Hi there,
Hope you are doing well.
Considering you are from general category, you can get following seats at IMU:-

• IMU Chennai:- BSc Nautical Science
• IMU Kochi:- BSc Ship Building and Repair
• IMU Mumbai:- BSc Maritime Science

Also, you can take a diploma in Nautical Science leading to BSc Nautical Science at any IMU.
Hope it would help.
Thank You