Wind and Water and Waves... Oh My

Ahoy! June 2024

Sailing is a dance. You and your partner (in this case, your boat) step onto the dancefloor (the water), and move to the music (the wind and the waves), with Mother Nature choosing the tune and conducting the orchestra.

Sailing sounds easy, right?

Think again.

Inside of a two week span, the Chesapeake Bay showed off her full springtime weather repertoire this year. Gales of 25-30 knot winds crested waves that catapulted our sailboat bow into the air, followed by wave troughs that slammed her hull back down with teeth-cracking power. Think mosh pit on water. Gusts pummeled us for hours, in 50° air temps, creating wind chills in the mid- to low 40s, chapping lips and testing under-caffeinated nerves: breakdancing. Overcast days with absolutely no wind and flat calm: slow dance, definitely. "Champagne sailing" days when we had the goldilocks of sun and wind, letting us fill the main and headsail, put the boat on a 15° heel on a close reach, and forget the world on land exists… a Viennese waltz in all its glory.

It's pretty obvious to those who ply the waterways, but most landlubbers don't realize the effect wind has on waves. It creates them. It nurtures them. Waves live and die on the whim and will of the wind. Without wind - powerboat wakes aside - there are no waves.

Creating wind is elegantly simple. You start with pressure: low and high. Here in the northern hemisphere, areas of high pressure circulate clockwise, while areas of low pressure circulate counter-clockwise. Turn your back to a steady wind on land, and the low pressure system will always be on your left.

Cold air is denser than warm air, and much more assertive. It pushes into areas of less density. Open your refrigerator door on a hot summer day. Feel the cold air rushing at you? Cold air pressure.

What does this have to do with sailing? Land breezes and sea breezes, for a start.

Every day on the Chesapeake in mid-summer the daily cycle repeats. Land warms and cools faster than water, thus influencing the temperature of the air above it. In the morning, the air over the land, cooled from its night without the sun, flows out into the warmer air over the water. This is a land breeze, the air flowing from the land to the sea. Hoist the sails and head out onto the Bay! In the afternoon, the air over the land is hotter than the air over the water, and the process reverses, creating the cooling sea breeze every beachgoing sunworshipper knows and loves. It's also very convenient in a sailboat, as the wind encourages you back towards land at the end of a beautiful sail.

But nature loves balance. In between these two is equilibrium, the time when the air temperature over land equalizes with the air temperature over water. The result is calm winds and few waves. It can turn the Chesapeake into glasslike smoothness, and from 11 AM to 2 PM on sunny summer days, experienced sailors expect it. Either heave-to and eat a leisurely lunch, or pray for a nearby powerboat to breeze past you.

But how does wind make waves? Friction.

Blow some air across your morning cup of caffeine for a real-world example. Do you see how the ripples are small with a gentle puff, but you can create little waves or even troughs in the water with a stronger blow? That's friction at work. The air molecules "catch" on the top of the liquid, and drag across the surface. The greater the force, the more liquid that is transported. Voila, waves.

Remember those 25-knot winds? They're brutal if you're beating into them, but - as nature loves balance - they have a playful, quickstep-style side. With preventers in place on the main (no accidental gibes, please), turn your bow away from the wind, and you'll experience the thrill of "surfing" in a sailboat. Those winds created 4-foot waves that lifted and propelled us, each in succession, back to our marina. Who needs a surfboard when you have a 33-foot fiberglass hull?

On the Chesapeake during sailing season, some nights end with a finale of Stomp on steroids (there's nothing so awe-inspiring as a thunderstorm over the water), but most end with an elegant foxtrot into the evening. The most memorable ones are shared with new sailing friends over raw oysters, fresh crabcakes, and cool beverages.

The best part? The wind will be back tomorrow. Polish up your dancing shoes….

Gale-force winds ebbed, and gave way to a stunning sunset. Sailor's Delight.

Daybreak the next morning on the Rock Hall seawall set us up for Champagne sailing as we traversed the Bay into Middle River, Maryland.

Kiki Mullen is The Gratitude Sailing Institute's webmaster and weathergirl. She has a Certificate in Weather Forecasting from Penn State, and several awards attesting her forecasting skills. She keeps a close eye out for pop-up thunderstorms, thick fog, gale warnings, or anything else that would pose a weather safety issue for our students and Captains around Baltimore during the sailing season.