Keep an Eye Out

The other day, while having few beers on rather a windy day, one of my fellow quaffters asked how the Beaufort wind scale came about.

This is the official version courtesy of Wikipedia.

Keep an eye out in 2 weeks for “Coarse Sailing Version”

Keep an Eye Out

To watch for something or someone, often when you are doing something else.This phrase originated from people using telescopes. Many years ago, when ships were one of the most common modes of transport, sailors used telescopes to watch for land or approaching disasters (e.g. icebergs). As they could only use one eye to look through the telescope, people started to use the phrase “keep an eye out”.

The scale was devised in 1805 by Francis Beaufort(later Rear Admiral Sir Francis Beaufort), an Irish Royal Navy officer, while serving in HMS Woolwich. The scale that carries Beaufort’s name had a long and complex evolution from the previous work of others, to when Beaufort was a top administrator in the Royal Navy in the 1830s when it was adopted officially and first used during the voyage of HMS Beagle under Captain Robert FitzRoy, later to set up the first Meteorological Office (Met Office) in Britain giving regular weather forecasts.

The initial scale of thirteen classes (zero to twelve) did not reference wind speed numbers but related qualitative wind conditions to effects on the sails of a frigate, then the main ship of the Royal Navy, from “just sufficient to give steerage” to “that which no canvas sails could withstand”.

The scale was made a standard for ship’s log entries on Royal Navy vessels in the late 1830s and was adapted to non-naval use from the 1850s, with scale numbers corresponding to cup anemometer rotations. In 1916, to accommodate the growth of steam power, the descriptions were changed to how the sea, not the sails, behaved and extended to land observations. Rotations to scale numbers were standardized only in 1923. George Simpson, C.B.E., Director of the UKMeteorological Office, was responsible for this and for the addition of the land-based descriptors. The measure was slightly altered some decades later to improve its utility for meteorologists. Today, many countries have abandoned the scale and use the metric system based units, m/s or km/h, instead, but the severe weather warnings given to the public are still approximately the same as when using the Beaufort scale.

The Beaufort scale was extended in 1946, when forces 13 to 17 were added. However, forces 13 to 17 were intended to apply only to special cases, such as tropical cyclones. Nowadays, the extended scale is only used in Taiwan and mainland China, which are often affected by typhoons. Internationally, WMO Manual on Marine Meteorological Services (2012 edition) defined the Beaufort Scale only up to Force 12 and there was no recommendation on the use of the extended scale.

Beaufort Force

Wave heights in the scale are for conditions in the open ocean, not along the shore.

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