Any person subject to this Act who commits any of the following offences, that is to say,--
         (a) uses criminal force to or assaults his superior officer; or
         (b) uses threatening language to such officer; or
         (c) uses insubordinate language to such officer; or
         (d) behaves with contempt to such officer,
shall, on conviction by a Coast Guard Court, be liable to suffer imprisonment for a term which may extend to ten years or such less punishment as is in this Act mentioned:
     Provided that in the case of offences specified in clauses (c) and (d), the imprisonment shall not exceed five years.