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ABSTRACTMaritime shipping is one of the most important activities of the global economy, with outstanding advantages in terms of volume and distance. According to projections by the International Transport Forum, Global demand for marine transportation is expected to grow dramatically over the next three decades. Along with that, maritime activities emit large amounts of greenhouse gases and other harmful emissions, causing negative impacts on the environment. Energy consumption trends (ECT) are formed by the application of potential emission reduction solutions such as technical improvement, use of alternative fuels, efficient and economical use of fuel and optimal vessel operation. However, ECT is, an issue related to various criteria to be assessed. The goal of this study is to make science assessment of ECT which can be developed national ship emission reduction strategy. Availability of energy supply and use, emission reduction potential, economic efficiency were simultaneously considered to evaluating ECT to cut GHG emission from shipping by using Fuzzy Analytic Hierarchy Process combined with opinions of 46 experts. The results show that hydrogen fuel ranks highest in ECT as the future fuel of the maritime industry. The findings of this study are expected as an important platform to develop national ship emission reduction strategy planning.

The use of computational fluid dynamics (CFD) to predict internal and external flows has risen dramatically in the past decade. This research aims to use the commercial software, ANSYS Fluent V.14.5, to illustrate the effects of the rudder and blade pitch on the hydrodynamic performance of the marine propeller by experimenting with propellers and rudders of the M/V Tan Cang Foundation ship, which has designed conditions as follows: diameter of 3.65 m; speed of 200 rpm; average pitch of 2.459 m; boss ratio of 0.1730. Using CFD, the characteristic curves of the marine propeller and some important results showed that the maximum efficiency of the propeller is 0.66 with the open water propeller and 0.689 with the rudder‒propeller system at the advance ratio of 0.6. The obtained outcomes of this research are a significant foundation to calculate and design an innovative kind of propulsion for ships with high performance.

ABSTRACTOil spill response measure that most maritime countries have developed and implemented is the mechanical recovery system because of its benefits. Several countries have developed a planning tool for estimating the potential of mechanical recovery systems. Vietnam is facing a high risk of oil spill, but lacking a quantitative method to ensure that facilities, regions and country maintain the levels of preparedness and adaptive response capabilities. This article will provide not only existing methodologies and its calculation formula but also propose formulas based on the present situation of mechanical recovery systems. Three typical mechanical recovery systems in Vietnam as samples to validate the new methodology, experimental results have shown that the recovery capacity decreases over time, especially the important of oil thickness and professional personnel. According to the new formula, enhancing the effective mechanical recovery systems is suggested for on-scene commanders.