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Rule 10: Port Tack Keeps Clear of Starboard

Rule 10 is the first right-of-way rule in the Racing Rules of Sailing 2025-2028. When two boats are on opposite tacks, the boat on port tack keeps clear of the boat on starboard tack. Starboard holds her course; port ducks behind her, tacks away, or crosses ahead only with room to spare.

RRS 2025-2028 · Rule 10, On Opposite Tacks · Updated

Your tack is the side the wind comes over, not the way you are heading. Wind over your starboard side and you are on starboard tack, with right of way over any boat on port. It holds on every leg, upwind and down, which is why "Starboard!" is the loudest word on the course.

Keeping clear means the starboard boat can sail her course without having to change it to miss you. Upwind, port has three choices: duck her stern, tack before the cross, or cross ahead when the gap is plain. A cross that makes her bear away to avoid you breaks rule 10, contact or not.

Starboard has limits too. Once she holds right of way, any course change has to leave port room to keep clear (rule 16), and both boats avoid contact if they reasonably can (rule 14).

Two boats sailing upwind on opposite tacks, converging, with the wind blowing from the top of the frame. The blue boat on the left, labeled PORT in amber, is on port tack and must keep clear. The red boat on the right, labeled STBD in green, is on starboard tack and holds right of way.
Rules Lab: port / starboard cross, upwind.
Two boats on opposite tacks crossing, with the wind blowing from the top of the frame. The red boat, sailing upwind on starboard tack, carries a green tag reading RIGHT OF WAY. The blue boat, on port tack, carries an amber tag reading KEEP CLEAR, and a dotted line shows its track: it sailed up on port, then bore away to duck behind the red boat's stern.
Rules Lab: the starboard-tack boat holds right of way, so the port-tack boat ducks behind it.

Sail it

Two boats beat to the windward mark on opposite tacks, tracks crossing. Sail the port-tack boat and keep clear: duck her or tack away.

Try it in the Rules Lab

Questions

Does port always give way to starboard?

Between two boats on opposite tacks, yes, unless another rule takes over. A boat that is tacking keeps clear under rule 13, a boat sailing back to start or taking a penalty keeps clear under rule 21, and off the beat rule 18 can give a port-tack boat mark-room.

What if the starboard boat has to change course to avoid me?

Then you did not keep clear, and you broke rule 10 even if the boats never touched. Unless the sailing instructions say otherwise, the penalty is a Two-Turns Penalty.

Does rule 10 apply before the start?

Yes. The right-of-way rules apply between boats sailing in or near the racing area that intend to race, so port keeps clear of starboard in the prestart too.

Paraphrased from rule 10 of the Racing Rules of Sailing 2025-2028, not quoted. The rule text is World Sailing's, and the rulebook is what a protest hearing reads.

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