Page "Weather gage" Paragraph 4

The concept of weather gage is still useful in modern yacht racing, although it is hardly ever referred to by that name.

The sails of a boat disrupt the wind to leeward-this disruption is often called " dirt " or " dirty air ".

An overtaking boat on a downwind course can position itself to focus its dirty air on the boat ahead of it.

Conversely a boat on an upwind course may find itself trapped in the dirty air of a boat immediately to windward.

However right-of-way rules, which give priority to the leeward boat, can make it advantageous to be the boat without the weather gage especially just before the start or when the boat to leeward can point higher into the wind.