Top Tekkers: picking the layline

In the latest of our daily race analysis pieces from the Sailing World Championships, renowned sailing expert Mark Chisnell looks at how to pick a layline.

Emma Wilson got her world championship campaign off to a flying start with a win in the first race of the Yellow fleet for the RS:X Women’s Qualifying. It pivoted on one key moment, when a big wind shift hit the starboard tack pack out on the left-hand side of the course (looking upwind). Wilson was the first and almost the only sailor to notice.

It was another day of offshore westerly breeze, stronger and more stable than yesterday though, and when the RS:X Women’s fleet took to the water we had a fantastic 15-20 knots blowing from just north of west.

Wilson had a solid, conservative and unexceptional start about a third of the way up from the pin or leeward end that we can see in Video 1. The bulk of the fleet wanted to play the (anticipated) favoured left-hand side of the first leg and headed that way on starboard tack as we can see in Image 1 – Wilson was the highlighted red boat GBR7.

Image 1

If we move ahead to Image 2 we can see that Wilson was just about holding her lane, but the line of starboard tackers above her were making it very difficult to tack and get onto port. Video 2 also shows the tactical problem she had – trapped on starboard tack by the boats behind and to windward.

Image 2

In Image 3 she has luffed to ty and get into the lane of starboard tackers to windward, but as we can see she was now overlapped with one board (PER50), and there were four more on starboard tack right behind her. There was no way she could tack to port and not foul someone.

Image 3

So… in Image 4 we see her gybe around to get onto port tack and get going towards the mark. I don’t think this was a feature of the analytics plot – although there were some data drop outs soon after – but maybe Wilson can confirm the move when she comes ashore. If it happened it was smart and radical.

Image 4

In Image 5 we zoom out and go forward a couple of minutes and we can see why Wilson was so anxious to get going onto port tack. She was comfortably laying the windward mark (the highlighted buoy directly ahead of her) and apart from three other boats the whole of the rest of the starboard tack pack was still going. Every metre that they were sailing was wasted distance in the wrong direction.

Image 5

If we also look at Wilson’s red track as it extended off the start line, we can see a distinct kink downwards that I’ve highlighted with the yellow arrow. This was the wind shift that created the situation that Wilson took advantage of – it was also visible in Image 6, an aerial view from the television coverage. We can see the darker water marking the wind shift moving down towards the pack of starboard tack boats.

This wind shift was what we call a header. It forced the starboard tack boats to turn slightly left and sail further from the mark. It made it easier to sail at the mark on the opposite port tack, and so brought the port tack layline closer. This seems to have surprised almost everyone but Wilson – but it also advantaged the left-hand side of the race course. This was why Wilson came back across so far in front of those boards on the right-hand side of the race course.

We can see the outcome in Video 3, as Wilson came across on port, tacked at the mark and sailed away down the second leg with a lead that was close to 200m. A great piece of heads up, eyes-out-of-the-boat sailing from Emma Wilson – who went on to extend her lead and get a very well deserved race win.