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Navigation Rules

The navigation rules call anything that floats on the water and can be used for transportation a "vessel." Whether your boat is a cabin cruiser or a raft built by Tom Sawyer, for the rest of this section, it will be called a vessel. Other definitions you need to understand:

Power-driven vessel: any vessel that is propelled by machinery

Sailing vessel: any vessel under sail and being propelled only by the wind

Vessel engaged in fishing: any vessel fishing with nets, lines, trawls, or other fishing apparatus that restricts its maneuverability

Floatplane or seaplane: any aircraft designed to maneuver on the water

Restricted visibility: any condition in which visibility is restricted by fog, mist, falling snow, heavy rainstorms, sandstorms, or any other similar causes.

Underway: any vessel not anchored, made fast to the shore, or aground

You also need to know which vessel needs to yield when two vessels approach each other. Unlike vehicles on the road, vessels in the water have different rules for yielding depending on their size, shape, and means of propulsion. Basically, the easier it is for you to get out of the way of another vessel, the more likely it is that you are responsible for yielding. A sailboat without a motor, for example, is harder to turn quickly than a motor boat of the same size, so the motor boat is the one that has to change course.

Rule 2, the rule of responsibility, requires boaters to consider all dangers of navigation and collision. It allows the boater to do whatever is necessary to avoid immediate danger of collision. This most often applies when three or more vessels are at a risk of colliding.

There are three different sets of navigation rules:

  • Inland
  • International
  • Great Lakes [including their connecting and tributary waters including the Calumet River as far as the Thomas J. O'Brien Lock and Controlling Works (between mile 326 and 327), the Chicago River as far as the east side of the Ashland Avenue Bridge (between mile 321 and 322), and the Saint Lawrence River as far east as the lower exit of Saint Lambert Lock], Western Rivers (including the Mississippi River, its tributaries, South Pass, and Southwest Pass, to the navigational demarcation lines dividing the high seas from harbors, rivers, and other inland waters of the United States, and the Port Allen-Morgan City Alternate Route, and that part of the Atchafalaya River above its junction with the Port Allen-Morgan City Alternate Route including the Old River and the Red River), or waters specified by the Secretary (Tennessee-Tombigbee Waterway, Tombigbee River, Black Warrior River, Alabama River, Coosa River, Mobile River above the Cochrane Bridge at St. Louis Point, Flint River, Chattahoochee River, Apalachicola River above its confluence with the Jackson River)

Navigation maps show the lines of demarcation between the inland and international bodies of water. If you are unsure which set of rules to follow, check the map or ask the local harbor master or other boating expert. Unless specified otherwise, you can assume the rules in this section are the same for all three classifications.

Types of Vessels

In terms of yielding, the two types of vessels are "stand on" and "give way." If you are the stand-on vessel like the sailboat in the following example, you should not alter your course unless there is a danger of collision. When you are the stand-on vessel, maintain your course and speed so the give-way vessel can predict what you will do.

If you are the give-way vessel like the motor boat above, you have to get out of the way of the stand-on vessel. When you are the give-way vessel, you make a significant course change early enough that the stand-on vessel knows you are responding correctly.

It is always better for both vessels to give way than to collide before they can decide who will give way and who will stand on.

Danger and Safe Zones

The area around your boat is divided into three sectors: port, starboard and stern. Each of these sectors is color coded the same as the navigation lights on your boat: the starboard sector is green, the stern sector is white, and port sector is red.

The starboard or green sector is known as the danger zone because when a boat approaches from that side, your boat is in danger if you don't get out of the way. When a boat approaches from the starboard side, you see the red light on their boat, and you are the give-way vessel. When you see the green light of the other boat, you are in the safe zone because you are the stand-on vessel and will continue going in the same direction. Seeing green on the other boat means go or continue, and seeing red means there is danger if you don't change your direction.

Lookout! — U.S. Coast Guard Navigation Rule 5

U.S. Coast Guard Navigation Rule 5 states that "Every vessel shall at all times maintain a proper lookout by sight and hearing as well as by all available means appropriate in the prevailing circumstances and conditions so as to make a full appraisal of the situation and of the risk of collision."

