(a) General. In addition to the requirements of part 10 of this subchapter,the applicant for an officer endorsement,whether original, renewal,duplicate, or raise of grade, must establish to the satisfaction of the Coast Guard that he or she possesses all the qualifications necessary (including but not limited to age, experience, character,physical health, citizenship, approved training, professional competence,and a test for dangerous drugs) before the Coast Guard will issue to him or her a merchant mariner credential (MMC). An applicant for any STCW endorsement must hold the appropriate national endorsement unless otherwise specified.