The Trawl Door is an indispensable core fishing equipment component in fishing operations. It is mainly installed on both sides of the trawl net and its main function is to expand the net opening by leveraging the force of water flow, providing a fundamental guarantee for efficient fishing. As a key accessory connecting the fishing boat and the trawl net, it not only determines the opening width and shape stability of the net opening, but also directly affects the fishing range, fishing efficiency, and operational safety. It is widely used in the fishing scenarios of bottom, middle-level fish and shrimp, crab and other aquatic products in both coastal and open-sea areas.
The core working principle is based on the characteristics of fluid mechanics: When the fishing boat moves forward with the trawl net, the water flow exerts a lateral thrust on the two sides of the trawl net doors, forcing the doors to open at a specific angle outward. Then, through the rope, the trawl net wings are pulled synchronously to expand, forming the net opening size that meets the fishing requirements. Traditional trawl net doors are mostly made of metal water-blocking plates and need to be combined with counterweights or floating devices to adjust the working depth.
To adjust the net opening size or the fishing water layer, multiple crew members need to operate collaboratively, which is a cumbersome and time-consuming process. Although these trawl net doors have a simple structure and low cost, their adjustment accuracy is limited, and they are difficult to adapt to complex fishing areas and diverse fishing requirements.
With the intelligent upgrading of fishing equipment, intelligent trawl doors have gradually replaced traditional devices and become the mainstream for high-end fishing operations. Crew members can precisely adjust the net opening width and working depth through the cockpit terminal or mobile app.
Within a few minutes, they can switch from mid-water fishing mode to deep-sea fishing mode, significantly reducing labor costs. At the same time, sensors can collect real-time data such as the trawl's posture and water flow speed and feed it back to the control terminal. They can also preset emergency operation modes, automatically adjusting the trawl's state in case of emergencies, and maximizing the avoidance of safety risks.
The design and material of the trawl net door need to be suitable for different fishing scenarios: The trawl net door for near-sea bottom trawling operations should have strong wear resistance and load-bearing capacity to cope with complex environments such as seabed mud and rocks; while for mid-water fishing in the open ocean, lightweight and adjustable flexibility are more important. In the current era with increasing ecological protection requirements, the intelligent trawl net door can also work in synergy with an environmentally friendly trawl system.
By precisely controlling the fishing area, it can reduce by-catch and contribute to sustainable fishery development. Practical data shows that the fishing system equipped with an intelligent trawl net door can increase the catch volume by more than 30%, becoming an important support for modern fishery's efficiency, intelligence and green development.