Hey Vishal.

The  Eligibility Criteria for admission B.Tech in Marine Engineering in CUSAT is that you must have secured at least 60% aggregate marks in Mathematics, Physics and Chemistry in 12th. You must have studied Physics, Chemistry, Mathematics and English as separate subjects in qualifying examination  

You also must have secured an aggregate of 50% marks in English in either Class 10th or 12th.   

For eligibility criteria for other branches in CUSAT or more details use the link below.

https://engineering.careers360.com/articles/cusat-cat-eligibility-criteria/amp