Rounding and validating a buoy

When the course includes marks to round, the direction of passage is shown by the white line tracing the course, and by the animated arrows circling the mark to be validated:

Once the passage has been validated, the mark turns from orange to green within minutes. Don't panic if it is not taken into account immediately, that is normal.

What the game actually requires

A mark has no size: it is reduced to a point. What triggers validation is not passing close to it, it is crossing the required axis in the right direction, the one shown by the course line and the arrows, in other words leaving the mark on the required side, port or starboard depending on the course.

• There is no minimum distance: the margin can be tiny.
• There is no maximum distance: passing far away validates just as well.
• Sailing over the mark does not validate it, because the axis is then never crossed. Always leave yourself a margin.

In these three diagrams, the pink arrow shows the required rounding direction and the dashed line the axis to cross. 1. A tiny margin is enough. 2. A wide margin works just as well. 3. The boat passes on the wrong side, over the mark: the axis is not crossed and the mark stays orange.

Validation only takes effect once you have passed level with the mark. That is why nothing happens at the exact moment you round it.

The string rule

There is a simple way to check for yourself, without any geometry. Do it in your head, in three steps:

1. Lay a string along the route you actually sailed, from your starting point to your boat.
2. Pull both ends. If the string catches on the mark and forms an angle, it passed behind it: the mark is validated.
3. If it pulls into a straight line and leaves the mark aside, your route did not round it: not validated.

The side matters. As you pull the string, look at which side the mark ends up on. It must stay on the side the course requires, port or starboard. If it ends up on the other side, the passage is not validated, even if you sailed very close.

1. The string is laid along the route sailed. 2. Pull: the string catches on the mark, which stays to port, the required side in this example: validated. 3. The string pulls straight and the mark ends up to starboard, the wrong side: not validated.

Six concrete cases

1 and 2. The route passes on the required side and crosses the axis: the mark is validated, whether the margin is wide or tight. 3 and 5. The route does end up crossing the axis, but after a loop or a U-turn: the passage is not validated. 4. The route passes on the wrong side and never crosses the axis. 6. The route sails over the mark, so the axis is not crossed either.

Beware of turning back

Turning back after the mark and crossing it again the other way invalidates the passage and turns the mark orange again. You cannot complete the course unless every mark is validated.

How to tell you missed a mark

Two signs leave no doubt:

• your distance to finish increases as you sail away from the mark;
• your provisional ranking drops even though you are getting closer to the finish.

In that case you have to turn back and round the mark again, crossing the axis in the right direction.

Why a waypoint rather than the heading programmer

You can round a mark with the heading programmer. Plenty of sailors have, and plenty have watched their mark stay orange without understanding why. If you have the choice, a waypoint will spare you that disappointment.

The difference comes down to one sentence: a waypoint names a place, a programmed change names a moment. The first tells your boat where to go, and it steers towards that point. The second tells it to take a given heading at a given time, and it will obey at that time, wherever it happens to be.

Validation, however, does not look at the time you turned. It looks at where you crossed the axis.

Picture the scene. You schedule your turn for three in the morning, reckoning you will be at the mark by then, and you go to sleep. The wind picks up a little and you arrive early: the turn fires before the mark and you cut the corner without crossing the axis. The wind drops and you arrive late: the turn fires when you have already sailed past. Either way the mark stays orange, and yet the programmed change did exactly what you asked of it.

Your arrival time at a mark is precisely the hardest thing to predict, since it depends on the wind. A waypoint spares you the guess: it triggers on reaching the point, not at a time. That is why we recommend it in every case, and not only for the tricky roundings.

Rounding cleanly: the two-waypoint method

The heading programmer holds a heading, it does not aim at a point: for a rounding, waypoints are safer. The method comes down to two points.

1. A first waypoint as close as possible to the mark, on the required side. That is what makes you cross the axis and validate.
2. A second waypoint to set the exit angle. Without it, once the first is reached your boat resumes its heading and the exit goes wherever, often the wrong way. See My heading after reaching my waypoint.

1. With a single waypoint the mark is validated but the exit is not chosen. 2. The second waypoint sets the exit angle.

Two waypoints means two slots taken from your allowance. How many do you have for this race? See How many waypoints and programmed changes can I use?

Three habits before confirming your waypoints

• Zoom in all the way. At low zoom, a point that looks glued to the mark can in fact sit several hundred metres off target.
• Keep a margin. You want to be close, never on the exact pixel: the margin absorbs the imprecision of placing a point by hand. And remember that sailing over the mark does not validate it.
• Check the dashed lines. The dashed track of your waypoints must visibly pass on the required side of the mark. That visual check takes two seconds and prevents most unpleasant surprises.

Offshore marks, coastal marks

The two cases are not sailed the same way.

• Offshore, the mark is just a coordinate on the water. Nothing around helps you judge distance, so it all comes down to zoom and margin.
• Near a coast or an island, the priority changes: terrain comes before the search for the shortest track. A generous margin and a safe route beat a rounding that shaves the rocks. See Reduce risk of grounding.

A few precautions

When marks are numbered, they must be passed in the order of their numbering.

A mark shown in red before the start is not a fault: the course was updated after entries opened. See A mark shows in red before the start.