Aft Propulsion Arrangement for Ice Breaking
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Solution Overview
Problem
Existing transport vessels, such as icebreakers and cargo ships, face challenges in efficiently navigating through heavy ice conditions due to limitations in propulsion power, space, weight, and cost constraints of rudder propeller devices, as well as inadequate ice penetration characteristics, particularly when encountering ice ridges and pack-ice.
Innovation Solution
A propulsion arrangement with at least three propulsion devices, including multiple rudder propeller devices positioned at different distances from the aft end of the vessel, allows for efficient ice breaking and disintegration, with one set closer to the aft end for direct ice penetration and another set farther away for removing broken ice chunks, enhancing the vessel's ability to move through pack-ice and ice ridges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If rudder propeller devices are used for ice breaking, then ice penetration capability is improved, but propulsion power is limited to about 20 MW per device
Solution Approach 1:
The propulsion system is divided into multiple rudder propeller devices (typically two or more) distributed along the aft end of the vessel. Each device contributes to ice breaking, and their combined power exceeds the 20 MW limitation of a single device, enabling larger vessels to operate in heavy ice conditions.
Solution Approach 2:
Multiple rudder propeller devices are combined in a coordinated arrangement where they work together to break ice and provide propulsion. The devices are integrated with the hull structure and steering system to achieve both ice penetration and maneuverability.
2Productivity
If multiple rudder propeller devices are arranged at different distances from the aft end, then ice breaking efficiency is improved, but device complexity increases
Solution Approach 1:
The ice breaking function is segmented between propellers at different positions: those closer to the aft end perform direct ice penetration, while those farther away remove broken ice chunks. This functional segmentation improves overall ice breaking efficiency despite increased complexity.
Solution Approach 2:
Different regions of the propulsion system are assigned different functions based on their position. The local arrangement of propellers is optimized for specific tasks (ice penetration vs. ice removal) to enhance overall productivity.
3Reliability
If the aft end is shaped for efficient ice penetration, then ice breaking capability is improved, but adaptability to varying conditions decreases
Solution Approach 1:
The vessel can dynamically change its operational mode by altering the orientation and positioning of rudder propeller devices. The system adapts between ice breaking mode (aft end leading with propellers positioned for penetration) and normal navigation mode, providing versatility across different operating conditions.
Solution Approach 2:
The rudder propeller devices serve multiple functions: they provide propulsion in open water, break ice when positioned for penetration, and remove broken ice chunks when positioned farther from the aft end. This multi-functionality allows a single configuration to handle varying conditions.
Data Source
AI summary
A watercraft has a hull with a first end and a second end and is equipped at its second end with a propulsion arrangement that includes at least three propulsion devices each provided with a propeller. A majority of the propulsion devices are rudder propeller devices, and the propeller of at least one of the propulsion devices is at a first distance from the second end of the hull and the propeller of at least another one of the propulsion devices is at a second distance, greater than the first distance, from the second end of the hull. In ice conditions the watercraft is operated with the second end ahead, so that at least one propeller at the first distance from the second end of the hull breaks ice and at least one propeller at the second distance from the second end of the hull moves disintegrated ice or ice chunks away from the ice build-up.