Many trawl fishers know the benefits of towing multiple trawl nets at once, including commonly used triple-rig and quad-rig systems. Now, some in Queensland have taken up the challenge to go one step further and use a five-rig prawn-trawl system.
This new system works in both shallow and deepwater operations, allowing a vessel to tow five connected nets with a single pair of otter boards. The trawl nets are smaller with reduced twine area, which reduces drag and improves fuel efficiency while maximising the catch. At fishing depths between 20-50m, this new system reportedly delivers an improvement in swept area between 5-10%.
Like any new technology. the five-rig comes with its own challenges, including complexity of setup, handling, and tuning the system. To bring the warps closer to the side of the vessel while gear is on the surface, small in-pull winches are used. The winches eliminate the need to haul the gear up to the boom blocks, ensuring the middle net stays clear of the stern when the gear is at the surface. This system helps streamline between-haul operations.
Other benefits include easier access to the boards and nets alongside the vessel, allowing for adjustments and repairs. It also improves safety; crew no longer need to climb out on the booms to connect recovery ropes or untangle gear. This system also reduces capsize risk when the gear is hooked up because warps alongside the vessel reduces capsizing forces.
The in-pull winch brings the gear close to the sides of the vessel
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