The short version
- Windward-leeward
- Straight up into the wind and straight back down. The most common club course, and the one most dinghy and one-design fleets sail.
- Triangle
- A beat, then two reaches via a wing mark. Older, and still common where boats are fast on a reach.
- Trapezoid
- Beats and runs joined by short reaches, with an inner and an outer loop so two fleets can share the water.
- Where to find yours
- In the sailing instructions. The course letter or number on the committee boat only means something next to the diagram they contain — every club labels courses its own way.
Beats, runs and reaches
Every racecourse is built from three kinds of leg, named for the boat's angle to the wind:
- A beat is a leg toward a mark that sits upwind. You can't sail straight at it, so you sail close-hauled and tack. This is where most places are won and lost.
- A run is a leg toward a mark that sits downwind. You sail with the wind behind you, or zig-zag at an angle to it (gybing), depending on the boat.
- A reach is a leg across the wind. You can usually point straight at the mark, so there are fewer decisions and less passing.
Race committees set the course from the wind, not from the shore. The first mark is almost always placed directly upwind of the start, so the first leg is a beat that rewards reading the wind rather than raw speed.
Windward-leeward
A windward-leeward course — sometimes called a "sausage" — is two marks, one directly upwind of the other. You beat up, run down, and repeat for as many laps as the sailing instructions say. It's popular because it's simple to set, it tests upwind and downwind sailing equally, and it keeps the fleet close together.
Two extras are common enough that you should expect them:
- An offset mark a short distance from the windward mark. You round the windward mark, sail a short leg to the offset, round that too, then start the run. It keeps boats bearing away from the windward mark out of the path of boats still coming up to it. See Offset marks.
- A leeward gate in place of a single leeward mark: two marks side by side. You sail between them and round whichever one you choose, so on a port-rounding course one of the two is rounded to starboard. It spreads the fleet out at the busiest moment of the lap. See Leeward gates.
The start line is often set near the leeward mark, either just below it or in the middle of the course with the gate below it. Where the finish goes varies just as much; more on that below.
Triangle and trapezoid
Triangle
A triangle adds a third mark, the wing mark, out to one side. From the windward mark you reach across to the wing mark, gybe around it, and reach down to the leeward mark. Many triangle courses then add a beat and a run — a "triangle-sausage" — so the race tests every point of sail. Reaches are good fun in a planing dinghy or a fast keelboat and less so in a slow fleet, where boats tend to stay in line and there's little to decide.
Trapezoid
A trapezoid is the standard course at many bigger dinghy regattas, including ILCA and 420 events. It is beats and runs joined by short reaches, and it has two loops so the committee can send different fleets around the same water. The usual layout:
- Start, then beat to mark 1.
- Outer loop: a short reach from 1 to mark 2, a run down the outer side to the 3s/3p gate, a beat back up to 2, and a run back to the gate.
- Inner loop: a run straight down from 1 to the 4s/4p gate, a beat back to 1, then the reach to 2 and a run to 3.
- Finish: round 3p and reach across to a finishing line set off to the side of the course.
The "s" and "p" say which way you round each gate mark: 3s to starboard, 3p to port. The number of laps, the exact order and where the finish sits all vary from event to event, so check the sailing instructions.
Marks to port or to starboard
The course tells you not just which marks to sail to but which side to leave each one. Rounding to port means the mark stays on your left (port) side as you go around it; to starboard, on your right. On a port-rounding course you turn left around every mark, and that is the most common arrangement.
It matters for more than getting the course right. On a port-rounding course the windward mark is best approached on starboard tack, which has right of way over port, and the final approach is along the starboard layline — see Staying inside the laylines. A starboard-rounding course flips that, and approaches get more crowded and tense because the port-tack layline brings you in without right of way.
Leaving a mark on the wrong side, or missing one out, means you haven't sailed the course. The Racing Rules of Sailing (rule 28, with the definition Sail the Course) use the idea of a string: tie one to your stern, follow your track, and when it's pulled tight it should pass each mark on the required side, in order. If you get one wrong, you can go back and correct it. Unwind first: sail back around the mark the way you came, so the string comes free of it, then round it the right way. Just sailing back past it on the correct side leaves the string wrapped around the mark, and you still haven't sailed the course.
Reading the course in the sailing instructions
The sailing instructions (SIs) are the document for the event or the series, and they contain the course diagrams. On the water the committee boat displays a signal — a letter, a number, a code like "W3" — that picks one of those diagrams. There's no universal system: one club's "Course 2" is a triangle and another's is two laps of a windward-leeward. Before you leave the dock, check:
- What each course signal means and how many laps it is.
- Which side each mark is left on, and whether any mark (an offset, a gate) is treated differently.
- What the marks look like — colour and shape. Many clubs use one colour for rounding marks and another for the start and finish.
- Where the finish is, and how to shorten or change course is signalled.
- Whether the committee can move a mark mid-race and how they'll tell you (usually a signal at the previous mark).
Signals that change the course
- Flag S (white with a blue square), with two sounds, means the course is shortened (rule 32). Usually the committee boat sits at a rounding mark or gate and you finish between it and that mark.
- Flag C (blue, white and red horizontal stripes), shown at a mark with repeated sounds, means the next mark has moved (rule 33). The committee shows the new compass bearing, or a green triangle or red rectangle for a move to starboard or port, and a "+" or "−" if the leg is longer or shorter.
The SIs win. Course systems, mark colours and finishing arrangements are local, and the sailing instructions can change how the racing rules apply. Read them for every new venue — this guide describes common practice, not any club's version.
Finishing lines
A finishing line is usually set between a mark and a staff on the committee boat, often flying a blue flag while it's on station to finish boats. You finish when any part of your hull crosses the line from the course side — the direction you're coming from on the last leg. Bowsprits and spinnakers don't count; the hull does.
Three arrangements are common:
- An upwind finish, near the windward mark, at the end of a final beat. Popular because a beat sorts the fleet out.
- A downwind finish, near the leeward mark or gate, at the end of a final run.
- A finish at the start line, common at small clubs with one committee boat and few marks.
Like the start line, a finishing line is rarely square. On an upwind finish, aim for the end that's further downwind — the nearer end — and on a downwind finish the end that's further upwind. The line itself is often short, so it's worth a look as you come up the last leg rather than after you arrive.
Doing it with Sail Tactician
Questions
What is a windward-leeward course?
A course with one mark directly upwind of another. Boats beat up to the windward mark and run back down to the leeward mark (or a gate), for a set number of laps.
Do you round marks to port or starboard?
Whichever the sailing instructions say. Port roundings are the most common, but some courses or individual marks are rounded to starboard.
What do the letters and numbers on the committee boat mean?
They select a course from the diagrams in the sailing instructions. There's no standard code, so the same signal means different courses at different clubs.
When have you finished a sailboat race?
When any part of your hull crosses the finishing line from the course side. Sails, spars and bowsprits don't count.
What if I round a mark the wrong way?
Unwind it: sail back around the mark the way you came, then round it correctly, so that a string following your track would pass the mark on the right side (rule 28). If you don't, you haven't sailed the course.
Sources
Sailing the course and finishing from the Racing Rules of Sailing 2025–2028: rules 28, 32 and 33, Race Signals (flags C and S), and the definitions Sail the Course and Finish, described in our own words. Course shapes and finishing-line arrangements from standard club-racing practice; the exact courses used at any event are set by its sailing instructions. Sail Tactician behaviour from the in-app User Guide, version 3.2.
What changed
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