1.7 Overtaking (Rules 11–13)

Rule 11 — In Sight of One Another

Rule 11 is one sentence with outsized exam power:

Rules in this Section apply to vessels in sight of one another.

"This Section" means the steering and sailing rules that include sailing vessels (Rule 12), overtaking (Rule 13), head-on (Rule 14), crossing (Rule 15), give-way (Rule 16), stand-on (Rule 17), and responsibilities between vessels (Rule 18). They operate only when the vessels can see each other by eye. If you detect another vessel solely by radar in restricted visibility, you are not in a Rule 13 overtaking or Rule 15 crossing situation — you are in Rule 19 restricted-visibility conduct. Confusing the two regimes is a classic Q100 trap designed to separate rote memorizers from operators who understand applicability.

For a Master on a passenger vessel: if fog closes in and you have only a radar paint, do not invent "I am stand-on in a crossing." Slow as required, keep a proper lookout by all means, and maneuver under Rule 19 principles.

Rule 12 — Sailing Vessels

When two sailing vessels are approaching so as to involve risk of collision, Rule 12 assigns duties by the wind:

1. Different tacks: the vessel with the wind on the port side shall keep out of the way of the other.
2. Same tack: the vessel which is to windward shall keep out of the way of the vessel which is to leeward.
3. Doubt: 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 starboard side, she shall keep out of the way of the other.

The windward side is the side opposite to that on which the mainsail is carried (or, with a square-rigged vessel, the side opposite to that on which the largest fore-and-aft sail is carried). Rule 12 applies only when both vessels are sailing. A sailboat running its engine is a power-driven vessel for the rules and loses pure sailing status. A Master 100 charter skipper under power meeting a pure sailing yacht uses power/sail hierarchy (Rule 18) or overtaking (Rule 13), not Rule 12 wind logic.

Rule 12 Quick Table

Rule 13 — Overtaking Overrides the Hierarchy

Rule 13 is the priority override inside the in-sight rules:

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.

"Any vessel" means type does not matter. A sailing vessel overtaking a power-driven vessel must keep clear. A vessel not under command being overtaken still remains the vessel being overtaken for Rule 13 purposes regarding the overtaking vessel's duty (other rules may also apply to the special vessel). The exam's favorite reverse of common sense: candidates recite "sail over power" and forget that overtaking kills that privilege for the overtaking sailboat.

The Geometric Definition: More Than 22.5° Abaft the Beam

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.

Unpack the geometry:

• The beam is 90° from ahead on each side.
• 22.5° abaft the beam is 112.5° from dead ahead.
• From that point aft around the stern to the matching point on the other side is the 135° sternlight sector.
• If you are inside that stern sector, you would see only white sternlight at night → you are overtaking.
• If you can see a sidelight (red or green), you are forward of that line → the geometry is typically a crossing (or meeting), not an overtaking.

Daytime, use relative bearings the same way: more than 22.5° abaft the other vessel's beam = overtaking.

Doubt Defaults to Overtaking

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. The rules intentionally push ambiguity toward the more cautious duty — keep clear — rather than toward claiming stand-on status.

Once Overtaking, Always Overtaking

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

You cannot "slide up" until a sidelight appears and then claim you are now stand-on in a crossing. The duty that attached when you began as overtaking continues through the entire pass. Finally past and clear means the overtaken vessel is no longer affected by your presence — not merely that you have drawn abeam.

Master Scenario: Dinner-Cruise Overtake

Your 90-foot passenger vessel is making 12 knots along a coastal track. A slower sightseeing boat is ahead. You approach from about 40° abaft her starboard beam — well inside the sternlight arc. You are overtaking and must keep out of the way until finally past and clear. Even if you later draw nearly abeam and could theoretically see her sidelight, Rule 13 keeps you give-way. If a pure sailing yacht comes up from your stern and begins to pass you, the yacht keeps clear despite ordinary sail-over-power logic. In a narrow channel, layer Rule 9/34: obtain proper signals and agreement when the pass requires the vessel ahead to take action.

Overtaking Decision Table

Exam Framing for Q100 (90%)

Memorize five phrases: in sight only (Rule 11); wind on port / windward keeps clear (Rule 12); any vessel overtaking keeps out of the way; more than 22.5° abaft the beam / only sternlight; when in doubt, assume overtaking; once overtaking, always overtaking until finally past and clear. Master stems dress these facts in passenger-vessel scenarios, but the rule language is identical. A single reverse of sail/power during an overtake is often the difference between a 90% pass and a Rules module retake.