Lake St. Clair Sailing School · Navigation & seamanship

U.S. Navigation Rules,
made easier to learn.

A practical, interactive guide to Rules 1–38: collision avoidance, right-of-way responsibilities, navigation lights, sound signals, and the differences between Inland and International Rules.

Explore real-life situations ↓Browse all 38 rules

Educational summary · Not a substitute for the official USCG Navigation Rules

Start with the essentials

Three principles every skipper should know.

These principles apply to sailboats and powerboats, day and night.

RULE 5

Keep a proper lookout

Use sight, hearing, and every appropriate means to understand what is happening around your vessel.

RULES 6–7

Travel safely. Assess risk.

Maintain safe speed, monitor approaching traffic, and treat doubt about collision risk seriously.

RULE 8

Act early and clearly

Make positive, timely maneuvers and verify that you are passing at a safe distance.

Learn by doing

Who must keep clear?

Select a common encounter. The applicable rule and practical answer appear below.

Rule 12 · Port tack gives way.

When two sailing vessels approach on opposite tacks with a collision risk, the vessel with wind on its port side keeps out of the way of the vessel on starboard tack.

Simplified encounters. Always assess collision risk and account for restricted visibility, narrow channels, traffic schemes, and other relevant rules.

Local knowledge

On Lake St. Clair: know the Inland Rules.

The U.S. side of Lake St. Clair and the Great Lakes is generally governed by U.S. Inland Navigation Rules. Other waters can fall under International Rules across the relevant demarcation lines.

RULE 34

Sound signals mean different things

Under International Rules, one short blast announces alteration to starboard; under Inland Rules it expresses an intent to leave the other vessel on your port side, with further agreement requirements as applicable.

RULES 9, 14 & 15

Great Lakes special provisions

Some provisions concerning following currents and crossing traffic differ from the International text. Consult the full Inland Rules.

RULE 28

Constrained by draft

This vessel classification is addressed by the International Rules. Inland Rule 28 is reserved.

Study and reference

All 38 navigation rules.

Choose a category and open a rule to read its short explanation. The full official text contains exceptions and important operating details.

Showing 38 rules

Part A · General · Rules 1–3

Rule 1Application

International and Inland Rules cover different waters. On the U.S. side of Lake St. Clair and the Great Lakes, Inland Rules generally apply. Check demarcation lines and special local rules.

Rule 2Responsibility

You remain responsible for good seamanship, taking precautions, and avoiding immediate danger. The Rules do not excuse neglect.

Rule 3General Definitions

Defines vessels, sailing and power-driven vessels, fishing, restricted ability to maneuver, not under command, underway, restricted visibility, and related terms.

Part B · Any visibility · Rules 4–10

Rule 4Application

Rules 4–10 apply in any condition of visibility.

Rule 5Look-out

Maintain a proper lookout by sight, hearing, and all available appropriate means at all times.

Rule 6Safe Speed

Travel at a speed allowing effective collision-avoidance action and stopping within an appropriate distance; consider conditions and radar limitations.

Rule 7Risk of Collision

Use all available means, including systematic observations and radar when fitted. If in doubt, assume a collision risk exists.

Rule 8Action to Avoid Collision

Act early and substantially. Make clear changes to course or speed, allow safe passing distance, and verify the action works.

Rule 9Narrow Channels

Keep near the starboard outer limit where safe; small and sailing vessels must not impede vessels constrained to the channel. Additional Inland Great Lakes/Western Rivers provisions apply.

Rule 10Traffic Separation Schemes

Follow traffic lanes in the proper direction; cross near right angles, avoid separation zones, and avoid impeding vessels using lanes.

Part B · In sight · Rules 11–18

Rule 11Application

Rules 11–18 apply to vessels in sight of one another.

Rule 12Sailing Vessels

On different tacks, port tack gives way to starboard tack. On the same tack, windward gives way to leeward. Additional uncertainty provision applies.

Rule 13Overtaking

The overtaking vessel keeps out of the way until finally past and clear, regardless of propulsion type.

Rule 14Head-on Situation

Two power-driven vessels meeting head-on generally both alter to starboard and pass port-to-port. Special Inland provisions can apply.

Rule 15Crossing Situation

Between two power-driven vessels, the vessel seeing the other on its starboard side gives way and should avoid crossing ahead.

Rule 16Action by Give-way Vessel

Take early and substantial action to keep well clear.

Rule 17Action by Stand-on Vessel

Initially keep course and speed; action may become permissible or required when the give-way vessel does not act or collision becomes unavoidable otherwise.

Rule 18Responsibilities Between Vessels

General responsibilities consider not-under-command, restricted-maneuverability, fishing, sailing, and power-driven vessels, subject to Rule 9, 10 and 13 and special provisions.

Part B · Restricted visibility · Rule 19

Rule 19Conduct in Restricted Visibility

For vessels not in sight of one another, maintain safe speed and heightened caution, using radar and sound signals as appropriate.

Part C · Lights & shapes · Rules 20–31

Rule 20Application

Display required navigation lights from sunset to sunrise and in restricted visibility; prescribed shapes by day.

Rule 21Definitions

Defines masthead, sidelights, stern, towing, all-round, flashing and special flashing lights, including arcs.

Rule 22Visibility of Lights

Sets required nominal visibility ranges based on vessel length and light type.

Rule 23Power-driven Vessels Underway

Normally show masthead light(s), red/green sidelights, and sternlight; alternate arrangements exist for smaller vessels.

