The aftmost part of a trawl fishing gear, the cod-end, has been successfully modelled as an axisymmetric network. Here we investigate the influence that the bending stiffness of the component twines has on the deformation of the network and accordingly on the degree to which the netting meshes open. A non-dimensional parameter EI/NM4P, where EI is the twine bending stiffness, N is the number of meshes around, M is the mesh size, and P is the internal pressure, is shown to characterize network deformation. We identify upper bounds on the network radius when subject to a constant internal pressure and demonstrate numerically how this varies as the value of this non-dimensional parameter increases. We also look at some specific examples and discuss how an increase in twine bending stiffness may affect fish escape from the cod-end.

This content is only available via PDF.
You do not currently have access to this content.