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Competitive ships must be designed to survive challenges of a globalized market, increase of speed, increase of cargo capacity, minimum fuel consumption and maximizing maneuverability are among them, in consequence, lots of efforts are being placed to overcome mentioned ideas. Regarding propulsion systems, our aim is to develop designs to give maximum propulsive efficiency without noise and vibration. 

The objective of this master thesis is to design a bulk carrier propulsion system; fundamental of the design is the selection and integration of the main components (prime mover, transmission and propulsor) into a functional system. For the propulsion system of the ship it was decided to use a low speed diesel engine with directly driven fixed pitch propeller. 

As stated before, propulsion systems consist of three components, engine, transmission, and propeller. Engine will be selected by its power (MCR) to overcome ship resistance accounting for losses, shaft line will be design using GL rules for its dimensioning, and propeller development will be divided in three stages, preliminary design, detailed design and analysis. 

Determination of the required propulsion power and engine sizing requires previous knowledge of the quasi-propulsive coefficient. At initial point, propeller diameter was estimated by considering ship draught in ballast condition, to avoid air drawing; Wageningen B Series data was used to obtain optimum propeller velocity of rotation rpm for maximum open water efficiency; once engine brake power was obtained, selection of engine was performed. 

Because main engine influences the propeller through the propeller rpm and delivered power, new propeller diameter for maximum efficiency was computed satisfying required clearance; also, propeller was designed to absorb a given delivered power (15% sea margin and 10 % engine margin taken into consideration). Main results of this stage are diameter D, number of blades z, expanded area ratio and propeller mean pitch ratio P/D. 

Second stage in propeller design procedure is to find the blade geometry for a specified distribution of blade loading over the radius. To achieve this goal, a wake adapted propeller was designed using an in-house code for lifting line theory with lifting surface corrections. 

Finally, propeller geometry was used as input data to start the third and last stage of propeller design, called analysis, where we perform numerical analysis of the open water characteristics and hydrodynamic performances of the wake adapted propeller. Primordial objective of this stage are the calculation of open water characteristics, calculations of pressure distribution on propeller blades and calculation of the unsteady forces and moments acting on propeller shaft. If satisfactory results are obtained at this stage, the design of the propeller is concluded, if not, an iterative design cycle will take place with a changed propeller geometry.

Ingénierie, informatique & technologie > Ingénierie civile

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Global environmental agencies and maritime authorities have become increasingly concerned by the environmental impact of CO2 emission. Increasing fleets of super yachts consume ever larger quantities of fossil fuel. Increasing social pressure and new legislative efforts to reduce environmental damage mean that the industry must respond accordingly. 

Current yacht design legislation has a focus on occupational safety and the environment. However the legislation surrounding environmental protection has been increasing significantly. Environmental legislation addresses both the protection of the environment in the event of an accident and also on reducing the operational environmental impact. 

EEDI or Energy Efficiency Design Index is a new standard, that was set by the IMO (the International Maritime Organization) for new ships greater than 400 GT with some exceptions that can be allowed by Administrative bodies until 2017 (regulation 19.4). The purpose behind the EEDI is to promote innovation from the initial ship design stage in order to reduce energy consumption at full load. It is applicable to many vessels: bulk carriers, tankers, container ships, general cargo ships, passenger ships, gas carriers, gen eral cargo and RO-RO vessels. Working class vessels such as offshore supply vessels, tugboats and dredgers are excluded for the present time. 

There are no conformations until this point in time whether EEDI will be implemented on yachts. Azimut-Benetti is taking an early initiative to investigate any possibilities for improvement. In such event this could become a driver for sales. As the EEDI is measurable figure, this could become a way for comparing shipyards, hence increasing competition on this field. At the conclusion of this research, Azimut-Benetti Yachts will be presented with guidelines that will assist in calculating the EEDI and selecting the most efficient technologies that optimise both cost and efficiency. Azimut-Benetti has a keen interest in the cost and potential savings over time from implementing the EEDI compared to existing technologies and offer to owner‟s efficient yachts

Energy Efficiency Design Index (EEDI), IMO, MEPC, Greenhouse Gas, MARPOL, Reference EEDI, Attained EEDI, United Nations Framework Convention on Climate Change, GHG --- Ingénierie, informatique & technologie > Ingénierie civile