Rule 24Towing and Pushing

Sets additional lights and shapes for towing, pushing, tow length, and specified configurations.

Rule 25Sailing Vessels and Vessels Under Oars

Sailing vessels generally show sidelights and a sternlight; permitted alternatives depend on length. When propulsion machinery is being used, power-driven rules apply.

Rule 26Fishing Vessels

Fishing vessels display distinct lights and shapes when engaged in fishing; trawling and other fishing have different signals.

Rule 27Not Under Command / Restricted Ability to Maneuver

Special red and white light patterns and day shapes identify these vessels and certain underwater operations.

Rule 28Vessels Constrained by Draft

International Rules: optional three red all-round lights and a cylinder shape for qualifying vessels. Inland Rule 28 is reserved.

Rule 29Pilot Vessels

Pilot vessels on pilotage duty show white-over-red all-round lights with other required lights according to status.

Rule 30Anchored Vessels and Vessels Aground

Anchor lights and a black ball by day may be required; aground vessels add appropriate red lights/black balls subject to exceptions.

Rule 31Seaplanes

When prescribed lights or shapes are impracticable, display the closest practical equivalents.

Part D · Sound & light signals · Rules 32–37

Rule 32Definitions

A short blast lasts about 1 second; a prolonged blast lasts 4–6 seconds.

Rule 33Equipment for Sound Signals

Prescribes whistle, bell and gong equipment based on vessel length, with International/Inland differences.

Rule 34Maneuvering and Warning Signals

Short-blast meanings differ between International (action) and Inland (intent/agreement). Five or more short rapid blasts signal danger or doubt.

Rule 35Sound Signals in Restricted Visibility

Prescribes sound sequences for different vessel types and conditions, often at intervals not exceeding two minutes.

Rule 36Signals to Attract Attention

Permits attention signals that cannot be confused with required signals or aids to navigation.

Rule 37Distress Signals

Annex IV lists recognized distress signals, including Mayday, SOS, flares and other signals.

Part E · Exemptions · Rule 38

Rule 38Exemptions

Limited transitional exemptions cover certain older vessels and equipment under specified conditions.

Also consult Annexes I–V (including the Inland-only pilot provisions), and Part F, Rules 39–41, where applicable. This page intentionally follows the scope of the original study guide: Rules 1–38.

Quick knowledge check

Test your seamanship.

QUIZ 01

Two sailboats, different tacks. Who gives way?

QUIZ 02

Two powerboats cross. You see the other to starboard. Who gives way?

QUIZ 03

You are overtaking another vessel. Who keeps clear?

Frequently asked questions.

Does a sailboat always have priority over a powerboat?

No. Rule 18 contains general vessel responsibilities, but overtaking, narrow channels, traffic separation schemes, and other circumstances may change the duties involved. Every vessel must avoid collision.

What is the difference between give-way and stand-on?

The give-way vessel takes early, substantial action to keep well clear. The stand-on vessel normally maintains course and speed initially, but may or must act when circumstances require it under Rule 17.

Are the rules different in fog?

Yes. Rule 19 governs vessel conduct in restricted visibility when vessels are not in sight of one another. Rules 5–8 still matter, and prescribed Rule 35 sound signals apply.

Where can I find the full official text?

Use the U.S. Coast Guard Navigation Center’s International and Inland Navigation Rules.

Put your knowledge into practice

Learn to sail with confidence.

Build hands-on seamanship skills with US Coast Guard licensed captains and American Sailing certified instructors at Lake St. Clair Sailing School in Harrison Township, Michigan.

Explore ASA courses Call (586) 770-2518

Lambrecht Marina · 31300 North River Road · Harrison Township, MI 48045 · Slip A3

U.S. Navigation Rules at a Glance

U.S. Navigation Rules,
made easier to learn.

Three principles every skipper should know.

Keep a proper lookout

Travel safely. Assess risk.

Act early and clearly

Who must keep clear?

On Lake St. Clair: know the Inland Rules.

Sound signals mean different things

Great Lakes special provisions

Constrained by draft

All 38 navigation rules.

Part A · General · Rules 1–3

Part B · Any visibility · Rules 4–10

Part B · In sight · Rules 11–18

Part B · Restricted visibility · Rule 19

Part C · Lights & shapes · Rules 20–31

Part D · Sound & light signals · Rules 32–37

Part E · Exemptions · Rule 38

Test your seamanship.

Two sailboats, different tacks. Who gives way?

Two powerboats cross. You see the other to starboard. Who gives way?

You are overtaking another vessel. Who keeps clear?

Frequently asked questions.

Learn to sail with confidence.

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Three principles every skipper should know.

Keep a proper lookout

Travel safely. Assess risk.

Act early and clearly

Who must keep clear?

On Lake St. Clair: know the Inland Rules.

Sound signals mean different things

Great Lakes special provisions

Constrained by draft

All 38 navigation rules.

Part A · General · Rules 1–3

Part B · Any visibility · Rules 4–10

Part B · In sight · Rules 11–18

Part B · Restricted visibility · Rule 19

Part C · Lights & shapes · Rules 20–31

Part D · Sound & light signals · Rules 32–37

Part E · Exemptions · Rule 38

Test your seamanship.

Two sailboats, different tacks. Who gives way?

Two powerboats cross. You see the other to starboard. Who gives way?

You are overtaking another vessel. Who keeps clear?

Frequently asked questions.

Learn to sail with confidence.

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