Rule 13 — Overtaking: Who Gives Way and When It Ends

TL;DR — Any vessel coming up on another from more than 22.5° abaft the beam is the overtaking vessel and must keep clear — no exceptions — until finally past and clear. 33 CFR §83.13

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What the Rule Says

The Core Obligation

Rule 13 opens with language that overrides nearly everything else in the steering and sailing rules: "Notwithstanding anything contained in Rules 4 through 18, any vessel overtaking any other shall keep out of the way of the vessel being overtaken." 33 CFR §83.13

That word "notwithstanding" is load-bearing. It means Rule 13 supersedes the vessel hierarchy established in Rule 18 — the pecking order of not-under-command, restricted-in-ability-to-maneuver, fishing, sailing, and power-driven vessels. 33 CFR §83.18 If you are overtaking, you give way. Full stop. A power-driven vessel overtaking a sailing vessel must keep clear of that sailing vessel, even though under Rule 18 the normal hierarchy would make the sailing vessel the stand-on vessel anyway. More critically, a sailing vessel overtaking a power-driven vessel must keep clear of that power-driven vessel, reversing the usual Rule 18 hierarchy. 33 CFR §83.13 33 CFR §83.18

The Geometric Definition

A vessel is deemed to be overtaking when she is "coming up with another vessel from a direction more than 22.5 degrees abaft her beam." 33 CFR §83.13

The rule provides a practical night-time test: if you are in a position where you can see only the sternlight of the vessel ahead — and neither of her sidelights — you are in the overtaking sector. 33 CFR §83.13 Sidelights each cover 112.5° from dead ahead. The sternlight covers the remaining 135° arc centered on dead astern. The boundary between the sternlight arc and each sidelight arc falls exactly 22.5° abaft the beam on each side. If you can see even a sliver of a sidelight, you are no longer in the overtaking sector — you are in crossing or head-on territory.

The Doubt Rule

When a vessel is in any doubt as to whether she is overtaking another, she shall assume that she is overtaking and act accordingly. 33 CFR §83.13 This is a conservative, safety-first default. Doubt resolves in favor of treating the situation as an overtaking — not a crossing.

The Duty Does Not End Until Past and Clear

Once established as the overtaking vessel, that status is permanent for the encounter. "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." 33 CFR §83.13

This is critical. As the overtaking vessel draws ahead, the relative bearing will shift forward of the overtaken vessel's beam. Without this provision, the overtaking vessel could theoretically argue she has become a crossing vessel and claim stand-on status. Rule 13(d) forecloses that argument entirely.

Application: Vessels in Sight of One Another

Rules 11 through 18 — including Rule 13 — apply only to vessels in sight of one another. 33 CFR §83.11 "In sight" means one vessel can be observed visually from the other. 33 CFR §83.03 In restricted visibility, Rule 13 does not govern; the restricted visibility rule applies instead.

Overtaking Sound Signals (Inland Rules)

Under the Inland Rules, when power-driven vessels are in sight of one another and one intends to overtake the other, the overtaking vessel shall signal her intention on the whistle: one short blast to mean "I intend to overtake you on your starboard side," or two short blasts to mean "I intend to overtake you on your port side." 33 CFR §83.34 The vessel about to be overtaken, if in agreement, sounds the same signal in return. If in doubt, she sounds the danger signal — at least five short and rapid blasts. 33 CFR §83.34

Note the Inland Rule distinction carefully: one blast = overtake on the overtaken vessel's starboard side; two blasts = overtake on the overtaken vessel's port side. This is a proposal-and-agreement system, not a unilateral declaration. 33 CFR §83.34

A vessel that reaches agreement by radiotelephone under the Vessel Bridge-to-Bridge Radiotelephone Act is not obliged to sound the whistle signals, but may do so. If agreement is not reached by radio, whistle signals shall be exchanged in a timely manner and shall prevail. 33 CFR §83.34

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Why It Matters on the Exam

Tested Concepts

OUPV and Master 100 GT exam questions on Rule 13 cluster around four areas:

1. The 22.5° boundary. Expect questions that describe a vessel's position relative to another and ask whether the situation is overtaking, crossing, or head-on. Know that 22.5° abaft the beam is the dividing line, and that the sternlight arc (135°) is the visual equivalent. 33 CFR §83.13

2. The "notwithstanding" override. Questions will present a sailing vessel overtaking a power-driven vessel, or a fishing vessel overtaking a vessel restricted in ability to maneuver, and ask who gives way. The answer is always the overtaking vessel, regardless of vessel type. 33 CFR §83.13 33 CFR §83.18

3. The doubt provision. If a question states that a vessel is uncertain whether she is overtaking or in a crossing situation, the correct answer is to treat it as overtaking. 33 CFR §83.13