When do I need a Lookout?

According to Rule 5, all vessels are responsible for maintaining a proper lookout at all times - this includes one-man crews, unmanned crafts, and recreational boats. The term lookout implies watching and listening so that he/she is aware of what is happening around the vessel. The emphasis is on performing the action, not on the person. Still, in all but the smallest vessels, the lookout is expected to be an individual who is not the helmsman and is usually located in the forward part of the boat, away from the distractions and noises of the bridge.

If you are on the boat by yourself, you alone are responsible for keeping a proper lookout.

If anyone else is on the boat with you, appoint another person to help. Tell them to use their eyes and ears to monitor the area around your boat. Watch and listen for other boats, people or debris in the water. Also, watch and listen for changing weather conditions. Your lookout can help you safely navigate around obstacles in the water.

While no specific location on a vessel is prescribed for the lookout, good navigation requires placement at the point best suited for the purpose of hearing and observing the approach of objects likely to be brought into collision with the vessel. The size of the vessel and crew affect the best placement of the lookout, however, the emphasis in every legal decision points to the need for a proper, attentive lookout.

While the use of radar to evaluate the situation is implied in the requirement to use all available means, that is still understood to be secondary to maintaining a lookout by sight and hearing.

Safe Speed

The Navigation Rules do not specifically define a safe speed or passing distance. According to Rule 16 — Action to Give-way when crossing, meeting, or overtaking another vessel, other than as the give-way vessel, you are to keep well clear.

Likewise, the distance a vessel may be required to take action to avoid collision will vary; however, it should be in accordance with Rule 6 — Safe Speed and Rule 8 — Action to Avoid Collision.

Rule 6 says that you should always move at a safe speed so that you can take proper and effective action to avoid a collision. Safe speed is determined with the following factors in mind:

  1. Visibility
  2. Traffic Density
  3. Maneuverability of the vessel, taking into account stopping distance and turning ability
  4. Presence of background lights, such as shore lights, at night
  5. State of the wind, sea, and current; proximity of navigational hazards; and the draft in relation to the water depth

Rule 8 states that any alteration of course or speed shall be large enough to be readily apparent to another vessel and taken early enough to allow sufficient sea room for the safe passage of the other vessel. You should do this at a safe speed so that the vessel can take proper and effective action to avoid collision and be stopped within a distance appropriate to the prevailing circumstances and conditions. Your vessel can slow down or stop completely if you need more time to assess the situation. If you have enough sea room, altering your course alone could be the most effective action used to avoid a collision as long as it is made early enough, is substantial, and does not result in another close situation with another vessel.

You must always operate your boat at a safe speed so that you have time to avoid a collision and stop within a safe distance. If you are new to boating, you might have difficulties determining how fast you can go and still be safe.

Below are some factors that will help you decide on a safe speed. If the answer to any of these questions is "yes," then you need to go slower. Remember, however, that safe speed is always a judgement call of the vessel operator and circumstances of the moment. Responsibility for maintaining a safe speed ultimately rests solely on the shoulders of the operator.

  • Is the visibility reduced? Is it foggy or raining?
  • Are there other boats on the water with you? Are there any fishing vessels nearby?
  • Is your vessel slow to maneuver? Does it take a long time to stop or turn?
  • Is it nighttime? Is there background light from the shore or your own boat?
  • Are the winds gusty? Are the waves high or currents strong? Are there any navigational hazards nearby?
  • Are you in shallow or rocky water?

Determining the Risk of Collisions

You obviously never want to be in a collision. According to Rule 7(a), you have to use all available means appropriate to the circumstances to determine if the risk of collision exists. Being able to determine the risk of collisions will help you avoid them. If you have any doubt, assume that the risk does exist. Rule 7(d) states that you are at risk of a collision if:

  • Another vessel is heading for your vessel and does not appear to be changing course, which can be determined from your compass bearing.
  • Another vessel is heading for your vessel but does not appear to be changing course soon enough or quickly enough. This most likely would happen when you are approaching a very large vessel or a tow or when you are approaching a vessel at close range.

