The Beaufort Scale
The Beaufort Scale describes wind force from 0 (calm) to 12 (hurricane). It links wind speed to observed sea and land conditions. For Day Skipper purposes, the most relevant forces are: Force 1–3 (light to gentle breeze, pleasant sailing), Force 4–5 (moderate to fresh breeze, good sailing but choppy), Force 6 (strong breeze, reefing required, inexperienced crews should seek shelter), Force 7+ (near gale and above, most yachts should be in harbour).
Key Points
- Force 0: Calm (< 1 knot), sea like a mirror
- Force 3: Gentle breeze (7–10 kn), large wavelets
- Force 4: Moderate breeze (11–16 kn), small waves, whitecaps
- Force 5: Fresh breeze (17–21 kn), moderate waves, many whitecaps
- Force 6: Strong breeze (22–27 kn), large waves, spray. Reef sails.
- Force 7: Near gale (28–33 kn), sea heaps up. Seek shelter.
- Force 8+: Gale and above. Dangerous for small craft.