The meteorological wind is not the wind we have when our dinghy is moving forward. The wind we touch, called apparent wind, will depend on the boat speed, the current and the meteorological wind. To represent the wind, we use a mathematical tool: the vector. Here are some of the characteristics of the vector that we’ll use.
The vector #
Vectors
- The length of the vector is proportional to the strength of the wind
- The arrow and direction of the vector give information about the wind direction
- We can add (or subtract) two vectors: to do this, we translate the second vector that we will position at the end of the first. The sum of the two is the vector starting from the beginning of the first one and ending at the end of the second one.
Definitions #
Wind nature #
Wind felt when completely still: without current. It is the meteorological surface wind.
It is noted vr.
The displacement of water masses (tides,current, …) is represented by a wind opposite to the speed of movement of the water mass.
It is noted vc.
The (vector) sum of the true wind and the current wind. This is the wind that one perceives when stopped ́s on the water.
It is noted vs.
Due to the movement of a mobile, it creates a “speed” wind which is equal to its speed of the same direction and opposite direction to its movement.
It is noted vv.
Wind that is felt in the face on a moving boat. It is the sum of the wind speed and the surface wind.
It is noted va.