What Are Sail Battens?

What Are Sail Battens? | Life of Sailing

Last Updated by

Jacob Collier

August 30, 2022

New to sailing? A beginner must learn about different parts of a sailboat, such as battens. So what are sail battens, and how do they function? Let's find out!

Sail battens are the primary structure of the mainsail that support the sail's shape, improve its overall durability and limit the effects of flogging on the sail's fabric. There are several types of battens, but the most common ones are full-length battens in the top sections of the sail.

There is no one-size-fits-all when it comes to sail battens. With several different options and uses, it can get confusing to pick one for your sailboat. This article will tell you all there is to know about sail battens and help you understand their role before adding or removing them from your sail structure.

As avid sailors, we thought it was important to pen down this article to help aspiring sailors learn all about battens. We conducted thorough research and coupled it with our knowledge and expertise to help you get started!


Table of contents

What Are Sail Battens and What Do They Do?

Sail battens are the framework of the tent across which the mainsail fabric is pulled taut and smooth. They support the region outside the straight slope between the head (the top of the sail) and the clew (the bottom back corner of the sail furthest from the mass). This region would flap uncontrollably because of the wind in the absence of battens.

Battens also help maintain sail shape since they're stiff at the back end and tapered towards the front. They act as beams and resist the forces that try to compress the leech (back edge of the sail) towards the luff (forward edge of a sail) when the sail is sheeted. This preserves the open sail shape and keeps it from becoming more semicircular and fuller (rounded leech) as the winds and loads increase. A flatter shape with a straight and open leech ensures the boat stays upright on the water.

A full-length sail batten that runs the entire width of the sail is most critical in the mainsail's top sections. This is because the mainsail's roach (outward curve of the leech) represents the greatest percentage of the straight line distance between leech and luff. In the lower sections of the sail, the roach represents a smaller percentage, so the battens don't have much work.

Full-length battens also carry the compression loads to the mast. If the battens are shorter, the loads are transferred to the sail fabric. Over time, the fabric breaks down, and hinging starts to occur.

Simply put, the more full-length sail battens you use, the more durable your sail will be. It will also hold its shape better in a breeze. Better structure automatically means less flogging and quieter luffing. This will hold the woven materials together and ensure they do not stretch.

Materials and Construction

Most battens are made of thin fiberglass and have rectangular cross-sections. A common alternative form is a hollow tube that rotates in the batten pocket. The tube is more compatible when you want to furl the staysail by rolling the sail around a stay. To prevent sail battens from chafing the sail at the ends of the pockets to which they're inserted, manufactures often give them a soft and blunt shape.

The Pros and Cons of Full-Length Battens

A lot of aspiring sailors question full-length sail battens for mainsails. If you're one of them, we've got you covered! Here is a list of the pros and cons of full-length sail battens:


  • Less flogging: Full-length battens prevent the sail from flapping like a flag. This increases the overall lifespan of the sail since flogging can be very hard on the fabric.
  • Easy furling: The battens ensure the sail drops onto the boom in a neat stack.
  • Improved draft shape: Full-length sail battens create a smooth sail shape that holds stiff, especially in strong winds and choppy waters.


  • Must have lazy jacks: If you want to enjoy the benefits of easier furling with full-length battens, you need to have lazy jacks (rigs that are put into your boom and mast to make raising and lowering the mainsail easier). Otherwise, the battens will fall past the boom and will be harder to handle.
  • Increased maintenance: The lazy jacks and shrouds tend to chafe the sail, especially at the battens when sailing off the wind. This means they require frequent re-stitching and patching.
  • Jamming: Full-length battens can easily jam or hang up when the sail is being raised and lowered. You can eliminate this problem by investing in the right luff hardware at the batten ends, but it will cost you a substantial amount of money.

How to Install Sail Battens

Now that you know what sail battens are, you should learn how to install them. To make full use of sail battens, you need to ensure you've installed them properly and tensioned them correctly. Checking your battens before sailing is a very important step as it can affect your performance at sea.

Here's how you can install sail battens the right way:

Define the Sail Shape

Ensure you insert the battens with the thick, stiffer end towards the leech and the thin, tapered end towards the luff. If you insert them the wrong way, the sail will not have the correct depth or curvature.

Maintain Sufficient Tension for a Smooth Sail

You also need to look at your batten tension before sailing. If the tension is insufficient, it will cause several vertical wrinkles along the length of the batten. Conversely, there will be evident horizontal pulling along both sides if there is too much tension. It will stress the fabric. The batten pocket will look smooth and correctly support the sail's flying shape when the tension is sufficient.

Ensure the Battens Are Secure

Before you sail, check the closure system where the battens have been inserted to see if you've properly secured them. Regardless of the type of sail battens you use, the correct installation will keep your battens securely in place for the sailing season.

What Are Sail Battens?
Jacob Collier

Jacob Collier

Born into a family of sailing enthusiasts, words like “ballast” and “jibing” were often a part of dinner conversations. These days Jacob sails a Hallberg-Rassy 44, having covered almost 6000 NM. While he’s made several voyages, his favorite one is the trip from California to Hawaii as it was his first fully independent voyage.

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