46 CFR § 12.401 - General requirements for able seaman (A/B) endorsements.
(b) Categories. The following categories of able seaman endorsements are established:
(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.
(c) Requirements for certification. To qualify for an endorsement as able seaman, an applicant must -
(1) Be at least 18 years of age;
(2) Pass the prescribed physical and medical examination requirements specified in 46 CFR, part 10, subpart C;
(4) Meet the sea service or training requirements set forth in this part;
(5) Pass an examination for able seaman;
(7) Speak and understand the English language as would be required in performing the general duties of able seaman and during an emergency aboard ship.
(d) Additional requirements.
(i) That the holder possesses the appropriate A/B endorsement for the service of the vessel; and