Crossing, Overtaking and Head-On: The Three Key Encounters

Most collision situations between two power-driven vessels boil down to just three geometries: you are crossing paths, one of you is overtaking the other, or you are meeting head-on. The COLREGs handle each of these with a clear rule, and once you can recognise which of the three you are in, the correct action is obvious. These three encounters form the backbone of the steering and sailing rules, and they appear on virtually every European boating exam.

This guide takes each encounter in turn, explains who gives way and what action to take, and shows you how to tell the three situations apart, which is often the real skill being tested.

The Head-On Situation

You are in a head-on situation when two power-driven vessels are approaching on reciprocal or nearly reciprocal courses, so that a risk of collision exists. At night you would see both of the other vessel’s sidelights, red and green together, and its masthead lights in line. By day you would see the other vessel more or less bow-on.

The rule here is beautifully symmetrical: neither vessel has right of way; both must give way. Each vessel alters course to starboard so that they pass port side to port side, like cars keeping right on a road. Because both turn the same way, the manoeuvre works even if only one skipper realises what is happening, which is exactly why the rule is designed this way. The action should be early and clear, and a vessel altering course to starboard may signal it with one short blast.

If you are genuinely unsure whether you are meeting head-on, the rules tell you to assume that you are and act accordingly. Turning to starboard is the safe default.

The Crossing Situation

A crossing situation exists when two power-driven vessels are on courses that cross, with a risk of collision, and it is not an overtaking or a head-on case. Here the rule assigns clear roles based on which side each vessel sees the other.

The vessel that has the other on its own starboard (right) side must give way. In other words, if another vessel is approaching from your right, you keep clear. The vessel on the left is the stand-on vessel and holds its course and speed. A common way to remember this is that you give way to the vessel on your right, much as you would at many road junctions.

The give-way vessel should take early and substantial action, and crucially it should avoid crossing ahead of the other vessel. The safe, textbook manoeuvre is usually to alter course to starboard and pass astern of the stand-on vessel. Cutting across the bow of a vessel that has right of way is exactly the kind of action the rules warn against.

At night, the give-way vessel in a crossing typically sees the stand-on vessel’s red port sidelight, a reminder captured in the saying that if you see red, you must give way and stop, as with a red traffic light.

The Overtaking Situation

You are overtaking when you are coming up on another vessel from a direction more than 22.5 degrees abaft its beam, roughly from behind. A practical test: at night you would see only the sternlight of the vessel ahead, not its sidelights. If in doubt about whether you are overtaking, the rules say you must assume that you are.

The rule is simple and strict: the overtaking vessel must keep clear of the vessel being overtaken. This applies regardless of vessel type, so even a sailing vessel overtaking a power boat gives way, and it stays the give-way vessel until it is finally past and well clear. You may pass on either side, but you should do so with plenty of room and without forcing the overtaken vessel to alter course.

Importantly, once you are classed as overtaking, that status does not change just because the geometry shifts as you draw level. You remain the give-way vessel until you are completely clear ahead. In a narrow channel, the overtaking sound signals covered elsewhere let you agree which side to pass.

Telling the Three Apart

The genuine skill, and what many exam questions test, is deciding which of the three situations you are in, because the correct action depends entirely on that classification.

• If you see the other vessel’s stern (its white sternlight only), you are overtaking: keep clear.
• If you see both sidelights and masthead lights in line, roughly bow-on, it is head-on: both turn to starboard.
• If you see one sidelight from the side, with the vessel crossing your path, it is a crossing: give way if it is on your starboard side, stand on if it is on your port side.

Run through these three checks in order and you will classify almost any encounter between power-driven vessels correctly.

Building Confidence Before the Exam

These three rules are the most examined part of the COLREGs, and examiners love scenarios that make you decide the situation type before deciding the action. The way to get fast is to practise many worded and light-pattern scenarios until classification is instant. In the boatingexamine course you can drill crossing, overtaking and head-on questions in exam format, so you walk into the test able to name the situation and the correct action without hesitation.

FAQ

In a crossing situation, which vessel gives way? The vessel that has the other on its own starboard (right) side gives way. If a vessel is approaching from your right, you keep clear, ideally by altering course to starboard and passing astern of it. The vessel on the left stands on.

What do we do in a head-on meeting? Both power-driven vessels give way. Each alters course to starboard so they pass port to port, mirroring how vehicles keep to the right. If you are unsure whether it is truly head-on, assume it is and turn to starboard.

Can I overtake on either side? Yes, you may overtake on the port or starboard side, but you must keep well clear of the vessel being overtaken and remain the give-way vessel until you are past and clear. In a narrow channel, use the overtaking sound signals to agree which side you will pass.