Go to these 2 links. I hope they can clear your doubts.
1. https://www.marineinsight.com/careers-2/what-is-the-difference-between-nautical-science-and-marine-engineering/
2. http://entrance-exam.net/forum/general-discussion/difference-between-bsc-nautical-sciences-b-tech-marine-engineering-8921.html
Good Luck.
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