## 1 Introduction
[20] conducted a hydrodynamic analysis of a DCM (deep cement mixing) vessel equipped with a lofty crane using HydroSTAR v. 7.3 and quantitatively assessed its stability. These studies on floating crane vessels provide a basis for research on recovering sunken ships. When salvaging a shipwck, it is crucial to consider wave elements and diverse salvage setups comprehensively by simulating the system's motion and tension responses. The preceding investigations offer the following insights: (1) Developing a rational salvage plan is vital. Investigating vessels' motion responses and cable tensions during salvage operations are fundamental aspects requiring examination. Wave elements and different salvage configurations must also be factored in to create a secure and stable strategy. (2) Furthermore, these investigations of ships' motion responses and cables' tension responses are conducted through experiments or other methodologies. Empirical inquiry is a conventional approach in shipbuilding and ocean engineering, albeit bearing relatively higher costs. Moreover, scholars have sought insights through analytical methods. For example, [PERSON] et al. [21] employed [PERSON]'s mathematical model and [PERSON]'s regression-based method for analysis and analyzed the fluid flow around a hull. A cadre of researchers has availed software based on potential flow theory, which encompasses both OrcaFlex and AQWA [22; 23]. Although these methods may overlook fluid viscosity, they provide the advantage of swifter calculation speeds. A research model grounded in computational fluid dynamics (CFD) theory takes cognizance of fluid viscosity and attains heightened calculation precision. With the unabated progress in CFD and burgeoning supercomputer technology, their applications to ship hydrodynamics have become increasingly pervasive [24; 25; 26; 27; 28; 29; 30; 31]. Given the protracted cycle of salvage operations and the fact that there is enough time for calculations, harnessing suitable CFD-based mature business software for numerical simulations presents a reasonable way to optimize accuracy and efficiency. (3) While analyzing ships' dynamic and cable-tension responses, developing a quantitative method for evaluating safety and stability can aid salvage-scheme design. Ship salvage is a controversial operation mode based on uncertain instruments formed with equipment by persons of doubtful reliability and questionable mentality [32]. The implementation of standardized technical guidelines is necessary for salvage operations. The development of criteria to assess safety and stability requires the consideration of various factors. Engineers in the salvage field aim to maximize operational safety, which prompts the key question of assessing the salvage system rationally and quantitatively. In shipbuilding and ocean engineering, evaluating safety based on physical principles is crucial for ensuring operational stability. With growing interest in salvaging shipwcks, scholars such as [PERSON] et al. [33; 34] have recently proposed a method to evaluate salvage operation safety for the first time quantitatively. These two references are also important sources for this paper. In their research, a typical salvage operation was divided into three phases: a barge was connected with four lifting cables. The root mean square (RMS), coefficient of variation (CV), and extreme amplitude were used to estimate the safety and stability of motion modes and cable tensions. The salvage system is a complex multibody system involving various components (engineering vessel, cables, shipw, etc.) with multiple degrees of freedom (DOFs) and load types, which necessitates an assessment pattern that can encompass all the DOFs [33]. This safety assessment method offers a valuable approach for researching salvages, enhancing planning, and identifying suitable operating conditions.