1.8 Head-On & Crossing (Rules 14–15)

Rule 14 — Head-On Situation

Rule 14 applies 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.

Unlike a crossing, there is no give-way/stand-on split. Both Masters have the same duty: turn starboard, arrange a port-to-port pass. The exam will sometimes offer "larger vessel stands on" or "pass starboard-to-starboard by mutual port turns" as distractors — reject them for the ordinary International/Inland head-on case.

How to Recognize Head-On

Rule 14 describes recognition cues:

• By day: the other vessel is dead ahead or nearly dead ahead, and by night you would see her masthead lights in a line or nearly in a line and/or both sidelights.
• By night: both red and green sidelights (and masthead lights in line) indicate a true head-on aspect.
• If in doubt whether a head-on situation exists, assume that it does and act accordingly — mutual starboard alteration.

One sidelight only means you are not head-on; that geometry is a crossing. Sternlight only means you are overtaking (Rule 13). Night light discrimination is pure Master exam currency.

Inland Exception — Downbound Head-On Rights (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 maneuvering signals. This breaks the usual both-turn-to-starboard symmetry for those waters. COLREGS has no equivalent clause. If the stem says "Western Rivers" or "Great Lakes" and names current, look for the downbound special rule.

Rule 15 — Crossing Situation

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 carry almost every Rule 15 question:

1. Other vessel on your starboard = you are give-way. Memory hooks: at night the other vessel's red (port) light coming from your starboard is a stop/give-way cue; her green light on your port side is consistent with you as stand-on holding course and speed (subject to Rule 17).
2. Avoid crossing ahead. The preferred resolution is an early, substantial alteration — usually to starboard — to pass astern of the stand-on vessel, not a race to cut the bow.

Rule 15 applies to power-driven vessels crossing. Mix sail, fishing, NUC, or RAM into the stem and you may need Rule 18 responsibilities between vessels — but pure power-vs-power crossing is Rule 15.

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 that river. Through river traffic is favored over the vessel cutting across, even if ordinary starboard-hand logic would suggest otherwise. COLREGS has no parallel "crossing a river" clause.

Master Scenario: Water Taxi vs Harbor Ferry

You are Master of a 60-foot water taxi making a harbor transit. A larger ferry appears about 25° on your starboard bow with a steady compass bearing (Rule 7 risk). Because the ferry is on your starboard side, you are give-way under Rule 15. Correct action chain: Rule 8 early, positive, substantial alteration — typically to starboard to pass astern — avoid crossing ahead, recheck until past and clear, and sound required maneuvering signals. Incorrect: hold course expecting the ferry to "make room," or accelerate to cut ahead "before she gets there."

Head-on variant: another power-driven vessel shows both sidelights nearly dead ahead. Both of you alter to starboard for a port-to-port pass. Do not wait for the other vessel to flinch first; Rule 14 is mutual and simultaneous in duty.

Meeting Geometry Summary

Night Light Discriminator

Connecting Back to Rules 7–8

Rule 14/15 tell you which geometry you are in and who must act. They do not replace Rule 7 risk detection (steady bearing, radar plotting) or Rule 8 execution quality (early, bold, verified). A Master who correctly labels a crossing but then makes a late 5° nudge still fails Rule 8 — and on a passenger vessel, still fails the passengers. Treat the rules as a chain: detect risk → classify situation → execute an apparent, safe pass → verify until past and clear.

Exam Framing for Q100 (90%)

Lock three International baseline statements: head-on = both alter to starboard, port-to-port; crossing give-way = other vessel on your starboard; avoid crossing ahead. Add Inland downbound following-current rights and crossing-a-river keeps clear of river traffic. Use night light cues as your instantaneous classifier. On the Master 100 path these items recur in scenario form with ferries, water taxis, and river tows — the rule text does not change, but the stakes of missing the 90% Rules module do.