I am not sure what you mean by "completed 12 with commerse", but regarding joining the merchant marine, here are a few suggestions for you to consider;
1) Talk with your high school or education organization for information and requirements of the Merchant Marine. One thing to remember- in today's world most recruits must have a high school diploma or GED to qualify to join the service.
2) See if there is a recruiting branch of the service in your community. If so, there should be a phone number in the phone book, or google the desired information online.
3) If you need further assistance, google Merchant Marine- United States Armed Services and find a phone number you can call for more information.
International Academy of Students (IAS) is an approved recruitment professional & many students’ benefits from our service every year. German, Indian and other all students have preference German universities mostly for Medical Studies, Engineering Studies; Pre-Studies Program (PSP) PSP is a One year program for students who have completed their schooling in their home country (min. 12 years) in bachelors and masters level.