Question 1

You are at sea and observe large waves with white foam crests and some spray. Sailing is uncomfortable. What Beaufort force does this most likely indicate?

Accepted Answer

Force 5-6. VISUAL SEA STATE recognition: Force 5 (17-21kt), moderate waves, many white horses. Force 6 (22-27kt), large waves, extensive white foam crests, some spray. Large waves + white crests + spray = Force 5-6 range. For a Day Skipper: Force 5-6 is challenging, consider seeking shelter. Force 7+ (near gale): sea heaps up, foam from breaking waves blown in streaks, dangerous for small craft.

Question 2

Force 10 (Storm) gives what approximate wave height and sea description?

Accepted Answer

9 to 12.5 metres, very high waves with long overhanging crests, dense foam streaks and visibility affected by spray. Beaufort Force 10 (Storm) is associated with approximate wave heights of 9 to 12.5 metres. Very high waves have long overhanging crests, and large patches of foam are blown into dense white streaks. The sea surface takes on a white appearance, the tumbling of the sea becomes heavy and shock-like, and visibility is affected. These wave heights are indicative of well-developed wind waves in the open sea, not fixed limits.

Question 3

The shipping forecast says 'Westerly, Force 5, occasionally 6, veering NW later, good.' You are planning to cross the Channel. What does this mean for your passage?

Accepted Answer

Westerly F5 (17-21kt), occasionally F6 (22-27kt), means generally beam winds on a southbound crossing, possible wind against tide and potentially uncomfortable seas.. A westerly blows from the west, so it is generally a beam wind on a roughly southbound UK to France crossing, rather than a headwind. Force 5 means 17-21 knots and Force 6 means 22-27 knots; 'occasionally 6' forecasts periods of stronger wind, not simply gusts. Wind against tide can produce steep seas where the tidal stream runs against the wind, so check local stream directions and timings rather than relying on the label 'ebb'. Veering NW means a clockwise change to wind from the north-west, generally abaft the beam southbound but forward of the beam northbound. It does not imply easing winds. 'Later' means more than 12 hours after the forecast period begins, and 'good' means visibility greater than 5 nautical miles. Assess the route, tidal streams, sea state, vessel and crew before deciding whether to cross; Force 5-6 may be uncomfortable or unsuitable.

Beaufort, questions and explanations

You are at sea and observe large waves with white foam crests and some spray. Sailing is uncomfortable. What Beaufort force does this most likely indicate?

Force 10 (Storm) gives what approximate wave height and sea description?

The shipping forecast says 'Westerly, Force 5, occasionally 6, veering NW later, good.' You are planning to cross the Channel. What does this mean for your passage?

Practise this properly

Beaufort, questions and explanations

Questions

You are at sea and observe large waves with white foam crests and some spray. Sailing is uncomfortable. What Beaufort force does this most likely indicate?

Force 10 (Storm) gives what approximate wave height and sea description?

The shipping forecast says 'Westerly, Force 5, occasionally 6, veering NW later, good.' You are planning to cross the Channel. What does this mean for your passage?

Practise this properly