19 CFR § 4.2 - Reports of arrival of vessels.
(a) Upon arrival in any port or place within the U.S., including, for purposes of this section, the U.S. Virgin Islands, of any vessel from a foreign port or place, any foreign vessel from a port or place within the U.S., or any vessel of the U.S. carrying foreign merchandise for which entry has not been made, the master of the vessel must immediately report that arrival to the nearest CBP facility or other location designated by the port director. The report of arrival, except as supplemented in local instructions issued by the port director and made available to interested parties by posting in CBP offices, publication in a newspaper of general circulation, and other appropriate means, may be made by any means of communication to the port director or to a CBP officer assigned to board the vessel. The CBP officer may require the production of any documents or papers deemed necessary for the proper inspection/examination of the vessel, cargo, passenger, or crew.
(b) For purposes of this part, “foreign port or place” includes a hovering vessel, as defined in 19 U.S.C. 1401(k), and any point in customs waters beyond the territorial sea or on the high seas at which a vessel arriving in a port or place in the U.S. has received merchandise.
(c) In the case of certain vessels arriving either in distress or for the limited purpose of taking on certain supplies and departing within a 24-hour time period without having landed or taken on any passengers or other merchandise (see section 441(4), Tariff Act of 1930, as amended), the report must be filed by either the master, owner, or agent, and must be in the form and give the information required by that statute, except that the report need not be under oath. A derelict vessel will be considered one in distress and any person bringing it into port must report its arrival.
(d) The report of baggage and merchandise required to be made by certain passenger vessels making three or more trips a week between U.S. and foreign ports and vessels used exclusively as ferryboats carrying passengers, baggage, or merchandise (see section 441(2), Tariff Act of 1930, as amended), is in addition to the required report of arrival, and must be made within 24 hours of arrival.