🔍 Key Concepts

• Navigable waters of the United States and how they relate to U.S. manning and watchstanding requirements (see 46 CFR Part 15 and 33 CFR Part 2) • The difference between territorial sea, contiguous zone, exclusive economic zone (EEZ), and emission control areas (ECAs) • What a periodically unmanned engine room (UMS) means for when a full maneuvering watch is required versus when at‑sea manning is acceptable

💭 Think About

• Which of the listed distances/zones is actually used in U.S. regulations to define where full bridge/engine watchstanding and manning rules clearly apply when you are departing a U.S. port? • Is an emission control area (ECA) or EEZ primarily about watchkeeping, or are they mainly about other issues such as air pollution control or resource rights? • Historically some countries used 3 nautical miles as a limit; what is the current U.S. distance for its territorial sea, and is that tied to the term ‘navigable waters of the United States’ for watchstanding purposes?

✅ Before You Answer

• Verify in 33 CFR Part 2 how the territorial sea/navigable waters of the U.S. are defined and the distance from the baseline in nautical miles. • Confirm in 46 CFR Part 15 that manning and watchkeeping requirements are linked to operation on the navigable waters of the United States, not to the outer edge of the EEZ or ECA. • Check which of the answer choices actually matches the current legal distance of the U.S. territorial sea, not an older or unrelated limit.