International Journal of Maritime Engineering

Enhanced Hydrodynamics of Planing Hull Using Energy Saving Devices

S Jangam — Fri, 03 Jan 2025 00:00:00 +0000

In calm water conditions, the moving planing vessels in semi-planing mode release the majority of their energy from the hull to the water. Depending on the Froude number, these moving vessels produce a Kelvin wave pattern in calm water. The Volume of Fluid (VOF) approach uses the overset grid method in a RANSE-based CFD solver to track the interface between water and air. The resistance components of a planing hull were computed using the obtained results. Data from experiments are compared with the numerically simulated findings. It is seen that the resistance values predicted by the numerical simulation results are in close agreement with the experimental results for the hull equipped with the interceptor. This work aims to record the wave profile, resistance, and trim at the free surface at the transom for different beam Froude numbers. The findings are compiled for hull placed on a high-speed planing ship with a 20-degree deadrise angle, both with and without an integrated interceptor-flap. For the hull with integrated interceptor-flap, there is a reduction in drag of 19–24%, trim of 50–53%, and the free surface wave elevation of 25–40% at the transom, which contributes to the vessel’s overall performance improvement.

Unveiling the Journey of Maritime Energy Efficiency: A Deep Dive into EEDI, EEXI, CII, Potential CII Regulation Enhancements, and Persistent Challenges

N K Baijal — Fri, 03 Jan 2025 00:00:00 +0000

The Energy Efficiency Design Index (EEDI) and the Energy Efficiency Existing Ship Index (EEXI), two crucial regulations in the maritime sector, are examined in detail in this paper. This study aims to understand the complexities of these restrictions and analyse how the Energy Efficiency Operational Indicator (EEOI) could be used to improve the way the maritime industry measures Carbon Intensity Indicator (CII).

This study offers insightful information on the regulatory environment governing energy efficiency in shipping by analysing the historical trajectory and transformation of the EEDI. It provides a thorough overview of the regulations now in effect, illuminating their tenets and guiding ideas.

Additionally, this study offers a path for prospective CII framework upgrades that goes beyond simple analysis. It investigates whether adding the EEOI is feasible and how it can improve the precision and applicability of emission measurement in the maritime industry.

In essence, this paper provides a comprehensive overview of the development of EEDI, the current regulatory landscape, and how creative modifications, such the inclusion of EEOI, could further improve existing methodologies to address the changing demands of sustainability in shipping.

Proposed Amendments in SOLAS and MARPOL Conventions to Limit VOC Emission from Oil Tanker Loading and Ship Bunkering Operations

Satinder Singh Virdi, A K Dev, S K Chin — Fri, 03 Jan 2025 00:00:00 +0000

Exhaust gas emissions are regulated at international and national levels, but venting vapours from oil tanks is a cause of concern due to a lack of regulatory control. Oil tanker loading operations and ship bunkering operation results in a considerable amount of ‘Volatile Organic Compound’ (VOC) in the surrounding environment. The presence of toxic components in this VOC emission has the potential to affect the health of seafarers as well as local air quality. Numerous tankers engaged in loading operations within the same port has a solid potential to increase the toxic emission to a dangerous level locally. Loading ports near highly populated areas expose the local population to toxic VOC concentration. A few ports in Europe, the USA and South Korea have strict local environmental rules prohibiting VOC emission from oil tanker loading operations. There is a need for international and national regulations to limit or stop the release of VOCs from oil tankers and monitor VOC exposure risks at the local level. The research objective is to analyse the current status of international and national rules and regulations related to VOC emission and monitoring VOC exposure risks during loading operations in an oil tanker and ship bunkering operations. Existing international (SOLAS and MARPOL Conventions) and national regulations (EU, USA, Norway) are described and analysed regarding the contemporary tanker design and standard tanker operating practice. A critical analysis determines the effectiveness and adequacy of the current regulations and tanker industry working practices. Finally, amendments to existing international conventions are proposed to minimise or stop the VOC emission and monitor VOC exposure risks to seafarers and the surrounding population near tanker terminals and ports. Solutions are also proposed to amend the existing tanker design and operating practices to stop the VOC emission, including toxic hazard assessment in vapour vent design and prevent exposure to VOC emission.

Digitalisation in Maritime Safety: A Breakthrough in Hull Structural Integrity Assessment Via Distortion Mode-Based Conversion Algorithms

D Y Lee, B S Jang, S S Song, D K Kim — Fri, 03 Jan 2025 00:00:00 +0000

With the advent of Industry 4.0, providing enhanced informatics for engineering products is expected to become crucial in establishing their competitiveness. By leveraging the capabilities of digital twins, efforts are being made to enhance the safety margin and operational efficiency of maritime structures, which inherently involve statistical uncertainties due to environmental loads. This study presents a method for constructing a digital twin of hull structures using finite element analysis data, along with a series of validation efforts. The method employs assumptions similar to those used in modal analysis, decomposing the arbitrary deformation states of the hull into a series of eigenmodes. Real-time connectivity between the physical vessel and its virtual twin is established by converting a set of hull strain measurements into eigenvalues. A novel mode selection method is introduced to improve the overall accuracy of structural response estimation. The real-time structural stress traceability of the digital twin model will be further demonstrated through a comparative study on a non-watertight bulkhead model of the vessel. A model validation study will also be presented using actual measurement data from the nearly 13,000 TEU class container ship. Additionally, application examples for the model that can be easily accessed via the commercial marine structure analysis software SESAM have been included to benefit fellow researchers who wish to conduct further studies.

Experimental Testing of Riveted Carvel Planks on Frames for Traditional Timber Structures

J-B R G Souppez — Fri, 03 Jan 2025 00:00:00 +0000

Traditional wooden boats are characterised by closely spaced frames, riveted to thick planks, leading to high thickness-to-span ratios. However, the effect of such closely spaced frames and thickness-to-span ratio remains uncharacterised. Consequently, four-point bending tests are undertaken to quantify the ultimate flexural strength and flexural modulus of wooden planks with up to 3 frames and thickness-to-span ratios from 0.0267 to 0.200. The results show that (i) a greater number of frames for a given span yields a reduction in specific stiffness but a constant specific strength; (ii) a maximum thickness-to-span ratio of 0.080 and 0.050 is recommended to ensure the strength and stiffness exceed regulatory default properties, respectively, and (iii) additional factors of safety would be needed for traditional construction to be included in existing structural regulations. These findings provide novel insights into the structural design of traditional wooden boats and may contribute to their future inclusion in regulatory frameworks.