Can I join Merchant Navy after completion of Mechanical Engineering Course????

Yes you can join Merchant Navy after Mechanical Engineering for the posts like junior engineer/fifth engineer. In order to get entry in Merchant Navy you have to for pre-sea course. Pre-sea is a one year course which is conducted by various Merchant Navy and Marine Engineering Institute in India.

1-year Pre-Sea Training for Mechanical Graduate Engineering

Minimum Academic Qualification--
-You should possess Graduation in BE (Mechanical) Engineering / Naval Architecture with minimum marks of 50% in final year and with minimum 50% marks in English language at 10th or 12th or in Degree Exam.
-Maximum age limit is 28 years

Physical requirements:
You should be physically and mentally fit.
Eye Sight = 6/6,
Height = 167 cms,
Weight = 50 Kg
Chest = 77 cm (Normal) / 82 cm (Expanding)

You can join any of the following training centers for 1year training course --

Training Ship Chanakya, Navi Mumbai
Marine Engineering & Research Institute (MERI) , Mumbai
Lal Bahadur Shastri College of advanced Maritime Studies and Research, Mumbai
Marine Engineering & Research Institute (MERI), Kolkata