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Top Tekkers: accurate laylines

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

It was another slow start today at the Hempel Sailing World Championships, with an extended postponement ashore for the 49er and 49erFX gold fleets. A light gradient wind from a distant high pressure was predicted to give way to a weak cold front, but not till late afternoon.

So by early afternoon when the 49erFX started there was still only 6-8 knots of south south-easterly wind on the stadium course where the two classes were scheduled to sail. I was hoping to bring you some action from the 49ers today, but they were second up and didn’t get underway until 5.40pm. They started and they tried, but racing was abandoned with huge wind shifts on the course.

So it will be a second turn under the analytical microscope for the 49erFX in which Sophie Weguelin and Sophie Ainsworth set up and picked a final layline so perfectly that it took them from fifth to third. It happened in the second race of the day and contributed to their charge up the standings to sixth place overall.

Getting the layline right is a basic but critical skill in sailboat racing. If you tack or gybe too early and cannot get to the mark then it will cost you two extra manoeuvres. In some boats and conditions that might not be a penalty, but in a 49erFX in these conditions it was costing between three and six metres per tack. Image 1 shows a few examples from the SAP tacking analysis.

Image 1

If you sail too far and go past the layline, then every metre you sail beyond it is wasted time and distance that can – as we will see – cost you places.

After a good start and playing the left-hand side of the first upwind, Weguelin and Ainsworth rounded the first mark in fifth. They held this position through the gate and to half-way up the third leg, the second upwind on this two-lap windward/leeward.

We’ll join the action there with Image 2, in which we see the top five all highlighted, lined up on port tack and headed right. Weguelin and Ainsworth were the yellow boat, GBR 28. The furthest boat right was NED 65 (highlighted in light blue) and they were getting very close to the layline.

Image 2

This is one of many disadvantages of getting into a corner. Not only did they have to pick and tack on the layline first – providing the rest of the fleet with a guide as to where it was – but they had to do it from the furthest point out. The further you are from the mark, the harder it is to be accurate.

If we go forward to Image 3 we can see that the critical moment has arrived for Weguelin and Ainsworth. The three boats to their right had picked their lanes and were on starboard tack. The British pair had to decide where to place themselves in relation to those boats, given their best estimate of where they all were relative to the layline.

Image 3

It’s also worth saying that they had an advantage in choosing after the others, and that was down to conservative and smart positioning in the middle of the race course and the lead pack.

In Image 4 we can see what they decided to do; Weguelin and Ainsworth sailed beyond the Japanese team (highlighted in orange) and tacked short of the pair coming at them from the right. We can also see this exchange in Video 1.

Image 4

The SAP Analytics had them ranked third already, but I suspect that it wasn’t quite so clear cut at this point. If the Dutch (light blue) and Polish (green) boats had got the layline right then they would have owned it. There would have been no good options for the British pair unless they could tack clear ahead, or get a very tight leebow tack under them.

In Image 5 we can see it play out, with both the Dutch leader NED 664 (highlighted in red), and JPN 611 (orange) having to put in the extra tacks to get around the mark. While Weguelin and Ainsworth were able to slide out in front of the Dutch and Polish boats to their right, who had both overstood.

Image 5

In Video 2 we see the group round the top mark with Weguelin and Ainsworth securely in third place, a position they held to the finish. It was a good passing move, and due as much to their approach to the layline in the middle of the pack, as it was to their selection of the moment to tack.

When combined with an almost wire-to-wire second place in the final race of the day, it pulled them up to sixth in the standings with one day of gold fleet racing left. Nice work.