The diesel engine has become an integral part of the Navy's propulsion capabilities. It consists of the combustion of a suitable fuel inside a cylinder containing a piston, whose movement results from the transformation of thermal energy into mechanical work. Marine propulsion is the mechanism or system used to generate thrust to move a boat through water. While paddles and sails are still used on some smaller ships, most modern ships are powered by mechanical systems that consist of an electric motor or an internal combustion engine that drives a propeller or, less commonly, in pump dispensers, an impeller.
Marine engineering is the discipline related to the engineering design process of marine propulsion systems. Human-powered oars and oars and, later, sails were the first forms of marine propulsion. Rowing galleys, some equipped with sails, played an important role early in navigation and primitive human wars. The first advanced mechanical means of marine propulsion was the marine steam engine, introduced in the early 19th century.
During the 20th century, it was replaced by two- or four-stroke diesel engines, outboard engines, and gas turbine engines on faster ships. Marine nuclear reactors, which appeared in the 1950s, produce steam to power warships and icebreakers; their commercial application, which was attempted at the end of that decade, was not successful. Electric motors that use battery packs have been used for the propulsion of submarines and electric ships and have been proposed for energy-efficient propulsion. The propulsion of the vast majority of modern merchant ships (for example, container ships and VLCCs) uses the marine diesel engine as the main engine of the propeller.
Typical marine propulsion plants include a single two-stroke, long-stroke, low-speed, turbocharged, two-stroke diesel engine, directly coupled to the vessel's single large diameter, fixed-pitch propeller. This configuration can achieve quite large power outputs (up to 30-40 MW with a single unit) and yet it is characterized by operational reliability due to its conceptual simplicity. These keywords were added by machine and not by the authors. This process is experimental and keywords can be updated as the learning algorithm improves.
Department of Naval Architecture and Marine Engineering, Marine Engineering Laboratory of the National Technical University of Athens, PO Box 64033, Zographers, 15710, Athens, Greece You can also search for this author in PubMed Google Scholar Provided by the Springer Nature SharedIT content sharing initiative More than 10 million scientific documents at your fingertips. The alternative marine diesel engine was first used in 1903, when Branobel put the Vandal diesel electric river tanker into service. In these combined cycles, the thermal efficiency may be equal to or slightly higher than that of diesel engines alone; however, the type of fuel needed for these gas turbines is much more expensive than that needed for diesel engines, so operating costs are even higher.