Boats.com - Rules and Regulations: Navigational Rules

Rule 11
The Rules of Section/Subpart II - Rules 11 through 18 - are applicable only when each vessel can see the other. They do not apply under conditions of "restricted visibility" - fog, mist, heavy rain or snow, etc., when the vessels cannot see each other. The mere darkness of night is not a status of restricted visibility, unless one or more of the conditions listed above prevail.

(a) When two sailing vessels are approaching one another, so as to avoid risk of collision, one of them shall keep out of the way of the other as follows:

(i) when each has the wind on a different side, the vessel which has the wind on the port side shall keep out of the way of the other;
(ii) when both have the wind on the same side, the vessel which is to windward shall keep out of the way of the vessel which is to leeward;
(iii) if a vessel with the wind on the port side sees a vessel to windward and cannot determine with certainty whether the other vessel has the wind on the port or on the starboard side, she shall keep out of the way of the other.

Rule 12
In considering the relative status of two vessels coming into a situation where danger of collision might exist, the Navigation Rules now use the terms of "stand-on" and "give-way." The long-used and well-known terms of "privileged" and "burdened" are no longer in the Rules, but continue in everyday speech. Note also that the term "right-of-way" for one vessel over another does not appear anywhere in either set of Rules.

This Rule requires that a sailing vessel that cannot determine whether or not she should keep out of the way of the other must assume that she should and act accordingly. This is an excellent consideration for any situation of two vessels of any type or size encountering each other.

(a) Notwithstanding anything contained in the Rules of Part B, Sections I and II, any vessel overtaking any other shall keep out of the way of the vessel being overtaken.
(b) A vessel shall be deemed to be overtaking when coming up with another vessel from a direction more than 22.5 degrees abaft her beam; that is, in such a position with reference to the vessel she is overtaking, that at night she would be able to see only the sternlight of that vessel but neither of her sidelights.
(c) When a vessel is in any doubt as to whether she is overtaking another, she shall assume that this is the case and act accordingly.

(d) Any subsequent alteration of the bearing between the two vessels shall not make the overtaking vessel a crossing vessel within the meaning of these Rules or relieve her of the duty of keeping clear of the overtaken vessel until she is finally past and clear.

Rule 13
The zone in which a vessel is deemed to be "overtaking" is the same as that defined for the arc of visibility of the overtaken vessel's sternlight. A vessel coming up astern of a slower vessel is considered to have greater maneuverability and, as such, is the "give-way" vessel. She must take appropriate action until she is finally past and well clear of the overtaken vessel - once a vessel's status is "overtaking," it does not change as she moves out of the sector that created that status.

Although not a part of this Rule, it is required that an overtaking vessel indicate its desire to pass with a whistle signal and get the consent of the overtaken vessel to be passed; see Rule 34(c). This is required by the Inland Rules for all waters, but by the International Rules only in a narrow channel or fairway. In actual practice, VHF radio contact, usually on Channel 13, is often substituted for the whistle signals - "I will pass you on one whistle (or two whistles) if that is OK with you." (See Rule 34(h).)

(a) When two power-driven vessels are meeting on reciprocal or nearly reciprocal courses so as to involve risk of collision, each shall alter her course to starboard so that each shall pass on the port side of the other.
(b) Such a situation shall be deemed to exist when a vessel sees the other ahead or nearly ahead and by night she could see the masthead lights of the other in a line or nearly in a line and/or both sidelights and by day she observes the corresponding aspect of the other vessel.
(c) When a vessel is in any doubt as to whether such a situation exists, she shall assume that it does exist and act accordingly.

Rule 14
Other than overtaking, the encounter of two vessels is either "meeting" or "crossing." Meeting is defined as "head-on or nearly head-on," with no numeric definition of "nearly"; courts have, however, accepted as meeting situations where each vessel was in a forward arc of not greater than one point (11°).

Meeting is a more serious and urgent matter than overtaking because the rate of closure is the sum of the speed of each vessel rather than the difference. If a vessel is in any doubt that the encounter is a meeting situation, she should assume that it is and act accordingly, steering to the right. Neither vessel is "stand-on" or "give-way"; both have responsibilities. Note that this Rule applies only to power-driven vessels meeting other power-driven vessels; a meeting of a power-driven vessel with, for example, a sailing vessel, is not covered.

Meetings are normally "port-to-port," but the Inland Rules do allow for deviation if agreed to by both vessels; this is most likely to occur in winding rivers and channels.

Whistle signals are required, and may be supplemented by flashing light signals, but are different between the International and Inland Rules; see Rule 34(a) and (b). In the Inland Rules, VHF radio communications may be substituted for the whistle signals; see Rule 34(h). In the International Rules, radio communications are not an acceptable substitute for whistle signals, but are often used as a supplement.

When two power-driven vessels are crossing so as to involve risk of collision, the vessel which has the other on her own starboard side shall keep out of the way and shall, if the circumstances of the case admit, avoid crossing ahead of the other vessel.

Rule 15
If the situation between two vessels encountering each other does not fit the definitions of overtaking or meeting, then it must be "crossing." Note that for the Rule to be applicable, there must be a "risk of collision" - no risk, no need to apply the Rule, but it is better to be safe than sorry!

This is the Rule that has led to the principle of a "danger zone," from dead ahead to two points (22°) abaft the beam on the starboard side (the same arc as covered by the green sidelight). If you see another vessel in your danger zone, with risk of collision, you must yield to her and take evasive action. But note that this applies only for visual contacts - if you "see" another vessel only by radar, then Rule 19 governs.

