水産および畜産生産

抽象的な

Structure and Applications of Small Fishing Vessels

Diriba Tulu

Small fishing vessels are involved in a significant number of maritime accidents in coastal waters. Performing dynamic simulations to estimate the trajectories and motions of vessels is frequently required in the investigation of maritime accident causes. For accurate simulations, vessels’ initial conditions, including main dimensions, loading conditions, and hydrostatic properties, are necessary. During their fishing operations, small fishing vessels typically have few records of hydrostatic properties. As a result, methods for estimating the hydrostatic properties of small fishing vessels are suggested in this research. The initial focus is on the hull form characteristics of Korean small fishing vessels. The majority of vessels share similar hull shapes and have hard-chines and centreline skegs. The vessel widths and depths are used to normalize the Bonjean curves of several small fishing vessels whose gross tonnages are below 10 tons. Normalized bonjean curves are used to derive representative bonjean curves, and a representative hull plan is also produced. The representative bonjean curves can be used to calculate fore and aft drafts under the condition that weights and buoyancies are in equilibrium if the vessel loading conditions, such as total weights and centers of gravity, are provided. The representative hull plan is also used to estimate metacentric heights. When the proposed iterative estimation procedures for estimating drafts and metacentric heights are compared to actual vessel data, the estimated values are in good agreement with the actual values. Metacentric heights of vessels, as well as normalized fore and aft drafts, can be expressed as linear functions of normalized total weights and centers of gravity. Drafts and metacentric heights empirical formulas are proposed and shown to yield reasonable results that are comparable to those obtained by iterative estimation procedures employing representative bonjean curves and hull plan.