Which tack has right of way in sailing?

Starboard tack has right of way. Rule 10 of the Racing Rules of Sailing states that when boats are on opposite tacks, a port-tack boat shall keep clear of a starboard-tack boat. This applies at all times when racing.

How do I know which tack I am on?

You are on the tack that corresponds to the side from which the wind is coming. If the wind comes over your port (left) side, you are on port tack. If it comes over your starboard (right) side, you are on starboard tack. When sailing upwind with a boom, a quick check is the boom position, since if the boom is to starboard, you are on port tack, and vice versa.

What does keep clear mean in sailing?

Keep clear means the right-of-way boat can sail its course without having to take avoiding action to miss you, and, when you are overlapped, can also change course without immediately making contact. A separate rule (Rule 14) requires both boats to avoid contact if reasonably possible. If you cannot safely cross ahead, you must tack, bear away behind, or slow down.

What if both boats are on the same tack?

Rule 10 (port-starboard) does not apply when both boats are on the same tack. Instead, Rule 11 applies if the boats are overlapped (windward boat keeps clear), and Rule 12 applies if they are not overlapped (boat clear astern keeps clear).

Port and starboard right of way in sailing racing

Rule 10 is the first right-of-way rule most sailors learn: when two boats are on opposite tacks, the boat on port tack must keep clear of the boat on starboard tack. It applies at all times when racing.

How to tell which tack you are on

Your tack is determined by the side from which the wind is coming across your boat:

Starboard tack: the wind comes over your starboard (right) side. The boom will be to port.
Port tack: the wind comes over your port (left) side. The boom will be to starboard.

A useful shortcut: look at your boom. If the boom is on the starboard side of the boat, you are on port tack. If the boom is on the port side, you are on starboard tack. This works for any point of sail, upwind or downwind.

On a run (sailing directly downwind), the wind may seem to be coming from behind on both sides. In this case, the tack is defined by the side on which the mainsail is set. The mainsail side is the leeward side, the opposite side is windward, and your tack is named for that windward side.

Sailing by the lee does not change this rule. You are sailing by the lee when you bear away past dead downwind, so the wind blows over the same side as your mainsail. Your leeward side is still the side the mainsail lies on, so your tack is still named for the opposite, windward side. You have not changed tack, and the same boom-side check still tells you whether you are on port or starboard.

Rule 10: starboard tack always has right of way

Rule 10 has no qualifications based on who got there first, who is faster, or which boat is closer to the mark. If you are on port tack and approaching a boat on starboard tack, you must keep clear.

What Rule 10 does not do is free the starboard-tack boat from every obligation. As the right-of-way boat it can hold its course, but it is still bound by Rule 14: if it becomes clear that the port-tack boat is not keeping clear, the starboard-tack boat must itself act to avoid contact if it is reasonably possible to do so. "Keep clear" means the starboard-tack boat can hold its course without having to take avoiding action to miss you.

If you cannot cross safely ahead of the starboard-tack boat, you must either tack onto starboard yourself, bear away to pass behind the other boat, or slow down to let them pass.

Common crossing situations

Port tacking across starboard. If you are on port tack and trying to cross ahead of a starboard-tack boat, you bear the burden of keeping clear. If there is any doubt about whether you will cross safely, pass behind or tack. The starboard-tack boat may hold its course and is not required to manoeuvre to make room for you, but it cannot simply sail into a collision: once it is clear you are not keeping clear, Rule 14 requires it to avoid contact if it reasonably can.

Starboard tack racing upwind. If you are on starboard tack heading upwind and a port-tack boat is on a collision course, you may hold your course. You may also hail "Starboard!" to alert the other boat, though this is not required by the rules. What you may not do is try to deliberately trap a port-tack boat into a collision.

Crossing at a mark. Rule 10 still applies near marks, but it interacts with Rule 18 (room at the mark) in complex ways when boats are overlapped entering the zone. On most upwind approaches, boats on opposite tacks will resolve the right-of-way question before the zone.

When both boats are on the same tack

Rule 10 does not apply when two boats are on the same tack. In that case:

Rule 11 (windward keeps clear) applies when the boats are overlapped.
Rule 12 (boat clear astern keeps clear) applies when they are not overlapped.

See the windward and leeward rule for a detailed explanation of these scenarios.

Last updated: 2026-06-15