1.8 Head-On & Crossing Situations (Rules 14-15)

Rule 14 — Head-On Situation

Rule 14 governs two power-driven vessels meeting head-on:

"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."

The outcome is a port-to-port pass, exactly like two cars on a two-lane road: each vessel turns right (to starboard). Note there is no give-way/stand-on split here — both vessels have the same duty to turn to starboard.

Recognizing head-on

Rule 14 tells you how to know you are in a head-on meeting:

• By day: you see the other vessel dead ahead or nearly so — you see her head-on, masts in line.
• By night: you see the masthead lights of the other vessel in a line (or nearly a line) and/or both of her sidelights (red and green together).

"When a vessel is in any doubt as to whether such a situation exists she shall assume that it does exist and act accordingly."

Seeing both sidelights is the tell-tale of a true head-on meeting; if you see only one sidelight, the geometry is a crossing, not head-on.

Inland exception — the downbound vessel (Rule 14(d))

Under the Inland Rules, on the Great Lakes, Western Rivers, or specified waters, a power-driven vessel proceeding downbound with a following current has the right-of-way over an upbound vessel, proposes the manner of passage, and initiates the signals. This overrides the ordinary both-turn-to-starboard symmetry of a head-on meeting on those waters. COLREGS has no such exception.

Rule 15 — Crossing Situation

Rule 15 governs two power-driven vessels crossing:

"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."

Two facts do all the work:

1. The give-way vessel is the one that has the other vessel on her OWN STARBOARD side. Equivalently: if the other vessel is off to your right, you give way. A memory hook: at night you would see the other vessel's red port-side sidelight coming from your starboard — and "red means stop / give way." The stand-on vessel sees the other's green starboard sidelight ("green means go / hold on").
2. The give-way vessel must avoid crossing ahead of the stand-on vessel. In practice you turn to starboard to pass astern of the other vessel, which is both the safest maneuver and consistent with the general preference against turning to port for a vessel on your port side.

The classic trap

Students routinely reverse this. The exam will describe a vessel "approaching on your starboard bow" and ask whether you stand on or give way. Other vessel on your starboard = you are the give-way vessel. You keep clear; you do not hold course expecting them to move.

Inland exception — crossing a river (Rule 15(b))

Under the Inland Rules, on the Great Lakes, Western Rivers, or specified waters, a power-driven vessel crossing a river shall keep out of the way of a power-driven vessel ascending or descending the river. The through-traffic on the river is favored over traffic cutting across it, regardless of the normal starboard-hand rule. COLREGS has no crossing-a-river exception.

Worked Example: Ferry on the Starboard Bow

You are running at 15 knots and a ferry appears 30 degrees off your starboard bow, its compass bearing steady (risk exists per Rule 7). Because the ferry is on your starboard side, you are the give-way vessel under Rule 15. Correct action: make an early, substantial alteration to starboard (Rule 8) to pass astern of the ferry — you must avoid crossing ahead. If instead the ferry were on your port bow, you would be the stand-on vessel, holding course and speed while the ferry keeps clear (Rule 17, next section).

Meeting-Geometry Summary

The single most useful discriminator at night is how many sidelights you see. Both sidelights (red and green together) with masthead lights in a line means head-on — both vessels turn to starboard. One sidelight means a crossing; if the other vessel shows you her green starboard light she is generally the give-way vessel and you stand on, while seeing her red port light warns that you may be the give-way vessel. No sidelight at all, only the white sternlight, means you are overtaking.

Exam Framing

Lock in three statements: head-on = both power-driven vessels alter to starboard, pass port-to-port; crossing give-way = the vessel that has the other on her own starboard side; and the give-way vessel avoids crossing ahead (turn to starboard, pass astern). Layer on the Inland river exceptions — downbound has head-on right-of-way (14(d)) and crossing-a-river gives way to river traffic (15(b)) — as the International-versus-Inland differences the exam likes to probe.