Lower Line shape and Tension of Shrimp Trammel Net Towed along the Hypotenuse of Right Triangle

Puspito Gondo, Yamamoto Katsutaro, Hiraishi Tomonori, Nashimoto Katsuaki

doi:10.2331/fishsci.63.1

Fishing efficiency of shrimp trammel net popularly used in Indonesia considerably depends on the area swept by its lower line. The lower line part substituted by a chain was investigated in the present study. As a simple experiment, the chain was towed by a lorry along the hypotenuse of a right triangle drawn on the floor. The tensions of the towed end of chain were measured by a two-component load cell installed in the lorry. The chain curves were photographed by a camera. From measurements of the trajectory of chain movement, the moving angle ø was given as a linear function of the tension angle θ for the parts of chain far from the hypotenuse, ø=αθ+b, and a constant, ø=α (α is the towing angle), for the parts of chain near the hypotenuse. Substituting these equations for the unknown moving angle function in the differential equations, the chain curve and the tension were numerically calculated. When the frictional coefficient was given as μ=μ₉₀ sin²(ø-θ)μ+₀ cos² (ø-θ), the calculated results well agreed with the experimental results. μ₉₀ and μ₀ are the frictional coefficients when the chain was perpendicular and parallel to the moving direction.

Lower Line shape and Tension of Shrimp Trammel Net Towed along the Hypotenuse of Right Triangle

Bibliographic Information

Search this article

Abstract

Journal

Citations (1)*help

References(23)*help

Keywords

Details 詳細情報について

Export

Report a problem