§ 56501. Definition
In this chapter, the term “essential vessel” means a vessel that is—
(1)
(A)
security for a mortgage indebtedness to the United States Government; or
(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)
necessary in the interests of commerce and national defense to be maintained in condition for prompt use.