Effect of Ship Size on the Hull Dimension Ratios of Purse Seiners

Abstract

In the preliminary ship design stage, the first approximations of speed, stability, structure, weight, and cost, among others, are reached by selecting the appropriate hull dimension ratios. This research was motivated by the noticeable lack of systematic data on these ratios in the literature on American-type semi-industrial purse seiners. Regression analysis was performed to investigate the relationship between hull dimension ratios and vessel size from a database composed of 130 purse seiners of the Peruvian fleet. This work aimed to determine the effect of vessel size, as characterized by length, breadth, depth, gross tonnage, net tonnage, and fish hold capacity, on the main hull dimension ratios of purse seiners, i.e., length/breadth, length/depth, and breadth/depth. A compilation of hull statistics for the ship attributes and ratios was elaborated, with the findings indicating that length significantly affects the slimness of Americantype semi-industrial purse seiners, whose structural strength and ship weight increase with length. These vessels exhibit an invariable minimum stability according to standard criteria since a breadth-to-depth ratio of 2 is maintained. In this vein, depth is half the value of breadth. The other parameters do not affect the hull dimension ratios. The estimated regression equations and the patterns presented in this research can be used in the preliminary design stage of American-type semi-industrial purse seiners.