Towing cylindrical fishing gear components on cohesive soils: Fid-Bau Portal

Towing cylindrical fishing gear components on cohesive soils

Ivanović, Ana / O’Neill, Finbarr G.

Abstract The analysis of penetration into cohesive soils of truncated rigid cylindrical objects that are associated with demersal trawl fishing is presented. Numerical simulations of three-dimensional models were performed using the finite element software ABAQUS to assess the influence that the dimensions, the weight, the cross-sectional geometry and the soil material properties have on penetration and drag. In general, over the parameter ranges examined: there is a non-linear increase in penetration and drag as the weight increases; there is a decrease in penetration and an associated reduction of drag as the Yield stress and Young’s modulus increase; and the drag and penetration of aerofoil shaped cylinders are less than those of circular ones of similar weights and dimensions. The non-dimensional form of the problem is examined and it is demonstrated that the penetration and drag values reduce respectively to expressions that are dependent solely, at least to a first order of approximation, on the non-dimensional weight, suggesting that the problem is essentially two-dimensional in nature and that three-dimensional effects at the edges of the clumps do not play a significant role. We illustrate how these expressions can be used to evaluate the physical impact of towed gears and ultimately contribute to the development of fishing gears/techniques of reduced impact.