It's a perfect boating day, sunny with a gentle breeze and a few small wavelets. Suddenly, the wind picks up and the wavelets are becoming ever larger waves. Your radio, which has chosen this moment to malfunction, is absolutely no help as you try to assess the situation.

If you're familiar with the Beaufort Scale (also called the Beaufort Scale of Wind Force), this would be a good time to refer to it.

Developed in 1805 by Sir Francis Beaufort, a British naval officer and hydrographer, the scale was devised as a practical way for sailors to gauge wind strength without the aid of instruments.

Beaufort rated these effects on a 13-point scale, with Force 0 being calm and Force 12 rated as a hurricane. Over the years, the scale was revised and expanded to include non-naval use such as land-based observables, to gauge the wind's effect on waves, smoke and trees, and to increase the measureable scale to 17 (which is used primarily for typhoon-prone areas). There have also been a number of efforts to correlate wind force to wind speed.

Today's meteorologists rely primarily on methods other than the Beaufort Scale. That being said, weather advisories for boaters include small craft advisories for Beaufort winds of 6 and 7, gale warnings for 8 and 9, storm warnings for 10 and 11, and hurricane warnings up to 12. And it is still useful for estimating wind speeds when other methods are not available.

Visit can visit the National Ocean and Atmospheric Administration online to view a chart of the Beaufort Scale.

– Linda Hoff