Wind force & Beaufort
Wind forces 0 to 12 with their names — what they mean on the water (exam term C.6).
What is the Beaufort scale?
Wind force is expressed on the Beaufort scale, from 0 (calm) to 12 (hurricane). Each force has a name and a matching speed range. For a small boat force 6 is often the limit to stay in; from force 8 (gale) you no longer put out.
The wind forces and their names
| Bft | Name | Speed (km/h) | What you see on the water |
|---|---|---|---|
| 0 | Calm | < 1 | Smoke rises straight up; the water is mirror-smooth. |
| 1 | Light air | 1–5 | Light ripples on the water; smoke shows the direction. |
| 2 | Light breeze | 6–11 | Small wavelets; you feel the wind on your face. |
| 3 | Gentle breeze | 12–19 | Light waves, the odd whitecap. Pleasant sailing weather. |
| 4 | Moderate breeze | 20–28 | Waves grow longer; whitecaps become frequent. |
| 5 | Fresh breeze | 29–38 | Moderate waves, whitecaps everywhere; small boats reef. |
| 6 | Strong breeze | 39–49 | Larger waves with foam crests; better to stay in with a small boat. |
| 7 | Near gale | 50–61 | The sea heaps up; foam blows in streaks with the wind. |
| 8 | Gale | 62–74 | High waves, twigs break off. Do not put out with a small boat. |
| 9 | Strong gale | 75–88 | High waves with toppling crests; visibility reduced by spray. |
| 10 | Storm | 89–102 | Very high waves, the sea turns white with foam; damage ashore. |
| 11 | Violent storm | 103–117 | Exceptionally high waves; heavy damage, rare on the coast. |
| 12 | Hurricane | ≥ 118 | The air is full of foam and spray; the sea is completely white. |
Remember the anchor points
You don't need all twelve by heart, but do learn the names around the limits: 3–4 moderate wind (nice sailing), 6 strong breeze (small boat stays in), 8 gale (do not put out) and 12 hurricane.
Turning wind: backing or veering?
The wind direction often changes during the day. Look at which way the wind turns on the compass rose: anticlockwise (backing) or clockwise (veering). That tells you something about the weather to come.
Backing wind
Usually signals worsening weather: a front or depression is approaching, often with rain.
Veering wind
Usually means improving weather: after a cold front passes, it clears up.
Example from the exam
Between 09:00 and 16:00 the wind turns from N to NW. On the compass rose that is anticlockwise — so the wind is backing. Conclusion: worsening weather is on the way (an approaching front/depression).