Analysis of Beam-to-Length Ratio Trends in Superyachts: Implications for Design, Performance and Regulatory Compliance

In recent decades, there has been a significant evolution in design configurations within the luxury yacht industry, particularly among vessels between 50 and 70 meters in length (LOA), known as superyachts. This study aims to analyse the increase in maximum beam width (BOA) in this category, specifically focusing on units intended for the charter market. A comparative approach was adopted, dividing selected yachts into five main time spans (up to 1997, 1997-2003, 2004- 2014, 2012-2018 and after 2018) to focus on the development and effectiveness of the new Rules (Large Commercial Yacht Code). The results show a growing trend in the maximum beam-to-length ratio driven by the need for greater habitability and comfort. It has been significantly affected by market demands for larger interior spaces, particularly in the charter sector, as well as regulatory frameworks such as the International Maritime Labour Convention (MLC) of 2006, which introduced minimum space standards for crew accommodations. These factors played a significant role in shaping the design paradigm of large yachts, as they required a balance between enhanced living spaces and performance requirements. This shift also impacts hydrodynamic resistance, speed, initial and secondary stability, fuel consumption, and manoeuvrability. However, these concerns are addressed by improved hull design, optimised propulsion configurations and modern integrated navigation and control systems. The study provides a useful framework for understanding the impact of increasing beam width on superyachts, illustrating how related factors have influenced design trends over time. It provides a comprehensive overview of the relationship between habitability, performance, and external constraints, highlighting the interplay of market demands and regulatory requirements in driving technical innovations in the maritime sector.