General Strength, Energy Efficiency (EEDI), and Energy Wave Criterion (EWC) of Deadrise Hulls for Transitional Mode

In the modern world, environmental issues come to the fore. The document of MARPOL for reducing the emission of pollutants into the atmosphere relates to the energy efficiency coefficient EEDI. This coefficient is directly related to the power of the main engine and, accordingly, to the water resistance. The way to reduce the energy efficiency factor EEDI by increasing the relative length LV3 {L \over {\root 3 \of V }} of the ship was proposed in this article. To determine the maximum value of the relative length, knowledge of the general strength of the vessel is required. The value of the relative section modulus of an equivalent girder for a small vessel of transitional mode is defined. The result of the graphic solution of two equations is the value of such a relative section modulus. This parameter is required to determine the limiting value of the relative length and to find solutions to reduce the coefficient EEDI. Comparative analysis of the obtained data with the data of the strength and weight of the H-girder with a length similar to the ship was conducted. The formula for determining the limiting value of the relative length was obtained from the equation of general strength. For a preliminary assessment of the future project of the ship, in terms of permissible design accelerations and the possibility of the ship moving against a sea wave of a certain height, a graph was built based on the application of the energy wave criterion EWC and the requirements of various classification societies.