The Chennai center of Indian Maritime University does not provide any course in Naval architecture. While the Mumbai center provides a 4-year undergraduate course - B.Tech. in Naval Architecture and Ocean Engineering. The total fee is around 9 lakh and the available number of seats is 20. The eligibility states that a candidate must have passed 10+2/equivalent (PCM-60% and the minimum of 50% marks in the english subject in 10th/12th Examination). 

For more clarifications, use the careers360 portal based on Indian Maritime University, Mumbai for the course

https://www.careers360.com/colleges/indian-maritime-university-mumbai/btech-naval-architecture-and-ocean-engineering-course

Hope this helps.