In this chapter, the term “essential vessel” means a vessel that is—

1. (1)

   1. (A) security for a mortgage indebtedness to the United States Government; or
   2. (B) constructed under this subtitle or required by a contract under this subtitle to be operated on a certain essential foreign trade route; and
2. (2) necessary in the interests of commerce and national defense to be maintained in condition for prompt use.

(Pub. L. 109–304, § 8(c), Oct. 6, 2006, 120 Stat. 1656.)