Water Jet Propulsion




marine insight

By Ajay Menon | In: Naval Architecture | Last Updated on September 25, 2020

Ships are enormous structures, weighing anywhere between 100000 tons and 500000 tons. Yet, they are moved with ease across the earth’s oceans.

At the other extreme of the vessel size spectrum, small fishing trawlers and pleasure yachts barely weigh over 10000 tons. They are commonly found speeding along the coastline at very high speeds.


So how are such different vessels and boats powered across water?

This is where marine propulsion comes into the picture.

Different vessel classes utilize various propulsion systems that use several techniques for generating power. Earlier vessels used fossil fuels such as coal to run large engines powering propellers.

Later models worked using reciprocating engines and diesel-run marine engines that

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De sphaera of Johannes de Sacrobosco in the Early Modern Period





De sphaera of Johannes de Sacrobosco in the Early Modern Period pp 161-184| Cite as

Sacrobosco’s Sphaera in Spain and Portugal


First Online: 24 January 2020



This paper analyzes sixteenth-century commentaries on Johannes de Sacrobosco’s Sphaera in Portuguese and Spanish. Between the fifteenth and seventeenth centuries, there were more translations of the Sphaera into Castilian and Portuguese than into all other European vernaculars combined. A major reason for the interest in Sphaera translations in Spain and Portugal was that the basic astronomical and geographical knowledge contained in this text could be used for navigation. Because of their enormous interests in overseas exploration and colonization, Iberian monarchs supported the development of cosmography, a subject that combined mathematics, astronomy, and geography. The astronomical information in the Sphaera was also valued on the Iberian Peninsula for its

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Educación mariíima en el Mundo



Maritime College. N.Y. Maritime -Training






Maritime training has evolved over the centuries from an apprenticeship-type education into a formal course of study. From the early days, hands-on experience has proven invaluable to future seafarers, where one would learn by practicing the procedures and using the tools of the trade. Today, that tradition continues, through the use of both computer simulators and hands-on experience, not to mention more formal training in math, science, navigation, engineering, international law, ship security, and protection of the marine environment.

In our Hall of Maritime Training, we trace the development of maritime training through the history of the State University of New York (SUNY) Maritime College and its training ships, the oldest institute of its kind in the United States, and one of the

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Dalian Maritime University (DMU) - Marine Engineering, Transportation & Logistics Education

Dalian Maritime University (DMU) is one of the largest and best maritime universities and is the only key maritime institution under the Ministry of Communications, People’s Republic of China. DMU enjoys a high reputation internationally as an excellent center of maritime education and training as recognized by the International Maritime Organization (IMO). DMU is located in southwestern Dalian, which is a famous coastal city in northeastern China with a population of six million. The University covers an area of one million square meters with almost half a million square meters occupied by buildings.

DMU was created in 1953 through the amalgamation of three merchant marine institutions: Shanghai Nautical College, the Northeast Navigation College and Fujian Navigation School. Presently

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