33 CFR § 125.53 - Requirements for credentials; certain vessels operating on navigable waters of the United States (including the Great Lakes and Western Rivers).
(a) Every person desiring access to vessels, except public vessels, falling within any of the categories listed below, as a master, person in charge, or member of the crew thereof, shall be required to be in possession of one of the identification credentials listed in § 125.09.
(2) Harbor craft, such as water taxis, junk boats, garbage disposal boats, bum boats, supply boats, repair boats, and ship cleaning boats, which in the course of their normal operations service or contact vessels, foreign or domestic, public or merchant, in the navigable waters of the continental United States other than the Great Lakes and Western Rivers.
(b) The term “master, person in charge, or member of the crew” shall be deemed to include any person who serves on board in any capacity concerned with the operation, maintenance, or administration of the vessel or its cargo.
(c) Where the Coast Guard Port Security Card (Form CG 2514) is to be used as the identification required by paragraph (a) of this section, application for such card may be made immediately by the persons concerned. The issuance of the Coast Guard Port Security Card shall be in the form and manner prescribed by § 125.11.
(d) At the discretion of the District Commander any person desiring access to vessels of the categories named in this section, who may be required by the provisions hereof to possess identification credentials, may be furnished a letter signed by the District Commander or the Captain of the Port and this letter shall serve in lieu of a Coast Guard Port Security Card and will authorize such access for a period not to exceed 60 days, and such a letter issued shall be deemed to be satisfactory identification within the meaning of § 125.09. The issuance of the letter shall be subject to the following conditions:
(1) The services of the person are necessary to avoid delay in the operation of the vessel;
(3) The person has filed his application for a Coast Guard Port Security Card or submits his application before the letter is issued; and,