46 U.S.C. § 31323

1. (a)On request of the mortgagee and before executing a preferred mortgage, the mortgagor shall disclose in writing to the mortgagee the existence of any obligation known to the mortgagor on the vessel to be mortgaged.
2. (b)After executing a preferred mortgage and before the mortgagee has had a reasonable time to file the mortgage, the mortgagor may not incur, without the consent of the mortgagee, any contractual obligation establishing a lien on the vessel except a lien for—
   1. (1)wages of a stevedore when employed directly by a person listed in section 31341 of this title;
   2. (2)wages for the crew of the vessel;
   3. (3)general average; or
   4. (4)salvage, including contract salvage.
3. (c)On conviction of a mortgagor under section 31330(a)(1)(A) or (B) of this title for violating this section, the mortgage indebtedness, at the option of the mortgagee, is payable immediately.