The Beaufort Scale: Why It Still Matters (Especially Here in the Canary Islands

During RYA Training and our Milebuilders  here in the Canary Islands, when the wind picks up noticeably, I will ask my Yachtmaster student straight away: “What’s the wind doing?” Almost every time, the response involves a pause, a look at the anemometer, a few button presses to find True Wind, a glance at the logbook, and finally a very specific answer like: “It’s gone from 14 to 17 knots.”

Accurate? Yes. Useful? Debatable.

If instead they'd looked up at the sea ahead—and compared it with what it looked like just 30 minutes ago—they’d likely have seen that we’ve gone from a Beaufort Force 4 to a Force 5, they could have felt that the boat started to heel at an unpleasant angle: we need to reef! And that kind of real-time, eyes-on awareness? That’s sailing gold.

A Little History

The Beaufort Scale wasn’t dreamed up over a pint by a bunch of French sailors (as some might assume). It was developed by Sir Francis Beaufort, a British naval officer in the early 1800s. The Royal Navy needed a standardised way to describe wind conditions to plot the invaluable tradewinds—something based not on guesswork or what sails you happened to have flying, but on actual, observable sea conditions.

Before Beaufort, windspeed was mostly referring to specific sails would carried for the prevelant conditions; you’d hear things like “double reefed topsail wind,” terms which varied wildly between ships and skippers. Beaufort’s system brought a widely used uniform scale and terminoloy,  and it’s still with us today—because it works.

Situational Awareness at Sea

The Beaufort Scale is based entirely on observation of the sea state—its wave patterns, height, the spread of white horses (those gently breaking wave tops), and in stronger winds, the streaks of foam left behind. Especially in the Force 2 to Force 6 range—where we spend most of our sailing time—it doesn’t take much training or experience to start judging wind strength just by looking around. These visual cues are incredibly reliable once you know what to look for.

In one of my earlier blogs, I wrote about the importance of situational awareness as a key element of onboard safety. That includes more than just keeping an eye on other boats and the chartplotter—it means observing and understanding the weather around us as it evolves, and taking timely action when necessary. The Beaufort Scale, when used as a visual reference, is a brilliant tool for developing this kind of awareness.

The Practical Side: Sailing by Beaufort

The beauty of the Beaufort Scale is that it gives us a clear, visual way to judge wind conditions and make sound decisions about sail area, comfort, and whether to even head out. It’s not just for meteorologists—it’s a sailor’s tool, essential during RYA Training and milebuilding passages in the Canary Islands.

Important is understanding the difference between Apparent Wind and True Wind. When judging true wind strength and predicting sailing performance, it’s essential to know how this effects the aparent wind (what you feel on deck). Sailing downwind, with the wind from behind, the apparent wind will be significantly lower than the true wind. When sailing upwind, the opposite is true—the boat’s forward motion increases the apparent wind speed. The actual difference depends on wind angle and boat speed, and it can hugely affect both comfort and sail choice.

Here’s how I usually apply the Beaufort Scale when sailing a typical modern 40-foot cruising yacht here in the Canary Islands. This quick guide helps decide when to reef, whether to head out, or when it’s better to grab a cold drink and enjoy the sunshine instead:

BF 1 (1–3 knots) CALM Ripples like scales

Go to the beach or the bar. Sailing? Not happening.

BF 2 (4–6 knots) LIGHT BREEZE Small wavelets with small crest

Upwind: Full sails, pleasant but slow.

Downwind: on a complete flat sea you might succeed to drift

BF 3 (7–10 knots) GENTLE BREEZE Large wavelets, a few, spread, white horses

Upwind: Fast, full sails, very comfy.

Downwind: Can be a struggle in an unsettled (wavy) sea

BF 4 (11–16 knots MODERATE BREEZE Small waves (1 mtr) becoming longer, frequent white horses

Upwind: Fast and starting to get a bit “fruity.” Full sails or Reef 1 depending on the boat and crew.

Downwind: Ideal. Fast and easy-going with full canvas.

BF 5 (17–21 knots) FRESH BREEZE Moderate waves (1.5 - 2.5 mtrs), frequent white horses

Upwind: Now it’s “sporty.” Reef 2 recommended. Expect heel and lively motion. Fun for an afternoon, very demanding on the crew for a longer passage.

Downwind: Still great fun, fast with full sails or relaxed with headsail only.

BF 6 (22–27 knots) STRONG BREEZE Large waves, white foam crests some spray

Upwind: Reef 3. Wet, bouncy, slow, moving around the boat becomes challenging— Not unsafe, but staying in port might be smarter.

Downwind: Easy manageable with headsail only, or fun and exciting keeping your reefed main up if the helm or autopilot can handle it.

BF 7 (28–33 knots) NEAR GALE Sea heaps up, waves (4-6 mtr) break, streaks of foam

Don’t go unless you really know what you’re doing.

Upwind: A fight.

Downwind: Serious surfing and lots of adrenaline. Fun for the pros, exhausting for the rest.

BF 8+ (34+ knots GALE Wavecrests breaking into spindrift, extensive streaks of foam

Possible dangerous. Stay in port. Watch Netflix. Bake brownies. Just don’t go out.

Why Beaufort 4 is the Sweet Spot

For most recreational sailors, Beaufort 4 is the gold standard and serves like a very practical benchmark.  It’s the perfect mix of performance and comfort on almost every point of sail. Less than that, and you migh struggle downwind. More than that, and upwind sailing can become uncomfortable and challenging.

Final Thoughts

The Beaufort Scale may be over 200 years old, but it still matters today—especially if you want to become a confident, observant sailor. You don’t need an expensive display to tell you what the wind’s doing. The sea speaks for itself. You just need to learn how to read it.

Next time you’re out training or joining a milebuilder with Atlantic Sailing in the Canary Islands, try leaving the anemometer alone for a bit. Look up, look out—and trust your eyes.