Note that Inland Rule 15(b), applicable in specified, but not all, inland waters, requires that a power-driven vessel crossing a river keep out of the way of another power-driven vessel going either up or downstream. There is no consideration of the relative maneuverability of the vessels, nor of which has the other on its starboard side. There is no corresponding International Rule. In October, 1996, Inland Rule 15(b) was changed. It now applies only to a power-driven vessel crossing a river. There is no corresponding International Rule.

Every vessel that is directed to keep out of the way of another vessel shall, so far as possible, take early and substantial action to keep well clear.

(i) Where one of two vessels is to keep out of the way the other shall keep her course and speed.
(ii) The latter vessel may, however, take action to avoid collision by her maneuver alone, as soon as it becomes apparent to her that the vessel required to keep out of the way is not taking appropriate action in compliance with these Rules.

(b) When, from any cause, the vessel required to keep her course and speed finds herself so close that collision cannot be avoided by the action of the give-way vessel alone, she shall take such action as will best aid to avoid collision.
(c) A power-driven vessel which takes action in a crossing situation in accordance with sub-paragraph (a)(ii) of this Rule to avoid collision with another power-driven vessel shall, if the circumstances of the case admit, not alter course to port for a vessel on her own port side.
(d) This rule does not relieve the give-way vessel of her obligation to keep out of the way.

Except where Rules 9, 10, and 13 otherwise require:
(a) A power-driven vessel underway shall keep out of the way of:

(i) a vessel not under command;
(ii) a vessel restricted in her ability to maneuver;
(iii) a vessel engaged in fishing;
(iv) a sailing vessel.

(i) a vessel not under command;
(ii) a vessel restricted in her ability to maneuver;
(iii) a vessel engaged in fishing.

(i) a vessel not under command;
(ii) a vessel restricted in her ability to maneuver.

(i) any vessel other than a vessel not under command or a vessel restricted in her ability to maneuver shall, if the circumstances of the case admit, avoid impeding the safe passage of a vessel constrained by her draft, exhibiting the signals in Rule 28.
(ii) A vessel constrained by her draft shall navigate with particular caution, having full regard to her special condition.

(e) A seaplane on the water shall, in general, keep well clear of all vessels and avoid impeding their navigation. In circumstances, however, where risk of collision exists, she shall comply with the Rules of this Part.

Rule 18
Note: that Rule 18 applies only if Rules 9, 10, and 13 do not require other specific action. For example, a sailing vessel that is overtaking a power-driven vessel is the give-way vessel, regardless of Rule 18(a)(iv), because Rule 13 takes precedence.

These lists are often thought of as a "pecking order" between various types of vessels for situations not involving narrow channels, Traffic Separation Schemes, and the overtaking encounter, but this is not correct! The sequence of the listing of various types of vessels in each paragraph is not an indication of relative status of these categories; the subparagraphs are a total list of applicable types of vessels, not a priority listing within any list. Each paragraph should be read independently of the others for the category of vessel concerned.

A vessel "not under command" is usually one that has suffered a loss of propulsion or steering control. A vessel "restricted in her ability to maneuver" would typically be a dredge, one laying an underwater cable, a Coast Guard vessel servicing an aid to navigation, etc.

Remember:
(1) A vessel under sail does not have the privileges of that category if she is also being propelled by machinery; and,
(2) a sport-fishing boat with trolling lines out is not a "vessel engaged in fishing."
International Rule 18(e) and Inland Rule 18(d), in practical terms, apply to a seaplane taxiing on the water. Such aircraft, when taking off and landing, are unable to maneuver to keep clear of vessels.

(a) This Rule applies to vessels not in sight of one another when navigating in or near an area of restricted visibility.
(b) Every vessel shall proceed at a safe speed adapted to the prevailing circumstances and conditions of restricted visibility. A power-driven vessel shall have her engines ready for immediate maneuver.
(c) Every vessel shall have due regard to the prevailing circumstances and conditions of restricted visibility when complying with the Rules of Section I of this Part.
(d) A vessel which detects by radar alone the presence of another vessel shall determine if a close-quarters situation is developing and/or risk of collision exists. If so, she shall take avoiding action in ample time, provided that when such action consists of an alteration of course, so far as possible the following shall be avoided:

(i) an alteration of course to port for a vessel forward of the beam, other than for a vessel being overtaken;
(ii) an alteration of course toward a vessel abeam or abaft the beam.

(e) Except where it has been determined that a risk of collision does not exist, every vessel which hears apparently forward of her beam the fog signal of another vessel, or which cannot avoid a close-quarters situation with another vessel forward of her beam, shall reduce her speed to the minimum at which she can be kept on her course. She shall, if necessary, take all her way off and in any event navigate with extreme caution until danger of collision is over.

Rule 19
Section/Subpart III of Part B consists of the single Rule 19. For this Rule to be applicable, both of two conditions must be met - vessels must be in or near an area of restricted visibility, and they must not be in sight of each other. A vessel might be in quite clear weather, but adjacent to a fog bank, rainsquall, etc., that did, or might, conceal another vessel - this Rule would then be applicable. The range of visibility is not specified; common sense must be applied - the distance would be less in confined waters than on the high seas.

The requirement of Rules 19(b) and (e) for a safe speed ties back to Rule 6(a) with its very specific conditions and requirement for stopping distance. The requirements of Rule 19(c) tie in with the provisions of Rule 5, Lookouts; Rule 7, Risk of Collision; and Rule 8, Action to Avoid Collision. If you have radar, Rule 19(d) should be read in conjunction with Rule 6(b). Sound signals are required; see Rule 35.

International Navigation Rules