## 1 Introduction
Through the utilization of numerical simulations [3; 4; 5], model testing [6; 7; 8], and field measurements [9; 10; 11; 12], researchers have conducted comprehensive research on the dynamic response characteristics of deep-water cages utilizing multi-point mooring systems and and yielded mature and reliable research outcomes. In contrast, single-point mooring enables the cage to rotate and drift around a central anchor point. This configuration facilitates the mitigation of the environmental impact of aquaculture waste on local water quality and simplifies installation procedures, and reduces the adverse effects of waves and currents on the cage. Due to only one mooring line, the mooring design, including the anchor design, is extremely important for the SPM floating net cages. Current research on single-point mooring for cages has been primarily focused on some large vessel-shaped offshore aquaculture cages [13; 14; 15; 16]. Previous research on net cages has focused on the hydrodynamic properties of the cage net. Given the vast number of mesh openings, the netting structure is simplified for analysis. The analysis methods include the Morison formula [17; 18], the Screen model [19; 20], and the porous media model [21]. Through experiments and simulations, a relatively systematic and mature understanding of the hydrodynamic characteristics of the netting has been achieved. However, as fishing activities extend into deeper and more remote oceanic regions, the issue of net breakage has attracted attention. Leveraging advancements in image recognition, machine learning, and artificial intelligence, significant progress has been made in monitoring and predicting the net damage [22]. The floating collar, as a crucial component of the net cage, provides both buoyancy and structural support. As the main load-bearing element, its structural deformation is of concern. [PERSON] et al. have employed the curved beam theory and finite element analysis to investigate the elastic response, stress-strain distribution, and estimated lifespan of the floating collar [23]. Additionally, [PERSON] et al. have addressed fatigue issues in the single-point mooring floating collar system, revealing that fatigue issues are concentrated in welding points, mooring points, pipe connections, and the edges of I-beam assemblies [24]. [PERSON] et al. established a cage model and studied the deformation of the cage's floating collar with the utilization of the OrcaFlex 10.0a software [25]. They recommended adding sleeves at the mooring line attachment points to reduce frame deformation. In addition, [PERSON] et al. conducted physical model tests in a water tank. They further studied the impact of different floating pipe wall thicknesses and mooring line lengths on the deformation of the floating collar and the forces acting on the mooring lines using simulation methods [26]. In order to more accurately investigate the deformation and stress distribution of the floating collar, the resistance coefficient was determined based on the immersion degree of HDPE collars [27]. In addition, [PERSON] et al. studied the structural performance of floating collars from the perspective of structural mechanics and predicted its critical load [28]. While many studies have been conducted on traditional circular gravity-type net cages, the new type of cages may exhibit distinct dynamic responses. There is a need to explore their dynamic response characteristics under wave and current forces. This study focuses on investigating the dynamic response of a novel single-point mooring gravity-type deep-water (SPM-GDW) net cage proposed for deployment in the Wanshan waters of Zhuhai, China. First, a hydrodynamic numerical model of the cage was established using the OrcaFlex software. Subsequently, the established model was validated through physical model experiments.