Rules of the Road -Series V

Conduct of Vessels in sight of one another and restricted visibility

In Series 3, the responsibility of vessels in all conditions of visibility was addressed. These rules are the foundation for everything to come when we start looking at how to specifically avoid a collision. When we started this blog series, I’ve continued to stress the importance of always thinking about the rules of the road and situations with respect to whether you have vessels in sight and not in sight, better known as restricted visibility.  If you separate the two, you will eliminate confusion.  Again, as with any rule or regulation, always look at the application.  The applicability rule for this section, Rule 11, simply states that Rules 12 thru 18 apply when vessels are in sight of one another. Note: Rule 19 is separate subpart.

So before we jump right into the rules in this section, it would be appropriate to go right to Rule 18, “Responsibility between Vessels.”  This rule identifies the hierarchy between different types of vessels engaged in different operations or work.  In my previous blogs, I explained how larger vessels are less maneuverable and take great distances to stop.  These physical factors affect their maneuverability.   In addition, there are vessels that strictly by the nature of their work or by some extenuating or extraordinary circumstance, are limited or unable to maneuver.  In order to account for these vast differences, the Rule of Responsibility was developed.

Taking all things into account, this hierarchy gives precedence or priority of right of way.  The list moves upward from small and maneuverable to large and un-maneuverable.  So, with the exception of Rules 9, 10 and 12, the following list establishes that hierarchy in ascending order.  A power-driven vessel underway shall keep out of the way of a vessel under sail, a vessel engaged in fishing, and the two classes of vessels with the highest priority, those not under command and restricted in their ability to maneuver.  Each class of vessel on the list must yield to those on the list ahead of it.  More detailed definitions of these vessels can be found in Rule 3. Always having this hierarchy in mind will help in the decision process when we look at the actions of the give-way vessel, stand-on vessel and the responsibility between vessels when meeting, overtaking and crossing.  Bottom line, as far as recreational vessels are concerned, the hierarchy is easy.  A recreational vessel, under all but the rarest of circumstances, will never be anything more than a power-driven vessel.  Confused?  Keep reading…

There are also situations where vessels listed higher in the hierarchy can change status to just a power-driven vessel.  For example, a sailing vessel operating on mechanical propulsion or mechanical propulsion and under sail at the same time is a power-driven vessel.  Only when the machinery is shut off and the vessel is only under sail does it step up in the hierarchy.  Now, an issue rising from that rule is what do you do when you have two sailing vessels under sail approaching each other?  In this case, a specific rule was written for that situation.  Rule 12 addresses the conduct of two sailing vessels under sail when they are approaching when the risk of collision exists.  Fishing vessels, by definition in Rule 3, only fall under higher hierarchy when they are actually engaged in the act of fishing. The same can be said for a vessel restricted in its ability to maneuver.  Once the operation or activity/job is discontinued they are considered a power-driven vessel.

Although there may be some exceptions, the majority of recreational vessels will never fall under the higher levels of the hierarchy so that makes application of the rules by recreational vessels pretty simple.  If it’s anything other than another power-driven vessel, you can pretty much bet that they have the right of way and your responsibility is to let it pass safely. The number of sound signals you will have to use and navigation lights you will need to understand are minimal, especially if you are following Rules 5, 6, 7 and 8.  Now before we jump into Rules 13, 14 and 15, we need to jump ahead once again to Rule 16 and 17, “Action By Give-way Vessel and Action by Stand on Vessel.”  Action by Give-way Vessel (Rule 16).

Image of a Chesapeake Bay collision between a power boat and sail boat in August 2018.

Chesapeake Bay collision in August 2018. Full story:

Every vessel which 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.  This relates back to Rules 7 and 8, “Risk of Collision” and “Actions to Avoid Collision.”  The common theme is to take “early and substantial action”. If you react in plenty of time, you can avoid collision simply by altering course as directed by the rules or slowing down.  It’s all pretty basic.  If you’re the stand-on vessel (Rule 17). (a)(i) Where one of two vessels is to keep out of the way, the other shall keep her course and speed.

