[Code of Federal Regulations] [Title 46, Volume 1] [Revised as of Octobery 1, 2004] From the U.S. Government Printing Office via GPO Access [CITE: 46CFR30.10-45] [Page 386] TITLE 46--SHIPPING CHAPTER I--COAST GUARD, DEPARTMENT OF HOMELAND SECURITY PART 30_GENERAL PROVISIONS--Table of Contents Subpart 30.10_Definitions Sec. 30.10-45 Ocean--TB/O. Under this designation shall be included all tank vessels normally navigating the waters of any ocean or the Gulf of Mexico more than 20 nautical miles offshore.