# Research on Path and Sequence Planning for Multi-Cabin Onboard Transportation of Large Cruise Ships
## 1 Introduction  
With the rapid growth of the cruise tourism industry, the design, construction, and related industries of large cruise ships are experiencing significant expansion. As one of the most complex products in modern shipbuilding, cruise ships differ significantly from traditional merchant vessels in structural complexity and outfitting logistics. Large cruise ships typically contain hundreds of passenger cabins distributed across multiple decks, interconnected by densely arranged structural reinforcements, HVAC ductwork, firefighting systems, and extensive cable networks. These intricate and highly integrated structural features impose considerable spatial constraints during modular unit transportation and installation, resulting in substantial logistical challenges [1, 2]. Among the various critical aspects, the design and manufacturing of passenger cabins play a particularly pivotal role. Typically, passenger cabins on large cruise ships are subject to specific standards and classifications, ensuring that cabins of the same standard share consistent structural layouts,floor areas, and interior designs. This uniformity has paved the way for the adoption of Pred fabricated Modular Cabin Units (PMCUs) [3], a concept that streamlines the construction process while maintaining high quality and efficiency. PMCU technology has become a critical technology in the design and construction of large cruise ships [4]. Shipyards commonly adopt third-party prefabricated modular units based on the scalability and standardization of cabin layouts. These units are pre-assembled on production lines in workshops, constructed simultaneously with the ship's hull. Once the modular units are assembled, they are transported to the shipyard construction site. Using lifting devices or cranes [5], the units are hoisted to the designated openings in the ship's hull, marking the starting point for the cabin transportation process. Using transport carts and other specialized equipment, the units are then moved to their designated locations for final assembly, as shown in Figure 1. The PMCU technology significantly reduces the onboard construction workload, increases work efficiency, and shortens the shipbuilding cycle [6]. Currently, this technology has been widely applied in the large cruise ship manufacturing industry [7; 8]. In recent years, digital and intelligent technologies have significantly advanced cruise ship outfitting and logistics management. Artificial intelligence (AI)-assisted production scheduling systems enable more efficient resource allocation, accurate prediction of potential bottlenecks, and adaptive optimization of complex shipbuilding tasks [9]. Integrating Building Information Modeling (BIM) with outfitting simulations allows detailed virtual validation of assembly and transportation processes, effectively reducing on-site conflicts and operational errors [10]. Furthermore, emerging technologies, such as augmented reality (AR)-based onboard logistics navigation and autonomous internal transportation robots, offer substantial potential for improving accuracy, efficiency, and safety in cabin transportation tasks [11; 12], thereby strongly supporting the practical implementation of PMCU installations. However, due to the large number of cabins to be transported, the factors that need to be considered during the transportation process have become increasingly complex. Each cabin not only requires a reasonable transportation path to be planned, but also, due to the complex internal structure of the ship and the dense layout of the cabins, the entry of one cabin may block the transportation of subsequent cabins, thus affecting the overall optimal transportation path. Therefore, when determining the optimal transportation path for each cabin, it is necessary to consider the specific transportation characteristics of the cabin and rationally plan the optimal transportation sequence. This optimization process is crucial for enhancing shipbuilding quality, reducing construction time, and lowering costs.