An experimental study of stabilizing ordinary fishing nets (SOFNets) on a stationary SWATH ship seakeeping behavior under irregular waves

Abstract

The present research aims to experimentally demonstrate the effectiveness of an innovative method for reducing the ship motions using Stabilizing Ordinary Fishing Nets that we call it SOFNets from now on. To this end, the influence of a range of SOFNets on the seakeeping behavior of a Small-Waterplane-Area Twin Hull (SWATH) ship in irregular waves is investigated physically in a towing tank laboratory. Understanding, controlling, and improving the seakeeping behavior of ships has always been a major concern of ship designers. As a result, various techniques have been utilized to stabilize ships, including the use of anti-rolling tanks, gyrostabilizers, and stabilizer fins, all three of which are bulky, heavy, and costly. These disadvantages have prevented many ships from using conventional rolling reduction methods. In contrast, the present idea, SOFNets, does not suffer from these shortcomings and can be used in any type of ship with any tonnage. The prepared model is tested in the towing tank of the National Iranian Marine Laboratory (NIMALA) using three different net samples in order to compare the behavior of those nets. This research has introduced for the first time the concept of using a SOFNets to reduce motion amplitude in waves. The length of the SWATH model was 2.1 m, and the tests were carried out according to the International Towing Tank Conference (ITTC) guidelines. The research findings for the SWATH ship indicate that the heave and pitch amplitudes in the head sea state were reduced by up to 21%, and the roll amplitude in the beam sea state was reduced by up to 36%.