Where the Inland Rules apply, and what they are
1The lesson in plain words
Inside the COLREGS demarcation lines and on the US Great Lakes, US vessels and visitors follow the Inland Rules: COLREG with some American changes.
Two rulebooks
In US waters you meet two sets of rules. Seaward of the COLREGS demarcation lines, COLREG applies. Shoreward of them, the Inland Navigation Rules apply (33 CFR 80.01). The lines cross harbour entrances, bays and inlets. They are listed in 33 CFR Part 80 and drawn on US charts as magenta dashed lines. Check the chart before you enter or leave port.
Rules as regulations
The Inland Rules began as the Inland Navigational Rules Act of 1980. They entered the Code of Federal Regulations (CFR) in 2010 and were updated in 2014. The rules are in 33 CFR Part 83. Parts 84–88 contain the annexes, including US-only Annex V. Part 89 implements the Inland Rules, including special-water lists; Part 90 provides interpretations.
Same numbers, same core
The Inland Rules keep COLREG’s numbers: Rule 15 is still the crossing rule. Most text is identical. They count as the special rules for inland waters that COLREG Rule 1(b) allows a state to make. COLREG-compliant construction and equipment are accepted (Inland Rule 1(b)(ii)); you must still follow Inland operating rules. The differences are mainly in whistle signals, river traffic and some lights.
Special waters
Western Rivers means the Mississippi, its tributaries, South Pass and Southwest Pass to the demarcation lines, plus the Port Allen–Morgan City Alternate Route and the Atchafalaya above its junction with that route, including the Old River and the Red River. The Great Lakes include their connecting and tributary waters, and the St Lawrence east to Saint Lambert Lock.
On board
The operator of every self-propelled vessel of 12 m or more must carry a copy of the Inland Rules on board for ready reference (Inland Rule 1(g)). The Coast Guard Navigation Center publishes the Rules free online. Compare COLREG Rule 1 and the COLREG vs US Inland Rules summary.
2Key data
- Inland Rules
- 33 CFR Part 83; annexes 84–88; supporting provisions 89–90
- Demarcation lines
- 33 CFR Part 80: Inland inside, COLREG outside
- In the CFR since
- 17 May 2010; updated in 2014
- Specified waters
- 33 CFR 89.25, e.g. Tennessee-Tombigbee Waterway
- Copy on board
- Self-propelled vessels of 12 m or more
3Key points
- 1
Seaward of the demarcation lines: COLREG. Shoreward and on the US Great Lakes: Inland Rules.
- 2
Inland Rules: 33 CFR Part 83; annexes in Parts 84–88; implementing rules and interpretations in Parts 89–90.
- 3
Rule numbers match COLREG; check the differences, not the whole text.
- 4
Self-propelled vessels of 12 m or more carry a copy of the Inland Rules.
4Frequent mistakes
Wrong: COLREG applies everywhere once you are in salt water.
Right: Shoreward of the demarcation lines the Inland Rules apply, even in salt-water bays and harbours.
Wrong: The Inland Rules are a completely different rulebook.
Right: They follow COLREG closely, with the same rule numbers. Learn where they differ.
5Practice case & exam keys
Your 13 m motor yacht enters a salt-water harbour in Maine. The chart places you shoreward of the demarcation line. A crew member says salt water means COLREG still applies. Which rules do you use, and what must be aboard?
Show the answer
Use the Inland Rules. The charted demarcation line decides, even in salt water. Your self-propelled yacht is at least 12 m long, so carry a copy of the Inland Rules aboard for ready reference. Check the Inland differences before proceeding.
Exam keys
- Demarcation lines (33 CFR 80): inside Inland Rules, outside COLREG.
- Inland Rules: Part 83 since 2010, updated 2014; annexes 84–88; implementing rules in 89, interpretations in 90.
- Western Rivers, Great Lakes and the waters in 33 CFR 89.25 carry extra rules.
- Copy of the Inland Rules on board self-propelled vessels of 12 m or more.
Finish this unit
When you've read it, match the terms, then answer three questions. Get them all right to finish the unit; opening the page alone doesn't count.
My notes for this unit
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