ABSTRACT

The rising demand for ocean floor resources has increased interest in Deep-Sea Mining (DSM) systems, which face significant operational challenges in harsh underwater environments. This study incorporates a three-dimensional (3D) potential flow method to numerically investigate the DSM vessel's dynamic responses. The hydrodynamic diffraction analysis for four different vessels were modelled and analysed ranging from 10,000 to 60,000 DWT's. The results included the Response Amplitude Operator (RAO) of the hull for the heave motion, which was found to be predominant in DSM deployment for different wave conditions and locations (side, aft, and moon pool). The findings provide essential insights for designing an efficient and robust DSM system capable of operating effectively in open-sea conditions. These results offer valuable theoretical guidance for the development of DSM systems to meet the growing global demand for minerals.

INTRODUCTION

Extensive research over the years has shown that the ocean, which covers about 71% of the Earth's surface, is a rich source of minerals, much more abundant than those found on land. Despite significant technological progress, deep-sea mining/expeditions are still in the preliminary research phase, unlike oil exploration. Three critical components of the deep sea mining process are the mining vessel, the riser system, and the seafloor crawler. Deep-sea mining vessels play a crucial role in the deep-sea mining system; it consist of navigation, operations, living quarters, and safety functions into one complex and highly integrated system (Zhang 2022). For large-scale mining operations, the entire mining system must maintain stability under complex sea conditions for efficient operation. During the initial design phases, the hull response and motion is directly linked to the structural design of the underwater operating subsystem and the identification of its fatigue strength. Under extreme sea conditions, mining production could possibly be halted, which may impose economic constraints. These vessels make up about 40% of the total cost of the deep-sea mining system. Due to the substantial size of the mining vessel's main body, external load response predictions are typically conducted through theoretical calculations and computer simulations. Some critical research activities related to the DSM are discussed below.

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