Mastering Sailing · Tip 03/25

In Light Winds, Wind Speed Matters More Than Wind Direction

In light winds, small differences in wind speed can make a big difference in boat speed.

Boat speed doesn’t increase linearly with wind speed. At very low wind speeds, a small increase in wind speed produces a large relative increase in boat speed. As the wind gets stronger, the curve gradually flattens, and the same increase in wind speed produces a much smaller relative gain.

The following graph illustrates this using the upwind performance of a TP52 racing yacht.

Source: King TP52 polar performance data.

For example, on this TP52, increasing wind speed from 4 to 6 knots produces approximately a 44% increase in upwind VMG. Increasing wind speed from 12 to 14 knots produces only about a 3% gain. This is a characteristic behaviour of sailing boats, and the same general trend can be observed in IOMs.

Looking for the side of the racecourse with more wind is an obvious choice. But in light winds, there are also less obvious situations where sacrificing what would normally be the logical tactical or strategic choice in order to find stronger wind can often pay off.

For example, at the start, it may be worth choosing the less favoured end of the line if there is more wind there, or if you expect stronger wind to arrive there first.

The same applies at the leeward gate.

Although I sail more often in medium winds, this is one of my favourite tips. I first saw this approach work at a start during my early years of RC sailing, and it has stayed with me ever since. Whenever I’ve had the opportunity to apply it, I’d say it has usually worked for me.

Of course, this doesn’t mean ignoring wind shifts or other tactical considerations. But the lighter the wind, the more important it becomes to identify where the stronger wind is and sail towards it, even if that means accepting some other tactical disadvantages.

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