(3) The term "port of documentation" means the port at which the vessel is documented, in accordance with law;
(4) The term "vessel of the United States" means any vessel documented under the laws of the United States and such vessel shall be held to continue to be so documented until its documents are surrendered with the approval of the board; and
(5) The term "mortgagee," in the case of a mortgage involving a trust deed and a bond issue thereunder, means the trustee designated in such deed.
RECORDING OF SALES, CONVEYANCES, AND MORTGAGES OF VESSELS OF THE UNITED STATES.
Subsection C.
(a) No sale, conveyance, or mortgage which, at the time such sale, conveyance, or mortgage is made, includes a vessel of the United States, or any portion thereof, as the whole or any part of the property sold, conveyed, or mortgaged shall be valid, in respect to such vessel, against any person other than the grantor or mortgagor, his heir or devisee, and a person having actual notice thereof, until such bill of sale, conveyance, or mortgage is recorded in the office of the collector of customs of the port of documentation of such vessel, as provided in subdivision (b) of this subsection.
(b) Such collector of customs shall record bills of sale, conveyances, and mortgages, delivered to him, in the order of their reception, in books to be kept for that purpose and indexed to show—
(1) The name of the vessel;
(2) The names of the parties to the sale, conveyance, or mortgage;
(3) The time and date of reception of the instrument;