If a collision is possible, it doesn't matter whether or not you are the give-way vessel -- you need to get out of the way as quickly and safely as possible.

Using a Bearing Compass

A bearing compass is a very useful tool to determine if you are on a collision course with another vessel. Take several bearings on the other vessel, if the bearing remains constant, you are on a collision course; if the bearing is moving aft with time, the other vessel will pass to your stern, and if the bearing is moving forward, the other vessel will pass in front of your vessel.

Avoiding Collisions

To recap, you can overlook a Navigation Rule only if necessary to avoid immediate danger (Rule 2). To avoid a collision, take as many of the following actions as the situation needs:

  • Move out of the way of the other vessel according to the Rules of Navigation in this chapter.
  • Move early enough that you have plenty of time to avoid a collision.
  • Make your course changes large enough (greater than 30) so that the other vessel has no doubt where you are headed.
  • Make sure when you change your course to avoid one vessel, you don't come too close to another vessel.
  • Watch the other vessel the whole time you are navigating around it to be sure you keep a safe distance.
  • Keep your speed constant unless that speed will cause a collision. If you need to change speed, either slow down, stop altogether, or reverse the propulsion of your vessel.
  • Slow down, stop altogether, or reverse the propulsion of your vessel if you need more time to figure out where the other vessel is headed.

Rules for Powerboats

Crossing Situations — Overtaking Another Vessel (Rule 13)

If you want to pass a slower vessel that's headed in the same direction, you can pass on either the port or starboard side. Before passing, be sure no other vessels are in the way, and be sure the water is deep enough and the channel is wide enough that you can safely pass. If you are the vessel being passed, do not change your course or speed except to avoid a collision.

The vessel in front of you will know you want to overtake it when you come from a direction more than 22.5° abaft (behind) its beam. If it were dark when you were approaching the vessel, you would only be able to see the stern light of the vessel in front of you, not either of the sidelights.

Action by Give-way Vessel (Rule 16)

If you are the give-way vessel (the one who needs to get out of the way), you must take early and substantial action to keep well clear of the other vessel. This is best accomplished by a hard turn to your port or starboard side to avoid the other vessel.

Action by Stand-on Vessel (Rule 17)

Where one of two vessels is to keep out of the way, one should get out of the way and the other must keep her course and speed (the stand-on vessel).

The stand-on vessel may, however, take action to avoid collision by her maneuver alone as soon as it becomes apparent to her that the give-way vessel is not taking appropriate action in compliance with these rules. She should not, however, alter her course to port for a vessel on her own port side.

If, for any reason, the vessel required to keep her course and speed (the stand-on vessel) finds herself so close that collision cannot be avoided by the action of the give-way vessel alone, she should also take whatever action that is best to avoid collision.

This rule does not relieve the give-way vessel of her obligation to keep out of the way.

Responsibilities Between Vessels (Rule 18)

If you are in a power-driven vessel while underway (Rule 18a), you need to keep out of the way of:

  • A vessel not under command
  • A vessel restricted in its ability to maneuver
  • A vessel engaged in fishing
  • A sailing vessel

If you are in a sailing vessel while underway (Rule 18b), you need to keep out of the way of:

  • A vessel not under command
  • A vessel restricted in its ability to maneuver
  • A vessel engaged in fishing

If you are in a fishing vessel while underway (Rule 18c), you need to keep out of the way of:

  • A vessel not under command
  • A vessel restricted in its ability to maneuver

Any vessel other than one not under command or that is restricted in her ability to maneuver needs to avoid impeding the safe passage of a vessel that is constrained by her draft. A vessel constrained by her draft must navigate with particular caution, with full regard to her special condition. (Rule 18d)

Inland Rules

Crossing Situations — Meeting Head-on (Rule 14)

When your power vessel is headed toward another power vessel, turn to the right so that you both pass each other on the port side. This situation exists when a vessel sees the other ahead or nearly ahead during the day, and during night, when she can see the masthead lights of the other in a line or nearly in a line and/or both sidelights. When in doubt as to whether this situation exists or not, assume that it does.

