Abstract:
In Bangladesh, numerous types of transportation facilities are available, including roads, railways, inland water transport (IWT), and air flights. Among these alternatives, the inland water transport system stands out for its cost-effectiveness and environmental aspects. Coastal vessels plying in inland waterways play an important role in transporting industrial goods, passengers, and consumer-level commodities between different areas of Bangladesh, as well as neighboring countries like India and Myanmar. Due to the important role of inland water transport vessels in Bangladesh's, economy and connectivity, ensuring their structural integrity is essential for both safety and operational efficiency. The structural strength of these vessels must withstand various environmental challenges, such as fluctuating water levels, high currents, and the stress of carrying heavy loads over distances. In addition to the physical demands, these vessels must also meet international standards for structural integrity. Hence, the structural strength requirements for these vessels are of utmost importance.
Classification societies establish and implement rules and regulations regarding the design, construction, and operation of vessels, thereby contributing to the overall safety of the maritime transportation system. However, it has been observed that different classification societies may impose various standards and criteria for ensuring the structural requirements of vessels operating within different geographical regions and operational conditions.
In the present study, f i ve cargo vessels and four oil tankers plying on the inland waterways of Bangladesh were studied using the structural rules and regulations of six different international classification societies i.e. RINA (Registro Italiano Navale), BV (Bureau Veritas), IRS (Indian Register of Shipping), TL (Turkish Loydu), KR (Korean Register), LR (Lloyd's Register) and the DoS (Department of Shipping) in Bangladesh. The weight of the structural components has been estimated according to scantling calculations, and a comparative study has been conducted across different classification societies based on structural weight. Only the plating thickness and weight have been considered in the present study. The calculation of the dimensions of each internal structural member has
been omitted. Instead, a more simplified approach has been adopted. The minimum required section modulus at midship is determined using the empirical formulas provided in classification society rulebooks. The results indicate that all classification societies yield similar outcomes, with slight variations observed in the RINA and BV classes compared to others. So, the overall trend of variation in structural weight is not affected. The study reveals that RINA and BV classi cations yield the minimum structural weight, while IRS and TL classi cations result in maximum structural weight. Then a reduction in weight is observed for KR and LR classifications, which is again followed by an increment in weight under DoS. This trend is consistent for all the ships, both cargo ships and oil tankers presently studied. Finally, an investigation has been undertaken to assess the underlying causes of variation in structural weight. The analysis reveals that geographical constraints, the selection of ship principal particulars for scantling calculations, allowance for corrosion addition and some specific coefficients and constants are possible causes behind the variation in structural requirements