So, if it is safe and you can maintain your course and speed you shall do so until the other vessel is clear.  But, if the stand-on vessel is not following Rule 16, the give way vessel has the responsibility to take necessary action to avoid collision in accordance with rules to (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, (c) A power-driven vessel which takes action in a crossing situation in accordance with 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 (passing port to port).

For example, say you have a boat approaching you and its bearing and range are constant.  For some reason, you’re distracted and lose track of the other boat and then notice you’re about to collide.  Regardless that the other boat is required to maneuver under the rules, you are still required, if they fail to take action, to take whatever action necessary to best avoid the collision, (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.  If a collision is inevitable and you have time to react, maneuvering to reduce the damage of impact may be your only course of action.  A glancing blow is much better than a “T” bone but always referring back to Rules 5, 7 and 8, if you maintain a proper lookout and identify the risk of collision early, when you realize the other vessel is not going to give way taking action to avoid the collision will keep you from ever getting into this sort of circumstance, (d) This Rule does not relieve the give-way vessel of her obligation to keep out of the way.

When meeting another vessel there are three basic scenarios that the rules address, overtaking, crossing and head-on, where the stand-on and give-way vessel rules in Rules 16 and 17 apply.  If you sit back and look at it, all three are similar to driving a car when meeting another car on a narrow street, intersection or passing.  In the inland rules, there should be an agreement between both vessels involved in order to establish which direction the give-way vessel will maneuver.  This can be established by communicating via marine VHF FM radio or sound signals with the vessel’s whistle.

Powerboat rules of the road infographic from BoatUS Foundation.

Powerboat rules of the road infographic from BoatUS Foundation.

“Overtaking,” Rule 13, is when you are passing another vessel. (a) Notwithstanding anything contained in Rules 4 through 18, any vessel overtaking any other shall keep out of the way of the vessel being overtaken. If you are passing another vessel you are considered the “give-way” vessel.   When overtaking another vessel, pass them on their starboard side. Going to the port may put you in the path of other vessel traffic traveling in the opposite direction.  There are some circumstances where you can pass on the port side, but that is only if it is unsafe to pass on the starboard side, due to some obstruction or hazard.  Passing another vessel on the port side should be taken using extreme caution.  Sound signals should be exchanged between you and the “stand-on” vessel prior to passing (being discussed in the next blog series).

So let’s say you are not exactly approaching another vessel from dead astern but off to the side?  (b) A vessel shall be deemed to be overtaking when approaching 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 stern light of that vessel but neither of her sidelights.   All this nautical lingo can make your head spin but if you look at your boat as the needle on a compass you have 360 degrees of radius around the vessel. Zero degrees is always dead ahead, 90 degrees directly to your right, 180 degrees astern, 270 on the left side and returning to dead ahead, zero or 360.  When this rule says 22.5 degrees abaft the beam means 22.5 degrees past 90 or 112.5 degrees from dead ahead. This means that when you approach another vessel and you are aft of that 112.5-degree point in reference from the other vessel, to their direction of travel, you are overtaking.

Figure 1, Relative Bearing

One thing you will notice is that with all these rules they are written to err on the side of safety.  If there is any doubt as to whether you are overtaking another vessel you must assume you are and act accordingly.  Once you have traveled beyond the point that is 22.5 degrees abaft the beam of the other vessel or there is any alteration of bearing between vessels it does not relieve you of your responsibility as the give way vessel.  You must keep clear of the overtaken vessel until you are safely past and clear. (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. In figure 2, where there is yellow, indicates the zone where an approaching vessel would be considered overtaking.  Again, once you pass the other vessel you are still obligated to remain at a safe distance and course until you are safely well clear, forward if the vessel being overtaken. The important thing to remember is that even if the vessel looks to be heading away from you as long as you have a constant bearing and decreasing range you’re at risk of collision.