4. The "past and clear" requirement. Questions may describe a scenario where the overtaking vessel has drawn ahead and ask whether she is now the stand-on vessel in a crossing situation. The answer is no — she remains the give-way vessel until she is finally past and clear. 33 CFR §83.13

5. Inland overtaking whistle signals. Know the signal meanings: one short blast = intend to overtake on the overtaken vessel's starboard side; two short blasts = intend to overtake on the overtaken vessel's port side. Know that the overtaken vessel must agree by sounding the same signal, and that doubt triggers the danger signal. 33 CFR §83.34

The Rule 18 Interaction

Rule 18 establishes the general hierarchy of vessel types, but it explicitly yields to Rule 13. The opening clause of Rule 18 reads: "Except where Rules 9, 10, and 13 otherwise require." 33 CFR §83.18 This means the examiner can construct a scenario where a vessel that would normally be stand-on under Rule 18 is actually the give-way vessel because she is overtaking. Candidates who memorize the Rule 18 hierarchy without understanding the Rule 13 override will answer these questions incorrectly.

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Common Pitfalls

Pitfall 1: Confusing the overtaking sector boundary. Some candidates remember "22.5 degrees" but apply it from dead ahead rather than from the beam. The 22.5° figure is measured abaft the beam — it is the aft edge of the sidelight arc, not a forward measurement. If you are more than 22.5° abaft the other vessel's beam, you are in the overtaking sector. 33 CFR §83.13

Pitfall 2: Assuming vessel type determines give-way status. Rule 18 hierarchy does not apply when Rule 13 is triggered. A sailing vessel overtaking a power-driven vessel is the give-way vessel. A vessel not under command being overtaken is the stand-on vessel for that encounter. 33 CFR §83.13 33 CFR §83.18

Pitfall 3: Thinking the situation converts to crossing once the overtaking vessel draws ahead. Rule 13(d) explicitly prohibits this. Bearing changes do not convert an overtaking situation into a crossing situation. The overtaking vessel's duty persists until she is finally past and clear. 33 CFR §83.13

Pitfall 4: Misreading the Inland overtaking whistle signals. The signals are from the perspective of the overtaken vessel's sides, not the overtaking vessel's sides. One blast = I will pass on your starboard side. Two blasts = I will pass on your port side. Candidates who reverse this will miss those exam questions. 33 CFR §83.34

Pitfall 5: Forgetting the "in sight" prerequisite. Rule 13, like all of Rules 11–18, applies only when vessels are in sight of one another — meaning visual observation is possible. 33 CFR §83.11 33 CFR §83.03

Pitfall 6: Ignoring the doubt provision. When doubt exists about whether a situation is overtaking or crossing, the rule mandates treating it as overtaking. This is not optional. 33 CFR §83.13

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Quick Check

Q1: A sailing vessel is coming up on a power-driven vessel from a direction 30° abaft the power-driven vessel's port beam. Which vessel is the give-way vessel?

The sailing vessel is the give-way vessel. She is approaching from more than 22.5° abaft the beam, placing her in the overtaking sector. Rule 13 overrides the Rule 18 hierarchy — the overtaking vessel keeps out of the way regardless of vessel type. 33 CFR §83.13 33 CFR §83.18

Q2: At night, you observe only a white sternlight ahead. Are you the overtaking vessel?

Yes. Seeing only the sternlight — and neither sidelight — means you are within the 135° sternlight arc, which corresponds to the overtaking sector (more than 22.5° abaft the other vessel's beam). You are the give-way vessel. 33 CFR §83.13

Q3: You have been overtaking a vessel and have now drawn well ahead. The other vessel is now on your port quarter. Are you still the give-way vessel?

Yes. Any subsequent alteration of the bearing does not relieve the overtaking vessel of her duty to keep clear. She remains the give-way vessel until she is finally past and clear of the overtaken vessel. 33 CFR §83.13

Q4: Under the Inland Rules, a power-driven vessel sounds one short blast to signal her intent to overtake. What does this mean, and what must the overtaken vessel do if she agrees?

One short blast means the overtaking vessel intends to pass on the overtaken vessel's starboard side. If the overtaken vessel agrees, she sounds the same signal — one short blast — in return. If she is in doubt, she sounds the danger signal of at least five short and rapid blasts. 33 CFR §83.34

Q5: You are unsure whether you are overtaking another vessel or in a crossing situation. What does Rule 13 require?

When in any doubt, you shall assume you are the overtaking vessel and act accordingly — meaning you keep out of the way of the other vessel. 33 CFR §83.13

Q6: Does Rule 13 apply when vessels cannot see each other visually due to fog?

No. Rules 11 through 18, including Rule 13, apply only to vessels in sight of one another. "In sight" requires that one vessel can be observed visually from the other. In restricted visibility, Rule 13 does not govern the encounter. 33 CFR §83.11 33 CFR §83.03