((a)) To qualify for an endorsement as able seaman authorized by this section, an applicant must provide satisfactory proof that the applicant—
((1)) is at least 18 years of age;
((2)) has the service required by the applicable section of this part;
((3)) is qualified professionally as demonstrated by an applicable examination or educational requirements; and
((4)) is qualified as to sight, hearing, and physical condition to perform the seaman’s duties.
((b)) The classifications authorized for endorsement as able seaman are the following:
((1)) able seaman—unlimited.
((2)) able seaman—limited.
((3)) able seaman—special.
((4)) able seaman—offshore supply vessels.
((5)) able seaman—sail.
((6)) able seaman—fishing industry.