To make trawling more sustainable, ECO Trawl has created a new concept for trawling
Can thrusters replace today's trawl doors?
Tuesday, July 14, 2020, 14:00 (GMT + 9)
In a recent feasibility study, it has been shown that steerable thrusters can replace traditional trawl doors and thus reduce energy consumption by as much as 30%.
The Norwegian Seafood Research Fund (FHF) announced funding in the spring of 2017 to develop the gear technology of the future as a contribution to making the Norwegian fishing fleet a world leader in environmentally friendly, sustainable and profitable fishing. The Eco Trawl project was one of two projects established on the basis of this call.
ECO Trawl has applied for a Norwegian patent for the core technology patent application number 20161043
The Eco Trawl concept consists of replacing the conventional trawl doors in pelagic and bottom trawls with two thruster units to reduce energy consumption, as well as having more control of the trawl (see figure 1). The project is a Project in Business that has been led by the company Eco Trawl, which has collaborated with the Institute of Marine Research and CFD Marine.
Thrusters that replace trawl doors in pelagic and bottom trawls
The calculations show that power consumption has been reduced by 30% compared with traditional trawl doors. With this as a starting point, 30% fuel can be saved, or a larger and more efficient trawl can be used. In addition, such thrusters will cause less damage to the seabed.
The findings have been obtained via so-called “computational fluid dynamics (CFD)” analyzes (numerical flow analyzes) by recognized experts and by using recognized software at CFD Marine and NTNU.
Extensive CFD calculations of the ECO Trawl concept have been performed, verifying the forces and controllability of the Thruster unit. The analysis have been performed by CFD Marine
Further use of the results depends on customer acceptance of the solution. It is a major investment for a vessel to install an ECO Trawl system. Cost-benefit is difficult to assess at this stage, but the analyzes show that a payback period on the project is approx. 7 years based on fuel consumption alone. Then increased catch and other benefits are not included. It remains to be documented that the thruster unit is linearly stable and controllable when the trawl is connected. Solutions must also be developed to pull the trawl up on deck and to set out and pull in thrusters.
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Author: Maja Bævre-Jensen / FHF