Reconfigurable Subsea Plough for Boulder Clearing and Cable Burial
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Solution Overview
Problem
Existing subsea ploughs face challenges in efficiently burying inter-array power cables in boulder clay due to surface boulders, which impede progress and cause damage, and require time-consuming reconfiguration and retrieval for trench formation and backfilling, leading to instability and increased costs.
Innovation Solution
A subsea plough with a chassis, boulder clearance and spoil clearance members, and a reconfigurable backfilling member, allowing for simultaneous boulder clearing and trenching in a single pass, followed by backfilling without seabed retrieval, using hydraulic actuators for depth control and blade configurations to maintain stability and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a subsea plough is used to form a stable trench in boulder clay, then the trench formation quality is improved, but the plough requires time-consuming reconfiguration and retrieval from the seabed
Solution Approach 1:
The plough incorporates adjustable skids that can be repositioned between different operational modes (trenching mode with skids at the front, backfilling mode with skids at the rear) without requiring retrieval from the seabed. This dynamic reconfiguration allows the plough to adapt to different tasks while remaining deployed, reducing time loss.
Solution Approach 2:
The plough is designed as a multi-functional device that can perform both trenching and backfilling operations. By integrating both functions into a single device with reconfigurable components (skids, share, spoil heap), it eliminates the need for separate equipment or multiple retrieval cycles, thereby reducing time consumption while maintaining high trench formation quality.
2Length of stationary object
If the plough chassis is pitched forwards to increase cutting depth, then the trench depth is improved, but the towing point becomes above the seabed reducing plough stability
Solution Approach 1:
The plough uses adjustable skids that can be positioned at different locations along the chassis to dynamically change the pivot point and towing point positions. This allows the system to maintain stability even when the chassis is pitched forward for deep cutting, as the skids can be repositioned to provide adequate support and balance.
3Ease of operation
If surface boulders are cleared before wind turbine installation, then the mobility of the seabed tractor is improved, but the cable protection is not assisted
Solution Approach 1:
The plough performs preliminary boulder clearance by pushing boulders onto spoil heaps positioned away from the trench line before cable installation. This preliminary action removes obstacles that would impede cable laying equipment while simultaneously preparing the trench environment, thus improving both mobility and cable protection.
Solution Approach 2:
The spoil heap acts as an intermediary structure that temporarily stores boulders during trenching operations. By positioning spoil heaps away from the trench centerline, the system uses this intermediary to separate boulders from the cable path, thereby protecting the cable while maintaining operational efficiency.
4Productivity
If the span of the boulder clearance member is greater than the span of the spoil clearance member, then the boulder clearing effectiveness is improved, but the device complexity increases
Solution Approach 1:
The plough divides the boulder clearance function into separate modular components (boulder clearance members with teeth) that can be independently adjusted and positioned. This segmentation allows the system to achieve effective boulder clearing with a larger span without proportionally increasing overall device complexity, as each module can be optimized independently.
Data Source
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AI summary
A subsea plough comprising a share coupled to a chassis, boulder clearance and spoil clearance members, front and rear support surfaces, wherein in a first configuration, a maximum span of the boulder clearance member in an extended position is greater than a span of the spoil clearance member, wherein the plough may be reconfigurable to comprise a backfill member; and a method of use of the plough for in a boulder clearing only mode, and optional modes of simultaneous boulder clearing and trenching, second pass trenching, and backfilling a trench to bury a flexible elongate member in a seabed.