Effect of Mesh Size on Sinking Characteristics of Purse Seine Net: a Parametric Study by Numerical Simulation

We numerically modeled the geometry of a purse seine net and evaluated the model's dynamic behavior during operation. The vessel position, wire payout and roll-up lengths, and current flow speed and direction in situ were collected as the dataset for computation. The mesh sizes of the upper, middle, and lower sections of the main net were changed to double and half their respective sizes, and the sinking speed and depth were compared among nets of different mesh sizes. The net with doubled mesh size in the lower section and constant mesh bar diameter strongly affected the sinking speed and depth. This implies that a large mesh size in the lower part of the main net, which eliminates the need for providing a thicker mesh bar, should be used for enhancing the efficiency of fishing operations.