Why is the beaufort scale necessary

Yachtsmen should learn to determine the wind force from the sea state. There are some excellent wall charts and other publications for this purpose. With a wind speed indicator on the boat it is possible to check your estimates but remember to allow for the boat speed and to take an average over several minutes rather than just the highest speeds. The yachtsman should become aware of what the various forces mean to him, his boat and crew. In this equation will come time of day, tiredness, experience and fitness of those on board.

At night, with a tired novice crew it might be better to take in an extra reef. A lightweight boat might bounce around and give an uncomfortable sail in a Force 5 or 6 hard on the wind but be easier off the wind. A heavy displacement, long keel boat is more likely to chomp through the waves and be easier for all. As ever, the effect of the wind force will depend upon the vessel and some personal calibration is needed. Nevertheless, the Beaufort scale concept is still valid.

Long live the good Admiral or, at least, his scale. For various versions of the Beaufort Scale, historical, current and tongue-in-cheek click here. See also measuring visibility and measuring wind from a yacht.

The section below is a summary of modern day reporting practice on ships that provide weather observations. For weather forecasting purposes, meteorologists use wind data averaged over minutes and professional observers are trained to take such averages. This is built in to the automatic systems increasingly coming into use. Waves result from the average wind at the time. Swell is caused by winds that have now died away or from winds occurring some distance away.

The wind deduced from the sea state is the nearest practical equivalent to the minute representative measurement made at land stations. Since , ships officers have reported the weather on behalf of Meteorological Services. Nowadays, some merchant ships transmit their reports in real time to provide valuable and otherwise unobtainable data for use by weather forecasters.

Most of the wind reports from these ships are still made by visual observations of the sea state and, no doubt, partly on the behaviour of the vessel.

Even a large tanker will have a motion that depends upon the wind, or more correctly, the sea generated by that wind. A few ships do use anemometers but these, surprisingly at first sight, do not give such good observations as the visual estimates. The officer of the watch on the bridge is likely to take a snapshot look at a wind indicator, be influenced by the gust speeds and tend to report exaggerated wind speeds.

That is unless he has some form of averaging device. Allowance has to be made for the speed and direction of the ship and there are great difficulties in positioning anemometers on ships so that the measurements are not affected by the superstructure.

Visual observations by seamen of wind have been remarkably consistent over the past years and form the basis of the climatology of the oceans. Heavy flag straight out and whipping.

Dense streaks of foam along direction of wind. Crests of waves begin to topple, tumble and roll over. Spray may affect visibility. The resulting foam, in great patches is blown in dense streaks along the direction of the wind. On the whole, the sea takes on a whitish appearance. Tumbling of the sea becomes heavy and shock-like. Visibility affected. The sea is completely covered with long white patches of foam lying along the direction of the wind.

Everywhere, the edges of the wave crests are blown into froth. Visibility greatly affected. The sea is completely white with driving spray. Visibility is seriously affected. Follow us on Twitter. Follow us on Facebook. Follow us on YouTube. Disclaimer Information Quality Help Glossary.

Ripples with the appearance of scales are formed, but without foam crests. Small wavelets, still short but more pronounced, crests have glassy appearance and do not break. Large wavelets, crests begin to break. Small waves, becoming longer. Moderate waves, taking more pronounced long form.

Large waves begin to form. Sea heaps up and white foam from breaking waves begins to be blown in streaks along the direction of wind. Moderately high waves of greater length. High waves. Very high waves with long overhanging crests. Exceptionally high waves small and medium-sized ships might be for time lost to view behind the waves. If you wish to order please visit our online shop. Skip to content About Us My account Contact. The Beaufort Scale The Beaufort Scale is an empirical measure that relates wind speed to observed conditions at sea or on land.

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