The environment protection is one of the main concerns of our society and this paper aims at presenting some of the international efforts in the maritime transport. Marine pollution consists of water pollution and also air pollution. Regardless of the delay in recognizing the latter type of pollution, it rapidly gains many organizations to argue on it. The first step was including a dedicated annex in the International Convention for the Prevention of Pollution from Ships, which seek to minimize the airborne emissions from ships. The efforts continued and the International Maritime Organization has developed a series of measures for monitoring the emissions. These are grouped in three main directions: technical, operational and management related. The subject of our study is the concept of Energy Efficiency Operational Index, developed to provide ship-owners and ship-operators with assistance in the process of establishing a mechanism to achieve the limitation or reduction of emissions from ships in operation. It serves as a monitoring tool and it represents the mass of CO2 emitted per unit of transport work. The paper presents the way how the commercial software can be used for estimating the EEOI value before the voyage, in comparison with the true value calculated on board. The true value is calculated based on unpredictable factors that might appear during the voyage: varying the speed, days on anchor, or waiting for orders period. The authors included these in a software solution, which allows to emphasize the influence of the on board measures over voyage energy efficiency

One of the main concerns of our society is certainly environmental protection. The international efforts for maintaining a clean environment are various and this paper refers to the efforts in the maritime transport field. The subject of our study is the concept of Energy Efficiency Operational Index (EEOI), developed to provide ship-owners with assistance in the process of establishing the emissions from ships in operation, and to suggest the methods for achieving their reduction. As a monitoring tool, EEOI represents the mass of CO2 emitted per unit of transport work. Using the software developed by the authors, it will emphasize the variation of the EEOI value for one vessel using different types of fuel during the laden and ballast voyages, for a period of three months, as stated in the Ship's Log Books. The main consumers considered are Main Engine, Diesel Generators and steam Boilers, and the types of fuel used will be as per charter party agreements and following the specific international and local rules and regulations. The results for the quality parameter EEOI and the average cost of achieving them will be included in compared cost-to-quality graphs, in order to underline the profitability of the studied methods for minimizing the air emissions

Container ships carry cargoes that are considered light from the weight point of view, compared to their volumetric capacity. This fact makes the still water vertical bending moment to be in hogging condition. Thus, the double bottom structure is permanent subject to compressive load. With the enlargement of container ships to the Post Panamax vessels, the breadth to depth ratio tends to be increased comparative to those of Panamax container ships that present restriction related to maximum breadth of the ship.The current studies on new build models reveal the impossibility for Panamax container ships to comply with the minimum metacentric height value of stability without loading ballast water in the double bottom tanks. In contrast, the Post-Panamax container ships, as resulted from metacentric height calculation, have adequate stability even if the ballast water is not loaded in the double bottom tanks. This analysis was conducted considering two partially loaded port-container vessels. Given the minimization of ballast quantities, the frequency with which the still water vertical bending moment reaches close to the allowable value increases.This study aims to analyse the ships' behaviour in partially loaded conditions and carrying ballast water in the double bottom tanks. By calculating the metacentric height that influences the stability of the partially loaded port container vessels, this study will emphasize the critical level of loading condition which triggers the uptake of ballast water in the double bottom tanks, due to metacentric height variation.

The maritime transportation sector constitutes a source of atmospheric pollution. To avoid or minimize ships pollutant emissions the first step is to assess them. Two methods of estimation of the ships' emissions are proposed in this paper. These methods prove their utility for shipboard and shore based management personnel from the practical perspective. The methods were demonstrated for a product tanker vessel where a permanent monitoring system for the pollutant emissions has previously been fitted. The values of the polluting agents from the exhaust gas were determined for the ship from the shipyard delivery and were used as starting point. Based on these values, the paper aimed at numerical assessing of ship's emissions in order to determine the ways for avoiding environmental pollution: the analytical method of determining the concentrations of the exhaust gas components, by using computation program MathCAD, and the graphical method of determining the concentrations of the exhaust gas components, using variation diagrams of the parameters, where the results of the on board measurements were introduced, following the application of pertinent correction factors. The results should be regarded as a supporting tool during the decision making process linked to the reduction of ship's pollutant emissions.