Before we get into the details of Rule 18, responsibilities between vessels, there is an overarching point I want to drive home again. “When determining the conduct of vessel in sight of one another the rules are set up so the burden is on the more maneuverable vessel to give way to the less maneuverable vessel”.  “It is reasonable that the more maneuverable vessel gives way to the less maneuverable vessel but, ultimately each vessel has the responsibility to avoid collision regardless of its status”.  It is also very important that there is a universal understanding of what defines each class of vessel in the hierarchy.  Always reference Rule 3, definitions, on how to accurately apply hierarchy.  Rule 18 (Inland) is as follows:

Except where Rules 9, 10, and 13 (§§83.09, 83.10, and 83.13) otherwise require:

  • 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.

(b) A sailing vessel underway shall keep out of the way of:

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

(c) A vessel engaged in fishing when underway shall, so far as possible, keep out of the way of:

(i) A vessel not under command; and,
(ii) A vessel restricted in her ability to maneuver

The take away for recreational boaters from Rule 18 is that unless you are under sail, you will never be more than a power-driven vessel.

The same rules apply for head-on and crossing situations. Rule 14 (a) Unless otherwise agreed, 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. One stark difference between overtaking and meeting situations is that because you and the other vessel are moving forward the rate of closure between both vessels significantly increases. This is why it is very important to establish when a risk of collision exists very early: (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. The key to this is standing a proper and vigilant lookout for other vessels and acting in ample time to safely pass.  As a rule of thumb, the yellow area or zone in Figure 2 is a good reference when a vessel should be deemed to be approaching head-on.  The only difference between a head-on and a crossing situation is that both vessels are burdened and required to turn to starboard. This maneuver opens the distance between both vessels to allow safe passage.  As always, if there is any doubt you should assume the risk of collision exists and take appropriate action.

Figure 2, Head On or Meeting

Rule 15, Crossing; (a) When two power-driven vessels are crossing so as to involve risk of collision, the vessel which has the other on her starboard side shall keep out of the way and shall, if the circumstances of the case admit, avoid crossing ahead of the other vessel.   You may have noticed the common theme in all of these situations – constant bearing and decreasing range rules.  If there is another vessel off your starboard side and in the zone indicated in yellow in figure 3, you’re in a crossing situation. I can’t emphasize enough that if you can recognize that the risk of collision exists early enough, a simple maneuver to starboard, slowing down or even coming to a complete stop immediately fixes the situation. When you observe the other vessel’s bearing moving to the left, risk of collision no longer exists and you’ve done your job! Never wait until the last minute and always pass astern of the other vessel.

Figure 3, Crossing

The last hurdle to jump in this section of the rules is Rule 19, “Conduct of vessels in restricted visibility.”  When we think of restricted visibility fog normally is the first thing that comes to mind.  You also can have restricted visibility during periods of heavy rain, snow, and glare from the sun or even smoke. When restricted visibility exists vessels are considered to be not in sight of one another.  As far as this section of the rules applies the rules are simple, (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 Rules 4 through 10 (§83.04 through §83.10).  Rule 4 through 10 were covered in the previous articles in this series but in short, they cover safe speed, proper lookout, risk of collision, actions to avoid a collision, narrowed channels and traffic separation schemes.

When dealing with restricted visibility the key is to make yourself as visible as possible and give yourself enough time to be able to react to the developing situation. This means energizing your navigation lights, sounding the signal for a power-driven vessel underway on your horn (one prolonged blast every two minutes) and adding extra lookouts for an extra set of eyes. The most important action to take when navigating in restricted visibility is to slow your speed so that you have ample time to stop within the limits of your visibility and to navigate with extreme caution.

Common sense and respect for others go a long way when applying these rules. If you are uncertain always act as if the risk of collision exists. Keep a sharp lookout and strive to pass others at a safe distance to avoid close quarter situations. If at all possible avoid making course alterations to port and if things just don’t feel like they are going well, slow down or stop until you can regain your situational awareness. Never assume what the other mariner will do, instead of reacting to events as they present themselves. Although this may seem complicated it is very simple. When everyone follows the overarching rules boating becomes more enjoyable and most importantly, safe.

US Coast Guard District 13 LogoBy: Dan Shipman,
Recreational Boating Safety Specialist
13th Coast Guard District

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