### Question
How is the "essential service" defined?


### Answer
The term **essential service** is defined in *APPENDIX U.S.C. § 1171* as follows -

> the operation of a vessel on a service, route, or line described in section 1121(a) of this Appendix or in bulk cargo carrying service described in section 1121(b) of this Appendix

#### Citation:
  - *APPENDIX U.S.C. § 1171*
  - Heading: **CHAPTER 24A-MERCHANT MARINE ACT, 1928 > SUBCHAPTER VI-OPERATING-DIFFERENTIAL SUBSIDY**

