Leeward means in the direction away from the wind, or on the side of a boat, object or course that is sheltered from the wind. It is pronounced “loo-ard” by most English-speaking sailors, although “lee-ward” is also heard and is not wrong. The opposite is windward. For the beginner, leeward is simply downwind: the leeward side of the boat is the low side when heeled, the leeward mark is the one at the bottom of the course, and the boom and the sails are to leeward of the mast. The experienced sailor knows that leeward is also a precisely defined word in the Racing Rules of Sailing, where it decides right of way between boats on the same tack, and that a boat’s leeward side is where the rulebook, the wind shadow and the sail shape all meet.
Leeward on the Boat
On a boat under sail, the leeward side is the one the wind blows toward, opposite the windward or weather side. It is the side the sails press out over, the low side when the boat is heeled, and the side where the loaded sheets, the boom and the spray are. The leeward shrouds go slack when the boat heels hard; the leeward rail may be awash. Crew sit to windward to balance the boat, and anything to be thrown or emptied goes over the leeward side so the wind carries it clear. A boat’s leeward side is defined relative to the boat’s own wind, so it changes with every tack: after a tack, what was leeward becomes windward. When a boat is head to wind, she is briefly without a leeward side; when she is dead downwind, the rules define her leeward side as the side on which she carries her mainsail.
Leeward in the Racing Rules
The Racing Rules of Sailing define a boat’s leeward side as the side away from the wind, or, when she is head to wind or sailing directly downwind, the side on which her mainsail lies. Two boats on the same tack that overlap are then the leeward boat and the windward boat, and Rule 11 says the windward boat shall keep clear. That single rule governs most of the crowded moments in a race – the start line, the run to the leeward mark, the approach to the finish – and it gives the leeward boat considerable power. She may luff the windward boat up to head to wind provided she gives room to keep clear, which is why a boat coming from astern usually tries to establish an overlap to leeward rather than to windward. The leeward mark is the turning mark at the downwind end of a windward–leeward course; rounding it well, with the spinnaker doused and the sheets trimmed for the beat, wins or loses more races than any other single manoeuvre.
Leeward and the Sails
The leeward side of a sail is where the interesting aerodynamics happen. Air flowing over the leeward surface must travel further and faster than the air on the windward side, and the resulting pressure difference is what pulls the boat forward. That flow is also the first to break away and stall, which is why the leeward telltales on a genoa luff are the ones to watch: when they lift and swirl, the sail is over-trimmed or the boat is sailing too low, and the leeward flow has separated. Sailmakers cut the entry of a sail and position the draft to keep the leeward flow attached across as wide a range of angles as possible; a genoa that is too full, or whose draft has crept aft with age, separates early and stalls.
Cruising and Racing Perspectives
- Racers think of leeward tactically: the leeward boat has rights, the leeward mark is where positions change hands, and a boat sitting to leeward and ahead is in the best place to lee-bow a competitor on the next tack. They also want the leeward telltales flying, because that is where power is made or lost.
- Cruisers think of leeward practically: the leeward side of an anchorage is the exposed one, the leeward berth in a marina is the one you will be blown onto, and the leeward rail is where to be sick and where not to leave a winch handle.
Frequently Asked Questions about Leeward
Which boat is the leeward boat when both are sailing downwind?
The one further from the wind – the boat on the side toward which the wind is blowing. If they are directly downwind of each other, the rules use the side each boat carries her mainsail on to decide which is leeward.
Does the leeward boat always have right of way?
Between boats on the same tack that are overlapped, yes: the windward boat keeps clear under Rule 11. But if the boats are on opposite tacks, the port-tack boat keeps clear regardless of which is to leeward, and other rules about room at marks and obstructions still apply.
Leeward is the direction the wind is going – the side where the sails do their work, where the rules give a boat her rights, and where a careless skipper ends up on the rocks. Know at every moment which side of your boat is leeward and you will trim better, race smarter and anchor more safely.