rudder to dynamically adjust its position based on water flow pressure. During high-throttle operations, the water flow overcomes the spring force and positions the rudder optimally, while during off-throttle conditions, the spring returns the rudder to a neutral position, providing automatic adaptation without complex control systems
Data Source
AI summary
A rudder device for a hydrojet vessel. The rudder device includes a mounting plate, a primary rudder and a secondary rudder coupled to a hydrojet. The primary rudder and the secondary rudder providing steerage as the hydrojet vessel is displaced through the water.