Hydrodynamic Analysis of A Semisubmersible Fish Cage With Different Drafts Subjected to Regular Waves

Abstract

Cage farming has historical roots spanning centuries, while its commercialization has only commenced within the past few decades. The unsustainability of captured fish production leads to the development of the aquaculture industry. The initial practice has been carried out in ponds, rivers and later moved on into sheltered zones of the sea as a part of nearshore farming. Nowadays, farmers are keen to relocate offshore due to space constraints and pollution-related issues. This article presents a hydrodynamic analysis of the semisubmersible square fish cage with a net solidity of 0.26 subjected to regular waves. The cage is studied numerically under different drafts of 17.5cm, 26.25cm and 35cm under regular waves with a water depth of 55cm. Frequency and time domain analyses are performed to investigate the hydrodynamic characteristics of the cage. Each case's motion responses and anchor line tension are studied and results are analysed. The results indicate that the increase in draft depths leads to decreased motion responses and anchor line tensions. The cage behaves well in three different submerged conditions and shows better performance at the draft of 35cm.