Mastering the Vang Upwind: A Comprehensive Guide to Sail Trim and Performance

For many sailors, the kicking strap, or vang, is one of the most misunderstood controls on their boat. Yet, understanding how to use your vang effectively is crucial for unlocking your boat’s full potential, especially when sailing upwind. It’s a powerful tool that, when used correctly, can significantly improve your sail shape, boat speed, and overall performance. This comprehensive guide will delve into the essentials of upwind vang trim, providing you with the knowledge to harness its full power and take your sailing to the next level.

What is a Vang or Kicking Strap?

The vang, or kicking strap as it’s commonly known in Australia, is a system that connects the boom to the base of the mast. Its primary function is to apply downward pressure on the boom, which in turn controls the twist of the mainsail. While the mainsheet also helps control twist, the vang becomes particularly important as the boom is eased out and the mainsheet loses its downward leverage. Think of the vang as your fine-tuning control for mainsail leech tension, allowing you to precisely adjust the sail’s shape and power.

Why is Vang Tension so Important Upwind?

When sailing upwind, maintaining the correct amount of mainsail twist is the single most important factor in achieving optimal performance. The right amount of twist allows the top of the sail to spill excess wind, keeping the boat on its feet, reducing weather helm, and allowing the boat to accelerate. The vang is your primary control for managing this twist, especially in gusty and shifty conditions. By adjusting the vang, you can fine-tune the shape of your mainsail to suit the prevailing wind and sea state, ensuring you are always sailing at your best. A well-trimmed vang will allow you to maintain a higher pointing angle without sacrificing speed.

Vang Settings for Different Wind Conditions

Your vang settings will vary significantly depending on the wind strength. Mastering these adjustments is key to all-around performance. Here’s a breakdown of how to approach different conditions:

Light Winds (0-10 knots)

In light airs, the goal is to create a fuller, more powerful sail shape to generate as much lift as possible. This means you want a more twisted mainsail to help promote airflow and prevent the sail from stalling. In these conditions, it’s best to keep the vang relatively loose, or just hand-tight. This allows the boom to rise naturally as you ease the mainsheet, creating the desired twist. The top telltale on your mainsail should be flying freely about 50-70% of the time, indicating that the top of the sail is open and not choking off airflow.

Keep the vang just snug to prevent the boom from bouncing in choppy seas, which can disrupt the delicate airflow over the sail.
Focus on using the mainsheet and traveller to control the majority of the sail’s twist and angle of attack.
Too much vang tension in light winds is a common mistake that will close the leech, stall the sail, and kill your boat speed.

Moderate Winds (10-18 knots)

As the wind builds and the boat becomes more powered up, you’ll need to start applying more vang tension to control the twist and keep the boat from becoming overpowered. The goal is to flatten the mainsail to reduce drag and control heeling. A good starting point is to have the top batten parallel to the boom. As gusts hit, you can use a technique called “vang sheeting” to maintain control and keep the boat on a level playing field.

Heavy Winds (18+ knots)

In heavy winds, the vang becomes a critical tool for depowering the mainsail and keeping the boat under control. When the traveller is all the way to leeward and you’re still overpowered, you’ll need to ease the mainsheet to spill wind. However, without sufficient vang tension, this will cause the top of the sail to twist off excessively, leading to a loss of power and control. By pulling on a significant amount of vang, you can maintain leech tension even with the mainsheet eased. This allows you to “drive off the leech” of the mainsail, keeping the boat sailing flat and fast, and preventing excessive heeling.

Ensure your outhaul and Cunningham are also on hard to create a flat, efficient sail shape.
In racing scenarios, it’s wise to have a dedicated crew member on “vang watch” to quickly dump the vang in big gusts, providing an instant release of pressure.

The Art of Vang Sheeting

Vang sheeting is a more advanced technique used by top sailors to maintain control and speed in puffy and shifty conditions. It involves using the vang to set the desired amount of twist in the mainsail, and then using the mainsheet to steer the boat through the gusts. Here’s a step-by-step guide to this powerful technique:

Apply enough vang tension to keep the top batten parallel to the boom, or slightly more open depending on the sea state.
As a gust hits, ease the mainsheet to depower the sail and reduce heel. The boat will want to round up into the wind, but the eased mainsheet will counteract this.
The vang will prevent the top of the sail from twisting off, keeping the leech tensioned and the boat driving forward with power.
As the gust passes, trim the mainsheet back on to power the sail up again and maintain your desired angle of heel.

This dynamic approach to sail trim allows for more precise and effective control, helping you to maintain a higher average speed and a better VMG (Velocity Made Good) upwind.

Common Vang Mistakes to Avoid

While the vang is a powerful tool, it’s also easy to misuse. Here are some common mistakes to avoid:

Set and Forget: The vang is a dynamic control that needs constant adjustment as conditions change. Don’t just set it at the dock and forget about it.
Too Much Tension in Light Air: This is the most common mistake. It chokes the sail and kills your speed. Remember, in light air, twist is your friend.
Not Enough Vang in Heavy Air: This leads to an open leech, excessive heel, and a loss of control. Don’t be afraid to use the vang to depower the main.
Forgetting to Ease the Vang Off the Wind: When you bear away to a reach or a run, the boom needs to rise. If the vang is on hard, it can put a huge amount of strain on the boom and rigging, potentially causing damage.

A Note on Racing Rules and Regulations

While optimising your vang system can make your boat more competitive, it’s important to be aware of your local class rules and regulations. Some one-design classes have strict rules about equipment modifications. Any changes to your vang system, such as increasing the purchase ratio or adding a gas strut, should be checked against your class rules to ensure they are legal for racing. Always make sure to check your local rules and regulations before making any modifications to your boat. Safety and fair competition are paramount in our sport.

Get the Right Advice and Equipment

Mastering the vang is a key step towards becoming a better, faster, and safer sailor. If you’re looking to upgrade your vang system or get expert advice on sail trim, the team at Kraken Sails is here to help. We can provide you with the right equipment and knowledge to get the most out of your boat. Contact us today for a quote and let us help you unlock your boat’s full potential and leave the competition in your wake.