The Beaufort Scale: Classifying Wind and Sea Scapes

Author:
Publish date:
Beaufort

Created in 1805 by Britain’s Admiral Sir Francis Beaufort, the “Beaufort Scale,” which classifies wind and sea states according to a dozen different “force” levels, is widely used in the UK, but much neglected in the United States, which is too bad. Associating, say, a 15-knot “Moderate” breeze with such tangible effects as “numerous whitecaps,” gives a much better idea what 15 knots of breeze really means. It’s also a lot of fun. Take a few minutes to memorize the characteristics and wind speeds of a few different forces and then try figuring out how things stand next time you go sailing. There’s no better way of getting in touch with the wind and waves. Here is a list of the 12 different force classifications and their associated appearance on open water.

Force Wind speed Appearance of Wind/Effects

(knots)

0 Calm 0-1 Sea surface smooth and mirror-like

1 Light Air 1-3 Scaly ripples, no foam crests

2 Light Breeze 4-6 Small wavelets, crests glassy, not yet breaking

3 Gentle Breeze 7-10 Large wavelets, crests begin to break, scattered whitecaps

4 Moderate Breeze 11-16 Small waves becoming longer, numerous whitecaps

5 Fresh Breeze 17-21 Moderate waves of 4-8ft taking longer form,

many whitecaps, some spray

6 Strong Breeze 22-27 Larger waves, whitecaps common, more spray

7 Near Gale 28-33 Sea heaps up, waves 13-19ft, white foam streaks

coming off breaking waves

8 Gale 34-40 Moderately high (18-25 ft) waves of greater length, edges of

crests begin to break into spindrift, foam blown in streaks

9 Severe Gale 41-47 High waves (23-32ft) begin to topple and roll over,

dense streaks of foam, spray may reduce visibility

10 Storm 48-55 Very high waves with overhanging crests, sea white with

densely blown foam, heavy rolling, lowered visibility

11 Violent Storm 56-63 Exceptionally high waves, foam patches cover sea,

visibility even more reduced

12 Hurricane 64-plus Air filled with foam, sea white with driving spray,

visibility greatly reduced

January 2021

Related

SailGP-Team

SailGP Announces Roster and Coach Additions

Athletes Daniela Moroz, CJ Perez and Paul Campbell-James have been added to The United States’ SailGP lineup. Also joining the team will be head coach Philippe Presti. Moroz is a four-time Formula Kite World Champion and two-time U.S. Sailing Rolex Yachtswoman-of-the-Year. ...read more

NEW-westcoastmultihullsmob

Chartering the West Coast

Although two-thirds of the U.S. boating population lives along the Eastern Seaboard, there are many hardy and enthusiastic cruising sailors on the “left coast” as well. Better still, if you’re looking to charter on the Pacific side, there’s plenty of great sailing and many clubs ...read more

01-LEAD-DSC_0067-2048x

Sailing Aluminum Boats

The first cruising couple I ever met who was sailing an aluminum boat told me an interesting story. They were French—of course. They’d been anchored a long time and had a lot of growth on their hull. When finally they decided to move on, they jumped in the water to scrape the ...read more

passagemaking

Weather Routing: Comfortable Passagemaking

A weather forecast—like an old-school dead-reckoning plot—will decrease in certainty with the passage of time. Over the past five years of arranging offshore charters aboard our Swan 48, Isbjørn, and our Swan 59, Icebear, we’ve tempted the gods by consistently breaking the ...read more

for-SAIL---2

A Night Approach to Cape Horn

In October of 2018, Randall Reeves departed for a second attempt at what he called his “Figure 8 Voyage,” a solo circumnavigation of both the North and South American and Antarctic continents in one season. He had something to prove. During his first attempt, knockdowns off Cape ...read more

43s(3)

Dolphins to the Rescue

We were sailing in the Indian Ocean from the Seychelles Islands to Madagascar on my brother’s plywood-built 40ft trimaran, Romany Road, a 1,000-mile voyage. It was a clear, calm day far from land. The gentle wind drove us smartly along through the royal-blue ocean. Out of ...read more

01-LEAD-Safe-at-Slip

A Problematic Rescue

February 2, 2020 was a beautiful Sunday afternoon. The temperature was in the upper 60’s, the wind from the southwest at a steady 8 knots—an ideal day to take my Catalina 270, Pneuma, out for the first sail of the year in my home waters of north Alabama. After a few extra ...read more

01-LEAD-MiaGlove-2048

Cruising: No Bad Weather, Only Bad Clothing

“The weather is rough and unpredictable,” says August Sandberg, skipper of our Swan 48, Isbjørn, and a native Norwegian, having grown up on an island outside Bergen at 60 degrees north latitude. “The sun never rises. The sky is dark, and the air cold. You’re constantly chipping ...read more