Who Has the Right of Way on the Water? Meeting, Crossing, and Overtaking

Most collisions come down to two vessels misreading the same situation. One thought it was a crossing. The other thought it was an overtaking. Each expected the other to keep clear. The rules are designed to prevent exactly that confusion, but only if both bridges read the situation the same way.

Here are the three basic encounters as a mariner explains them to a jury. Counsel should cite the rules directly in any brief.

Overtaking (Rule 13)

A vessel is overtaking when she comes up on another from more than 22.5 degrees abaft the other vessel's beam. In practice: if you are coming up from behind and, at night, could see only her stern light, you are overtaking.

The overtaking vessel must keep out of the way. That duty continues until she is finally past and clear, even if the bearing changes as she goes by. If there is any doubt whether she is overtaking, she must assume she is.

Head-on (Rule 14)

When two power-driven vessels meet on reciprocal or nearly reciprocal courses with risk of collision, each alters course to starboard so they pass port to port. At night, each would see the other's masthead lights in line or nearly in line, and both sidelights.

Crossing (Rule 15)

When two power-driven vessels are crossing with risk of collision, the one that has the other on her own starboard side must keep out of the way. If the circumstances allow, she should avoid crossing ahead of the other vessel.

What the give-way vessel must do (Rule 16)

Take early and substantial action to keep well clear. Small course changes that the other vessel cannot see are not enough.

What the stand-on vessel must do (Rule 17)

This is the part people forget. The stand-on vessel does not simply have the right of way. She must hold her course and speed. She may take action on her own once it becomes apparent the give-way vessel is not doing what the rules require. And when the vessels are so close that the give-way vessel alone can no longer avoid a collision, the stand-on vessel must act.

There is no such thing as an absolute right of way on the water.

Where the Inland Rules differ

On U.S. inland waters, the Inland Navigation Rules mostly track the international rules, with some important differences:

• Sound signals. Inland, one and two short blasts are signals proposing how to pass, and the other vessel is expected to answer and agree. Internationally, they announce a maneuver being made.
• Western Rivers. On the Western Rivers and certain other waters, a vessel proceeding downbound with a following current has the right of way over an upbound vessel and proposes how they will pass.
• Crossing on rivers. On the Western Rivers, a vessel crossing a river must keep out of the way of a power-driven vessel ascending or descending it.

Radio agreements matter a great deal on inland waters, which is why bridge-to-bridge recordings are worth preserving.

Why classification is the whole case

Once the situation is classified correctly, the duties follow. Getting there means building a timeline from AIS, radar, and testimony, checking relative bearings and aspects, and deciding when risk of collision first existed. That is the technical core of most collision cases, and it is where I spend most of my time on them.

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About the author

Captain Mitchell S. Stoller is a Master Mariner Unlimited, former Exxon tanker master, and former Los Angeles Harbor pilot. About Captain Stoller