33 CFR §161.23

1. (a)Unless otherwise directed, the following vessels are exempted from providing Position and Final Reports due to the nature of their operation:
   1. (1)Vessels on a published schedule and route;
   2. (2)Vessels operating within an area of a radius of three nautical miles or less; or
   3. (3)Vessels escorting another vessel or assisting another vessel in maneuvering procedures.
2. (b)A vessel described in paragraph (a) of this section must:
   1. (1)Provide a Sailing Plan at least 5 minutes but not more than 15 minutes before navigating within the VMRS area; and
   2. (2)If it departs from its promulgated schedule by more than 15 minutes or changes its limited operating area, make the established VMRS reports, or report as directed.