(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.