Reading Wind Direction Using a Map | Adventuress Luxury Catamaran

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How to Read Wind Direction Using a Map

How to Read Wind Direction Using a Map

Feb 26, 2019

Reading wind direction is vital for anyone who wants to sail. The wind is the force that drives the sailboat in the desired direction. The way the wind hits the sails determines the direction that the boat goes.

Why Wind Direction Matters

A sailboat gliding across the water is a physics problem in motion. The wind blows against the sail at an angle, causing it to inflate. The resulting foil shape of the sail shifts the pressure into a direction that is perpendicular to the wind.

The force created by the sail is just one factor that makes the boat sail. The long, thin design of the boat’s keel helps to keep the sailboat balanced. Most vessels require the wind to move against the boat at a minimum of 40°. Otherwise, the boat will move sideways instead of going forward.

Reading the wind direction and speed helps you plan a safe and enjoyable trip. It also provides indicators of approaching weather. A licensed sailor with in-depth experience knows how to predict the impact the wind or waves will have on a boat. They know what to do when they face unexpected conditions, too. While the weather in San Diego is usually mild, sailors must prepare for sudden storms or squalls. They also need to know if the temperatures will soar. An experienced captain and crew know the weather before setting sail. They stay updated on changes throughout their trip.

wind direction indicator

Types of Wind Indicators

The simplest way of reading wind direction is with the latest technology. Larger sailboats have electronic wind instruments that measure the wind and speed direction. These gadgets are often very expensive and not a practical solution for smaller private vessels.

Another method of reading the wind direction is with a wind vane or masthead fly. These methods provide an estimate of the wind direction rather than the true wind direction. Some sailors rely on indicators off the boat, such as observing smoke from a chimney or from observing other sailboats.

Reading the water is sometimes effective when the wind is fairly light. The water is flat when there isn’t any wind. Gradual increases in wind cause ripples that are visible at some distance.

A weather map and its symbols also provide a lot of weather information quickly. Even if you aren’t a sailor, learning some basics will help you speak the language. Once you learn some of the symbols, you’ll know how to get the same information from a weather map that a captain does. Your knowledge will make it even more fun to talk about your adventure with your friends!

A good place to start is by learning some of the terminology used by sailors for centuries.

  • Port – While facing the front of the boat, anything to your left is “port.” Just learn to say port any time you mean left and you’ll have it.
  • Starboard– This term refers to anything on the right of the boat while facing forward.
  • Bow– The front of the boat. If a crew member is standing toward the bow, they are “forward.’
  • Stern– The back of the boat. If you are standing toward the back of the boat, you are “aft” or “astern.”
  • Point of Sail– This term refers to the direction of the boat relative to the wind. The RYA lists ten points of sail everyone should know before going out on the water.
  • Helm– This is the area used to steer the boat. On larger vessels, the helm is a large wheel. On smaller ones, it might be a long wooden stick.
  • Keel– The keel is the fin-like structure on the bottom of the boat. The keel gives the sailboat its stability.
  • Heeling– When the wind pushes the boat over in the water, it’s called heeling. Although some people enjoy the thrill of heeling, others prefer a more stable sailing experience. A catamaran offers a more stable ride for cruising or dolphin watching.
  • Tack– One meaning of tack is to change directions by turning the bow. The same term also refers to your current course when it is relative to the wind. For example, if the wind blows over the starboard side, you’re on a starboard tack.
  • Jibe– Jibe means changing direction by bringing the stern through the wind.
  • Windward– This is the side of the boat closest to the wind. When heeling, the windward side is the highest side.
  • Leeward– This is the side of the boat furthest from the wind. When heeling, the leeward side is the lowest side.
  • Lines– This is simply the word used in place of ropes.
  • Mainsail– This is the biggest and most important sail on the sailboat. It has a triangular shape and sits just aft of the mast.
  • Boom– This is the pole that runs along the bottom edge of the Mainsail.
  • Jib– This is a smaller sail found forward of the mast.

Reading the Weather Map

The parts of the sailboat contribute to its navigation in different ways. Learning these terms will help you know how to navigate. Reading the wind direction on a weather map will tell you how to predict the wind direction and speed.

Prevailing winds are those which generally move westward across the earth’s surface. These winds are the result of the rotation of the earth around its axis. Traditional weather reports show the wind direction using a “wind barb.” Digital wind maps use color to specify wind speeds and arrowheads to represent wind direction. The map key will indicate which symbols it implements.

The Language of Wind Directions

Words describing wind direction get their meaning from their suffix. A word that ends with -ly means from. An easterly wind blows from the east. A word that ends with -ward means towards. A westward wind blows towards the west.

A complete circle is 360° with each quarter equal to 90°. Locate a wind barb on the weather map represented by a plain circle. The amount of the circle that is filled in tells you the direction the wind is blowing from.

Northerly winds– a circle that is completely filled in

Easterly winds – a circle that is filled in other than one 90° area

Southerly winds – a circle that is halfway filled in

Westerly winds – a circle that has one 90° section filled in

A wind barb with a circle and a line which extends out shows both the wind’s direction and speed. A short line at the top represents wind blowing at 5 knots, or 1.5 mph. A long line represents wind blowing at 10 knots, or 11.5 mph. Triangular flag-shaped pennants represent an additional 20 knots of wind speed for each one depicted.

Sailing in San Diego

Everyone should enjoy the experience of sailing in San Diego. It’s the perfect location for everything from adventures on the open waters to romantic dinner cruises on the bay. You’re always in good hands when you sail with Adventuress Luxury Catamaran. Get even more from your experience when you learn the language of sailing.

Contact Adventuress Luxury Catamaran and book your sailing adventure today!