If you are boating on the Great Lakes, Western Rivers, or waters specified by the Secretary, the direction of the current changes which vessel is the give-way vessel and which is the stand-on vessel. If you are proceeding downbound with a following current, you are the stand-on vessel, and the upbound vessel is the give-way vessel.

Crossing Situations — Crossing Paths (Rule 15)

When the path of your vessel will cross the path of another power vessel and the other vessel is on your starboard side, you will see their red light and you are the give-way vessel. When possible, cross behind the other vessel, not in front of it.

If you are boating on the Great Lakes, Western Rivers, or waters specified by the Secretary and you are crossing the current, you need to keep out of the way of a vessel going with or against the current.

Crossing Situations — Narrow Channels

If you are navigating through a narrow channel or fairway, keep as close as safely possible to the outer limit of the channel on your starboard side.

If you are in a narrow channel on the Great Lakes, Western Rivers, or waters specified by the Secretary and are headed down-current with a following current, you are the stand-on vessel. If you are traveling against the current, you are the give-way vessel and must give the other vessel plenty of space to permit safe passing.

If your boat is less than 20 meters long or you are on a sailboat under sail, you must not impede the passage of a vessel that can only navigate through a narrow portion of the channel.

Unless it's an emergency, never anchor in a channel.

Special Rules for Sailboats

For sailboats, the direction of the wind determines which vessel is the give-way vessel and which is the stand-on vessel.

The windward side is the side the wind is coming from. The leeward side is the downwind side.

If you are on a sailing vessel and you see another sailing vessel approaching, use the following rules:

When each vessel has the wind on a different side, the vessel with the wind on the port side (port tack) is the give-way vessel and must move out of the way of the other vessel. When a vessel is on a port tack, the boom is on the starboard side. If the wind is very light, the position of the boom determines if the boat is on a port or starboard tack.

When both vessels have the wind on the same side, the vessel that is windward is the give-way vessel and must move out of the way of the leeward vessel.

If you can't tell which side the wind is on for another sailboat, that vessel is the stand-on vessel and you are the give-way vessel.

Sometimes the vision of the person on the windward sailboat is blocked by the sails. Even when you are on the leeward side and are the stand-on vessel, never assume the windward boat can see you and will give way.

Restricted Visibility (Rule 19)

Whenever navigating with restricted visibility caused by heavy fog, mist, rain, or simply nighttime darkness, you should always slow to minimum speed allowing yourself a chance to safely maneuver your vessel whenever you may be at risk of collision.

The overall circumstances while boating effectively determine what would be considered to be restricted visibility. Generally speaking, if you cannot see five miles in all directions in open water, then you are operating in or near restricted visibility. Of course, this distance may be less in confined bodies of water.

If you have radar equipment on your vessel and see another vessel on radar alone, take whatever action is necessary to avoid a collision as soon as you can. Follow the rules you learned for safe navigation.

Whenever there is a risk of collision, if you hear a fog signal that seems to be coming from forward of your vessel, slow your speed to the minimum that lets you keep on course. Use extreme caution until the danger of a collision is over.


The navigation rules contained in this course summarize basic navigation rules for which a boat operator is responsible on inland waterways. Additional and more in-depth rules apply regarding various types of waterways, such as International Waters and Western Rivers, and operation in relation to commercial vessels and other watercraft. It is the responsibility of a boat operator to know and follow all the navigation rules. In those states that Inland Rules do not apply, the equivalent International, Western Rivers or Great Lakes rule(s) may be substituted by the Course Provider.

For a complete listing of the navigation rules, refer to the document "Navigation Rules of the Road" published by the U.S. Coast Guard (COMMANDANT INSTRUCTION 16672.2 Series. For State-specific navigation requirements, refer to the state laws where you intend to boat.

You can download official pages of the Navigation Rules book in PDF format M16672.2D_NavRules(Corrected).pdf. You can also order a copy of the Navigation Rules (International - Inland), COMMANDANT INSTRUCTION M16672.2D from the Government Printing Office at 202-512-1800 for $23 (NSN 7642-01-448-2151, 050-012-00407-2).

For state-specific rules, see Chapter 7.


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