Hi aspirant,

You cannot join merchant Navy with physics chemistry and Biology as your subjects as mathematics is one of the compulsory subjects for being eligible to the same. To be merchant navy officer one needs to do either B.tech in Marine Engineering or BSc in nautical science and both of them requires PCM as compulsory subjects. However I request you not to lose hope and try looking for some other career options as there is a plenty of them.

Hope it helps!